Objectives The aim of this study was to evaluate the antitumor activity of bevacizumab in low-grade serous ovarian carcinoma (LGSOC).

Methods We retrospectively identified patients with LGSOC treated with bevacizumab.

Results Twelve patients with LGSOC who received bevacizumab were identified. Eleven patients received bevacizumab alone. Only 1 (8.3%) of 12 patients had evidence of a partial response. Ten (90.9%) of the 11 patients were progression free at 6 months. All but 1 patient who received only 2 courses before treatment interruption had a progression-free survival (PFS) of greater than 6 months. The median PFS was 48 months (range, 5–123+ months). Three of the patients reported in this series had extended disease stabilization that lasted for 123+, 48, and 15+ months after progression-free intervals on prior chemotherapy regimens of 2.5, 4, and 7 months, respectively. The median overall survival was not reached at a median follow-up of 32 months, with only 1 of the 12 patients dying of disease.

Conclusions In our series, in patients with LGSOC treated primarily with bevacizumab, primarily as a single agent, a low response rate but very long PFS is observed. In addition, patients have had secondary PFS durations that exceeded their prior PFS, which is a sign of anticancer activity.