10,700 patients (305 patients < 40 years of age) diagnosed between 1988 and 2007 with EC from the Metropolitan Detroit Cancer Surveillance System (MDCSS), and 884 patients (42 patients < 40 years of age) diagnosed between 1996 and 2008 with EC from our institutional database were identified. Differences in clinical and demographic variables by age (< 40 vs. ?#xA0;40) were assessed for statistical significance by chi-square tests. Cox proportional hazards models were used to calculate adjusted hazard ratios (HR) and their 95 % confidence intervals (95 % CI) to assess the risk of death from all causes.
MDCSS based analysis: Patients < 40 were more likely to present with low grade tumors (p < 0.0001) and endometroid histology (p = 0.0004) but less likely to undergo surgery (p = 0.0007) or radiotherapy (p = 0.0007). A multivariate analysis confirmed the significance of age, grade, and stage in all patients, and that of histologic type, surgery, and race in patients ?#xA0;40 as independent prognostic factors for overall survival. Institution based analysis: Patients < 40 had a higher proportion of patients with BMI ?#xA0;30 (p = 0.04), and presented with a higher frequency of well differentiated (p = 0.04) endometrioid tumors (p = 0.004) that are less prone to have deep myometrial invasion (p = 0.008).
This study supports the hypothesis of a disease that is biologically and genetically heterogeneous among women of different ages and ethnicities.