Impact of Early Testing and Analysis of Germline Genetic Mutation in Patients with Breast Cancer: A Single Institution Experience.

Abstract

Breast cancer is the most common cancer among women worldwide, with germline mutations in high-penetrance genes like BRCA1 and BRCA2, and moderate-penetrance genes such as CHEK2 and ATM contributing majorly to the onset of the same. Universal germline genetic testing offers an avenue to improve early identification and develop appropriate management guidelines. Our retrospective cohort study analyzed data from 525 newly diagnosed breast cancer patients at Mercy Hospital Fort Smith from January 2020 to December 2023. Patients underwent germline genetic testing using next-generation sequencing panels irrespective of family history of cancer. Details on patient demographics, clinical characteristics, and genetic test results were collected and analyzed. The median age at diagnosis of patients was 66, with invasive ductal carcinoma (IDC) being the major subtype (66%). CHEK2 mutations were the most common pathogenic mutations (9 patients), followed by BRCA1 and MUTYH (6 each). Pathogenic mutations were more prevalent in patients over 60 years (63%). Germline mutations were identified more frequently in IDC than in ductal carcinoma in situ. Among patients with germline mutations, there was a significant drift toward mastectomy over breast-conserving surgery. Universal germline genetic testing identified pathogenic mutations in a significant proportion of breast cancer patients, especially among the older patient population. The findings further emphasize the importance of integrating universal genetic testing into routine care to guide surgical and risk-reduction management protocols effectively. Further research is needed to regularize genetic testing in similar patients.