using radiolabeled antibodies date back to the 1950s (2), thefirst data obtained in patients were reported by Goldenberg in1978 (3). Improvement of immunoscintigraphy was achievedsince then by the development of monoclonal antibodies(MAbs) for clinical use. Especially in colorectal cancer, antibodies directed against CEA have given promising results.Also, the B72.3 antibody (11‘In-CYT-103; OncoScint®) directed against the tumor-associated glycoprotein-72 has gainedwidespread clinical interest (4). This murine monoclonal antibody was first described in 1981 (5) and has been used invarious studies both in animals (6) and man (7—11) since thenbecause of its reactivity with a variety of mucin producingadenocarcinomas (12, 13) including colorectal, gastric, pancreatic and ovarian cancer. Sensitivity rates of up to 100% forradioimaging of colorectal carcinomas in patients with risingserum CEA-levels, but otherwise negative workup (10) havebeen reported. The exact effect of II11n-CYT-103 for thedetection and follow-up of gastrointestinal cancers, however,has yet to be established. The exploration ofalternative methodsis also warranted.

Recently, we demonstrated that ‘231-labeledvasoactive intestinal peptide (VIP) has potential for localizing even smallgastrointestinal tumors expressing receptors for VIP (14). VIPconsists of 28 amino acids and acts as a neuroendocrinemediator under physiologic conditions, with an important rolein water and electrolyte secretion in the gut (15). Recentfindings suggest that VIP also promotes growth and proliferation of normal as well as malignant cells (16—18). Thesebiologic effects are mediated via receptors located on the cellsurface membrane of normal and various neoplastic tissues,including carcinoids (19), colorectal cancer (19—21) and pancreatic cancer (20,22). The high specificity of ‘23I-VIPreceptorscanning for human adenocarcinomas is most probably due tothe very high number of VIP binding sites, while normal cellsexpress much lower amounts of receptors (19).

The promising results obtained by ‘231-VIPreceptor imagingin patients with intestinal adenocarcinomas (14,23) promptedus to initiate a single-blinded, prospectively randomized trial toallow for a direct comparison between VIP receptor scanningand immunoscintigraphy using 11‘In-CYT-103.

METHODS

Patients and Study DesignForty patients with histologically verified adenocarcinoma of the

colon, pancreas and stomach were randomized between scanningwith either ‘231-VIPor ‘‘In-CYT-l03.All patients had advanceddisease and underwent palliative chemotherapy. For patient characteristics see Table 1. A treatment-free interval of at least 2 wk

Recently, we have shown that the expression of receptors forvasoactive intestinal peptide (VlP@on intestinal adenocarcinomascan be used for in vivo targeting of primary or metastatic tumor sitesusing 123l@,@ \.IP. Several other receptors and antigens including the TAG-72 protein have also been implemented for in vivolocalization purposes. In this study, we have compared the in vitroand in vivo binding of 123l-V1Pand of the 111ln-labeled monoclonalantibody (MAb) directed against TAG-72 (OncoScint®;1111n-CR103) in patients with intestinal adenocarcinomas in a single-blinded,prospectively randOmIzedtrial. Methods Twenty patients wereadministered either 1@l-V1P(150-200 MBq; 1 @g)or 111ln-CYT-103(150 MBq; 1 mg) for one imaging study. After interim analysisdemOnStrated superior imaging with 1@l-V1P,the next 10 patients(accounting for a total of 50 patients) enrolled in this trial underwentboth studies in random order to allow for a direct comparison.ResuItslntotal,1@lMPscanswerefrue-positivein28of3Opatients (93%) versus 17 of 30 patients administered 111ln-CYT-103(56%). In the subgroup of 10 patients enrolled in the second part ofthe study, primary intestinal adenocarcinomas were imaged in fiveof five patients with 1@IMP and in only two of these patients with111ln-CYr-103. Liver metastases were VlaUalIZedin five of sixpatients by 1@lMP receptor scanning and in four of these patientswith 111ln-CYF-103.The in vitro results indicated significant bindingof1@lMPtoprimarycolorectaltumorsasweilastoHT29andC0L0320 adenocardnoma cells. In vitro, adenocarcinoma cellsalso expressed abundant numbers of the TAG-72 antigen.Conclusion: Intestinal adenocarcinomas co-express ViP receptorsand the TAG-72 antigen. Despite significant in vitro binding of bothagents, however, the\.IP receptorscan is more sensitive in localizingintestinal adenocarcinomas and metastatic spread.Key Words vasoactive intestinal peptide; tumor-associated glycoprotein 72; gastrointestinal adenocarcinomas; imaging

J Nuci Med 1996;37:1480-1487

Gastrointestinalmalignanciesareamongtheleadingcausesof morbidity and mortality worldwide (1 ). Because of thestrong association between early detection of primary and/orrelapsing cancers and prognosis, such patients present a specialchallenge to clinicians. Apart from endoscopy, noninvasiveconventional radiologic imaging by CT or ultrasound measurements, especially in patients suffering from liver metastases,remain the methods most widely applied. Despite their clinicalrelevance, these techniques still suffer from major shortcomings, as small-sized tumors or peritoneal carcinosis may escapedetection by conventional imaging. The use of radiolabeledantibodies directed against certain tumor epitopes seems to bean appealing concept to further enhance the diagnostic armamentarium. Though the experimental results of tumor imaging

Received Sept. 18, 1995; twision accepted Jan. 24, 1996.ForcorrespondenceormptiritscontactIreneW9OIInI,MD,DepartmentofNuclear

Medicine, Unhtersity of Vienna, WâhringerGUrteI 18-20, A-1090 Vienna, Austria

1480 THEJOURNALOFNUCLEARMEDICINE•Vol. 37 •No. 9 â€September 1996

Comparison of Iodine- 123-Vasoactive IntestinalPeptide Receptor Scintigraphy and Indium- 111-CYT- 103 ImmunoscintigraphyMarkus Raderer, Alexander Becherer, Amir Kurtaran, Peter Angelberger, Shuren Li, Maria Leimer, Georg Weinlaender,Gabriela Kornek, Kurt Kletter, Werner Scheithauer and Irene VirgoliniDepartments ofNuclear Medicine and Oncology, and Ludwig Boltzmann Institutefor Nuclear Medicine, University of Vienna,Vienna; and Department ofRadiochemistry, Research Center Seibersdorf Austria

by on June 1, 2020. For personal use only. jnm.snmjournals.org Downloaded from

was required for application of the radiotracers, and no priortherapeutic or diagnostic antibody injections were allowed. Afterhistologic verification of target lesions, informed consent according to institutional guidelines was obtained. Randomization wasperformed by the oncologist; nuclear physicians were blinded tothe exact nature, stage and location of disease. All patients had CTscans, ultrasound or endoscopic evaluations not older than 6 wk atthe time of tracer application. Patients randomized to receive‘231V1Pwere given sodium perchlorate and potassium iodide forthyroid gland blockade. Patients were followed by means of CT,sonography and x-ray, respectively, until death or for at least 6 moto document the exact course of the disease, i.e., development ofnew metastatic lesions or progression of known lesions.

