Feasibility and Early Results of Interstitial Intensity-Modulated HDR/PDR Brachytherapy (IMBT) with/without Complementary External-Beam Radiotherapy and Extended Surgery in Recurrent Pelvic Colorectal Cancer

BACKGROUND: A new multimodality treatment concept consisting of extended resection and postoperative fractionated intensity-modulated interstitial brachytherapy (IMBT) was introduced for pelvic recurrence of colorectal carcinoma. PATIENTS AND METHODS: 46 patients received extended resection and single plastic tubes were sutured directly onto the tumor bed. IMBT was started within 2 weeks postoperatively with a median dose of 24.5 Gy (5-35 Gy). Patients were treated either with high-dose-rate brachytherapy (HDR; n = 23) or with pulsed-dose-rate brachytherapy (PDR; n = 23). 25 patients received complementary 45-Gy external-beam irradiation (EBRT) to the pelvic region after explanting the plastic tubes. RESULTS: Median follow-up was 20.6 months (7-107 months) and mean patient survival 25.7 +/- 25.8 months (median 17, range 1-107 months). After 5 years overall survival, disease-free survival and local control rate were 23%, 20% and 33%, significantly influenced by the resectional state. There was a trend in favor of PDR compared to HDR, which reached statistical significance in patients who had not received additional EBRT. CONCLUSION: The combination of extended surgery and postoperative interstitial IMBT is feasible and offers effective interdisciplinary treatment of recurrent colorectal cancer. In this small and inhomogeneous cohort of patients PDR seems to be more effective than HDR, particularly when application of complementary EBRT is not possible. None of the patients who required resection of distant metastasis survived > 2 years in this study.