Late rectal complications evaluated by computed tomography-based dose calculations in patients with cervical carcinoma undergoing high-dose-rate brachytherapy.
OBJECTIVE
To investigate the efficacy of dose calculations at the computed tomography (CT)-based rectal point (CTRP) as a predictive factor for late rectal complications in patients with cervical carcinoma who were treated with a combination of high-dose-rate intracavitary brachytherapy and external beam radiotherapy.


METHODS
Ninety-two patients with uterine cervical carcinoma undergoing definitive radiotherapy alone were retrospectively analyzed. The median follow-up time for all patients was 32 months (range, 13-60 months). The cumulative biologically effective dose (BED) was calculated at the rectal reference point as defined by the International Commission on Radiation Units and Measurements Report 38 (BED(RP)) and at the CTRP (BED(CTRP)). Late rectal complications were recorded according to the Radiation Therapy Oncology Group grading system.


RESULTS
The late rectal complications were distributed as follows: Grade 0, 68 patients (74%); Grade 1, 20 patients (22%); Grade 2, 4 patients (4%). Univariate analysis showed that BED(RP), BED(CTRP), RP dose/point A dose ratio, and CTRP dose/point A dose ratio were significantly correlated with late rectal complications (p < 0.05). On multivariate analysis, patients with a rectal BED(CTRP) >/=140 Gy(3) presented with significantly greater frequency of rectal complications (p = 0.031).


CONCLUSIONS
The present results suggest that BED(CTRP) is a useful predictive factor for late rectal complications.
Noda
Shin-Ei
SE
Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, Anagawa, Chiba, Japan.
Ohno
Tatsuya
T
Kato
Shingo
S
Ishii
Takayoshi
T
Saito
Osami
O
Wakatsuki
Masaru
M
Tamaki
Tomoaki
T
Watanabe
Kazuhiro
K
Nakano
Takashi
T
Tsujii
Hirohiko
H
D000230:Adenocarcinoma / Q000473:pathology / Q000532:radiotherapy; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D001918:Brachytherapy / Q000009:adverse effects*; D018196:Carcinoma, Adenosquamous / Q000473:pathology / Q000532:radiotherapy; D002294:Carcinoma, Squamous Cell / Q000473:pathology / Q000532:radiotherapy; D005260:Female; D006801:Humans; D008875:Middle Aged; D011832:Radiation Injuries / Q000000981:diagnostic imaging* / Q000473:pathology; D011879:Radiotherapy Dosage; D012007:Rectum / Q000000981:diagnostic imaging / Q000528:radiation effects*; D012062:Relative Biological Effectiveness; D014057:Tomography, X-Ray Computed; D002583:Uterine Cervical Neoplasms / Q000473:pathology / Q000532:radiotherapy*