evaluation of a simple belly-board device for reduction of small bowel inside rectal cancer radiotherapy fields

background: we evaluated the efficacy of a simple belly-board device (bbd) designed and made in our department for reduction of small bowel inside the post-operative pelvic radiotherapy fields of rectal carcinomas. methods: a very simple bbd was designed and manufactured in our department. it was made of acrylic glass, and was 128 cm long, 40 cm wide, and 9 cm high, with a 25x25 cm square opening, the lower border of which was set to be positioned about 3 cm above patients’ iliac crest. patients to be treated post-operatively for rectal cancers were simulated using oral contrast with and without the bbd for postero-anterior (pa) and lateral fields. the small bowel surface area (sbsa) inside the fields was measured and compared in the films with and without the bbd. results: twenty-one patients, mean age 56 years, male-to-female ratio 2:1, 12 abdominoperineal (apr) and 9 low anterior resection (lar), gave consent for this study. the mean sbsa were 7 and 13 cm 2 in the lateral fields and 29 and 60 cm 2 in the pa fields with and without the bbd, respectively (p = 0.001). the mean reduction in sbsa was 61% in the lateral fields, 53% in the pa fields, and 57% in both lateral and pa fields (p<0.001). the mean reduction in sbsa in lateral fields was 77% after lar and 49% after apr (p=0.08). this difference was not significant for pa fields. the only factor with a significant effect was operation type (lar versus apr) for reduction of sbsa in lateral fields (p=0.05). gender, age, body mass index, and field sizes did not have a significant effect. conclusion: the simple bbd could significantly reduce the sbsa inside the pelvic radiotherapy fields of rectal cancers. this reduction seems more pronounced after lar in the lateral fields, compared to apr.