Endoscopic investigations were performed only initially forbiopsy, but were not routinely repeated during the trial. Endpointsof the first part of the trial were the number of true positive andnegative scan results as compared with conventional radiologic andendoscopic diagnosis, and results of surgical exploration. Theserepeated measurements were aimed to indirectly assess the scanresults, and to exclude possibly false-positive scan results (definedas tracer accumulation without documented radiological counterpart at the time of the scan). According to the study protocol, afalse-positive scan result in the final evaluation would have to bechanged to a true-positive result if radiological or surgical proofwas provided. Furthermore, autopsy results, if available, weretaken into account for patients who died during the 6-mo follow-upperiod.

Of 20 patients (9 women, 11 men) randomized to receive‘23I-VIP,14 had colorectal cancer and 6 had pancreatic adenocarcinomas. Five patients with colorectal cancer presented with localrecurrence of their disease; in nine patients the primary tumor hadbeen resected and metastases were known at the time of scintigraphy. Whereas lesions were confined to the liver in five patients andto the lung in one, two patients suffered from disease metastatic toboth liver and lymph nodes, and one patient to liver and lung,respectively. Locally inoperable pancreatic cancer as the onlymanifestation of disease was present in two patients. In the otherfour patients with pancreatic cancer, the primary tumor had beenresected and liver metastases were known at the scanning time.

Primary tumor types in the 20 patients (1 1 women, 9 men)randomized to application of ‘‘‘In-CYT-103were as follows:pancreatic cancer (3 patients), gastric cancer (4 patients), andcolorectal cancer (13 patients). The three patients with pancreaticcancer and three of the four patients with gastric cancer hadinoperable disease confined to the primary tumor site, whereasliver metastases were present in the fourth patient with gastriccancer. In all patients with colorectal adenocarcinomas, the primary tumor was resected and liver (all 13 patients), lung (3patients) and lymph node (2 patients) metastases were known at thescanning time.

Three women and seven men with histologically verified adenocarcinomas of the gastrointestinal tract were enrolled in thesecond part of the trial. Eight patients suffered from colorectalcancer, one had gastric cancer and one pancreatic cancer. In allcolorectal cancer patients, resection of the primary tumor had beenperformed. Of this group, four patients had liver metastases as theonly site of recurrence at the time of study entry, one wasdiagnosed with tumor recurrence in the lung, two patients sufferedfrom locally recurrentdisease and one patient presented both withlocally recurrentcancer and liver lesions at the time ofstudy entry.The remaining two patients (one patient with gastric and one withpancreatic adenocarcinoma) were deemed unresectable at the timeof diagnosis. While local tumor spread without evidence ofmetastases was present in the patient with gastric cancer, the otherpatient also had liver metastases along with the primary pancreatic

tumor. Gastroenteroanastomosis had been performed in both patients for symptomatic palliation. All patients had advanced diseaseand were undergoing 5-fluorou.racil-basedpalliative chemotherapy.A treatment-free interval of at least 2 wk was required forapplication of the VIP- or CYT-103-scan in random order with atime of 4 to 6 wk between these two modes of imaging. Noprevious diagnostic or therapeutic antibody injections were allowed, and all patients gave informed consent according toinstitutional guidelines. All patients had CT scans, ultrasound orendoscopic investigations not older than 6 wk at the time of studyentry.

Endpoints ofthe trial were the evaluation of the number of truepositive and true-negative scan results with regards to primarytumor site, liver metastases and further radiologically verified sitesof tumor spread. Again, nuclear physicians were blinded not onlyto the nature of the primary malignancy (colorectal, pancreatic orgastric cancer), but also to the extent of tumor manifestations untilthe final evaluation of all scans performed during the trial. Patientswere randomized by the medical oncologist by tossing a coinbetween application of the VIP-scan or CYT-l03 scan as the firstimaging modality. Follow-up procedures, including repeated radiologic assessment of tumor growth, were identical to those performed in patients randomized to only one scanning modality (videsupra).

According to the study protocol, HAMA testing was to beperformed in this trial only in patients developing side effectsand/or in whom repeated ‘‘‘In-CYT-l03 scintigraphy would berepeated.

Preparation of Radioiodinated VIPThe preparation of radioiodinated VIP has been described

previously in detail (12,21). In brief, VIP was generated by apeptide synthesizing machine and labeled with 1231using a modifled lodogen method. Iodine-123-VIP was purified by preparativeHPLC (column: RP Cl8, 5 p.m. 4 X 250 mm, eluent: 74%(volume/volume) aqueous 0.25 M triethylammoniumformiate, pH3, 26% (volume/volume) acetonitrile at 1 ml/min) to obtain a highspecific activity. The column eluent passed through a scintillationradioactivity detector and UV (280 nm) detector in a series. Thesystem was calibrated with unlabeled VIP and enabled collectionofpure radioiodinated VIP, separated from unlabeled VIP, reagentsand inorganic iodine species. The eluent was evaporated at reducedpressure. The product was dissolved in phosphate-buffered salinecontaining 0.1% (weight/volume) Tween 80 (Koch-Light Lab.Ltd., Colnbroke, UK). The labeled product was analyzed byanalytical HPLC (corresponding to the preparative system, however, using a dedicated analytical column) and zone electrophoresis(Whatman 3 MM paper, 0. 1 M barbital buffer, pH 8.6, using a fieldof 300 V for 10 mm). The percentage of unbound iodine (<3% inall preparations)remained stable over at least 24 hr. The biologicalactivity of labeled and unlabeled VIP was identical as determinedby its ability to enhance cAMP-formation, 32P-ATP-incorporationas well as 3H-thymidine-uptake (12,18). Before injection, ‘231-VIPwas filtered through sterile Millex GV 0.2 pm membranes (Millipore, Milford, MA). Iodine-123-VIP was administered as a singleintravenous bolus injection in 3 ml 0.9% NaCl-solution (150—200MBq; 1 i.@gVIP). During application of labeled VIP, all patientswere monitored for blood pressure (12).

