Effect of race/ethnicity and treatment delay on breast cancer survival

Abstract

6063 Background: Several papers have examined the relationship between treatment delay and survival among patients who are diagnosed with cancer. None has yet relied on a large, population-based dataset to systematically examine survival among women within different ethnic/racial groups who delay breast cancer treatment. Methods: Subjects were 49,865 female Medicare enrollees age 65 and older who were diagnosed with breast cancer between 1992 and 1999 and identified by the Surveillance, Epidemiology, and End Results (SEER) program. Dates of their health care visits were identified through the linkage of SEER with Medicare claims data. Mortality from breast cancer was assessed through linkage with death certificates. Propensity score analyses that compared patients matched according to their propensity to receive treatment were used to balance patient characteristics between treatment groups, as would occur in a randomized clinical trial. Results: A propensity score analysis and a Cox proportional hazards model of survival (with adjustments for ER/PR status, treatment type, race/ethnicity, stage, age, comorbidities, marital status, poverty status, geographic location, and average number of service contacts) revealed that subjects with 1-month delay in the start of treatment had a reduced likelihood of survival (adjusted HR=1.17, 95% CI, 1.06–1.30) relative to those with less delay. Blacks had significantly lessened survival than women in other races/ethnicities (adjusted HR=1.23, 95% CI, 1.00–1.52). Receipt of radiation (adjusted HR=1.45, 95% CI, 1.24–1.69), chemotherapy (adjusted HR=1.73, 95% CI, 1.51–1.99), stage three diagnosis (adjusted HR=1.35, 95% CI, 1.08–1.70), being age 70 or older (adjusted HR=1.24, 95% CI, 1.09–1.41), or having 2 or more comorbidities (adjusted HR=1.47, 95% CI, 1.12–1.92) also predicted reduced survival from breast cancer. Conclusions: One month delay in accessing breast cancer treatment has a clear relationship to reduced survival, particularly among older, later-stage, comorbid black women who receive chemotherapy or radiation. Mechanisms for rapid access to treatment, using both provider- and system-based strategies, are recommended for these women who are at increased risk for breast cancer-related mortality. No significant financial relationships to disclose.