Outcome and prognostic factors of low‑grade serous ovarian cancer: An observational retrospective study

Low-grade serous ovarian cancer (LGSOC) is a very rare histological subtype of serous ovarian cancer, representing ~2% of all epithelial ovarian cancer cases. LGSOC has a better prognosis but a lower response rate to chemotherapy in comparison to high-grade serous ovarian carcinoma (HGSOC). The present study is a retrospective review of the medical records of all patients with histologically proven LGSOC diagnosed and treated in a single institute between January 2003 and December 2019. A total of 23 patients diagnosed with LGSOC and treated at King Faisal Specialist Hospital and Research Center (Riyadh, Saudi Arabia) were identified. The median age at diagnosis was 45.5 years (range, 26-66 years) and the median body mass index was 26.1 (range, 18-43). A total of 21 patients (91.3%) had de novo LGSOC, whereas only 2 patients (8.7%) had LGSOC that had transformed from serous borderline ovarian tumors and recurred. A total of 8 patients (34.8%) were diagnosed with International Federation of Gynecology and Obstetrics stage IV, whereas 3 (13.0%), 3 (13.0%) and 9 (39.1%) were diagnosed with stages I, II and III, respectively. In addition, 10 (43.5%), 5 (21.7%), and 3 (13.0%) patients had complete response, stable disease and partial response statuses after first-line therapy, respectively. At a median follow-up time of 34 months [95% confidence interval (CI), 25.32-42.69], the median progression-free survival (PFS) time was 75.2 months (95% CI, 17.35-133.05) and the median overall survival (OS) time was not reached. In conclusion, LGSOC exhibited better PFS and OS times than HGSOC as compared with data from the literature, and there is the option for systemic treatment (chemotherapy or hormonal therapy). Optimal cytoreduction showed numerically higher, but non-significant, PFS and OS times compared with suboptimal debulking; however, the optimal systemic chemotherapy or hormonal treatment remains controversial.