Re@on of Indkim-111-CYT-103The commercially available antibody (OncoScint®,“In-CR

103) was purchased from Cytogen (Princeton, NJ) and labeled with11‘InCl3 according to the manufacturer's recommendations. The

final specific activity amounted to approximately 150 MBq/mgMAb per patient. Radiochemical purity was assessed by paperchromatography and yielded more than 96% in each preparation.

‘231-VIPAND11‘IN-CY'r-103IMMUNO5CINTIGRAPHYINADENOCARCINOMAS•Raderer et al. 1481

by on June 1, 2020. For personal use only. jnm.snmjournals.org Downloaded from

TABLE IPatient Characteristics

1.5-8 cm median3.2 cm1-4 cm median2.2 cm2—3.5cm median 2.5 cm

*Asmeasured by conventionalradlologicimaging(i.e.,CT,US).

In Vitro Binding StudiesBinding studies were performed with primary tumor cell mem

brane fractions, tumor cell lines (C0L0320, HT29) and normalblood cells (platelets and peripheral mononuclear cells, PMNCs).Assays were performed under essentially the same conditionsreported earlier for other tumor tissues (24) and cells (25). Primarytumor specimens were obtained at surgery and kept at —70°Cuntilused in receptor assays. Cell membrane fractions were preparedaccording to previously reported methods (18,23). The fmalprotein content of the membrane suspension amounted to 100 @gprotein/ml. Saturation studies were performed with intact cells ormembrane fractions by incubating increasing concentrations of‘231WPor ‘‘‘In-CYT-l03(0.01 to 100 nM) in the absence (totalbinding) and the presence of the same unlabeled ligand (100 nM,nonspecific binding). After incubation, the reaction mixture wasdiluted 1:10 with assay buffer (4°C)and rapidly centrifuged (5000g, 10 mm, 4°C)to separate membrane-bound from free ligand. Theresulting pellet was washed twice with buffer and counted in agamma counter for 1 mm. Binding data were calculated accordingto Scatchard (26).

Gamma Camera Imagjng and AnsiysisPlanar and SPECT acquisitions were performed with a large

field ofview gamma camera equipped with a low-energy (‘231-VIPreceptor scintigraphy) or medium-energy (‘‘‘In-CYT-l03immunoscintigraphy) parallel-hole collimator.

For VIP-receptor scanning, sequential images (abdominal view)were recorded every minute for 30 mm (matrix 128 X 128 pixels).Thereafter,planar images in anterior,posterior and lateralviews ofat least two regions covering the thorax and abdomen wereacquired at 30 mm, 2—4hr and 18—24hr after injection (matrix128 X 128 pixels; 150—300kcs were acquired). SPECT imaging ofthe abdomen was performed at 2—4hr after tracerapplication in 21of 30 patients.

For ‘‘‘In-CYT-103scanning, planar imaging was performed at48 and 72 hr after injection in anterior, posterior and lateral viewsof at least two regions covering the thorax and abdomen (matrix128 X 128, 500 kcounts were required). SPECT imaging of thesame regions was performed after completion ofthe planar study at48 hr as well as 72 hr postinjection. For ‘‘‘In-CYT-103scanning,both energy peaks (set at 173 keV and 247 keV) were used, bothwith a 20% window. All 30 patients underwent the 48-hr SPECTstudy, while 4 missed the 72-hr SPECT study.

SPECT was performed in a 360°circle in 6°steps, 30 sec perstep. After processing by a dedicated computer (prefiltering with aWiener filter or low-pass filter 4th order with a multiplier of 1.00,10% cutoff frequency, postfiltering with a ramp filter), the datawere reconstructed in three planes with slice with thicknesses of 7

mm. All scans were reconstructed and viewed by at least two, andin case of disagreement, by a third nuclear medicine physician. Asimple yes-or-no evaluation system was used to evaluate thetumors or metastases as visualized by gamma camera imaging.

RESULTS

In Vitro Binding of Iodine-VIP and Indium-CYT-I03 toAdenocardnomas

Primary tumor specimens derived from patients with adenocarcinomas as well as the HT29 and C0L0320 adenocarcinomacells expressed significant amounts of VIP receptors as well asthe TAG-72 antigen. The respective binding data are listed inTable 2, which indicates significantly (j < 0.001 ) highernumbers of 1231-VIPreceptors as compared with normal peripheral blood cells (platelets and PMNCs). In all experiments, theaffinity constants were in the lower nanomolar range for bothligands. On adenocarcinoma cells, high numbers of antibodyrecognition sites were also demonstrated, whereas antibodysurface binding to platelets and PMNCs was not found.

Imaging of Gastrointesthal AdenocardnomasResults ofthe First Study Phase (Randomized Study Phase).

All 40 patients, randomized between imaging with ‘23I-VIPandI I ‘In-CYT-103 as well as the 10 patients receiving both tracers

randomly, were evaluated (for results see Tables 3—5).Asassessed by CT, endoscopy and/or surgery, the size of theprimary tumor masses ranged between 2 and 10 cm (median 4.5cm) and the size of liver metastases ranged between 1.5 and 8cm (median 3.2 cm).

Positive ‘23I-VIPscans were obtained in 13 of 14 patientswith colorectal and 5 of6 patients with pancreatic cancer (Table3). Primary tumors were imaged in five of five patients withlocally recurrent colorectal and in one of two patients withpancreatic cancer. Visualization of liver metastases was successful in all eight patients with colorectal and in four patientswith pancreatic cancer. Lymph node metastases were imaged intwo of two patients and lung metastases in two of two patients.In total, only one scan was false-negative (one patient withlocalized adenocarcinoma of the pancreatic head).

