University of North Carolina at Chapel Hill Graduate School
Doi
Abstract
Background. National guidelines recommend that the benefits and risks associated with adjuvant radiation therapy (RT) for older cancer patients should be assessed carefully, evaluating the impact on life expectancy and quality of life. We used the Surveillance Epidemiology and End Results and the Medicare Health Outcomes Survey (SEER-MHOS) and the SEER-Medicare linkages to examine health-related quality of life (HRQOL) and mortality outcomes, as well as non-cancer factors associated with adjuvant RT for older women with early-stage EC Methods. In aim 1, we identified 1,140 women (aged≥65 years) diagnosed with first primary stage I-II EC who underwent hysterectomy and completed a survey ≥1-year post-diagnosis in the SEER-MHOS linkage (1998-2017). HRQOL T-scores were compared across treatment groups: hysterectomy alone, adjuvant external beam radiation therapy (EBRT), adjuvant vaginal brachytherapy (VBT), or adjuvant VBT+EBRT. In aim 2, we identified 25,654 women (aged ≥66 years) diagnosed with first primary stage I-II EC who underwent hysterectomy in the SEER-Medicare linkage (2004-2017). The prevalence of adjuvant RT associated with patient characteristics and health system factors were estimated. In aim 3, a subset of 19,880 women diagnosed with the disease during 2004-2016 were identified from the aim 2 cohort. All-cause- and EC-specific mortality risks were compared across the treatment groups.Results. Aim 1: Adjuvant VBT was associated with better general health on the HRQOL subscale measure (mean difference, 3.59; 95% CI, 0.56–6.62) vs hysterectomy alone. Aim 2: Adjuvant RT was less commonly administered to Asian Americans and Pacific Islanders than non-Hispanic Whites, residing in rural or high neighborhood-poverty counties. Adjuvant RT was more commonly administered to women treated by a gynecologic oncologist at larger academic hospitals. Aim 3: Adjuvant VBT was associated with reduced all-cause mortality (Hazard Ratio [HR], 0.84; 95% CI, 0.77–0.93) and EC-specific mortality (HR, 0.69; 95% CI, 0.54–0.88) vs hysterectomy alone. Conclusions. VBT may be considered as the possible adjuvant treatment of choice for older women with early-stage EC, given the favorable HRQOL and mortality outcomes. Our analyses also suggest that various non-cancer factors may affect the delivery of RT in real-world oncology practice.Doctor of Philosoph
