Provider- and facility-level factors in relation to patients’ receipt of chemotherapy, time to chemotherapy initiation, and receipt of guideline regimens: Results from the optimal breast cancer chemotherapy dosing study.

Abstract

540 Background: How provider and facility characteristics relate to delivery and attributes of chemotherapy administration is not well understood. Methods: In a cohort of 31,336 women with stage I-IIIA breast cancer diagnosed and treated at Kaiser Permanente Northern California between 2006-2019, we evaluated the relationships between provider-level factors (gender, age, provider-patient racial/ethnic concordance) and facility-level factors (practice size, defined by number of oncologists in the service area, and rurality, defined by the % rurality of the treatment facility) in relation to chemotherapy receipt (yes/no), time to initiation (>/≤90 days after diagnosis), and planned regimen outside of the National Comprehensive Cancer Network guidelines (yes/no). In secondary analyses, the ‘receipt of a planned non-guideline regimen’ outcome was disaggregated into component pieces: regimens that were planned using non-guideline drug combinations, and regimens that were planned using a non-guideline schedule of administration of a guideline drug combination. Logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (95% CI). Results: Results suggest that provider- and facility-level factors are associated with various aspects of chemotherapy administration. For example, patients whose race and ethnicity matched that of their provider were less likely to experience a >90-day gap to initiation of chemotherapy (OR=0.83; 95% CI: 0.75-0.91). People treated by older providers were more likely to receive a non-guideline regimen than those treated by younger providers (≥60y vs <40y, OR=1.67, 95% CI: 1.37-2.04), with the effect estimate stronger for non-guideline drug combinations (OR=1.97). People treated by providers practicing in a larger service area (>10 vs ≤5 oncologists) were also less likely to receive non-guideline regimens; this was largely driven by use of drug combinations outside of the guidelines (OR=0.33, 95% CI: 0.15-0.71). People treated by female providers were less likely to receive a non-guideline regimen, specifically a non-guideline administration schedule (OR=0.79, 95% CI: 0.70-0.89). These results were robust to adjustment for several patient-level factors, including age, stage, race/ethnicity, comorbidity, and hormone receptor status, as well as adjustment for significant provider and facility-level factors. Conclusions: Further work is needed to better understand how these associations have changed over time, reasons for guideline non-concordance, and potential impact on patient outcomes.