Imaging ofprimary tumors with II‘In-CYT-l03was successful in two of six patients (one patient with pancreatic, one withgastric cancer. Liver metastases were imaged in 8 of 13 patientswith colorectal cancer and in one patient with gastric cancer.The primary tumor could not be visualized in 4 of6 patients andliver metastases were not detected in 5 of 14 patients. Lungmetastases (three patients) and abdominal lymph node metastases (two patients) were not visualized on II‘In-CYT-103images (Table 4).

In both studies, no side effects were seen, with the exceptionof a mild drop in blood pressure in patients in the ‘231-VIPgroup as reported previously (14).

Results of the Second Study Phase (Direct ComparativeStudy). Of the 10 patients receiving radiotracers randomly, 6were given ‘231-VIPbefore@@ ‘In-CYT-103and 4 received thelatter in their first study. VIP receptor scanning gave positiveresults in five of five patients with primary or recurrent tumorsites (colorectal (Figs. 1, 2), one pancreatic and one gastricadenocarcinoma) and was true-negative in five of five patientswho had undergone resection of their primary tumor beforetracer application (Table 5). Comparative ‘I‘In-CYT-103-scanning (Fig. 2) was true-positive in two of five of these patientsand true-negative in two of five patients, respectively. Imagingof metastatic liver lesions (Fig. 3) was true-positive in five ofsix and true-negative in four of four patients with ‘231-VIP

50 (23women,27 men)64(range32—80)1 (0-2)

(2—10cm, median4.5 cm)4—10cm median 5.3 cm2—8cm median4.2 cm4—8cm median 5.1 cm

Numberof patientsMeanage (yr)Medlan @ancestatus

Diameterof primarytumors*:ColorectalcancerPancreaticcancerGastriccancer

Diameterof@UverLungLymph-nodes

1482 THEJOURNALOFNUCLEARMEDICINE•Vol. 37 •No. 9 •September 1996

by on June 1, 2020. For personal use only. jnm.snmjournals.org Downloaded from

123I@P111ln-CYT-103Sites/mg

proteinK,@,Sites/mgproteinK@Prim.

adenocarcinomasH0.3 ±0.1 X 10141.0 ±0.42.5 ±0.9 X 10133.2 ±1.5(n= 8)L1.0 ±0.3 x 10143.1 ±0.7HT29

cells (n = 6)HL0.8

±0.4 x 10145.2 ±1.2 x 10140.5

±0.22.0 ±0.95.6

±2.0 x i0@5.4 ±2.5C0L0320

cells(n= 6)HL1.0

±0.6 x 10146.3 ±1.3 x 10140.4

±0.21.8 ±0.86.8

±2.5 x 10143.5 ±1.5Platelets

(n = 6)H0.6 ±0.2 x 10111 .3 ±0.3NobindingPMNCs(n= 6)H

L0.7±0.3 X 1011

2.1 ±1.2 x 10110.2±0.1

11 ±0.3NobindingKd

@flnmoVliter. H = high-affinitysites, L = low affinitysites.

TABLE 2In Vitro Binding of Iodine-i 23-VIP and Indium-i i i -CYT-i03 to Adenocarcinoma Cells and to Normal Peripheral Blood Cells

versus four of six and one of four patients with@@ ‘In-CYT-103,respectively. The lung metastases documented in one patientwere not imaged with either ‘231-VIPor ‘@ ‘In-CYT-103.

Overall Scan Evaluation. Iodine-123-VIP scans were positive in 28 of 30 patients (93%). Indium-i 11-CYT-i03 scanswere positive in 17 of 30 patients (56%), providing a statisticalsignificance of p < 0.01 (@ test). In total, 32 of 35 lesion sites(91%) were depicted with ‘231-VIPin 30 patients, whereasI 1 ‘In-CYT-103 depicted 21 of 37 lesion sites (57%) in 30

patients (x2 test: p < 0.01).When compared with the overall scan results, a similar

difference also was found in patients investigated in the secondstudy phase alone in which 10 of 12 lesion sites (83%) wereimaged with ‘23I-VIPand only 6 of the same 12 lesion sites(50%) were detected by ‘‘‘In-CYT-l03 (@ test: p < 0.01).

Follow-up PeriodDuring the 6-mo follow-up period, repeat CT and ultrasound

investigations, routinely performed at least every 8 wk or inshorter intervals at the physician's discretion, were used tomonitor disease course as shown in Tables 3—5.

Initial scan results indicated an abdominal mass in twopatients by ‘23I-VIP(Table 3, Fig. 1) not visualized byconventional methods at the time of tracer application. Duringthe follow-up period, local tumor recurrence was stronglysuggested by appearance ofcorresponding lesions on CT (6 and8 wk after tracer injection, respectively). Surgical explorationwas not performed in both individuals due to the patients'refusal of interventional measures. Both patients requestedconservative treatment and started radiochemotherapy immediately after the CT results were available. They died fromprogressive disease 5.5 and 7 mo after initiation of therapy,respectively, and autopsy confirmed the presence of malignanttissue in both. The initial evaluation ofa false-positive VIP scantherefore was turned into a true-positive VIP scan in the finalevaluation. As determined by follow-up procedures, no@@ ‘InCYT-103 results were changed retrospectively.

DISCUSSION

Comparative Receptor and Antibody ScanningThe results of this prospective, randomized and single

blinded study indicate that the targeting of VIP receptors haspromising aspects for further clinical evaluation. As previouslyreported (14,23), ‘231-VIPcan be safely administered to patients. When using ‘231-VIPno adverse reactions, apart from atransient mild decrease in blood pressure, were observed. Ourfindings confirm previous results showing that even relatively

small tumor masses, such as 2 cm in diameter, can be imagedwith ‘231-VIP(14,23).

In this study, VIP compared favorably with ‘‘‘In-CYT-103.The overall rate ofpositive scans obtained with ‘23I-VIPwas ashigh as 93% (28 of 30 scans; positive in 11 of 12 patients withprimary/recurrent tumors and in 17 of 18 patients with livermetastases), whereas (false) negative VIP scan results wereobtained in only 2 patients. Correspondingly, only 55% of all, 1 ‘In-CYT-i03 scans were positive.

