Javier Retamales, Adrián Daneri-Navarro, Nora Artagaveytia, Daniela Alves da Quinta, Eliana Abdelhay, Osvaldo L. Podhajcer, Carlos Velázquez, Diego Giunta, Susanne Crocamo, Adriana Garibay-Escobar, Alicia Del Toro-Arreola, Robinson Rodriguez, Marta Aghazarian, Elsa Alcoba, Isabel Alonso, Renata Binato, Alicia I. Bravo, Juan Canton-Romero, Dirce M. Carraro, Mónica Castro, Juan Castro-Cervantes, Sandra Cataldi, Natalia Camejo, Laura Cortes-Sanabria, Maria Flores-Marquez, Guillermo Laviña, Eduardo Musetti, Benedicta Caserta, Mauricio Cerda, Alicia Colombo, Raul Delgadillo-Cristerna, Marisa Dreyer Breitenbach, Elmer Fernandez, Jorge Fernandez, Ramon Franco-Topete, Carolina Gabay, Fancy Gaete, Jorge Gamboa, Ricardo García-Gaeta, Mariana Gomez del Toro, Leivy P. Gonzalez-Ramirez, Marisol Guerrero, Manuel Herrera-Miramontes, Alejandra Lopez-Vasquez, Silvina Maldonado, Andrés Morán-Mendoza, Gilberto Morgan-Villela, Maria Aparecida Nagai, Nancy Navarro-Ruiz, Antonio Oceguera-Villanueva, Miguel Angel Ortiz, Jael Quintero, Antonio Quintero-Ramos, Gladys Ramirez-Rosales, Maritza Ramos-Ramirez, Marcia Maria Chiquitelli Marques, Ernesto Rivera Claisse, Diego Rodriguez-Gonzalez, Ana Romero-Gomez, Cristina Rosales, Efraín Salas-Gonzalez, Verónica Sanchotena, Laura Segovia, Aída A. Silva-García, Olivia Valenzuela-Antelo, Laura Venegas-Godinez, Livia Zagame, Jorge Gomez, Andrea S. Llera, and Bettina Müller
PURPOSEBreast cancer mortality rates in Latin America (LA) are higher than those in the United States, possibly because of advanced disease presentation, health care disparities, or unfavorable molecular subtypes. The Latin American Cancer Research Network was established to address these challenges and to promote collaborative clinical research. The Molecular Profiling of Breast Cancer Study (MPBCS) aimed to evaluate the clinical characteristics and treatment outcomes of LA participants with locally advanced breast cancer (LABC).PATIENTS AND METHODSThe MPBCS enrolled 1,449 participants from Argentina, Brazil, Chile, Mexico, and Uruguay. Through harmonized procedures and quality assurance measures, this study evaluated clinicopathologic characteristics, neoadjuvant chemotherapy response, and survival outcomes according to residual cancer burden (RCB) and the type of surgery.RESULTSOverall, 711 and 480 participants in the primary surgery and neoadjuvant arms, respectively, completed the 5-year follow-up period. Overall survival was independently associated with RCB (worse survival for RCBIII-adjusted hazard ratio, 8.19, P < .001, and RCBII [adjusted hazard ratio, 3.69, P < .008] compared with RCB0 [pathologic complete response or pCR]) and type of surgery (worse survival in mastectomy than in breast-conserving surgery [BCS], adjusted hazard ratio, 2.97, P = .001). The hormone receptor–negative-human epidermal growth factor receptor 2–positive group had the highest proportion of pCR (48.9%). The analysis of the ASCO Quality Oncology Practice Initiative breast module revealed high compliance with pathologic standards but lower adherence to treatment administration standards. Notably, compliance with trastuzumab administration varied widely among countries (33.3%-88.7%).CONCLUSIONIn LABC, we demonstrated the survival benefit of BCS and the prognostic effect of the response to available neoadjuvant treatments despite an important variability in access to key treatments. The MPBCS represents a significant step forward in understanding the real-world implementation of oncologic procedures in LA.