Prolonged endocrine therapy in the management of hormone receptor‐positive early‐stage breast cancer: What is the appropriate duration?

Aim: The clinical benefits associated with 5 years of endocrine therapy in the treatment of hormone receptor‐positive, early‐stage breast cancer (ESBC) have been well‐substantiated. However, numerous studies have reported on the results of extended (i.e., >5 years) endocrine therapy to further effectuate a clinical benefit, with varying outcomes. Hence, the purpose of this study is to review these prolonged investigations and endeavor to clarify their corresponding treatment implications. Methods: We reviewed the study findings from several randomized controlled trials and meta‐analyses, which incorporated clinical outcomes from pre‐and postmenopausal, hormone receptor‐positive, ESBC patients. Results: Hormone receptor‐positive, ESBC patients treated with 5 years of endocrine therapy, who are node‐negative with tumors <2 cm, will unlikely benefit from five additional years of treatment. Conversely, in women with larger tumors and node‐positive disease, 7–8 total years of endocrine therapy may be indicated. Ultimately, clinicians should also consider the attendant side effects from endocrine therapy, namely bone fractures, namely cardiovascular symptoms, and vasomotor symptoms, when considering the appropriate treatment regimen. Conclusions: While increased duration of endocrine therapy may selectively accord significant clinical benefits, prior to determining the patient's treatment interval, physicians should also assess the cumulative side effects from endocrine therapy when endeavoring to maintain treatment compliance and bolster quality of life. [ABSTRACT FROM AUTHOR]