{"doi":"10.1186/s13058-024-01822-9","title":"Trends in chemotherapy use for early-stage breast cancer from 2006 to 2019","abstract":"BACKGROUND: Little is known about how use of chemotherapy has evolved in breast cancer patients. We therefore describe chemotherapy patterns for women with stage I-IIIA breast cancer in the Optimal Breast Cancer Chemotherapy Dosing (OBCD) Study using data from KPNC (Kaiser Permanente Northern California) and KPWA (Kaiser Permanente Washington). FINDINGS: Among 33,670 women, aged 18 + y, diagnosed with primary stage I-IIIA breast cancer at KPNC and KPWA from 2006 to 2019, we explored patterns of intravenous chemotherapy use, defined here as receipt of intravenous cytotoxic drugs and/or anti-HER2 therapies. We evaluated trends in chemotherapy receipt, duration over which chemotherapy was received, and number of associated infusion visits. In secondary analyses, we stratified by receipt of anti-HER2 therapies (trastuzumab and/or pertuzumab), given their longer duration. 38.9% received chemotherapy intravenously, declining from 40.2% in 2006 to 35.6% in 2019 (p-trend < 0.001). Among 13,089 women receiving chemotherapy, neoadjuvant treatment increased (4.1-14.7%; p-trend < 0.001), as did receipt of anti-HER2 therapies (20.8-30.9%) (p-trend < 0.001). The average treatment duration increased (5.3 to 6.0 months; p-trend < 0.001), as did the number of infusion visits (10.8 to 12.5; p-trend < 0.001). For those receiving anti-HER2 therapies, treatment duration and average number of visits decreased; among those not receiving anti-HER2 therapies, number of visits increased, with no change in duration. CONCLUSIONS: While the prevalence of chemotherapy receipt has decreased over time, the use of neoadjuvant chemotherapy has increased, as has use of anti-HER2 therapies; duration and number of administration visits have also increased. Understanding these trends is useful to inform clinical and administrative planning.","journal":"Breast Cancer Research","year":2024,"id":436836,"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":11,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.7544,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2024-01-01","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":820583,"name":"Isaac J. Ergas","orcid":"0000-0002-3187-9754","position":2,"is_corresponding":false},{"id":1245674,"name":"Marilyn J. Foley","orcid":null,"position":3,"is_corresponding":false},{"id":1233964,"name":"Grace Gallagher","orcid":"0009-0004-9277-5002","position":4,"is_corresponding":false},{"id":330753,"name":"Jennifer J. Griggs","orcid":"0000-0002-1598-4562","position":5,"is_corresponding":false},{"id":1186987,"name":"Narre Heon","orcid":"0009-0003-5239-0821","position":6,"is_corresponding":false},{"id":662762,"name":"Tatjana Kolevska","orcid":null,"position":7,"is_corresponding":false},{"id":1194829,"name":"Yuriy Kotsurovskyy","orcid":"0000-0002-1288-518X","position":8,"is_corresponding":false},{"id":390224,"name":"Candyce H. Kroenke","orcid":"0000-0002-6128-3118","position":9,"is_corresponding":false},{"id":373342,"name":"Cecile A. 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