Is tumor size a prognostic factor in lymph node-negative stage 1 endometrioid endometrial cancer recurrence?

Background: To investigate whether tumor size is a prognostic factor in lymph node-negative stage 1 endometrioid-type endometrial cancer recurrence. Methods: A total of 294 patients diagnosed with stage I (FIGO 2009) endometrioid-type endometrial cancer (EEC) were included in the study. The cases were evaluated in terms of age, histologic grade, tumor diameter, myometrial invasion, lymphovascular space invasion (LVSI), adjuvant radiotherapy, overall (OS) and disease-free (DFS) survival time. The data for the cases were analyzed according to median tumor diameter. Results: For the 294 patients, the mean age was 63.7 +/- 10.0 years. Among patients, 65.3% were >= 60 years, 86.1% were stage 1A, 74.1% were grade 1, 1.7% (5 cases) had malignant peritoneal fluid and 8.5% had LVSI positivity. Recurrence was detected in 21 (7.1%) cases and adjuvant radiotherapy was administered to 36.4% of cases. The median DFS was calculated as 36 months (1-167). OS and DFS durations were 155.1 +/- 4.3 and 155.2 +/- 4.2 months, respectively. A statistically significant difference was found between 149 patients with median tumor diameter of <= 35 mm and 145 patients with diameter of >35 mm in terms of >= 50% myometrial invasion, grade 2, LVSI positivity, OS and DFS durations (respectively, p=0.001, p=0.001, p=0.014, p=0.021 and p=0.027). In terms of OS and DFS times, only tumor diameter was found to be a significant factor in Cox regression analysis (p=0.039, OR=5.611 95% CI 1.090-28.880 and p=0.044, OR 5.406 95% CI 1.050-27.838). The rates for OS and DFS at 5 years were calculated as 97.6% and 94.9%, respectively. Conclusions: Median tumor diameter of 35 mm is a prognostic factor in terms of OS and DFS durations in stage 1 endometrioid type endometrial cancer. Myometrial invasion >= 50%, grade 2 and LVSI positivity were significant prognostic factors based on tumor diameter