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 wisdom suggests that reirradiation should be avoided and radical pelvic surgery is hazardous after ultra high-dose radiation. METHODS AND MATERIALS: In a unique Phase I/II pilot study, 32 patients with recurrent rectal cancers following previous pelvic radiation underwent planned reirradiation to the pelvis. Initial radiation doses had ranged from 30-64.87 Gy (median dose 45 Gy). Seventeen patients underwent reirradiation followed by radical resection. Fifteen patients were reirradiated for palliative relief of symptoms. Treatment techniques consisted of two lateral fields (7 x 7 to 12 x 10 cm) encompassing the tumor with 2 cm 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 111.6 Gy.
RESULTS: Treatment was well tolerated. Four patients had radiation interrupted/discontinued for diarrhea or leukopenia. Follow-up ranges from 6 months to 36 months. No late sequelae of radiation have been observed to date. Seventeen patients underwent surgical exploration 6-8 weeks following reirradiation. Two patients had extensive disease and were not resected. Fifteen patients underwent radical resection of residual tumor (4 posterior exenterations, 6 APR, 3 transanal abdominal transanal proctocolectomy with coloanal anastomosis (TAATA), and 2 LAR). No patients died postoperatively. No excessive edema, hemorrhage, or adhesions were observed. Two patients developed pelvic abscess and one developed a coloanal stricture. Eleven of 15 resected patients are alive from 6 to 36 months with a 2-year survival of 66%. Of the patients treated palliatively, symptomatic relief was observed in 13/15 patients. No objective complete response was observed, but 6/15 patients had measurable partial response. Median survival in this group was 14 months.
CONCLUSION: Based on this experience, we believe that in selected patients radical surgical resection after 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.