Recurrent ovarian cancer. Effective radiotherapeutic palliation after chemotherapy failure

Recurrent ovarian cancer after frontline chemotherapy is incurable; however, palliation of focal lesions often is needed to alleviate symptoms. Because published response rates to palliative irradiation (RT) among patients failing cisplatin-based chemotherapy are scarce, the authors attempted to define the palliative role of radiotherapy for symptomatic, localized ovarian cancer recurrences. Factors predicting a response to RT also were sought.

Between 1987 and 1993, 33 patients with ovarian cancer were irradiated at 47 sites with palliative intent after failing cisplatin-based chemotherapy regimens. Sites irradiated included the pelvis (n = 33), abdomen (n = 5), chest (n = 4), brain (n = 3), and other (n = 2). Median RT dose was 35 Gy (range: 7.5-45 Gy). The median fraction size was 2.5 Gy (range, 1-5 Gy). To determine dose effectiveness, the biologic effective dose (BED) was calculated according to the following formula: BED = total dose (1 + fractional dose/alpha/beta) using an alpha/beta value of 10. The median BED10 was 44 (range, 9-72).

For the entire group, complete palliative response was 51% and overall palliative response was 79%. The median duration of palliation was 4 months, which reflected palliation until death in 90% of cases. The overall response rates by symptoms were: pulmonary symptom relief in 75%, vaginal bleeding control in 90%, rectal bleeding control in 85%, pain relief in 83%, and neurologic symptoms controlled in 50%. The likelihood of obtaining complete symptomatic response was significantly increased among those with high Karnofsky performance status (KPS > or = 70 vs. KPS < 70; 69% vs. 36%, P < 0.03) and among those who received a higher biologically effective dose of irradiation (BED10 > or = 44 vs. BED10 < 44; 68% vs 35%, P < 0.03). Complete palliative response rates were not influenced by histologic differentiation, the number of previously administered cisplatin regimens, or patient age. Treatment-related acute morbidities included diarrhea in 5 of 38 (13%) patients treated through abdominal or pelvic fields, and esophagitis in 2 of 5 treated through thoracic portals. Only one severe late morbidity (small bowel obstruction) was observed.

Durable palliation of patients with ovarian cancer that recurs after cisplatin-based chemotherapy can be achieved with local radiotherapy, especially among patients with high performance status. Biologically effective doses of at least 44 Gy10 (e.g., 3500 cGy/14 fractions = BED10 of 44) should be sought to maximize the probability of complete response. Such dose-fractionation schedules can be delivered expeditiously with acceptable tolerance. These results are comparable to the published experience of second-line chemotherapy in the treatment of focally symptomatic ovarian cancer recurrences.