Radiation therapy for unresectable rectal cancer

Abstract

The standard approach to patients with unresectable rectal cancer is pre-op radiation therapy followed by surgery. To determine the impact of RT on local failure and survival, we present an analysis of our preliminary results of this approach in patients with unresectable rectal cancer. A total of 22 patients were analyzed (9 primary, 13 recurrent). The median follow-up was 22 months. There were two groups of patients. Group 1 included 12 patients with unresectable tumors in whom surgery was planned following pre-operative radiation therapy. Group 2 included 10 patients in whom no surgery was planned following radiation therapy due to extensive pelvic bone destruction. The whole pelvis received 4680 cGy followed by a boost of 360-1440 cGy. Six underwent brachytherapy. For the total patient group, the 3-year actuarial survival was 52% (Group 1: 91% vs Group 2: 30%). Patterns of failure as a component of failure were: local failure (or local progression): 50%, abdominal: 23%, and distant: 9%. The dose of pelvic radiation had no significant impact on the local failure rate (5040 cGy: 55% vs greater than 5700 cGy:45%). None of the seven patients with negative margins developed local failure compared with 73% of those with positive margins. The complete resection rate in Group 1 patients was 58%, and all are alive without local failure. Further follow-up will be needed to determine the ultimate local failure and survival rates.