Objectives Endometrial cancer presents well-defined risk factors such as depth of myometrial invasion, histological subtype, tumour differentiation grade and lymphovascular space invasion (LVSI). The aim of this study was to investigate other clinical-pathological factors that might influence the recurrence of patients diagnosed with low and intermediate risk endometrial cancer.

Methods Case-control study from a cohort retrospective of 196 patients diagnosed with low and intermediate risk endometrial cancer at a single institution between 2009 and 2014 was conducted. Medical records were reviewed to compare clinical (race, smoking, menopause, body mass index (BMI)) and pathological (histological subtype (endometrioid vs endometrioid with squamous differentiation), tumour differentiation grade, tumour localization, endocervical invasion, LVSI) carachteristics into patients with recurrence (case) and without recurrence (control) of disease. Three controls for each patient case was matched for age and staging.

Results Twenty-one patients with recurrence was found (10.7%), of which 14 were stage IA and 7 were stage IB. We selected 63 patients without recurrence (controls). There were no significant differences in any clinical carachteristic between case and control patients. Among pathological variables, presence of squamous differentiation (28.6% vs. 4.8%, p=0.007), tumour differentiation grade 2 or 3 (57.1% vs. 30.2%, p=0.037) and presence of endocervical invasion (28.6% vs. 12.7%, p=0.103) were associated with disease recurrence from univariate analysis. On multivariable analysis, only squamous differentiation was a significant risk factor for recurrence (p=0.031).

Conclusions Our data suggest that squamous differentiation may be a poor prognostic factor in patients with low and intermediate-risk endometrial carcinoma, had a 5.6 fold increased risk for recurrence.