Impact of lymph node ratio on survival in stage IIIC endometrioid endometrial cancer: a Turkish Gynecologic Oncology Group study

OBJECTIVE: The purpose of this study was to investigate the prognostic value of lymph node ratio (LNR) in women with stage IIIC endometrioid endometrial cancer (EC). METHODS: A multicenter, retrospective department database review was performed to identify patients with stage IIIC pure endometrioid EC at 6 gynecologic oncology centers in Turkey. A total of 207 women were included. LNR, defined as the percentage of positive lymph nodes (LNs) to total nodes recovered, was stratified into 2 groups: LNR1 (≤0.15), and LNR2 (>0.15). Kaplan-Meier method was used to generate survival data. Factors predictive of outcome were analyzed using Cox proportional hazards models. RESULTS: One hundred and one (48.8%) were classified as stage IIIC1 and 106 (51.2%) as stage IIIC2. The median age at diagnosis was 58 (range, 30-82) and the median duration of follow-up was 40 months (range, 1-228 months). There were 167 (80.7%) women with LNR ≤0.15, and 40 (19.3%) women with LNR >0.15. The 5-year progression-free survival (PFS) rates for LNR ≤0.15 and LNR >0.15 were 76.1%, and 58.5%, respectively (p=0.045). An increased LNR was associated with a decrease in 5-year overall survival (OS) from 87.0% for LNR ≤0.15 to 62.3% for LNR >0.15 (p=0.005). LNR >0.15 was found to be an independent prognostic factor for both PFS (hazard ratio [HR]=2.05; 95% confidence interval [CI]=1.07-3.93; p=0.03) and OS (HR=3.35; 95% CI=1.57-7.19; p=0.002). CONCLUSION: LNR seems to be an independent prognostic factor for decreased PFS and OS in stage IIIC pure endometrioid EC.