Computed tomography-based high-dose-rate intracavitary brachytherapy for uterine cervical cancer: preliminary demonstration of correlation between dose-volume parameters and rectal mucosal changes observed by flexible sigmoidoscopy.
OBJECTIVE
To compare the dose-volume histogram (DVH) parameters obtained by three-dimensional gynecologic brachytherapy planning with the rectosigmoid mucosal changes observed by flexible sigmoidoscopy.


METHODS
Between January 2004 and July 2005, 71 patients with International Federation of Gynecology and Obstetrics Stage IB-IIIB uterine cervical cancer underwent computed tomography-based high-dose-rate intracavitary brachytherapy. The total dose (external beam radiotherapy [RT] plus intracavitary brachytherapy) to the International Commission of Radiation Units and Measurements rectal point (ICRU(RP)) and DVH parameters for rectosigmoid colon were calculated using the equivalent dose in 2-Gy fractions (alpha/beta = 3 Gy). Sigmoidoscopy was performed every 6 months after RT, with the 6-scale scoring system used to determine mucosal changes.


RESULTS
The mean values of the DVH parameters and ICRU(RP) were significantly greater in patients with a score of > or =2 than in those with a score <2 at 12 months after RT (ICRU(RP), 71 Gy(alpha/beta3) vs. 66 Gy(alpha/beta3), p = 0.02; D(0.1cc), 93 Gy(alpha/beta3) vs. 85 Gy(alpha/beta3), p = 0.04; D(1cc), 80 Gy(alpha/beta3) vs. 73 Gy(alpha/beta3), p = 0.02; D(2cc), 75 Gy(alpha/beta3) vs. 69 Gy(alpha/beta3), p = 0.02). The probability of a score of > or =2 showed a significant relationship with the DVH parameters and ICRU(RP) (ICRU(RP), p = 0.03; D(0.1cc), p = 0.05; D(1cc), p = 0.02; D(2cc), p = 0.02).


CONCLUSIONS
Our preliminary data have shown that DVH values of the rectosigmoid colon obtained by computed tomography-based three-dimensional brachytherapy planning are reliable and predictive of score > or =2 rectosigmoid mucosal changes.
Koom
Woong Sub
WS
Research Institute and Hospital, National Cancer Center, Goyang, Gyeonggi, South Korea.
Sohn
Dae Kyung
DK
Kim
Joo-Young
JY
Kim
Jong Won
JW
Shin
Kyung Hwan
KH
Yoon
Sang Min
SM
Kim
Dae Yong
DY
Yoon
Myonggeun
M
Shin
Dongho
D
Park
Sung Yong
SY
Cho
Kwan Ho
KH
D000230:Adenocarcinoma / Q000532:radiotherapy; D000328:Adult; D000368:Aged; D001918:Brachytherapy / Q000379:methods*; D002294:Carcinoma, Squamous Cell / Q000532:radiotherapy; D016009:Chi-Square Distribution; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006801:Humans; D007413:Intestinal Mucosa / Q000473:pathology / Q000528:radiation effects*; D008875:Middle Aged; D011446:Prospective Studies; D011832:Radiation Injuries / Q000473:pathology*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D012007:Rectum / Q000473:pathology / Q000528:radiation effects*; D012044:Regression Analysis; D012812:Sigmoidoscopy; D047368:Tumor Burden; D002583:Uterine Cervical Neoplasms / Q000532:radiotherapy*