Improvements to the FIGO staging for ovarian cancer: reconsideration of lymphatic spread and intraoperative tumor rupture

OBJECTIVE: To evaluate the improvement in prognosis prediction with reassignment of International Federation of Gynecology and Obstetrics (FIGO) stages for ovarian carcinoma. METHODS: This was a retrospective study of patients with epithelial ovarian, fallopian tube, and primary peritoneal cancers. Sub-staging criteria used in stage reassignment were defined as follows: surgical spillage (IC1), capsule rupture before surgery or tumor on the surface (IC2), and positive cytology results (IC3); microscopic (IIB1) and macroscopic (IIB2) pelvic spread; microscopic extrapelvic spread (IIIA1) and retroperitoneal lymph node (LN) metastasis without extrapelvic spread (IIIA2); and supraclavicular LN metastasis (IVA) and other distant metastasis (IVB). Survival outcomes associated with the current and reassigned stages were compared. RESULTS: Overall, 870 patients were eligible for analysis. The median follow-up period was 45 months (range, 0 to 263 months). The 5-year overall survival rates (5YSRs) according to the current staging were 93.5% (IA), 82.5% (IC), 75.0% (IIB), 74.5% (IIC), 57.5% (IIIA), 54.0% (IIIB), 38.5% (IIIC), and 33.0% (IV). The 5YSRs of patients with IC1, IC2, and IC3 after sub-staging were 92.0%, 85.0%, and 71.0%, respectively (p=0.004). Patients who were reassigned to stage IIIA2 had a better 5YSR than those with extrapelvic tumors >2 cm (66.3% vs. 35.8%; p=0.005). Additionally, patients with newly assigned stage IVA disease had a significantly better 5YSR than those with stage IVB disease (52.0% vs. 28.0%; p=0.015). CONCLUSION: The modified FIGO staging for ovarian carcinoma appears superior to the current staging for discriminating survival outcomes of patients with surgical spillage, retroperitoneal LN metastasis without extrapelvic peritoneal involvement, or distant metastasis to supraclavicular LNs.