In previous reports@the percentage of positive scan resultsobtained with ‘â€In-CYT-103 antibody in primary (5,8, 10) orrecurrent colorectal cancer patients (7,9, 11 ) was somewhathigher. For instance, in a multicenter trial performed in 155patients with colorectal cancer (11 ), the sensitivity and specificity ofimmunoscintigraphy with ‘‘‘In-CYT-103was 69% and77%, respectively, which compares well with the patients' CTresults. In contrast to previous studies with ‘‘‘In-CYT-103,thelower proportion of positive scans found in the present studymay be deduced from the fact that nuclear medicine physicianswere blinded to the exact nature and localization of themalignancy. Furthermore, comparison with conventional radiologic imaging results was performed after completion of analysis of all scans obtained during the trial. Therefore, bias infavor of ‘231-VIPresulting from beforehand knowledge oftumor localization can be excluded.

We cannot, however, offer a definitive explanation for thedifferences between our findings with ‘‘‘In-CYT-l03and theresults mentioned above. Quality assessment was similar toother trials reported, as histologic verification of all targetlesions had been performed before randomization and accuratefollow-up was done until death or for at least 6 mo (see alsoTables 3—5).Given the fact that histologic confirmation ofmalignant disease by biopsy/surgery was one of the entrycriteria, and that all patients had advanced-stage disease, suspected (new) lesions on VIP/OncoScint®scans were not subjected to repeated biopsy or surgery for histological proof.Instead, patients were followed until death, or for at least 6 moby conventional radiologic methods to allow for an exactdocumentation of sites of disease progression or appearance ofnew lesions, thus allowing for delayed verification of falsepositive results. According to the study protocol, appearance ofa lesion on conventional images in a site where the scan hadbeen false-positive changed the results into true-positive in ourfinal evaluation. Given these facts, it seems very unlikely thatthe presence of tumor disease was underestimated, even if theradiographic method of proof has the tendency to miss smallextrahepatic intestinal tumors. Therefore, in turn, it seems also

‘231V1P AND ‘@ ‘IN-CYT-103 IMMUNO5CINTIGRAPHY IN ADENOCARCINOMAS •Raderer et al. 1483

by on June 1, 2020. For personal use only. jnm.snmjournals.org Downloaded from

AgePatientno.Sex(yr)LocalizationScan resuttCT @nitiaI)CT at 6moColorectal

cancer1M64LocoregionalrecurrencePosP05—2M72Locoregional

recurrencePosPosPos,P3F60LocoregionalrecurrencePosNegPos,P4M65Locoregional

recurrenceP05P05—@5F60LocoregionairecurrencePosPosPos,NC6M62Uver

metastasesPosPoePos,P7M64UvermetastasesPosPos—@8F71UvermetastasesP05P05Pos,P9F63Uver

metastasesP05P05—@10M72UvermetastasesPosPos—h11F73Lung metastasesPosPosPos,P12M73Uver

metastasesAbdominal lymph nodesP05 PosP05 PosPos,

NCPos,P13

14M F64 73Uver

metastasesAbdominal lymph nodesUvermetastasesLungmetastasesPos

PosPosP05Pos

PosPosPos—@

—‘

—“

—@Pancreatic

Cancer15F32LOcallyinoperablePosNegPos,P16F65LOCally

inoperableNegPos—“17M54UvermetastasesPosPos—‘18F62Uver

metastasesPoeP05—@19M59UvermetastasesPosPos—@20M61Uver

metastasesPosP05—“*Patient

died.P= disease progressionon CT;NC =no change on CT.

TABLE3Results of Iodine-i 23-VIP Receptor Scintigraphy

unlikely that the sensitivity to image the tumors was overestimated for ‘231-VIPand underestimated for ‘‘‘In-CYT-103.Furthermore, as opposed to other trials we used a state-of-theart multidetector SPECT system in our study that allowed us toperform several SPECT studies in one patient.

It is generally believed that antibodies or peptides of highbinding affinity are desirable for tumor imaging. As indicatedby our in vitro studies (Table 2), ‘23I-VIPas well as ‘‘‘In-CYT103 bound to adenocarcinoma cells both in primary tissues andcultured cells (HT29 and C0L0320 cells) with affinity constants in the lower nanomolar range suggesting the expressionof high-affinity binding sites at the cell surface for both ligands.The high expression of VIP receptors on the cell surface ofadenocarcinoma cells as opposed to normal peripheral bloodcells provided the basis for the use of radioiodinated VIP forVIP-receptor scanning (14) in vivo. VIP-receptor-deficientprimary adenocarcinomas have not been observed so far. Thenegative ‘231-VIP-scansobtained in two patients may be explained by loss of affinity for the radioligand, occupation byendogenous ligands or dedifferentiation of receptors. As opposed to peptide receptor scanning, targeting of the TAG-72antigen by ‘‘‘In-CYT-103has been achieved even when only15% of the cells expressed the target antigen (9). We foundhigh level expression of the TAG-72 antigen by adenocarcinoma cells, while normal peripheral blood cells did not expressthe TAG-72.3 antigen. The possibility of upregulating theexpression of TAG-72 antigens on tumor cells by cytokinessuggests that immunomodulatory pretreatment may lead toimproved ‘‘‘In-CYT-103Scanning results (27,28).

Advantages of Peptide Scanning over ImmunoscintigraphyAccumulation of the MAt, in the normal liver makes the

visualization of hepatic metastases difficult. This fact is re

flected by the relatively low percentage of true-positive andtrue-negative ‘‘‘In-CYT-l03 scans found in this trial in cornparison to ‘23I-VIP(see also (14)) and CT (11 ). A similar lowproportion of detectable liver metastases in patients with primary or recurrent colorectal cancer has been reported repeatedly for ‘‘‘In-CYT- 103 (9, 11 ). Due to these facts, the use of‘I ‘In-CYT-l03 can not be advocated for routine visualization of

known or suspected hepatic lesions, and potential problems ininterpreting scans can also result from appearance of lesionsboth as cold or hot spots (29).

However, we felt justified in including patients with hepaticmetastases in our trial not only for scientific reasons, but alsobecause a high percentage of such patients is encountered ingeneral oncologic practice. Since many of these subjects diefrom hepatic manifestations of gastrointestinal cancer, evaluation of a tracer for potential clinical routine use for thelocalization of these lesions seems highly important.

