Single Center Experience of Genetic Testing in Patients Undergoing Breast Cancer Treatment.

Background: Breast cancer remains the most frequently diagnosed cancer in female population worldwide. However, germline mutations are responsible for a small proportion of these cases. The aim of our study is to assess how germline mutations influence the management and outcome of these patients taken into consideration both their cancer diagnosis and genetic assessment.

Methods: We performed a retrospective analysis in a women's single-center during a period of six years to assess the contribution of germline mutation in the treatment, prognosis and survival of breast cancer patients. Statistics were collected from both the patients' medical records and genetics department.

Results: From the total number of patients treated for breast cancer in our department between 2017 and 2022, 243 were eligible for genetic testing, comprising either BRCA1/2 or extended panel, taking into consideration their personal and family history. Of all subjects included in our study cohort, 5% were carriers of a pathogenic(P) or likely pathogenic(LP) variant of cancer susceptibility gene, of which 78% were diagnosed before the age of 50; triple negative disease was diagnosed in the majority of cases, and therefore, 62% of patients started treatment with systemic neoadjuvant chemotherapy and 32% of subjects underwent upfront surgery. Prophylactic surgery for contralateral breast and bilateral salpingo-oophorectomy was considered and performed for 20% of patients. Less than 2% of cases had metastatic disease and received PARP inhibitors, with excellent treatment response and a very low rate of mortality in the study group.

Conclusion: Carriers of pathogenic variants with breast cancer diagnosis may have a greater benefit from a tailored approach, including both surgical and oncological treatment, with better long-term outcomes.