Tumor size is an independent predictor of lymph node metastasis and survival in early stage endometrioid endometrial cancer

Objective(s) To analyze the impact of tumor size (TS) on risk of lymph node metastasis (PLN) and prognosis in endometrioid endometrial cancer grossly confined to the uterus (EEC). Method(s) Patients with EEC grossly confined to the uterus were identified from Surveillance, Epidemiology, and End Results dataset from 1988 to 2007. Only surgically treated patients were included. TS was analyzed as a continuous and categorical variable (TS ≤ 2 cm, >2–5 cm and >5 cm). Multivariable logistic regression and Cox proportional hazards models were used. Result(s) 19,692 patients met the inclusion criteria. In patients with TS ≤ 2 cm, only 2.7 % (88/3,244) had PLN; this increased to 5.8 % (372/6,355) with TS > 2–5 cm and 11.1 % (195/1,745) with TS > 5 cm. The odds of PLN increased by 14 % for each 1 cm increase in TS after controlling for age, race, depth of myometrial invasion and grade (HR 1.14, 95 % CI 1.10–1.19, p < 0.001). Further, TS was an independent predictor of disease-specific survival (DSS) even after adjusting for age, race, grade, depth of myometrial invasion, lymph node status and adjuvant radiation therapy (HR 1.13 for each 1 cm increment in TS, 95 % 1.08–1.18, p < 0.001). In multivariable analysis, larger TS (>5 cm) was significantly associated with worse DSS (HR 2.09, 95 % 1.31–3.35, p = 0.002); however, there was no significant difference between TS > 2–5 cm versus ≤2 cm (HR 1.25, 95 % 0.85–1.83, p = 0.25). The impact of TS remained significant on DSS in subset of patients who underwent lymphadenectomy with negative lymph nodes. Conclusion(s) TS was an independent predictor of lymph node metastasis and disease-specific survival in patients with EEC grossly confined to the uterus. Tumor >5 cm was a predictor of disease-specific survival but no difference in outcome was noted between tumor >2–5 cm and tumor ≤2 cm.