Triple-negative breast cancer (TNBC) is a heterogenous subtype involving different patterns of behavior and clinical course, demanding a complex, individualized sequence of treatment. The knowledge and attitudes of the affiliated members of the Brazilian Society of Mastology regarding TNBC were evaluated and a consensus regarding management and treatment was reached. Affiliates completed a survey involving 44 objective questions. In addition, a specialist meeting was held with 27 experts and 3 ad hoc consultants. The panelists completed the survey before and after brainstorming. Answers achieving 70% of agreement were considered consensual. The chi-square test was used to compare answers between panelists and affiliates and the Kappa coefficient to calculate agreement. Consensus among the panelists increased from 26 (59.1%) to 32 questions (72.7%) following brainstorming (p = 0.17), including 7/10 questions on systemic treatment. Among the affiliates, consensus was achieved for 24 questions (54.5%), resulting in moderate agreement (κ = 0.445). Neoadjuvant chemotherapy should be indicated for almost all cases (except cT1a-b N0) and should include platinum agents. When indicated, immunotherapy is part of the standard of care. The panel reaffirmed the concept of no ink on tumor as indicative of adequate margins and the possibility of sentinel lymph node biopsy for cN1 patients who become cN0 following neoadjuvant therapy. Controversies remain on combining immunotherapy with capecitabine/olaparib in pertinent cases. Expert consensus was achieved for > 70% of the questions, with moderate agreement between panelists and affiliates. Educational interventions on systemic breast cancer treatment affected decision-making in 60% of the questions.

RESUMO INTRODUÇÃO: O câncer de mama é a neoplasia maligna visceral mais frequente em mulheres, sendo a principal causa de morte por câncer no sexo feminino em todo o mundo. O subgrupo triplo negativo apresenta prognóstico pobre e comportamento biológico agressivo. OBJETIVOS: Delinear os aspectos clínicos e histomorfológicos e o perfil de tratamento, além de sugerir quais fatores podem predizer pior prognóstico nas pacientes com câncer de mama invasivo triplo negativo na região dos Campos Gerais do Paraná. MÉTODOS: Estudo de corte retrospectivo observacional, longitudinal e comparativo, realizado em uma clínica de anatomia patológica e no Instituto Sul Paranaense de Oncologia, em Ponta Grossa, Paraná. Os critérios de inclusão foram pacientes do sexo feminino com laudo anatomopatológico de carcinoma de mama invasor, cuja imuno-histoquímica apresentou-se negativa para os receptores hormonais e receptor de crescimento epidérmico humano 2 (HER2), diagnosticadas no período entre 01 de janeiro de 2002 a 31 de dezembro de 2012. As pacientes foram divididas em dois grupos, mulheres vivas e as que faleceram. RESULTADOS: O índice de recidiva, o tipo de quimioterapia, a invasão angiolinfática, o tamanho do tumor, a invasão linfonodal e os tipos de cirurgia realizadas foram variáveis significativas na análise univariada entre os grupos. Após a regressão de cox para análise multivariada, apenas a invasão angiolinfática (p = 0,012, risco relativo [RR] 5,0518, intervalo de confiança [IC] 95% 1,4261-17,8952) e o tamanho do tumor permaneceram significativos (p = 0,0385, RR 1,2605, IC 95% 1,0123-1,5695). CONCLUSÃO: A invasão angiolinfática e o tamanho do tumor mostraram-se fatores de risco para óbito, por todas as causas, em pacientes com câncer de mama triplo negativo. Diferenças entre os grupos podem indicar diferentes subtipos moleculares dentro do fenótipo triplo negativo. Palavras-chave: neoplasias da mama; imuno-histoquímica; prognóstico; óbito. ABSTRACT INTRODUCTION: Breast cancer is the most common visceral malignancy in women, the leading cause of cancer death among women worldwide. The triple negative subgroup has poor prognosis and aggressive biological behavior. OBJECTIVES: To outline the clinical and histopathological aspects, the treatment profile, and to suggest which factors may predict poor prognosis in patients with triple-negative invasive breast cancer in the Campos Gerais region of Paraná. METHODS: A retrospective observational cohort study, longitudinal, comparative, performed in a clinic of anatomic pathology in the Instituto Sul Paranaense de Oncologia, in Ponta Grossa, Paraná. The inclusion criteria were female patients with pathology report of invasive breast carcinoma, whose immunohistochemistry showed negative for hormone receptors and human epidermal growth factor receptor (HER2), diagnosed in the period between January 1, 2002 and December 31, 2012. The patients were divided into two groups, living women and patients who have died. RESULTS: The recurrence rate, chemotherapy type, angiolymphatic invasion, tumor size, lymph node invasion, and type of surgery performed were significant variables in the univariate analysis between the groups. After Cox regression for multivariate analysis, only the angiolymphatic invasion (p = 0.012, relative risk [RR] 5.0518, confidence interval [CI] 95% 1.4261-17.8952), and tumor size (p = 0.0385, RR 1.2605, CI 95% 1.0123-1.5695) remained significant. CONCLUSION: The angiolymphatic invasion and tumor size proved to be risk factors for death, from all causes, in patients with triple-negative breast cancer. Differences between groups can indicate different molecular subtypes within the triple-negative phenotype. Keywords: breast cancer; immunohistochemistry; prognosis; death.