REIRRADIATION FOR RECTAL-CANCER AND SURGICAL RESECTION AFTER ULTRA-HIGH DOSES

Purpose: Local recurrence of rectal cancer following high-dose pelvic radiation presents a difficult management challenge. Conventional wisd om suggests that reirradiation should be avoided and radical pelvic su rgery is hazardous after ultra high-dose radiation. Methods and Materi als: In a unique Phase I/II pilot study, 32 patients with recurrent re ctal cancers following previous pelvic radiation underwent planned rei rradiation to the pelvis. Initial radiation doses had ranged from 30-6 4. 87 Gy (median dose 45 Gy). Seventeen patients underwent reirradiati on followed by radical resection. Fifteen patients were reirradiated f or palliative relief of symptoms. Treatment techniques consisted of tw o lateral fields (7 X 7 to 12 X 10 cm) encompassing the tumor with 2 c m margins. Reirradiation doses ranged from 19.80-47.66 Gy, (median 34. 2 Gy). Patients also received concurrent low-dose continuous infusion chemotherapy, (5-FU 200-300 mg/day). Total cumulative radiation doses ranged from 70.6 to 11 1.6 Gy. Results: Treatment was well tolerated. Four patients had radiation interrupted/discontinued for diarrhea or l eukopenia. Follow-up ranges from 6 months to 36 months. No late sequel ae of radiation have been observed to date. Seventeen patients underwe nt surgical exploration 6-8 weeks following reirradiation. Two patient s had extensive disease and were not resected. Fifteen patients underw ent radical resection of residual tumor (4 posterior exenterations, 6 APR, 3 transanal abdominal transanal proctocolectomy with coloanal ana stomosis (TAATA), and 2 LAR). No patients died postoperatively. No exc essive edema, hemorrhage, or adhesions were observed. Two patients dev eloped pelvic abscess and one developed a coloanal stricture. Eleven o f 15 resected patients are alive from 6 to 36 months with a 2-year sur vival of 66%. Of the patients treated palliatively, symptomatic relief was observed in 13/15 patients. No objective complete response was ob served, but 6/15 patients had measurable partial response. Median surv ival in this group was 14 months. Conclusion: Based on this experience , we believe that in selected patients radical surgical resection afte r cumulative ultra high doses (70-90 Gy) of radiation can be performed safely. A viable anastomosis is also possible in spite of these high doses. Planned reirradiation for palliative relief of symptoms can be effective without unusual risks of complication. Long-term effects of such ultra high dose radiation and surgery continue to be monitored.