An Update on Early‐Onset Breast Cancer: Incidence, Risk Factors, Genetic Testing, and Treatment

ABSTRACT Early‐onset breast cancer presents in patients typically under the age of 40, while very early‐onset breast cancer is usually viewed as breast cancer occurring before the age of 35. Early‐onset breast cancer demonstrates specific molecular properties and has worse outcomes compared to its late‐onset breast cancer counterpart. Furthermore, the global burden of early‐onset breast cancer, mortality rates, and incidence are on an upward trajectory on a global scale, highlighting the importance of gaining a better comprehension of this disease. This study aims to examine the global burden and incidence of early‐onset breast cancer and a myriad of risk factors that contribute to the development of this cancer. Furthermore, the study will dissect the early‐onset breast cancer patient knowledge, attitudes, and outcomes, in addition to aspects about genetic testing, disparities, diagnosis, and treatment. By advancing our understanding and knowledge of the molecular and clinical properties of early‐onset breast cancer, the scientific community can lay the groundwork for improving patient experiences, outcomes, and therapy.