Abstract P3-12-23: Characterization of triple-negative breast cancer in two Central American countries

Abstract Background. Triple-negative (TNBC) is the most aggressive subtype of breast cancer and represents 12% of all cases in the US. In the Mexican population, the prevalence of TNBC is 23%. The prognosis is poor for most of these women, with a higher risk of locoregional recurrence, lower disease-free survival, and lower cancer-specific survival. The sociodemographic characteristics of Central American women, such as indigenous, afro descendants, and Hispanic descent, have been associated with factors such as high nuclear grade, high proliferation index, aggressive clinical presentation with advanced stages, high recurrence rates, and an increased risk of cancer fatality rate. Yet, no epidemiological characterization of women treated for TNBC in specialized hospitals in Central American countries exists to this date. Therefore, we describe the characteristics of women diagnosed with TNBC in three specialized hospitals in Guatemala and Honduras. Methods. We identify 1,501 women with breast cancer who attended three specialized hospitals, two in Guatemala and one in Honduras, from 2015 to 2021. Self-reported sociodemographic and clinical characteristics were determined, as well as pathologic data from medical records. Results. Of the 1,501 women, 272 (18.12%) were diagnosed with triple-negative phenotype. The median age was 49.5 years, with 25% under 40.5 years of age, 95.2% reported mestizo race, 51.5% were pre-menopausal, 49.6% had a high histologic grade (grade 3), and 98.8 had locally advanced disease (Table 1). Conclusions: The characteristics described in our sample were similar to those in other Hispanic populations. The prevalence of TNBC in our sample was lower than in Mexico but higher than that of the US. Our sample was made of primarily young women with locally advanced disease and pathologic factors associated with aggressive cancer behavior, such as high grade, lymphovascular invasion, and high Ki67 index. This first report is the product of a multidisciplinary team with interest in breast cancer subtypes. Our objectives include expanding the collaboration of clinical researchers to all the Central American and Caribbean countries and contributing to the understanding of molecular behavior of TNBC and support advances in treatment. Table 1.Characterization of women diagnosed with TNBC in three hospitals in Central AmericanCHARACTERISTIC% (95% CI)n = 272RaceMestizo95.2 (91.9 - 97.2)Indigenous4.8 (2.8 - 8.1)AgeMean (SD)49.5 years (11.7)IQR40.5 - 57Tobacco useYes3.7 (2.0 – 6.7)Number of pregnanciesMean (SD)1.5 (0.5)IQR1 – 2MenopauseYes48.5 (42.6 – 54.5)Use of contraceptivesYes14.0 (10.3 – 18.7)MulticentricYes19.2 (14.9 – 24.5)HypertensionYes8.4 (5.7 – 12.4)DiabetesYes8.8 (6.0 – 12.9)IMCLess than 3042.3 (36.5 – 48.3)Family history of cancerYes12.9 (9.4 – 17.5)Histologic grade15.5 (3.3 – 9.0)244.8 (39.0 – 50.8)349.6 (43.7 – 55.6)Lymphovascular invasionYes44.5 (38.6 – 50.5)Clinical stageI1.1 (0.3 – 3.4)II40.4 (34.7 – 46.4)III54.4 (48.4 – 60.8)IV4.0 (2.2 – 7.2)KI 67Mean (SD)46.9 (24.1)IQR30 - 70TherapyNeoadjuvant chemotherapy29.2 (21.3 – 38.7)RPC32.1 (23.9 – 41.6)Surgery97.4 (94.5 – 98.7)Adjuvant chemotherapy55.0 (49.0 – 60.8)Radiotherapy94.4 (90.8 – 96.6)MetastasisYes4.0 (2.2 – 7.2)BRCAMutated0.4 (0.0 – 2.6)WT2.2 (1.0 – 4.8) Citation Format: Agatha Reyes-Morales, Juan Francisco Alvarado-Muñoz, Suyapa Bejarano, Hugo Castro, Victor Puac-Polanco, Marco Chivalan, Silvana Torselli. Characterization of triple-negative breast cancer in two Central American countries [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P3-12-23.