In contrast to the these pharmacologic properties of@ I‘In..CYT-103, the lung is the major organ of VIP uptake afterinjection of ‘231-VIP,while uptake in the normal liver is lowand radioactivity is excreted through the urinary tract (14,23).This biodistribution behavior makes the ‘23I-VIPreceptor scana valuable means for imaging of VIP receptor-expressinghepatic metastases. Potential problems arising with the interference of background activity in the urinary tract with theimaging of small rectal cancers can be avoided by performinglateral view images and/or SPECT studies. Since gastrointestinal cancers metastasize preferentially to the liver, the highproportion ofliver metastases detected by ‘23I-VIPis especiallyattractive for further clinical approaches. Especially noteworthyis the high percentage oftrue-positive ‘231-VIPscans in patientswith pancreatic adenocarcinornas. Since this tumor entity offers

1484 THEJOURNALOFNUCLEARMEDICINE•Vol. 37 •No. 9 â€September 1996

by on June 1, 2020. For personal use only. jnm.snmjournals.org Downloaded from

AgePatientno.Sex(yr)LocalizationScan resuttCT (initial)CT at 6moColorectal

cancer1

2M F58 79UV&metaStaSeSLungmetastasesUvermetastasesLungmetastasesNeg

NegPosNegPos

PosPosPos—@

—@Pos,PP05,NC3

4

5

6F

M

F

M62

69

78

80Uvermetastases

LungmetastasesUvermetastasesAbdominal lymph nodesUvermetastasesAbdominallymphnodesUvermetastasesNeg

NagNegNegNegNegPosP05

PosP05PosP05PosPos—@

Pos, NCPos, NC

—@Pos,P7M48UvermetastasesPoePosPos,NC8F64Uver

metastasesPoePos—‘9F55UvermetastasesP05P05P05,P10F61Uver

metastasesPosPosPos,P11F72UvermetastasesNegPos—@12F78Uver

metastasesP05PosP05,P13F59UvermetastasesPoePos—@Pancreatic

cancer14F66LOcallyinoperableprimaryPosPos—@15M63LOCallyinoperableprimaryNegP05—@16M67LOcallyinoperable primaryNegPosP05,NCGastric

cancer17M52LOCallyinoperableprimaryP05P05—@18M36LOCallyinoperable primaryNegPosPos,P19M68Uver

metastasesPosPos—@20F60LOCallyinoperableprimaryNegPos—“*Patient

died.P= progressionon CT;NC = no change on CT.

Patient no.SexAge (yr)Verified localizationViP-scanCYT-103CT finitisi)CT at 6moColorectal

cancer1F72UvermetastasesPosPosPosP05,P2M80UvermetastasesPosNegPosPos,P3

4M M66 73Locoregional

recurrenceUvermetastasesUvermetastasesPos

NegPosPos

NegPosP05

P05Poe—@ P05,NC5F77Lung

metastasesNagNegPosPos,P6F78LocoregionalrecurrenceP05NagNegP05,P7M49UvermetastasesPosP05P05—@8M48Locoregional

recurrencePosPosPosPos,PGastric

cancer9M68LOCallyinoperableprimaryPosNegPos—@Pancreatic

cancer10M53Primary tumor

UvermetastasesPos PosNag P05Pos Pos—@—@*Patient

died.P= progressionon CT,NC = nochange on CT.

TABLE 4Results of Indium-ii i-CYT-i 03 scanning

a special diagnostic challenge, further investigations are war- and 72 hr after ‘‘‘In-CYT-103injection, similar to the imagingranted. protocols previously used by others (11 ). In contrast to this

Usually, the highest tumor-to-background ratio achieved at immunoscintigraphic procedure, ‘231-VIPreceptor scanning canthe earliest time after antibody injection makes an antibody provide valuable results to the clinician within a few hours (Fig.ideal for imaging. In this study, we imaged the patients at 48 2). Although this may not be of major importance for clinical

TABLE 5Results of Comparative Scanning with Iodine-i23-VIP and Indium-i i i -CYT-i 03

‘23IVIPAND@@ ‘IN-CYT-103IMMUNOSCINTIGRAPHYINADENOCARCINOMAS•Raderer et al. 1485

by on June 1, 2020. For personal use only. jnm.snmjournals.org Downloaded from

i»

FIGURE 1. Recurrent adenocarcinoma (arrow) visualized by 123I-VIP(Table

5, Patient 6). SPECT reconstruction (four transverse slices, left panel; foursagittal slices, right panel) identified the recurrent tumor at 3 hr postinjectionin the transverse colon. In this patient, CT did not indicate tumor recurrenceat the time of VIP receptor scanning. However, during the follow-up period,CT scan also indicated tumor mass at 8 wk after 123l-VIP-injection. Indium-111-CYT-103 scintigraphy performed 4 wk after VIP receptor scanning gave

negative results.

management, the psychological effect on patients facing aninterval of anxiety between radiotracer application and definiteresults is far from negligible.

Apart from its high sensitivity, I23I-VIP also offers other

advantages over the use of MAbs. The estimated costs for123I-VIP receptor scanning are lower than those for ' "in-CYT-

103 or MAbs generally. The cost-effectiveness of the receptorscan will even be higher once a 99mTc-labeled VIP receptor

imaging compound will be available. Furthermore, there isample evidence in the current literature that HAMA-develop-ment can be a problem encountered with the clinical use ofwhole antibodies. In a study applying 1 mg of the TAG-72antibody, anti-mouse antibodies (HAMA) were developing (11 )in 40% of patients, while in another trial 17% of all patientsinjected had a positive HAMA test (30). HAMA formationmight prevent repeated successful imaging procedures withantibodies of murine origin in such patients, apart from theproblem of potential hypersensitivity reactions with repeatedadministration. Our protocol was structured to investigate thepresence of HAMA only in case of side effects, or in patients in

FIGURE 2. Liver métastases(arrow) visualized by 123I-VIP and 1"ln-CYT-103 (Table 5, Patient 1). Corresponding SPECT-reconstruction indicated the

liver métastasesin a patient suffering from colonie adenocarcinoma. Upperpanel: 123I-VIP SPECT study performed at 2 hr after injection (left: coronalslice, right: transverse slice). Lower panel: 111ln-CYT-103 SPECT study

performed at 48 hr after injection (left: coronal slice, right: transverse slice).

