IMPACT OF PHYSICAL DOSE RATE EFFECT ON THE LONG TERM RESULTS OF THE CF-252 BRACHYTHERAPY OF CERVIX CARCINOMA

E. Janulionis; K.P.Valuckas; V.Atkocius; V.SamerdokieneInstitute of Oncology, Vilnius University, Lithuania

2011-04-17-21, Porto Alegre, Brazil

PURPOSE

EVALUATE EFFECT OF Cf-252 DOSE RATE ON THE LONG TERM CLINICAL RESULTS AFTER COMBINED RADIATION THERAPY FOR STAGE IIB AND IIIB OF CERVIX UTERI CARCINOMA

PATIENTS 1994-1999

Ca cervicis uteri, IIB and IIIB342 PTS TREATED BY

EBRT (60Co) + 252Cf BRACHYTHERAPYNo chemotherapy

CALCULATION OF THE DOSES FROM 252Cf SOURCES

CfCf

nCf

nCf

isoeffCf dRBEdRBED

1CfRBE

nCfRBE

2.0 :fractions If k

nCf

nCf

kk RBERBE

,958lgW0,698 n

n 117,0lgW0,2628,2

(J.S. Rjabukin, 1985)

Gy/h1027,1W4Gy/h if,6

n

4Gy/hW0,05Gy/h if, n

MOST FREQUENTLY USED 252Cf BRACHY REGIMEN

5 x 8 iGy=40iGy5 x (1,32÷1,44) neutronGy + 5 x (0,88÷0,96) gammaGy

6,6÷7,2 neutronGy + 4,4÷4,8 gammaGy

PATIENTS BY YEAR AND STAGE

YearFIGO

TotalIIB IIIB

1994 25 37 621995 22 53 751996 23 48 711997 20 67 871998 7 27 341999 5 8 13Total 102 240 342

252Cf BRACHYTHERAPY BY FRACTIONATION

FIGOTotalIIB IIIB

5-6 x 8 iGy 90 223 3135 x 9 iGy 8 16 244x 10 iGy 4 1 5

Total 102 240 342

IRRADIATION TIME AND PHYSICAL DOSE RATE

YEARFRACTION DOSE, iGy

PHYSICAL DOSE neutron+gamma,

Gy

IRRADIATION TIME, h

PHYSICAL DOSE RATE AT POINT A,

Gy/h

1994.01 8iGy

2,2-2,4

0,5-0,7 3,7-4,8

1997.01 8iGy 1 2,2

1999.12 8iGy 1,6-2,0 1,2-1,4

LATE COMPLICATIONS, IIB + IIIB, % (GRADE 2-3)

IIB IIIB IIB + IIIB

CYSTITIS 8.4 8.7 8.6

PROCTITIS 2.1 2.6 2.5

TOTAL 10.5 11.3 11.1

LATE COMPLICATIONS (CYSTITIS + PROCTITIS), IIB + IIIB, 1994-1996 vs. 1997-1999

1994-1996 1997-199922+8=30 6+0=6

14,4% 5,2%Statisticaly significant higher late complications rate

in 1994-1996

Exact Sig. (2 sided)Fisher's Exact Test 0.010

SIGNIFICANCE OF SURVIVAL IIB1994, 1995, 1996, 1997, 1998,

1999 no significance

Sig.Log Rank (Mantel-Cox)

0.518

Breslow (Generalized Wilcoxon)

0.422

Tarone-Ware 0.462

1994-1996 vs. 1997-1999 no significance

Sig.Log Rank (Mantel-Cox) 0.921

Breslow (Generalized Wilcoxon) 0.918

Tarone-Ware 0.914

yr

months

yr

months

SIGNIFICANCE OF SURVIVAL IIIB1994, 1995, 1996, 1997, 1998,

1999 no significance

Sig.Log Rank (Mantel-Cox) 0.086Breslow (Generalized Wilcoxon) 0.141

Tarone-Ware 0.109

1994-1996 vs. 1997-1999 statisticaly significant higher

survival in 1997-1999Sig.

Log Rank (Mantel-Cox) 0.035Breslow (Generalized Wilcoxon) 0.053

Tarone-Ware 0.042

yr

months

yr

months

CONCLUSIONS

During period 1994-1999 342 pts with Ca cervicis uteri received combined RT: EBRT(60Co) + Brachytherapy (252Cf)

The brachytherapy physical dose rate (or irradiation time) changed about 4-fold

The overall survival rate was the same for each year of treatment

The statistically significant difference was found for survival of stage IIIB and late complications (1994-1996 vs 1997-1999)

There was not found clinical proof of the Cf-252 dose rate effect on overall survival

Thank you for attention