Revisiting the role of radiation treatment for non-serous subtypes of epithelial ovarian cancer.

Except for its palliative use, radiation has been largely abandoned in the management of ovarian cancers because of the recognized efficacy of chemotherapy agents. Whole abdominal irradiation (WAR), however, has been shown to be of adjuvant and curative value in ovarian cancer with microscopic or minimal residual disease in the pelvis, the so-called "intermediate risk group." Recent hypothesis generating data from the use of adjuvant radiation following adjuvant chemotherapy in ovarian cancer has shown an incremental survival benefit for the rarer non-serous ovarian subtypes including clear cell, endometrioid, and mucinous. No incremental benefit was observed for the more common serous subtype. A retrospective examination of early trials using WAR as the sole postoperative treatment in ovarian cancer has determined that the majority of patients in these studies and cured by radiation actually had the non-serous subtypes. The recognition that the non-serous subtypes differ from the serous cancers in their stage of presentation, their molecular characteristics, their response to classic chemotherapy, and their outcomes suggest the non-serous subtypes should be treated as rare and different cancers. In addition to specific targeting therapies that may be developed, radiation should be reconsidered as part of the treatment armamentarium for these diseases.