Temporal pattern of recurrence of stage i endometrial cancer in relation to histological risk factors

Objective: To study the temporal pattern of endometrial cancer recurrence in relation to histological risk factors in a large multicenter setting. Methods: 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. Results: 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. Conclusions: 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.