The American Society of Clinical Oncology (ASCO) recently convened an Expert Panel to create recommendations for endocrine therapy for women with hormone-receptor (HR)-positive, metastatic breast cancer. The panel conducted “a systematic review of evidence from 2008 through 2015 to create recommendations informed by that evidence.” These updates were recently published in the Journal of Clinical Oncology.
The majority of breast cancers are referred to as HR-positive, meaning their cancer is stimulated to grow from exposure to the female hormones estrogen and/or progesterone. These patients are treated with endocrine therapy (sometimes referred to as hormone, or anti-estrogen therapy), which reduces the cancer cells’ exposure to estrogen through varying mechanisms. Endocrine therapy has proven extremely effective in reducing HR-positive cancer growth and spread for extended periods of time.
Metastatic breast cancer refers to cancer that originated in the breast, but has spread to several and/or distant sites in the body. The goals of treatment for metastatic breast cancer are to improve duration of survival while maintaining quality of life.
The recommendations set forth by the recent convening of the Expert Panel specifically for women with HR-positive, metastatic breast cancer included the following:
- Patients whose cancer cells express any level of HR-positivity should be offered endocrine therapy as initial therapy.
- Sequential endocrine therapy (using one endocrine agent until the patient’s cancer progresses, then switching to a different endocrine agent until the cancer progresses again, etc.) is the preferred treatment of choice for this group of patients.
- Among postmenopausal women, aromatase inhibitors (AIs) are the initial treatment of choice, with or without the addition of Ibrance® (Palbociclib).
- If the patient’s cancer starts to progress on AIs, Faslodex® (fulvestrant) should be the second-line therapy.
- Among premenopausal women, ovarian suppression or ablation should be included in the treatment strategy.
- Afinitor® (everolimus) plus Aromasin® (exemestane) should be considered as treatment if the patient’s cancer progresses while receiving treatment with a non-steroidal AI.
- Patients whose cancer is HER2-positive, agents targeted against HER2 in addition to endocrine therapy is recommended if patients are not able to tolerate chemotherapy.
- Treatment choices should include variables such as prior treatment regimens, menopausal status, organ function and cancer-free interval since prior treatment.
- Tumor markers should not be solely used as an indicator of cancer progression; additional biomarkers indicating cancer progression or responsiveness to therapy are experimental.
For the ASCO publication regarding newly set forth recommendations specifically for HR-positive, metastatic breast cancer, go to: http://jco.ascopubs.org/content/34/25/3069.abstract?jco-home for the abstract, and http://www.asco.org/practice-guidelines/quality-guidelines/guidelines/breast-cancer#/11751 for a more complete review.
Reference: Rugo H, Rumble R, Macrae E, et al. Endocrine therapy for hormone receptor-positive metastatic breast cancer: American Society of Clinical Oncology Guideline. Journal of Clinical Oncology. 2016; 34 (25): 3069-3103. doi:10.1200/JCO.2016.67.1487JCO.