Transcript IMPACT OF PHYSICAL DOSE RATE EFFECT ON THE LONG …

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.Samerdokiene
Institute 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 IIIB
342 PTS TREATED BY
EBRT (60Co) + 252Cf BRACHYTHERAPY
No chemotherapy
CALCULATION OF THE DOSES
FROM 252Cf SOURCES
(J.S. Rjabukin, 1985)
Cf
Cf
Cf
Cf
Cf
D
 RBE
d
 RBE
d
isoeff
n
n


RBE
Cf

1
0,698 lgW n    8,95 ,if 0,05Gy/h  Wn    4Gy/h
RBE
Cf
n
2,8
0,262 lgW n    0,117
6
,if 4Gy/h  Wn   1,27 10 Gy/h
Cf
Cf
0.2
If k fractions: RBE
 RBE
k
k
n
n
MOST FREQUENTLY USED 252Cf
BRACHY REGIMEN
5 x 8 iGy=40iGy
5 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
Year
FIGO
Total
IIB
IIIB
1994
25
37
62
1995
22
53
75
1996
23
48
71
1997
20
67
87
1998
7
27
34
1999
5
8
13
Total
102
240
342
252Cf
BRACHYTHERAPY BY
FRACTIONATION
FIGO
Total
IIB
IIIB
5-6 x 8 iGy
90
223
313
5 x 9 iGy
8
16
24
4x 10 iGy
4
1
5
Total
102
240
342
IRRADIATION TIME AND PHYSICAL
DOSE RATE
YEAR
FRACTION
DOSE, iGy
1994.01
8iGy
1997.01
8iGy
1999.12
8iGy
PHYSICAL DOSE
neutron+gamma,
Gy
2,2-2,4
IRRADIATION
TIME, h
PHYSICAL
DOSE RATE
AT POINT A,
Gy/h
0,5-0,7
3,7-4,8
1
2,2
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
10.5
11.3
11.1
TOTAL
LATE COMPLICATIONS
(CYSTITIS + PROCTITIS), IIB + IIIB,
1994-1996 vs. 1997-1999
1994-1996
1997-1999
22+8=30
6+0=6
14,4%
5,2%
Statisticaly significant higher late complications rate
in 1994-1996
Fisher's Exact Test
Exact Sig. (2 sided)
0.010
SIGNIFICANCE OF SURVIVAL IIB
1994, 1995, 1996, 1997, 1998,
1999
no significance
Log Rank (Mantel-Cox)
Sig.
0.518
yr
Breslow (Generalized
Wilcoxon)
0.422
Tarone-Ware
0.462
months
1994-1996 vs. 1997-1999
no significance
Sig.
Log Rank (Mantel-Cox)
0.921
yr
Breslow (Generalized
Wilcoxon)
0.918
Tarone-Ware
0.914
months
SIGNIFICANCE OF SURVIVAL IIIB
yr
1994, 1995, 1996, 1997, 1998,
1999
no significance
Sig.
Log Rank (Mantel-Cox)
0.086
Breslow (Generalized
Wilcoxon)
0.141
Tarone-Ware
0.109
months
1994-1996 vs. 1997-1999
statisticaly significant higher
survival in 1997-1999
Sig.
Log Rank (Mantel-Cox)
0.035
Breslow (Generalized
Wilcoxon)
0.053
Tarone-Ware
0.042
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