Influence of Bladder Distension Control on Postoperative IMRT for Rectal Cancer

Preoperative chemoradiation has gained acceptance as the standard of care for patients with clinical stage II and III rectal cancer. However, it does not reduce distant metastases and improve survival times compared to postoperative radiotherapy. Furthermore, 20%–30% of patients will have stage I disease and will receive unnecessary treatment. Postoperative radiotherapy as an adjuvant treatment still plays an important role in the management of rectal cancer. Adjuvant chemoradiation therapy showed an advantage in local control, disease-free interval, and overall survival after surgical resection. But the toxicity of the small bowel seems to increase (Sauer et al., 2001; 2004; Baxter et al., 2007). After abdominoperineal or anterior resections, the small bowel settles deeper into the lower pelvis and becomes fixed by adhesions, thereby increasing the volume and toxic effects of the bowel exposed to radiation. The small bowel has potential risk for radiation injury due to lower radiation tolerance than either the urinary bladder or the rectum. Among various methods to reduce the irradiated small bowel volume, prone position with a belly board