Morphologic change of rectosigmoid colon using belly board and distended bladder protocol

PURPOSE: This study investigates morphologic change of the rectosigmoid colon using a belly board in prone position and distended bladder in patients with rectal cancer. We evaluate the possibility of excluding the proximal margin of anastomosis from the radiation field by straightening the rectosigmoid colon. MATERIALS AND METHODS: Nineteen patients who received preoperative radiotherapy between 2006 and 2009 underwent simulation in a prone position (group A). These patients were compared to 19 patients treated using a belly board in prone position and a distended bladder protocol (group B). Rectosigmoid colon in the pelvic cavity was delineated on planning computed tomography (CT) images. A total dose of 45 Gy was planned for the whole pelvic field with superior margin of the sacral promontory. The volume and redundancy of rectosigmoid colon was assessed. RESULTS: Patients in group B had straighter rectosigmoid colons than those in group A (no redundancy; group A vs. group B, 10% vs. 42%; p = 0.03). The volume of rectosigmoid colon in the radiation field was significantly larger in group A (56.7 vs. 49.1 mL; p = 0.009). In dose volume histogram analysis, the mean irradiated volume was lower in patients in group B (V45 27.2 vs. 18.2 mL; p = 0.004). In Pearson correlation coefficient analysis, the in-field volume of rectosigmoid colon was significantly correlated with the bladder volume (R = 0.86, p = 0.003). CONCLUSION: Use of a belly board and distended bladder protocol could contribute to exclusion of the proximal margin of anastomosis from the radiation field.

Morphologic change of rectosigmoid colon using belly board and distended bladder protocol

PURPOSE: This study investigates morphologic change of the rectosigmoid colon using a belly board in prone position and distended bladder in patients with rectal cancer. We evaluate the possibility of excluding the proximal margin of anastomosis from the radiation field by straightening the rectosigmoid colon. MATERIALS AND METHODS: Nineteen patients who received preoperative radiotherapy between 2006 and 2009 underwent simulation in a prone position (group A). These patients were compared to 19 patients treated using a belly board in prone position and a distended bladder protocol (group B). Rectosigmoid colon in the pelvic cavity was delineated on planning computed tomography (CT) images. A total dose of 45 Gy was planned for the whole pelvic field with superior margin of the sacral promontory. The volume and redundancy of rectosigmoid colon was assessed. RESULTS: Patients in group B had straighter rectosigmoid colons than those in group A (no redundancy; group A vs. group B, 10% vs. 42%; p = 0.03). The volume of rectosigmoid colon in the radiation field was significantly larger in group A (56.7 vs. 49.1 mL; p = 0.009). In dose volume histogram analysis, the mean irradiated volume was lower in patients in group B (V45 27.2 vs. 18.2 mL; p = 0.004). In Pearson correlation coefficient analysis, the in-field volume of rectosigmoid colon was significantly correlated with the bladder volume (R = 0.86, p = 0.003). CONCLUSION: Use of a belly board and distended bladder protocol could contribute to exclusion of the proximal margin of anastomosis from the radiation field.

Tumor height from the anal verge before and after complete mobilization of the rectum

Rectal tumor height has been observed to increase after complete mobilization.OBJECTIVES: 1.) to measure tumor height in resectable rectal cancers before and after complete mobilization, 2.) to describe changes in tumor height measurements at different levels of the rectum, and 3.) to determine the probability of a two centimeter increase in tumor height after mobilization in low rectal cancers. METHODS: Prospective cross-sectional series including all resectable rectal cancer treated at our hospital from January to December, 2003. Proctoscopy measurements of rectal tumor height after induction of anesthesia were compared to measurements done after complete rectal mobilization. Logistic curve fitting was used to calculate the probability of a two centimeter increase in tumor height for low rectal cancers after complete mobilization.RESULTS: In the 12-month period, 37 patients with adenocarcinoma of the rectum were seen. Ages of patients ranged from 26 to 86, with mean age of 57.8 years. Thirty-three patients had resectable rectal cancer. Tumor height ranged from zero to 11 cm, with mean height of 5.7 cm. After complete mobilization, tumor height increased in 50 percent of upper rectal cancers, 92 percent of mid-rectal cancers, and 32 percent of low rectal cancers. Logistic curve fitting showed probability of a two-centimeter increase in tumor height was 52 percent at seven centimeters, 40 percent at six centimeters, 28 percent at five centimeters, and 19 percent at four centimeters. DISCUSSION: The decision to perform APR for low rectal cancers must not be based solely in pre-operative tumor height measurements since pre-operative measurements of rectal tumor height can increase when the rectum is completely mobilized.