{"doi":"10.1093/jnci/djaf314","title":"Associations between age and chemotherapy dose reductions in women with stage I-IIIA breast cancer","abstract":"BACKGROUND: Older women (>65 years) diagnosed with breast cancer may be at risk for chemotherapy dose reductions. We evaluated associations of age at diagnosis with 2 measures of chemotherapy dose reductions: first cycle dose proportion (FCDP) < 90% and average relative dose intensity (ARDI) < 90%. METHODS: From the Optimal Breast Cancer Chemotherapy Dosing study, we included 10 166 women aged 18+ years treated with adjuvant chemotherapy for stage I-IIIA breast cancer at Kaiser Permanente Northern California (KPNC) and Washington (KPWA) between 2004 and 2019. We examined associations between age at diagnosis with FCDP < 90% (reflecting clinician intent at chemotherapy initiation) and ARDI < 90% (reflecting average dose across the chemotherapy course). We used generalized linear models of the Poisson family with a log-link function and robust standard errors to calculate prevalence ratios (PR) for FCDP < 90% and ARDI < 90% with 95% confidence intervals (CI) adjusted for patient and tumor characteristics, with and without adjusting for pre-existing comorbidities. All tests for statistical significance were 2-sided. RESULTS: The proportion of women with FCDP < 90% ranged from 2.9% among women aged 18-39 years to 18.6% among women aged 75+ years. Before adjusting for comorbidities, women aged 75+ years were more likely to have FCDP < 90% (PR = 4.88; 95% CI = 3.58 to 6.66) and ARDI < 90% (PR = 1.91; 95% CI = 1.58 to 2.32) versus women aged 40-49 years. Results were similar after adjusting for comorbidities as a composite comorbidity score or individual comorbidities. CONCLUSION: Older age at diagnosis was strongly associated with chemotherapy dose reductions in this population-based cohort, particularly at chemotherapy initiation but also across the course of treatment.","journal":"JNCI Journal of the National Cancer Institute","year":2025,"id":548237,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":1,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.8541,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2025-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":402147,"name":"Kelli O’Connell","orcid":"0000-0002-4021-0788","position":1,"is_corresponding":false},{"id":925631,"name":"Jenna Bhimani","orcid":"0000-0002-9962-7019","position":2,"is_corresponding":false},{"id":1233964,"name":"Grace Gallagher","orcid":"0009-0004-9277-5002","position":3,"is_corresponding":false},{"id":311738,"name":"Victoria Blinder","orcid":"0000-0002-1448-8671","position":4,"is_corresponding":false},{"id":1354591,"name":"Rachael Doud","orcid":null,"position":5,"is_corresponding":false},{"id":820583,"name":"Isaac J. Ergas","orcid":"0000-0002-3187-9754","position":6,"is_corresponding":false},{"id":1440823,"name":"Jennifer J. Griggs","orcid":"0000-0002-9587-5621","position":7,"is_corresponding":false},{"id":1186987,"name":"Narre Heon","orcid":"0009-0003-5239-0821","position":8,"is_corresponding":false},{"id":662762,"name":"Tatjana Kolevska","orcid":null,"position":9,"is_corresponding":false},{"id":1194829,"name":"Yuriy Kotsurovskyy","orcid":"0000-0002-1288-518X","position":10,"is_corresponding":false},{"id":390224,"name":"Candyce H. Kroenke","orcid":"0000-0002-6128-3118","position":11,"is_corresponding":false},{"id":373342,"name":"Cecile A. Laurent","orcid":"0000-0001-9332-6971","position":12,"is_corresponding":false},{"id":806754,"name":"Raymond Liu","orcid":"0000-0002-4667-9632","position":13,"is_corresponding":false},{"id":1186988,"name":"Kanichi G. Nakata","orcid":"0000-0001-6730-6045","position":14,"is_corresponding":false},{"id":1153500,"name":"Sonia Persaud","orcid":"0009-0008-5666-7994","position":15,"is_corresponding":false},{"id":105131,"name":"Donna R. Rivera","orcid":"0000-0002-4565-4556","position":16,"is_corresponding":false},{"id":564649,"name":"Janise M. Roh","orcid":"0000-0002-8615-4320","position":17,"is_corresponding":false},{"id":1178366,"name":"Sara Tabatabai","orcid":"0000-0002-5498-7176","position":18,"is_corresponding":false},{"id":914162,"name":"Emily Valice","orcid":"0000-0003-2408-9727","position":19,"is_corresponding":false},{"id":979067,"name":"Peng Wang","orcid":"0000-0003-4303-6081","position":20,"is_corresponding":false},{"id":71791,"name":"Elisa V. Bandera","orcid":"0000-0002-8789-2755","position":21,"is_corresponding":false},{"id":233924,"name":"Lawrence H. Kushi","orcid":"0000-0001-9136-1175","position":22,"is_corresponding":false},{"id":448928,"name":"Elizabeth D. Kantor","orcid":"0000-0002-9124-5323","position":23,"is_corresponding":false},{"id":441921,"name":"Erin J. Aiello Bowles","orcid":"0000-0001-6287-7391","position":0,"is_corresponding":true}],"reference_count":43,"raw_metadata":null,"created_at":"2026-07-19T02:53:58.530220Z","pmid":"41183113","pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}