Generating evidence on the use, effectiveness, and safety of new cancer therapies is a priority for researchers, health care providers, payers, and regulators given the rapid pace of change in cancer diagnosis and treatments. The use of realworld data (RWD) is integral to understanding the utilization patterns and outcomes of these new treatments among patients with cancer who are treated in clinical practice and community settings. An initial step in the use of RWD is careful study design to assess the suitability of an RWD source. This pivotal process can be guided by using a conceptual model that encourages predesign conceptualization. The primary types of RWD included are electronic health records, administrative claims data, cancer registries, and specialty data providers and networks. Careful consideration of each data type is necessary because they are collected for a specific purpose, capturing a set of data elements within a certain population for that purpose, and they vary by population coverage and longitudinality. In this review, the authors provide a highlevel assessment of the strengths and limitations of each data category to inform data source selection appropriate to the study question. Overall, the development and accessibility of RWD sources for cancer research are rapidly increasing, and the use of these data requires careful consideration of composition and utility to assess important questions in understanding the use and effectiveness of new therapies.

Background The population of 17 million cancer survivors in the US is projected to steadily increase by 29% in 2029. With advancing age, cancer incidence increases; therefore, the increase of cancer survivors aged 65 and older is expected to place undue burden on the healthcare system. Older cancer patients have higher prevalence of comorbid conditions, which contributes to a higher overall illness burden compared to younger cancer patients and may require complex medication management during cancer treatment. Cancer patients with multiple comorbid conditions report lower health-related quality of life (HRQOL). Women with breast cancer (BC) experience noticeable comorbidity prevalence rates (30%) that can negatively influence HRQOL and increase breast cancer mortality by 20-50%. The causes of HRQOL deficits are likely multifactorial, including demographic and clinical factors which require further investigation. Furthermore, research examining the relationship between medication management, comorbidities, and HRQOL in cancer patients, including stratifying the potential role of obesity that contributes to changes in HRQOL, is limited. Further research addressing the medication management of comorbid conditions can improve understanding of HRQOL in BC patients. Objectives To investigate the association of the medication management of hypertension, diabetes, and respiratory conditions on BC survivor's HRQOL. The secondary objective is to evaluate the role of obesity in medication management for these conditions and resultant changes in HRQOL. Methods Patients diagnosed with Stage I-IV BC between 2007-2016 were identified from the Surveillance Epidemiology and End Results (SEER) and Medicare Health Outcomes Survey (MHOS; SEER-MHOS) data resource. Descriptive statistics and multivariate models, including demographics, clinical characteristics, and Medicare Part D claims, was used to evaluate medication management and potential underlying associations. HRQOL was assessed using the VR-12. Obesity was calculated from self-reported height and weight at the time of survey. Results The study population for this analysis includes 1,016 breast cancer patients diagnosed between 2007-2016 in the SEER-MHOS dataset with continuous Part D coverage one year before and after diagnosis. Among these patients, 85% reported at least one comorbid condition. Further analysis is in progress. Conclusions Understanding the potential aspects of treatment that influence HRQOL can provide further insights into patient-reported experiences and may improve standards of care to support older BC survivors with chronic comorbid conditions. Citation Format: Melissa A. Bruno, Roxanne Jensen, Catherine Wang, Dannielle Kelley, Erin Kent, Donna R. Rivera. Examining the relationship between medication utilization and health-related quality of life (HRQOL) among breast cancer patients with comorbidities: A Surveillance Epidemiology and End Results and Medicare Health Outcomes Survey (SEER-MHOS) analysis [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5756.