TWICE-DAILY, SPLIT-COURSE ABDOMINOPELVIC RADIATION-THERAPY AFTER CHEMOTHERAPY AND POSITIVE 2ND-LOOK LAPAROTOMY FOR EPITHELIAL OVARIAN-CARCINOMA

Between July 1983 and December 1988, 34 patients with ovarian carcinoma received whole abdominal irradiation in an attempt to eliminate residual disease following second-look laparotomy. Three additional patients who had initial complete responses to chemotherapy were treated for a recurrence of their disease. All patients had been treated with chemotherapy that included cisplatin and cyclophosphamide. Three patients had also received doxorubicin with some or all chemotherapy cycles. Thirty Gray of abdominopelvic radiation therapy (APRT) was delivered using a twice-daily, split-course schedule. Eleven patients also had a boost of 9-20 Gy to sites of residual disease. Treatment was well tolerated. Only one patient did not complete therapy and two patients had 1-week prolongations of treatment because of hematologic toxicity. Thirty-two percent of patients had grade 2 neoplasms and 61% had grade 3 disease. Three patients with grade 1 tumors continue to have no evidence of disease 20-50 months after irradiation. Patients with grade 2 and 3 neoplasms who had microscopic residual disease prior to APRT had relapse-free survival rates at 3-years of 10% and 14%, respectively. Twelve patients with gross residual disease had rapid recurrences (median time to relapse, 4.9 months) and all have died of their disease. Although 14 patients (38%) have experienced small bowel obstructions, all of these had known recurrent abdominal disease at the time. Twenty patients (54%) had undergone more than two abdominal surgeries prior to APRT, and several were noted to have extensive adhesions at second-look laparotomy. None of the five patients currently believed to be free of disease has experienced a small bowel obstruction. Radiation is only one of several factors that contributed to bowel obstructions. Although APRT may be able to eliminate residual disease in a small proportion of patients with microscopic residual disease after chemotherapy, the aggressive biology of tumors that respond incompletely to chemotherapy and the compromises in radiation dose and schedule that must be made in these heavily treated patients probably contribute to the disappointing results of this treatment.