Implementing Standard Diagnosis and Treatment for Locally Advanced Breast Cancer Through Global Research in Latin America: Results From a Multicountry Pragmatic Trial
Authors: Retamales Javier , Daneri-Navarro Adrián , Artagaveytia Nora , Alves da Quinta Daniela , Abdelhay Eliana , Podhajcer Osvaldo L. , Velázquez Carlos , Giunta Diego , Crocamo Susanne , Garibay-Escobar Adriana , Del Toro-Arreola Alicia , Rodriguez Robinson , Aghazarian Marta , Alcoba Elsa , Alonso Isabel , Binato Renata , Bravo Alicia I. , Canton-Romero Juan , Carraro Dirce M. , Castro Mónica , Castro-Cervantes Juan , Cataldi Sandra , Camejo Natalia , Cortes-Sanabria Laura , Flores-Marquez Maria , Laviña Guillermo , Musetti Eduardo , Caserta Benedicta , Cerda Mauricio , Colombo Alicia , Delgadillo-Cristerna Raul , Dreyer Breitenbach Marisa , Fernandez Elmer , Fernandez Jorge , Franco-Topete Ramon , Gabay Carolina , Gaete Fancy , Gamboa Jorge , García-Gaeta Ricardo , Gomez del Toro Mariana , Gonzalez-Ramirez Leivy P. , Guerrero Marisol , Herrera-Miramontes Manuel , Lopez-Vasquez Alejandra , Maldonado Silvina , Morán-Mendoza Andrés , Morgan-Villela Gilberto , Nagai Maria Aparecida , Navarro-Ruiz Nancy , Oceguera-Villanueva Antonio , Ortiz Miguel Angel , Quintero Jael , Quintero-Ramos Antonio , Ramirez-Rosales Gladys , Ramos-Ramirez Maritza , Chiquitelli Marques Marcia Maria , Rivera Claisse Ernesto , Rodriguez-Gonzalez Diego , Romero-Gomez Ana , Rosales Cristina , Salas-Gonzalez Efraín , Sanchotena Verónica , Segovia Laura , Silva-García Aída A. , Valenzuela-Antelo Olivia , Venegas-Godinez Laura , Zagame Livia , Gomez Jorge ,   Latin American Cancer Research Network (LACRN), Llera Andrea S. , Müller Bettina 
Published: May 2024

PURPOSE

Breast 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 METHODS

The 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.

RESULTS

Overall, 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%).

CONCLUSION

In 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.