Abstract 887: Clinicopathological and genetic features of breast cancer in Algerian population: A multicenter study

Background: Breast cancer is the most commonly diagnosed cancer and the leading cause of morbidity and mortality among Algerian women.The objective of this retrospective cohort study was to analyze some clinicopathological and molecular characteristics of breast cancer diagnosed between 2011 and 2019. Here we also report the experience of our research laboratory for the screening of BRCA1 and BRCA2 genes in hereditary breast and ovarian cancer (HBOC) patients. Materials and Methods: The population study included 7655 consecutive breast cancer patients. Data were collected from cancer registries of three medical oncology services and two anti-cancer centers located in north central region and eastern region of Algeria, respectively. Breast cancers were diagnosed between 2011 and 2019. Patient and tumor information included: age at diagnosis, menopausal status, receptor status, Ki-67 score, histological type,TNM stage and histological grade. Recurrent germline mutations on BRCA1 and BRCA2 genes previously found in Algerian patients were screened using PCR-Sanger sequencing in 230 HBOC patients. In addition, 18 HBOC patients were analyzed by NGS using a cancer panel of 30 hereditary cancer genes or BRCA1/2 genetic test. Results: The median age at diagnosis of the patients was 49.52 years. Data for age at diagnosis were available for 7389 patients. 55.29% patients were diagnosed under the age of 50 years and 55.83% had a premenopausal status. Data for receptor status were available for a total of 5599 patients. Of these, 55.75% patients were luminal A, 19.79% were TNBC, 17.39% were luminal B and 7.05% were HER2+. Data for Ki-67 score were available for 3357 cases. We noticed that 62.73% patients had a Ki-67 score ≥ 20% and 37.27% had a score