Prospective study of risk of second primary breast cancer in young breast cancer survivors

Among women diagnosed with primary breast cancer (BC) at or younger than age 40 years, prior data suggest that their risk of a second primary BC is higher than that of women who are older when they develop a first primary BC. In the multicenter prospective Young Women’s Breast Cancer Study, among 685 BC survivors aged 40 years or younger at primary BC diagnosis who underwent lumpectomy or unilateral mastectomy, the 10-year risk of developing a second primary BC was approximately 2% among women who did not carry a germline pathogenic variant compared with approximately 9% among women who carried such a variant. The authors conclude that germline genetic testing is important among young patients with BC to determine future risk of developing a second primary BC and to inform treatment decision-making and follow-up care.