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Gas in the rectum tends to reduce during radical external beam radiotherapy for localised prostate cancer
Author(s) -
Nakamura Naoki,
Hatanaka Shogo,
Takahashi Osamu,
Mizuno Norifumi,
Endo Haruna,
Tamaki Seiichi,
Shikama Naoto,
Ogita Mami,
Kawamori Jiro,
Sekiguchi Kenji
Publication year - 2014
Publication title -
journal of medical imaging and radiation oncology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.31
H-Index - 43
eISSN - 1754-9485
pISSN - 1754-9477
DOI - 10.1111/1754-9485.12141
Subject(s) - medicine , rectum , radiation therapy , prostate cancer , prostate , external beam radiotherapy , radiation oncologist , nuclear medicine , cancer , radiology , surgery
Purpose This study aims to clarify the time‐course of gas accumulation in the rectum during treatment as guidance for the management of rectal volumes. Materials and Methods We reviewed 2042 sets (35.2 sets per patient) of anteroposterior and right–left mega voltage ( MV ) images obtained for daily set‐up from 58 patients who underwent radical external beam radiotherapy for localised prostate cancer. The patients were instructed to take magnesium oxide tablets during radiotherapy. They were also encouraged to avoid foods that might cause intestinal gas during radiotherapy. Gas accumulation in the rectum was graded into three classes by the same radiation oncologist. If no gas was seen in the rectum, it was classified as grade 0. A small amount of gas was classified as grade 1, whereas a marked amount of gas that required removal was classified as grade 2. Results Of the 2042 sets of MV images, grades 1 and 2 gas accumulation were seen in 332 (16%) and 156 (8%), respectively. By the trend test, gas accumulation significantly decreased towards the end of treatment ( P = 0.02 for grade 1 or 2 and P = 0.02 for grade 2). On multivariate analysis, we did not identify any significant independent predictors for either baseline gas accumulation or gas reduction. Conclusion Gas accumulation tended to decrease until the end of treatment. This tendency should be reconfirmed by other institutions.