Dose–volume analysis of predictors for chronic gastrointestinal complications in patients with cervical cancer treated with postoperative concurrent chemotherapy and whole-pelvic radiation therapy

The purpose of this study is to evaluate dose-volume histogram (DVH) predictors for the development of chronic gastrointestinal (GI) complications in patients with cervical cancer who have undergone postoperative concurrent chemotherapy and whole-pelvic radiation therapy (WPRT). The subjects were 135 patients who had undergone postoperative WPRT with concurrent nedaplatin-based chemotherapy between 2000 and 2014. Associations between selected DVH parameters and the incidence of chronic GI complications of G3 or higher were evaluated. Chronic GI complications of severity G3 occurred in 18 (13%) patients. Patients with GI complications had significantly greater V5-V45, mean dose and the generalized equivalent uniform dose (gEUD) of the small bowel loops, compared with those without GI complications. V30-V45, mean dose and gEUD of the bowel bag also showed significant differences between patients with and without GI complications. In contrast, no parameter for the large bowel loop was correlated with GI complications. Receiver operating characteristics curve analysis indicated that V30-V45 of the small bowel loops were better predictors than these respective parameters for the bowel bag. Next, patients were divided into four groups based on the median V15 and V40 of the small bowel loops. The group with both a high V15 and a high V40 showed a significantly higher probability of chronic GI complications. In conclusion, the small bowel loops are better predictors of chronic GI complications compared with the bowel bag, and a relatively high-dose volume (e.g. V40) of the small bowel loops is a useful predictor of chronic GI complications.