Intramedullary spinal cord metastases treated with CyberKnife

radiosurgery:

Robert E. Lieberson, MD, John R. Adler, MD,Scott G. Soltys, MD, Iris C. Gibbs, MD and

Steven D. Chang, MD

ten cases, a brief review of the literature, and treatment recommendations

Presentation of SCIM’s• Of all patients with cancer:

– 33% get vertebral body mets– 4% get leptomeningeal mets– only 0.1 to 0.4% get

intramedullary mets• Primaries similar to brain

– Lung, breast, melanoma, renal

CyberKnife Radiosurgery• Well established for bony,

epidural, and extramedullary mets

• Well established for intramedullary AVMs and hemangioblastomas

• Used for ependymomas• Only case reports and

one mixed series on SCIM’s

SCIM Patient Characteristics

• With in cord substance including pial based• Age 39 to 77 years (median 66, SD 14.6)• 7 women, 3 men (10 patients)• 7/11 cervical, 4/11 thoracic (11 tumors)• All CTCAE grade ≥ 3

Clinical• 5 breast, 2 NSC lung, 1 prostate,

1 teratoma, 1 hemangioepithelioma• All had numerous other lesions,

– 5/10 with brain mets– 6/10 with vertebral body mets

• 2 with 1, 2 with 3, and 2 with TNTC– 3/10 with intradural mets, 1/10 carcinomatosis

• 1/10 patients underwent biopsy– Diagnosis known, MRI characteristic,

biopsy risky

Examples

SCIM Treatment Parameters• Tumor volume 0.12 to 1.98

cc’s (median 0.39, SD 0.62)• 14 Gy to 27 Gy (median 21,

SD 4.2)• 2 to 5 sessions (median

3.0, SD 0.9)• Conformity index

1.21 - 2.88 (median 1.64, SD 0.55)

Clinical

• 5 of 5 evaluable patients stabilized or improved

• 3/5 with less pain, 2/5 with no pain,

• Survival 2.2 to 27.2 months (median 5.4, SD 8.9)

Radiographic

• Post-treatment MRIs improved in 4 of 4 evaluable patients – 2 smaller– 2 same size, less contrast enhancement

• No MRI evidence radiation toxicity (4 Pts)– No edema– No increase in T2 signal

Dose Escalation for Cord AVMs

19972000

20032006

0

10

20

30

40

50

60

70

80

5.2 Gy x 4 = 21 Gy38 Gy

7 Gy x 3= 21 Gy47 Gy

10 Gy x 2= 20 Gy60 Gy

10 Gy x 2= 20 Gy60 Gy

16 Gy x 1= 16 Gy72 Gy

Year

BED

Cord AVM Results• 22 / 29 with > 24 month follow-up• Pre-SRS, 16 hemorrhaged,

8 w/ multiple bleeds• Symptoms improved in > 50%• No hemorrhage after SRS• No mortality• 3 patients had increased

symptoms (10%)• 1 radiation myelopathy

(3%)

Other IM Lesions• Ependymomas

– 3 tumors in 2 pts reported in 2003 (now 5/4)

– Mean 18 Gy, 1 or 2 sessions– All smaller, no complications

• Hemangioblastomas– 16 spinal in 12 pts reported in

2003 (now 31/19)– Mean 21.3 Gy, 1 to 4 sessions– 15/16 stable or smaller,

no complications– Cysts poorly treated

Spinal Cord Dose

• Other published “guidelines” for cord dose– Chang, et al, and others Vmax less than ~ 10 – 14 Gy– Ryu, et al, 10% under 10 Gy (cord contoured 6 mm

above and below lesion)– Gibbs, et al, V8 ≤ 1 cc

• Daly, et al, in IM hemangioblastomas the cord receives the full marginal dose– Single fraction Dmax as high as 22.4 Gy – All

“guidelines” exceeded– No radiation toxicity – true limit unknown–

Hemangioblastomas / Daly, et al, IJROBP 80:213 (2011)

Conclusions• Largest series of SCIMs treated with CyberKnife• Our patients had multiple other metastases,

overall survival was poor, but …– Treatment preserved function– There were no local recurrences– There was no radiation toxicity – Fewer sessions than conventional radiation– Less morbidity than open surgery

• SRS a good option for intramedullary spinal cord metastases.

Merci

Pt Rx Date Age M/F Dx Rx Site

Size (cm3) Fx’s Dose

(cGy)

1 12/2000 75 F Breast, Inflamatory C1 0.64 4 1400

2 12/2003 39 F Breast, Adeno C2-3 1.98 2 2200

3 11/2005 67 F Lung, NSC C6-7 0.38 3 2100

4 2/2006 43 M Epitheliod Hemangio-epithelioma

C5 0.29 3 2700

T2 0.30 3 2700

5 3/2006 77 M Breast , Adeno T6 0.20 2 1800

6 9/2007 67 M Lung, NSC T2 0.80 5 2500

7 4/2010 51 F Teratoma C1-2 0.64 2 2000

8 6/2010 68 M Prostate T10-12 0.55 3 2700

9 8/2010 40 F Breast, Infiltrating Ductal C3 0.12 2 2000

10 8/2010 65 F Breast, Adeno C5-6 1.35 3 2100