Intensity-modulated radiotherapy with a belly board for rectal cancer

Background and aim: Intensity-modulated radiotherapy (IMRT) techniques can reduce the irradiated small bowel volume in rectal cancer patients, but combined use of IMRT and a belly board is yet to be reported on for rectal cancer patients. The aim of this study was to determine whether additional use of a belly board reduced the irradiated small bowel volume observed using IMRT alone in rectal cancer patients. Materials and methods: Twenty patients scheduled to receive preoperative radiotherapy for rectal cancer underwent two series of CT scans, with and without a belly board. IMRT planning was performed using 6-MV photon beams and seven equispaced fields. The bladder, small bowel, and planning target volume (PTV) were analyzed for doses between 10% and 100% of the prescribed dose at 10% intervals. Data were analyzed using Wilcoxon signed rank tests. Results: There were no significant differences between patients undergoing IMRT with a belly board and those without a belly board in terms of total small bowel volumes, bladder, and PTV (p = 0.571, p = 0.841, and p = 0.870, respectively). Statistical analysis showed that the irradiated small bowel volume with a belly board was smaller than that without a belly board (p < 0.05 at 20-100% dose levels), with the mean relative reduction in the irradiated small bowel volume being 37.8 ± 32.8%. Conclusion: IMRT with a belly board is more effective than IMRT alone in reducing the irradiated small bowel volume. These findings suggest that the use of a belly board with IMRT may reduce small bowel complications in preoperative radiotherapy.