Clinical outcomes of patients with endometrioid epithelial ovarian cancer following surgical treatment

Background Endometrioid epithelial ovarian cancer (EEOC) is rare, and its management poorly defined. We examined factors associated with 5‐year progression‐free survival (PFS) after surgery for EEOC. Methods Retrospective study: treatment and outcomes of all EEOC patients undergoing initial surgery at, or presenting to, our institution within 3 months of initial surgery, 1/2002‐9/2017. Results In total, 212 patients were identified. Median follow‐up, 63.9 months (range, 0.7–192); median age at diagnosis, 52 years (range, 20–88); disease stage: I, n  = 145 (68%); II, n  = 47 (22%); III/IV, n  = 20 (9%); FIGO grade: 1, 127 (60%); 2, 66 (31%); 3, 17 (8%); unknown, 2 (1%). One hundred twenty‐eight (60%) had endometriosis; 75 (35%), synchronous endometrioid endometrial cancer (80%, IA); 101 (48%), complete surgical staging; 8 (5%), positive pelvic lymph nodes (LNs); 6 (4%), positive para‐aortic LNs; 176 (97%), complete gross resection; 123 (60%), postoperative chemotherapy; 56(28%), no additional treatment. Five‐year PFS, 83% (95% confidence interval [CI]: 76.6%–87.8%); 5‐year overall survival (OS), 92.7% (95% CI: 87.7%–95.8%). Age, stage, and surgical staging were associated with improved 5‐year PFS, and younger age at diagnosis with improved 5‐year OS ( p  < 0.001). Chemotherapy did not improve 5‐year PFS in IA/IB versus observation, but improved survival in IC (hazard ratio [HR]: 1.01, 95% CI: 0.22–4.59, p  = 0.99; HR: 0.17, 95% CI: 0.04–0.7, p  = 0.006). Conclusions Age, stage, and full surgical staging were associated with improved 5‐year PFS. Chemotherapy showed no benefit in IA/IB disease.