FIGURE 3. Recurrent rectal adenocarcinoma (arrow) visualized by 111ln-CYT-103 and 123I-VIP(Table 5, Patient 8). Upper panel: The 111ln-CYT-103

scan (SPECT reconstruction; left: coronal slice; right: transverse slice) indicated the tumor recurrence at the resection site at 48 hr (images) and at 72hr (not shown) after injection. Lower panel: 123I-VIP planar imaging of the

abdomen in anterior view showing the corresponding lesion indicating therecurrent tumor.

whom application of a second dose of "'ln-CYT-103 would

seem necessary.On the other hand, HAMA is not a problem in patients

undergoing peptide receptor scanning. Peptide-based tracerscan therefore be considered for repeated administration and thusfor possible routine follow-up and tumor assessment in cancerpatients undergoing therapy.

CONCLUSIONIodine-123-VIP receptor scanning was diagnostically supe

rior to "'ln-CYT-103 immunoscintigraphy. Our cohort of

patients, however, was highly unselected. Its exact effect onlocalization and early detection has yet to be established andfurther studies against other antibodies and/or fragments such as99mTc-labeled Fab fragments (31,32) are warranted. Although it

is tempting to speculate that VIP-receptor scanning could beincorporated into routine use, further investigations, especiallyin presurgical patients, are clearly necessary.

ACKNOWLEDGMENTSWe thank Judith Bednar, Ingrid Blazek, Bettina Mosing and

Karoline Krivanek for technical assistance as well as to BrigitteMaca and her team of nursing staff in the Department of Oncology.This study was supported by the Foundation of the Mayor of theCity of Vienna (Bürgermeisterfonds),the Austrian National Bank

1486 THEJOURNALOFNUCLEARMEDICINE•Vol. 37 •No. 9 •September 1996

by on June 1, 2020. For personal use only. jnm.snmjournals.org Downloaded from

(Jubilaumsfonds no. 4560 and 5439) and the Hochschuljulnlaumsfonds.

REFERENCES1. Silverberg E, Boring CE, Squires 15. Cancer statistics, 1990. CA 1990;40:9—26.2. PressmanD, Korngold D. The in vivo localization ofanti-wagner osteogenic sarcoma

antibodies. Cancer 1953;6:619—625.3. Goldenberg DM, Deland F, Kim EE, et al. Use of radiolabeled antibodies to

carcino-embryonic antigen for the detection and localization of diverse cancers byexternal photoscanning. N Engi J Med 1978;298: I 384—I390.

4. Goldenberg,DM, LarsonSM. Radioimmunodetectionin canceridentification.J NuciMed 1992;33:803—8l4.

5. ColcherD, HandHP,Nuti M, Ctal. A spectrumofmonoclonalantibodiesreactivewithhuman mammary tumor cells. Proc Nail Acad Sci USA 198l;78:3199—3203.

6. KeenanAM, ColcherD, LarsonSM, et al. Radioimmunoscintigraphyofhuman coloncancer xenografts in mice with radioiodinated monoclonal antibody B72.3. JNucl Med1984;25:l 197—1200.

7. Renda A, Salvatore M, Sava M, et al. Immunoscintigraphy in the follow-up of patientsoperated on for carcinoma of the sigmoid and rectum. Preliminaiy report with a newmonoclonal antibody B72.3. Dis Colon Rectum 1987;30:683—686.

8. EstebanJM, CoicherD, SugarbakerP. et al. Quantitativeand qualitativeaspectsofradiolocalization in colon cancer patients of intravenously administered MAb B72.3.mii Cancer1987;39:50—59.

9. Doerr Ri, Abdel-Nabi H, Krag D, et al. Radiolabeled antibody imaging in themanagement of colorectal cancer. Ann Surgery I991;214:1 18—124.

10. Abdel-Nabi H, Herrera L, Evans N, et al. Indium-I I 1 CYT-l03 MoAb imaging inpatients with suspected recurrent colorectal cancer [Abstract]. J NucI Med 1991 ;32:1053.

1 1. Collier BD, Abdel-Nabi H, Doerr Ri, et al. Immunoscintigraphy performed withIn-I 1I-labeled CYT-103 in the management ofcolorectal cancer: comparison with CT.Radiology1992;185:179—186.

12. Loy IS, Nashelsky MB. Reactivity of B72.3 with adenocarcinomas. An immunohistochemical study of 476 cases. Cancer 1993;72:2495—2498.

13. Roselli M, Hitchcock CL, Molinolo A, Ct al. Autoradiographic evaluation of radiolabeled monoclonal antibody B72.3 distribution in tumor and lymph nodes of adenocarcinoma patients. Anticancer Res 1995;15:975—984.

14. Virgolini I, Raderer M, Angelberger P. et al. vsao@ctive intestinal peptide (VIP)receptor imaging for the localization of intestinal adenocarcinomas and carcinoidtumors.NEnglJMed l994;331:1II6—l121.

15. Schwartz Ci, Kimberg DV, SheerinHE,ci al. Vasoactive intestinalpeptide stimulationofadenylate cyclase and active electrolyte secretion in intestinal mucosa. J Clin Invest1974;54:536—544.

16. Cohn J. Vasoactive intestinal peptide stimulates protein phosphorylation in a colonic

epithelial cell line. Am J Physiol l987;16:420—424.17. Pincus D@, DiCicco-Bloom EM, Black lB. Vasoactive intestinal polypeptide regu

lates mitosis, differentiation and survival of cultured sympathetic neuroblasts. NatureI 990;343:564—567.

18. Haegerstrand A, Jonzon B, Daalsgard Ci, et al. Vasoactive intestinal polypeptide

stimulates cell proliferation and adenylate cyclase activity of cultured human keratinocytes. Proc Nail Acad Sci USA 1989;86:5993—5996.

19. Virgolini I, Yang Q, Li SR. Ct al. Cross-competition between vasoactive intestinal

peptide (VIP) and somatostatin for binding to tumor cell receptors. Cancer Res1994;54:690—700.

20. Battari A, Martin JM, Luis J, et al. Solubilization of the active vasoactive intestinal

peptide receptor from human colonic adenocarcinoma cells. J Biochem Res 1989;263:17685—17689.

21. Sreedharan SP, Robichon A, Peterson KE, et al. Cloning and expression ofthe humanvasoactive intestinal peptide receptor. Proc Nail Acad Sci USA 1991;888:4986—4990.

22. Svoboda M, Neef de P. Tastenoy M, et al. Molecular characteristics and evidence forinternalization of vasoactive intestinal peptide receptors in the tumoral rat pancreaticacinar cell line AR 4-2J. Eur J Biochem 1988;l76:707—7l3.

