Even with multi-modality therapy, disease-free survival for locally-advanced primary and recurrent rectal cancer is poor. Preliminary studies suggest that intraoperative radiotherapy (IORT) may improve disease-free survival; however, complicated logistics and high cost have limited evaluation. We are investigating the role of IORT using a mobile accelerator for select patients with marginally-resectable, primary and recurrent rectal cancer.

All patients with locally-advanced primary or recurrent rectal cancer are considered for IORT. The operative procedure is dictated by the location of the tumor and any previous interventions received. After tumor resection, IORT (10-15 Gy) is delivered in the operating room using a self-shielded, magnetron-driven X-band linear accelerator.

30 patients (8 primary, 22 recurrent) have been treated since April 2001: 10 low anterior resections, 9 pelvic exenterations, 5 transabdominal pelvic tumor resections, 4 abdominoperineal resections, 2 node resections. Mean operative time was 9 hours 51 minutes; mean IORT time was 1 hour 6 minutes. Average length of stay was 11 days. Median disease-free interval after IORT is 34 months. Median survival after IORT has not yet been reached.

Using a mobile accelerator, incorporation of IORT into the multimodality approach to locally-advanced primary and recurrent rectal cancer is feasible. Use of IORT may offer a disease-free survival advantage to select patients with marginally-resectable disease.