HIGH-DOSE-RATE INTRAOPERATIVE RADIATION-THERAPY (HDR-IORT) AS PART OFTHE MANAGEMENT STRATEGY FOR LOCALLY ADVANCED PRIMARY AND RECURRENT RECTAL-CANCER

Purpose: Primary unresectable and locally advanced recurrent rectal ca ncer presents a significant clinical challenge. Local failure rates ar e high in both situations. Under such circumstances, there is a signif icant need to safely deliver tumoricidal doses of radiation in an atte mpt to improve local control. For this reason, we have incorporated a new approach utilizing high dose rate intraoperative radiation therapy (HDR-IORT). Methods and Materials: Between 11/92-12/96, a total of 11 2 patients were explored, of which 68 patients were treated with HDR-I ORT, and 66 are evaluable. The majority of the 44 patients were exclud ed for unresectable disease or for distant metastases which eluded pre operative imaging. There were 22 patients with primary unresectable di sease, and 46 patients who presented with recurrent disease. The histo logy was adenocarcinoma in 64 patients, and squamous cell carcinoma in four patients. In general, the patients with primary unresectable dis ease received preoperative chemotherapy with 5-fluorouracil (5-FU) and leucovorin, and external beam irradiation to 4500-5040 cGy, followed by surgical resection and HDR-IORT (1000-2000 cGy). In general, the pa tients with recurrent disease were treated with surgical resection and HDR-IORT (1000-2000 cGy) alone. All surgical procedures were done in a dedicated operating room in the brachytherapy suite, so that HDR-IOR T could be delivered using the Harrison-Anderson-Mick (HAM) applicator . The median follow-up is 17.5 months (1-48 mo). Results: In primary c ases, the actuarial 2-year local control is 81%. For patients with neg ative margins, the local control was 92% vs. 38% for those with positi ve margins (p = 0.002). The 2-year actuarial disease-free survival was 69%; 77% for patients with negative margins vs. 38% for patients with positive margins (p = 0.03). For patients with recurrent disease, the 2-year actuarial local control rate was 63%. For patients with negati ve margins, it was 82%, while it was 19% for those with positive margi ns (p = 0.02). The disease-free survival was 47% (71% for negative mar gins and 0% for positive margins) (p = 0.04). Prospective data gatheri ng indicated that significant complications occurred in approximately 38% of patients and were multifactorial in nature, and manageable to c omplete recovery. Conclusion: HDR-IORT using our technique is versatil e, safe, and effective. The local control rates for primary disease co mpare quite well with other published series, especially for patients with negative margins. For patients with recurrent disease, locoregion al control and survival are especially encouraging in patients with ne gative resection margins. Further follow-up is needed to see whether t hese encouraging data will continue. (C) 1998 Elsevier Science Inc.