Intraoperative irradiation for locally recurrent colorectal cancer in previously irradiated patients.

PURPOSE: Information in the literature regarding salvage treatment for patients with locally recurrent colorectal cancer who have previously been treated with high or moderate dose external beam irradiation (EBRT) is scarce. A retrospective review was therefore performed in our institution to determine disease control, survival, and tolerance in patients treated aggressively with surgical resection and intraoperative electron irradiation (IOERT) +/- additional EBRT and chemotherapy. METHODS AND MATERIALS: From 1981 through 1994, 51 previously irradiated patients with recurrent locally advanced colorectal cancer without evidence of distant metastatic disease were treated at Mayo Clinic Rochester with surgical resection and IOERT +/- additional EBRT. An attempt was made to achieve a gross total resection before IOERT if it could be safely accomplished. The median IOERT dose was 20 Gy (range, 10--30 Gy). Thirty-seven patients received additional EBRT either pre- or postoperatively with doses ranging from 5 to 50.4 Gy (median 25.2 Gy). Twenty patients received 5-fluorouracil +/- leucovorin during EBRT. Three patients received additional cycles of 5-fluorouracil +/- leucovorin as maintenance chemotherapy.
RESULTS: Thirty males and 21 females with a median age of 55 years (range 31--73 years) were treated. Thirty-four patients have died; the median follow-up in surviving patients is 21 months. The median, 2-yr, and 5-yr actuarial overall survivals are 23 months, 48% and 12%, respectively. The 2-yr actuarial central control (within IOERT field) is 72%. Local control at 2 years has been maintained in 60% of patients. There is a trend toward improved local control in patients who received > or =30 Gy EBRT in addition to IOERT as compared to those who received no EBRT or <30 Gy with 2-yr local control rates of 81% vs. 54%. Distant metastatic disease has developed in 25 patients, and the actuarial rate of distant progression at 2 and 4 years is 56% and 76%, respectively. Peripheral neuropathy was the main IOERT-related toxicity; 16 (32%) patients developed neuropathies (7 mild, 5 moderate, 4 severe). Ureteral narrowing or obstruction occurred in seven patients. All but one patient with neuropathy or ureter fibrosis received IOERT doses > or =20 Gy.
CONCLUSION: Long-term local control can be obtained in a substantial proportion of patients with aggressive combined modality therapy, but long-term survival is poor due to the high rate of distant metastasis. Re-irradiation with EBRT in addition to IOERT appears to improve local control. Strategies to improve survival in these poor-risk patients may include the more routine use of conventional systemic chemotherapy or the addition of novel systemic therapies.