- To study the temporal pattern of endometrial cancer recurrence in relation to histological risk factors in a large multicenter setting. 843 patients with apparent stage I endometrial cancer were followed for a median time of 38 months, documenting all recurrences. Patients were stratified as high risk based on the presence of at least one of the established histological risk factors: high tumor grade, penetration to the outer half of the myometrium, lymphvascular space involvement, lower uterine segment involvement and non endometroid histology. Survival analysis, including Kaplan-Meier curves, log-rank tests and multi-variate Cox proportional hazard regression were used to evaluate the equality of recurrence-free distributions for different levels of risk. Recurrence was documented in 66 cases. The presence of one or more of the histological risk factors was associated with significantly shorter recurrence free survival, not attenuating over time (p < 0.001). Age-adjusted Cox regression model demonstrated a significantly decreased recurrence-free survival (HR = 2.8 95% CI 1.5, 5.1) in the presence of risk factors. In patients with stage I endometrial cancer, the presence of histological risk factors is associated with a significantly higher recurrence rate, which does not attenuate over follow up time. This may allow for a selective approach in the follow- up of endometrial cancer patients.