Risk-adjusted outcomes in elderly endometrial cancer patients: implications of the contrasting impact of age on progression-free and cause-specific survival

Objective: To reexamine the tenet that advanced age independently impacts progression-free and cause-specific survival in patients with endometrial cancer (EC).

Methods: Patients undergoing surgery for stages I-IIIC EC between 1999 and 2008 were stratified by age (<70 vs ≥70years). Three propensity score (PS) methods were utilized to adjust for confounding risk factors. The PS, or conditional probability of being ≥70years old, given a patient's baseline covariates, was derived using logistic regression. The Cox proportional hazards models were fit to estimate the effect of age≥70years on outcomes.

Results: Of 1182 eligible patients, 822 (69.5%) were <70 and 360 (30.5%) were ≥70. Patients ≥70 were more likely to have multiple adverse risk factors. The total standardized difference of these factors was reduced by 74% and 81%, respectively, using PS-stratification and PS-matching analyses. The nonsignificant trend toward an association between progression-free survival and age≥70 in an unadjusted analysis (hazard ratio [HR], 1.40; 95% CI, 0.95-2.04) was further attenuated in the 3 PS analyses. The unadjusted HR for the association between age≥70 and cause-specific survival was 2.03 (95% CI, 1.32-3.13). HRs were attenuated in PS analyses but retained significance (except for PS matching), potentially reflecting differences in salvage therapies (P<.001), including a 3-fold greater use of chemotherapy in those <70.

Conclusion: When risk-adjusted for the higher prevalence of adverse prognostic factors in elderly EC patients, progression-free survival after primary therapy is not age dependent but the less favorable cause-specific survival in this cohort may reflect age-related postrecurrence treatment differences.