Background: Breast cancer (BC) is the most common malignancy and one of the leading causes of cancer death in Latin American women, with an estimated age-standardized annual incidence of 38.3 and 56.8 and mortality rates of 10.1 and 13.4 cases per 100,000 females, in Central and South America respectively. However, BC incidence in Latin America (LATAM)is largely underestimated and lacks updated information. Furthermore, the shortage and quality of cancer registry data hinders a more reliable assessment of treatment and outcomes for these patients. The goals of LATINA Breast study is to build an electronic platform/database to allow a standardized collection of epidemiological data of BC in LATAMin addition to describe real world data on patients characteristics, treatment patterns and outcomes of this population. Methods: LATINA Breast (LACOG 0615) is a prospective, international, multicentre and non-interventional study of primary data collection designed to describe the diagnosis, oncologic treatment and outcomes of patients with BC in LATAM. Patients aged ≥ 18 years with stage I to IV newly diagnosed BC (i.e. <12 months since site activation) will be considered eligible for inclusion.Patient data will be collected from medical records at diagnosis and every 6 months for up to 5 years of follow-up. At baseline, data on socioeconomic, demographic, medical history and BC clinicopathological characteristics will be collected. Thereafter, information regarding treatment patterns, sequencing, response to treatment, adverse events, disease relapse/ progression and overall survival will be collected at each time-point. This study has a planned sample size of a minimum of 2.200 to a maximum of 4.500 patients accrued from approximately 30 sites in 10 LATAM countries: Argentina, Brazil, Cuba, Colombia, Chile, Dominican Republic, Ecuador, Mexico, Peru and Uruguay. The expected number of patients per country is based on age-standardize BC incidence rate by GLOBOCAN 2012 and not in a formal statistical estimation.Co-primary endpoints are (1) to describe patients’ characteristics, prevalence of BC subtypes at diagnosis, local and systemic treatment patterns and outcomes; (2) to build an electronic platform/database of epidemiological data of BC in LATAM. Secondary endpoints are to evaluate regional differences in treatment strategies, to describe treatment efficacy parameters such as locoregional relapse, invasive disease-free survival, progression-free survival, overall survival and to evaluate treatment safety. The trial is registered at clinicaltrials.gov NCT04158258.Results The first site was activated for patient accrual on February 13, 2020, in Argentina. As of July 6, 2020, a total of 243 patients have been included in Argentina (n=81), Brazil (n=123), Colombia (n=37), and Guatemala (n=2) within 19 active sites. Regulatory approval and activation are ongoing in the other countries. Recruitment is estimated to last until December 2021 to achieve the planned sample size. Patients will be followed-up for 5 years, therefore we estimate the last follow-up data collection in December 2026. ConclusionLATINA Breast is the first multinational, prospective cohort study of BC in Latin America that will generate detailed information on diagnosis, treatment and outcome in real-world clinical practice. It will address important gaps in BC management and will likely single out some of the main inequities in this large and diverse population of BC patients and consequently support strategies for the improvement of BC cancer care in LATAM.

Citation Format: Gustavo Werutsky, Cynthia Villareal-Garza, Henry Gomez, Juan Manuel Donaire, José Bines, Luis Fein, Mariano Nicolas Carrizo, Facundo Zaffaroni, Paulo Ricardo Nunes Filho, Carlos H Barrios. A study to observe patients characteristics, treatment patterns and outcomes in patients with newly diagnosed breast cancer in Latin America - LATINA breast (LACOG 0615/ MO39485) [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr OT-10-01.