Endocrine Therapy for Breast Cancer in the Primary Care Setting

The treatment of hormone-positive breast cancer (BCA) is a rapidly evolving field. Improvement in the understanding of the mechanisms of action and resistance to anti-hormonal therapy has translated, in the past decade, into multiple practice-changing clinical trials, with the end result of increased survivorship for patients with all stages of hormone-positive cancer. The primary care physician will thus play an increasing role in the routine care, surveillance, and treatment of issues associated with anti-hormonal therapy. The aim of the present review was to provide a focused description of the issues relevant to primary care, while briefly highlighting recent advances in the field of anti-hormonal therapy. Key Points: (1) Hormone-positive bca is the most prevalent form of bca and, compared with the other subtypes, is usually associated with better survival. (2) Survivorship has significantly increased for all stages of hormone-positive bca, making the primary care physician a key player in the care of affected patients. (3) The two most common classes of anti-hormonal agents used in these patients are selective estrogen receptor modulators and aromatase inhibitors. Each class of medication is associated with signature side effects. (4) Within the past decade, multiple novel estrogen receptor blockers (for example, fulvestrant) and agents aimed at circumventing resistance to endocrine therapy [inhibitors of cyclin-dependent kinase 4/6 and of mtor (the mechanistic target of rapamycin)] have gained clinical ground. Understanding their side effects will be increasingly relevant to primary care physicians. (5) Multidisciplinary care is always encouraged in the care of cancer patients receiving anti-hormonal therapy.