Comparison of intraoperative radiation therapy-containing multimodality treatment with historical treatment modalities for locally recurrent rectal cancer

PURPOSE: Treatment protocols for patients with locally recurrent rectal cancer have changed in the last two decades. Subsequently, treatment goals shifted from palliation to possible cure. In this retrospective study, we explored the treatment variables that may have contributed to the improvement in outcome by comparing three treatment modalities from two collaborating institutions in patients with similar tumor characteristics. METHODS: Ninety-four patients were treated with electron-beam radiation therapy only (1975-1990), 19 with combined preoperative electron-beam radiation therapy and surgery (1989-1996). and 33 with intraoperative radiation therapy-multimodality treatment (1994-1999). Intraoperative radiation therapy was delivered either as intraoperative electron-beam radiotherapy (10-17.5 Gy) in 20 patients or as intraoperative high-dose-rate brachytherapy (10 Gy) in 13 patients. No patient had received prior electron-beam radiation therapy. RESULTS: The three-year survival, disease-free survival, and local control rates were 14, 8, and 10 percent, respectively, in the electron-beam radiation therapy-only group and 11, 0, and 14 percent, respectively, in the combined electron-beam radiation therapy-surgery group. The overall intraoperative radiation therapy-multimodality treatment group showed significantly better three-year survival, disease-free survival, and local control rates of 60, 43, and 73 percent, respectively, compared with the historical control groups (P < 0.001). CONCLUSION: The outcome of patients with locally recurrent rectal cancer was improved after the introduction of intraoperative radiation therapy-multimodality treatment.