Variation in guideline-concordant care for elderly patients with metastatic breast cancer in the united states

Purpose Prior studies have identified shortcomings in the quality of care for early-stage breast cancer. Guidelines recommend systemic therapy for metastatic breast cancer (MBC), but few studies have examined guideline concordance for these patients. Methods We used Surveillance, Epidemiology, and End Results (SEER)-Medicare data to identify patients aged ≥ 66 diagnosed in 2010–2011 with de novo MBC who were continuously enrolled in fee-for-service Medicare. We described initial care (within 6 months of diagnosis) for hormone receptor (HR)-positive/human epidermal receptor-2 (HER2)-negative, HER2-positive, and triple-negative (TN) tumors. We identified factors independently associated with receiving no initial systemic therapy, and compared hospice and hospital utilization for treated versus untreated patients. Results Among 446 patients, 65% were HR-positive, 21% were HER2-positive, and 14% were TN. Most patients (76.9%) received initial systemic treatment. Among treated HR-positive patients, 15% received chemotherapy as initial treatment; among treated HER2-positive patients, 34% did not receive HER2-targeted initial therapy. Factors independently associated with receiving no initial systemic therapy included older age (OR_{age continuous/year} = 1.08, 95% CI 1.04–1.11), being not married (OR_{not married vs. married} = 2.87, 95% CI 1.42–5.81), and subtype (OR_{TN vs. HR+} = 4.95, 95% CI 2.53–9.71). Of patients who did not receive initial systemic therapy, 41.1% did not receive hospice services. Conclusions In this population-based MBC cohort, almost one quarter did not receive initial systemic therapy and a substantial proportion of treated patients did not receive guideline-concordant first-line therapy. Further research should explore underuse of chemotherapy and HER2-targeted therapies, investigate whether patterns of care are consistent with patient preferences, and identify opportunities to optimize hospice utilization for patients not receiving treatment.