Despite improvements in the diagnosis and management of early stage breast cancer, about one third of the patients still progress to metastatic disease. Most of the patients with metastatic breast cancer have a hormone receptor positive and human epidermal growth factor receptor 2 negative subtype with a median survival of more than 3 years. For these patients, endocrine therapy with its favorable toxicity profile is the current standard of care. However, patients with metastatic breast cancer have an incurable disease. Therefore, not only efficacy but also quality of life are key when selecting a therapy regimen. Areas covered: This paper aims to discuss the efficacy and toxicity profile of the new endocrine-based therapy option palbociclib together with endocrine treatment. Expert opinion: The addition of targeted agents like palbociclib can overcome intrinsic or acquired resistance to endocrine therapy and substantially prolong progression free survival. The combination of palbociclib plus endocrine therapy is associated with a tolerable and well manageable toxicity profile as well as maintenance of quality of life. Thus, addition of palbociclib to endocrine therapy offers a new and important treatment option for hormone receptor positive metastatic breast cancer.
Keywords: CDK 4/6; HER2 negative; Palbociclib; advanced; breast cancer; endocrine therapy; everolimus; hormone receptor positive; metastatic.