23. Virgolini I, Kurtaran A, Raderer M, Ct al. Vasoactive intestinal peptide receptorscintigraphy. J Nucl Med 1995;36:1732—l739.

24. Virgolini I, Muller C, Klepetko W, et al. Human hepatocellular cancers show adecreased prostaglandin E, binding capacity. Br J Cancer l990;61:937—941.

25. Virgolini I, Sillaber C, Majdic 0, et al. Characterization ofprostaglandin binding sitesexpressed on human blood basophils. Evidence for a prostaglandin E@ , ‘2and D2receptor. J Biol Chem 1992;267:12700—l2708.

26. Scatchard G. The attraction ofproteins for small molecules and ions. Ann NYAcad Sci1949;51 :660—672.

27. Greiner JW, Guadagni F, Goldstein D, et al. Intraperitoneal administration ofinterferon gamma to carcinoma patients enhances expression of tumor-associatedglycoprotein-72 and carcinoembryonic antigen on malignant ascites cells. J Clin Oncol1992;lO:735—746.

28. Becherer A, Raderer M, Scheithauer w, et al. Evaluation of in vivo targeting ofadenocarcinomas with@@ ‘In-CYT-I03 antibody under treatment with interferongamma [Abstract]. J NucI Med 1994;35:85—86.

29. Vijayakumar v, Blend Mi, Johnson DK, et al. Improved detection of hepatic lesions

using MoAb B72.3 and a modified ‘@ ‘Inlabeling technique in patients with recurrentcolon cancer. Nucl Med Commun 1993;14:658—666.

30. Lamki LM, PodoloffDA, Singletary SE, et al. Indium-l 11-labeled B72.3 monoclonalantibody in the detection and staging of breast cancer: a phase I study. J NucI Med1991 ;32:1326—1332.

31. Serafini AN, Vargas-Cuba R, Bendetto P. Ctal. Technetium-99m-labeled Fab fragmentof anti-CEA monoclonal antibody for the radioimmunodetection of colorectal adenocarcinoma. Antibody Immunoconjugates Radiopharm 199I;4:561—567.

32. Pall YZ, Podoloff DA, Curley 5, et al. Technetium-99m-labeled IMMU-4, a monoclonal antibody against carcinoembryonic antigen, for imaging of occult disease inpatients with rising serum carcinoembryonic antigen levels. J Clin Oncol I994;12:489—495.

scans (in nine patients) identified multiple metastatic lesions,whereas the thallium scans were interpreted as either negative,nonspectñcorshowing fewerleaions. Infourstudy pairs, the thalliumscans showed solitary lesions that were not detected by the corresponding radioiodine scans. In i 6 scans, the thallium studies gavefalse-positive results. Conclusion: lodine-13i scintigraphy for diiferentiated thyroid carcinoma is more sensitive and more specificthan @°iiscintigraphy for detection of dletant metastases andresidual activity in the neck following thyroidectomy.

Key Words thyroki carcinoma; thyroidectomy; iodine-i3i ; thallium-20i ; thyroglobulin

J NucIMed199637:1487—1491

‘Lyroidcanceristhemostfrequentlydiagnosedmalignantendocrine lesion. The incidence in the United States is approximately 15,600 new cases occur annually, with 1200 deathseach year (1 ). Most of these tumors are well-differentiated and

The purpose of this study was to determine the concordance anddiscordance between diagnostic 1311and 201fl @,fr@e-@Jyscintigraptly in patients with differentiated carcinoma of the thyroid.Methods: Following thyroidectorny for differentiated thyroid cardnoma, 50 patients underwent whole-body 1311and 201fl scanning(60 pairs of scans in total). Fifteen pairs of studies were obtainedbefore ablative therapy, 30 pairs after ablative therapy and 15 pairsafter 1311therapy for metastalic disease. Serum thyrogkbulin levelswere concurrendy determined by radioimmunoassay. Results Thirty-six 1311whole-body scans (in34 patients) showed residual uptakein the neck, but only six (i 7%) of the corresponding whole-bodythallium studies had detectable uptake in the neck. Fourteen 1311

ReceivedOct.26, 1995;revisionaccepted Mar.6, 1996.For correspondence or reprints contact Mordechsi Lorberboym, MD, OMsion of

Nuclear Medicine, Box 1141, Mount Sin@Medical Center, One Gustave L Levy Place,NewYork,NY10029.

THALLIUM-201VERSUSIoDmiE-131 IN PATIENTSWITHTHYROIDCARCINOMA•Lorberboym et al. 1487

Thallium-20 1 and Iodine- 13 1 Scintigraphy inDifferentiated Thyroid CarcinomaMordechai Lorberboym, Sumathy Murthy, Jeffrey I. Mechanick, Donald Bergman, John C. Morris and Chun K. KimDepartments ofRadiology and Medicine, Divisions ofNeoplastic Diseases and Nuclear Medicine, Mount Sinai School ofMedicine, New York, New York

by on June 1, 2020. For personal use only. jnm.snmjournals.org Downloaded from

1996;37:1480-1487.J Nucl Med.   Gabriela Kornek, Kurt Kletter, Werner Scheithauer and Irene VirgoliniMarkus Raderer, Alexander Becherer, Amir Kurtaran, Peter Angelberger, Shuren Li, Maria Leimer, Georg Weinlaender,  Indium-111-CYT- 103 ImmunoscintigraphyComparison of Iodine-123-Vasoactive Intestinal Peptide Receptor Scintigraphy and

http://jnm.snmjournals.org/content/37/9/1480This article and updated information are available at:

  http://jnm.snmjournals.org/site/subscriptions/online.xhtml

Information about subscriptions to JNM can be found at:  

http://jnm.snmjournals.org/site/misc/permission.xhtmlInformation about reproducing figures, tables, or other portions of this article can be found online at:

(Print ISSN: 0161-5505, Online ISSN: 2159-662X)1850 Samuel Morse Drive, Reston, VA 20190.SNMMI | Society of Nuclear Medicine and Molecular Imaging

is published monthly.The Journal of Nuclear Medicine

© Copyright 1996 SNMMI; all rights reserved.

by on June 1, 2020. For personal use only. jnm.snmjournals.org Downloaded from