Clinician- and facility-level factors associated with chemotherapy dose reductions in stages I-IIIA breast cancer
Menée aux Etats-Unis à partir de données de vie réelle portant sur 8 540 patientes atteintes d'un cancer du sein de stade I/IIIA, cette étude identifie les facteurs associés à une réduction de la dose de chimiothérapie
Background: Chemotherapy dose reductions are associated with poorer survival. To better understand the role of clinician- and facility-level factors in chemotherapy dosing, we conducted an analysis within a large, real-world cohort of women with stages I-IIIA breast cancer.
Methods: Our cohort included 8,540 breast cancer patients receiving chemotherapy at Kaiser Permanente Northern California between 2006 and 2019. Patients were treated across 22 facilities by 198 clinicians. We evaluated associations between clinician- and facility-level factors related to dose reductions at the start of chemotherapy (first cycle dose proportion, FCDP, <90%) and throughout treatment (average relative dose intensity, ARDI, <90%). Prevalence ratios (PR) and corresponding 95% confidence intervals (CI) were estimated for the clinician and facility factors in relation to chemotherapy dose reductions.
Results: Factors associated with an increased likelihood of dose reduction were increased clinician years since medical school (FCDP < 90%: PR≥30 vs <10 years : 1.78, p-trend = 0.03; ARDI < 90%: PR≥30 vs <10 years : 1.29, p-trend = 0.03) and treatment at less urban facilities (ARDI < 90%: PR<100% vs 100% urban : 1.38, p-trend = 0.002). Factors associated with a decreased likelihood of dose reduction were higher annual clinician volume of stages I-IIIA breast cancer patients (FCDP < 90%: PR≥30 vs ≤15 patients : 0.64, p-trend = 0.03; ARDI < 90%: PR≥30 vs ≤15 patients : 0.76, p-trend = 0.01), higher treatment facility annual volume of stages I-IIIA breast cancer patients (ARDI < 90%: PR≥200 vs <75 patients : 0.85, p-trend = 0.03), and a larger practice size (FCDP < 90%: PR≥10 vs ≤5 oncologists : 0.53, p-trend = 0.02).
Conclusions: Clinician- and facility-level factors were associated with chemotherapy dose reductions. Practice-level changes, such as increasing breast cancer patient volumes and practice size, may support optimal dosing practices.
Journal of the National Cancer Institute , résumé, 2026