Intraoperative electron beam radiotherapy (IOERT) in the management of recurrent ovarian malignancies

Objective: To investigate disease control, survival outcomes, and tolerance of intraoperative electron beam radiation therapy (IOERT) as a component of treatment for women with recurrent ovarian malignancies. Methods: From November 1987 to January 2009, 20 patients with recurrent ovarian malignancies received IOERT after maximal surgical cytoreduction. Areas treated included the pelvis (14), para-aortic nodes (6), or inguinal nodes (1). The median IOERT dosewas 12.5 Gy (range, 10-22.5 Gy). Sixteen patients also received perioperative external beam radiotherapy as a component of treatment (median, 50 Gy; range, 20-54.3 Gy). All patients were followed prospectively for outcome and toxicity evaluation. Results: Median follow-up for surviving patients was 76.2 months (range, 1.5-175.8 months). The 5-year Kaplan-Meier estimate of local control was 59%, and central control (within the IOERT field) was 76%. All local relapses occurred in patients who had microscopic margin-positive resections. The 5-year freedom from distant relapse was 37%. The median disease-free interval after IOERTwas 14 months. The median survival was 30 months, and the 5-year Kaplan-Meier estimate of survival was 49%. Six patients (29%) experienced grade 3 or higher toxicities, 2 of which (10%) were at least partly attributable to IOERT. Three patients experienced grade 1 or 2 peripheral neuropathy related to IOERT. Conclusions: Combined modality therapy with external beam radiotherapy, surgery, and IOERT is an option for the treatment of localized recurrent ovarian cancer, with acceptable rates of in-field failure and toxicity. Durable disease control is possible in select women treated with this regimen.