Introduction: The benefit of adjuvant chemotherapy for Stage IC grade 1 and stage IA/IB grade 2 endometrioid ovarian adenocarcinoma (EOOC) remains unclear as the NCCN guidelines recommend either observation only or adjuvant chemotherapy. Therefore, we sought to determine whether patients with stage I EOOC had improved overall survival (OS) following receipt of adjuvant chemotherapy.
Methods: Patients with pathological stage I ovarian endometrioid adenocarcinoma diagnosed between 2004 and 2014 were identified from the National Cancer Database. Demographics, pathologic factors including tumor grade, and treatment information including receipt of adjuvant chemotherapy were collected. The impact of chemotherapy on OS was evaluated with Kaplan-Meier curves, and compared with log-rank tests. Multivariate Cox analysis was performed to control for confounders.
Results: A total of 4538 patients were identified and the median age was 55 years The rate of adjuvant chemotherapy use was 50.9%. Higher rates were noted among patients with stage IC and grade 3 tumors. Following stratification by tumor grade, substage and extent of lymphadenectomy, adjuvant chemotherapy was associated with a survival benefit for patients with grade 2 tumors who did not undergo (stage IA/IB: 95.7% vs 83%, p = 0.038; stage IC: 84.5% vs 84.8%, p = 0.39) or had limited lymphadenectomy (stage IA/IB: 96% vs 89.5%, p = 0.03; stage IC: 97.2% vs 83.9%, p = 0.001). A survival difference was also seen for patients with grade 3 tumors who did not undergo lymphadenectomy but did not reach statistical significance.
Conclusion: Adjuvant chemotherapy was associated with an overall survival benefit for patients with inadequately-staged, grade 2 stage I ovarian endometrioid adenocarcinoma. A possible benefit for inadequately-staged patients with grade 3 tumors cannot be excluded.
Keywords: Carcinoma; Chemotherapy; Endometrioid; Ovary.
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