Clinician- and facility-level factors associated with chemotherapy dose reductions in stages I-IIIA breast cancer.
[BACKGROUND] Chemotherapy dose reductions are associated with poorer survival.
APA
Sampathkumar Y, Zakaria Z, et al. (2026). Clinician- and facility-level factors associated with chemotherapy dose reductions in stages I-IIIA breast cancer.. Journal of the National Cancer Institute. https://doi.org/10.1093/jnci/djag063
MLA
Sampathkumar Y, et al.. "Clinician- and facility-level factors associated with chemotherapy dose reductions in stages I-IIIA breast cancer.." Journal of the National Cancer Institute, 2026.
PMID
41782330
Abstract
[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.
[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.