{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,12,8]],"date-time":"2025-12-08T06:00:40Z","timestamp":1765173640723,"version":"3.46.0"},"reference-count":32,"publisher":"BMJ","issue":"6","license":[{"start":{"date-parts":[[2025,6,30]],"date-time":"2025-06-30T00:00:00Z","timestamp":1751241600000},"content-version":"unspecified","delay-in-days":29,"URL":"http:\/\/creativecommons.org\/licenses\/by-nc\/4.0\/"}],"funder":[{"name":"Pfizer 2020 Breast Cancer Competitive Research Grant Program","award":["62205951"],"award-info":[{"award-number":["62205951"]}]}],"content-domain":{"domain":["bmj.com"],"crossmark-restriction":true},"short-container-title":["BMJ Open"],"accepted":{"date-parts":[[2025,6,9]]},"published-print":{"date-parts":[[2025,6]]},"abstract":"<jats:sec>\n                    <jats:title>Introduction<\/jats:title>\n                    <jats:p>Breast cancer survival rates in low-income and middle-income countries significantly differ from those in high-income countries, indicating limited access to first-line systemic therapy for advanced and metastatic tumours. Recent studies have demonstrated the benefits of combining cyclin-dependent kinase 4 and 6 inhibitors (CDK 4\/6) with endocrine therapy in hormone receptor-positive, human epidermal growth factor receptor 2-negative advanced or metastatic breast cancer. However, in Brazil, the population faces limited access to these drugs, particularly in the public healthcare system.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods and analysis<\/jats:title>\n                    <jats:p>This prospective observational study will enrol 300 female patients from 20 cancer centres across Brazil, divided into two groups based on healthcare coverage: those treated in the public healthcare system (group 1) and those treated in the private healthcare system (group 2). The use or non-use of CDK 4\/6 inhibitors is not dictated by the study protocol but rather reflects real-world treatment decisions made by attending physicians. Patients will be followed for 24 months, stratified according to CDK 4\/6 inhibitor usage. The project aims to assess health inequities by evaluating the prognosis of patients treated in the public versus private healthcare systems. Outcomes include progression-free survival (PFS), overall survival (OS), quality of life and cost-effectiveness. Kaplan-Meier curves will be used to analyse PFS and OS, while the Cox proportional hazards frailty model will be employed to compare outcomes between healthcare systems, adjusting for prognostic variables.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Ethics and dissemination<\/jats:title>\n                    <jats:p>The study protocol was approved by the Ethics Committee of the HCor Research Institute (Hospital do Cora\u00e7\u00e3o\/Associa\u00e7\u00e3o Beneficente S\u00edria), which served as the central ethics board for the trial (study number: CAAE 42538621.5.1001.0060; approval letter number: 4.571.507; date: 3 March 2021). All participating centres also obtained approval from their respective local ethics committees prior to patient enrolment: Ethics Committee of Hospital de C\u00e2ncer de Barretos\u2014Funda\u00e7\u00e3o Pio XII; Ethics Committee of Universidade Estadual de Campinas\u2014UNICAMP; Ethics Committee of Faculdade de Minas Muria\u00e9\u2014FAMINAS; Ethics Committee of Hospital Santa Paula\u2014SP; Ethics Committee of Hospital Alem\u00e3o Oswaldo Cruz\u2014SP; Ethics Committee of Hospital Regional do C\u00e2ncer de Presidente Prudente\u2014HRCPP; Ethics Committee of Instituto Brasileiro de Controle do C\u00e2ncer\u2014IBCC\/Oncologia Cl\u00ednica\u2014SP; Ethics Committee of Instituto de Medicina Integral Prof. Fernando Figueira\u2014IMIP\/PE; Ethics Committee of Hospital S\u00e3o Rafael; Ethics Committee of Universidade Federal de S\u00e3o Paulo\u2014UNIFESP; Ethics Committee of Hospital Geral de Fortaleza\u2014HGF; Ethics Committee of Casa de Sa\u00fade Santa Marcelina; Ethics Committee of Centro Universit\u00e1rio FMABC; Ethics Committee of Liga Norte Riograndense Contra o C\u00e2ncer; Ethics Committee of Hospital M\u00e3e de Deus\/Associa\u00e7\u00e3o Educadora S\u00e3o Carlos\u2014AESC; and Ethics Committee of Instituto do C\u00e2ncer Brasil\u2014ICB. All patients will provide written informed consent. Study findings will be disseminated through scientific publications and presented to a broad range of stakeholders, including patients, physicians, the general public and policymakers.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Trial registration number<\/jats:title>\n                    <jats:p>\n                      ClinicalTrials.gov identifier:\n                      <jats:ext-link xmlns:xlink=\"http:\/\/www.w3.org\/1999\/xlink\" ext-link-type=\"clintrialgov\" xlink:href=\"NCT05559528\">NCT05559528<\/jats:ext-link>\n                      \u2014BRaziLian outcomE for metAStatic breasT cancer (BREAST).\n                    <\/jats:p>\n                  <\/jats:sec>","DOI":"10.1136\/bmjopen-2024-087877","type":"journal-article","created":{"date-parts":[[2025,6,30]],"date-time":"2025-06-30T14:40:14Z","timestamp":1751294414000},"page":"e087877","update-policy":"https:\/\/doi.org\/10.1136\/crossmarkpolicy","source":"Crossref","is-referenced-by-count":0,"title":["Study protocol to assess clinical outcomes of breast cancer and its relationship with access to healthcare in Brazil\u2014BREAST trial (BRaziLian outcomE for metAStatic breasT cancer): a prospective observational study in HER2-negative\/hormone receptor-positive metastatic disease"],"prefix":"10.1136","volume":"15","clinical-trial-number":[{"clinical-trial-number":"nct05559528","registry":"10.18810\/clinical-trials-gov"},{"clinical-trial-number":"nct05559528","registry":"10.18810\/clinical-trials-gov"}],"author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-3116-3550","authenticated-orcid":false,"given":"Vanessa Monteiro","family":"Sanvido","sequence":"first","affiliation":[{"name":"HCor Research Institute, HCor Hospital, Sao Paulo, SP, Brazil"},{"name":"Escola Paulista de Medicina - 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