Relevance of abdominal gas analysis and transit study after colorectal cancer surgery

Background: Colon gas volume analysis using abdominal radiographs is an objective and reproducible method for evaluating functional bowel disorders. The aim of this study was to clarify the relevance of colon gas distribution and transit time in rectosigmoid cancer patients after surgery. Methods: Segmental colon gas volume score was calculated using plain abdominal radiography and evaluated in 40 patients who had undergone sphincter-saving resection. Segmental colonic transit time was analysed using radiopaque markers in the same patients. Results: Transit times in the right colon (RCT) were 15.3 ± 1.1 h and in the left colon (LCT) 11.2 ± 1.1 h. Gas volume scores in the RCS and LCS were 1.10 ± 0.13% and 1.06 ± 0.14%, respectively. Neither colonic transit time nor colon gas volume score correlated with the operation methods for rectosigmoid colon cancer. A positive correlation of RCS and a negative correlation of LCS/RCS with ageing were noted in male patients but not in female patients. There was no correlation between RCT and RCS (r = 0.028); however, LCT correlated with LCS (r = 0.318, P < 0.05). The ratio of colonic transit time (LCT/RCT) was 0.84 ± 0.10, while that of colon gas volume score (LCS/RCS) was 1.29 ± 0.21. There was a significant correlation between LCT/RCT and LCS/RCS (r = 0.541, P < 0.001). Conclusions: Analysis of colon gas volume is useful for evaluating colonic transit time in rectosigmoid cancer patients after sphincter-saving surgery.