Variation in guideline-concordant care for elderly patients with metastatic breast cancer in the United States

Abstract

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.

Keywords: Chemotherapy; Endocrine therapy; Metastatic breast cancer; Quality of care.