Abstract P1-08-26: Factors associated with survival in a 20-year historical cohort in Brazil

Abstract

In Brazil (population over 200 million), breast cancer is the leading cause of death from cancer among women. Nevertheless, little information is available regarding the characteristics of patients. Given this scenario, a private non-profit hospital located in Porto Alegre – the Brazilian city with the highest incidence of breast cancer (crude rate estimated at 114.25/100,000 for 2018) (1) – established a comprehensive breast cancer center (Núcleo Mama Moinhos, NMM). We investigated variables associated with mortality in 896 women diagnosed and treated at NMM over 20 years. The study was approved by the research ethics committee. Only women with centrally reviewed histological confirmation of breast cancer were included. The primary outcome was survival following diagnosis. The correlation between survival and the following variables was tested: age at diagnosis, disease stage at diagnosis, schooling, smoking, body mass index (BMI), menopausal status, hormone replacement therapy (HRT), family history of breast cancer, pathological grading, hormone receptor status, HER2 status, molecular subtype, and biomarker KI67. The impact of variables as predictors of mortality was analyzed using Cox and Kaplan-Meyer models. Mean age at diagnosis was 53.7 years (SD 13.087). Clinical staging at diagnosis was: 107 patients with stage 0 (12.3%), 440 stage I (50.7%), 244 stage II (28.1%), 67 stage III (7.7%), 10 stage IV (1.2%), and 28 with missing data. At 5 years, 96.4% of the patients were alive, and at 10 years 86.6% were alive. At the end of the observation (20 years), 67% were alive. Obesity (BMI>30) was detected in 136 (15%) women; 574 (64.0%) were menopausal, and 244 (27.2%) received hormone therapy. HER2 status was available for 782 cases of invasive breast cancer (87.3%), and 131 (16.8%) were HER2-positive. Triple negative cases were 14.3%. According to multivariate analysis (table 1), increasing stage and age at diagnosis, KI67, and distant recurrence were significantly associated with survival. None of the other variables, including smoking status, years in school, BMI, and HER2 status, was associated with mortality. To the best of our knowledge, this is the largest breast cancer cohort with the longest follow-up time in Brazil. These results suggest that Brazilian patients who receive early treatment at a comprehensive cancer center will achieve outcomes that are similar to those of developed countries. The high breast cancer mortality in Brazil seems dependent on the health care that is available to women (2). Table 1.Risk of mortality in a historical cohort of 896 women from South BrazilVariableHazard ratioPathological staging 0 I1.504II2.406III3.198IV12.186Age at diagnosis1.051KI67 Negative Low3.869Intermediate/high5.801Distant recurrence Yes5.55No Missing information: 26 patients for staging; 138 patients for KI67. Age: hazard ratio for each additional year. 1. Instituto Nacional do Câncer José Alencar Gomes da Silva. Estimativa 2018. Incidência de câncer no Brasil. Available at: http://www1.inca.gov.br/estimativa/2018/rio-grande-sul-porto-alegre.asp 2. Justo N, Wilking N, Jönsson B, Luciani S, Cazap E. A review of breast cancer care and outcomes in Latin America. Oncologist. 2013;18(3):248-56. doi: 10.1634/theoncologist.2012-0373. Epub 2013 Feb 26. Citation Format: Caleffi M, Ribeiro RA, Rosa DD. Factors associated with survival in a 20-year historical cohort in Brazil [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-08-26.