Recurrent Low-grade Serous Ovarian Carcinoma is Relatively Chemoresistant

Purpose: Previous studies have suggested that low-grade serous ovarian carcinoma is more chemoresistant to first-line or neoadjuvant chemotherapy than high-grade serous carcinoma. The purpose of this study was to further characterize this chemoresistance in recurrent low-grade serous ovarian carcinoma.

Methods: From a 1990-2007 search of the departmental databases at our institution, we identified recurrent low-grade serous ovarian carcinoma patients; abstracted chemotherapy response information from the medical records of those whose disease was: 1) histologically-confirmed, 2) measurable or evaluable, and 3) treated with chemotherapy; and retrospectively reviewed these data. Response was determined based on modified RECIST. Time to progression and overall survival were also calculated.

Results: We identified 58 evaluable patients with recurrent low-grade serous ovarian carcinoma who received 108 separate chemotherapy regimens ("patient-regimens"), which produced 4 responses-(1 complete and 3 partial; overall response rate, 3.7%). The overall response rate for the platinum-sensitive cohort was 4.9%, and for the platinum-resistant cohort, 2.1%. Stable disease was observed in 65 (60.2%) of 108 patient-regimens. Median overall survival was 87.1 months. The median time to progression was 29.0 weeks (34.7, platinum-sensitive cohort; 26.4, platinum-resistant cohort) (P=0.32).

Conclusions: Compared with high-grade ovarian cancers, recurrent low-grade serous ovarian carcinoma appears relatively chemoresistant. Whether the latter's high rate of stable disease owes more to the tumor's biology or the influence of chemotherapy remains unclear. Based on these findings, phase II trials of novel targeted agents in recurrent low-grade serous ovarian carcinoma are warranted.