Cancer treatment among the elderly in the United States: Examining the interplay of race/ethnicity and comorbidities.

Abstract

e18547 Background: As the life expectancy of Americans continues to increase, so does the number of individuals who are diagnosed with cancer and other comorbidities. Management of these patients can become increasingly complicated as physicians administer multiple combinations of interventions and drug therapies. To further complicate this issue, the average number of comorbidities among racial/ethnic minority patients is higher than non-Hispanic (NH) white patients, and this disparity could adversely affect receipt of curative cancer treatment among these minority groups. Therefore, we explored the association between race/ethnicity, comorbidities, and curative cancer treatment among elderly Americans diagnosed with the four most common cancer types. Methods: SEER-Medicare linked data was used to identify 727,136 individuals over 65 years old diagnosed with breast, colorectal, lung, or prostate cancer from 1992-2011. Comorbidity burden was measured using the Charlson Comorbidity Index (CCI) and analyzed as tertiles (T1: lowest CCI score to T3: highest CCI score). Treatment with curative intent was defined as receipt of any cancer-type-specific surgery, chemotherapy, radiation, hormone, or immune therapy within 6 months of cancer diagnosis. Modified Poisson regression models were used to assess the joint association between comorbidities and race/ethnicity on cancer treatment. Results: For all cancers, the percentage of patients receiving treatment declined rapidly with increasing age, CCI scores, number of comorbidities, and advanced cancer stage. In addition, variability in receipt of treatment by race/ethnicity was observed: 76% for NH-White patients, 75% for Hispanic patients, and 68% for NH-Black patients. Taking into account age, genders (for colorectal, lung cancer), year of diagnosis, stage at diagnosis, and socioeconomic status, we found that treatment proportions among NH-Black and Hispanic patients with low CCI score (T1) were 2%-15% lower than NH-White patients with the same CCI score (all p < 0.001). Although treatment proportions decreased with increasing CCI among NH White patients (ranging from 2.5-11.3%; p < 0.01), there was little difference in treatment by CCI among NH Black and Hispanic patients (ranging from 0.5%-2%; p > 0.05). Conclusions: Our findings suggested that racial disparities may exist in cancer treatment among patients with low comorbidities. This finding was unexpected as these patients are less likely than highly comorbid patients to experience drug interactions and other complications due to concurrent disease management therapies.