Predictive role of TDF values in late rectal recto-sigmoid complications in irradiation treatment of cervix cancer.
Radiation-induced late rectal and recto-sigmoid complications for different doses per fraction were analyzed retrospectively in 203 cases of Stage IIIB carcinoma of the uterine cervix. The patients were treated with a combination of external irradiation and a single intracavitary insertion during January 1979 to December 1983. The external irradiation was randomised to deliver by four different fractionation regimens having dose per fraction of 2 Gy, 3 Gy, 4 Gy and 5.4 Gy. The doses for various fractionations were matched with the daily regimen using the time-dose factors (TDF) model. A single intracavitary insertion delivered a dose of 22 to 24 Gy to point A using Fletcher-Suit applicator. All patients had a minimum follow-up of 30 months. Thirty nine cases of late radiation induced rectal and recto-sigmoid complications were observed. The complication rate of 8.2% for daily treatment regimen delivering 2 Gy per fraction was increased to 33.3% for once weekly treatment regimen delivering 5.4 Gy per fraction (p = 0.041). Despite similar Time-Dose Factors (TDF) values in four different treatment regimens, the complication rate increased significantly in the once weekly regimen. The analysis suggest that the Time-Dose Factors (TDF) values do not predict correctly the late normal tissue reactions for different dose fractionation schedules.
Deore
S M
SM
Department of Medical Physics, Tata Memorial Hospital, Bombay, India.
Viswanathan
P S
PS
Shrivastava
S K
SK
Supe
S J
SJ
Dinshaw
K A
KA
D000328:Adult; D000368:Aged; D001918:Brachytherapy; D012809:Colon, Sigmoid / Q000528:radiation effects*; D005260:Female; D006801:Humans; D007194:India / Q000453:epidemiology; D008875:Middle Aged; D011379:Prognosis; D011832:Radiation Injuries; D011878:Radiotherapy / Q000009:adverse effects*; D011879:Radiotherapy Dosage; D012007:Rectum / Q000528:radiation effects*; D012189:Retrospective Studies; D013997:Time Factors; D002583:Uterine Cervical Neoplasms / Q000453:epidemiology / Q000532:radiotherapy*