Key Points
➤ Breast cancer is the most prevalent cancer in women in the developed
world and is the second most common cause of cancer-related death for
women in the United States.
• It was estimated that in 2015, approximately 231,840 women in the United States
would be diagnosed with the disease, and almost 40,000 would die as a result of it.
➤ Currently, a majority of patients presenting with localized disease will
experience long-term disease-free survival, whereas those presenting with
or who develop metastatic disease have a 5-year relative survival of only
24%, and almost none are cured.
➤ Hormone receptor-positive (HR+) breast cancer represents the most
common subset in both the early- and late-stage settings, with >70% of
tumors expressing these receptors.
➤ A greater understanding of the biologic pathways that contribute to hormone
resistance has led to approval of targeted agents administered in combination
with hormone therapy, including trastuzumab, everolimus, and palbociclib.
Treatment
➤ Treatment should take into account the biology of the tumor and the
menopausal status of the patient, with careful attention paid to ovarian
production of estrogen (Figure 2) (Moderate Recommendation; EB/CB-B-I).
➤ Hormone therapy should be offered to patients whose tumors express any
level of estrogen receptor (ER) and/or progesterone receptor (PR) (Strong
Recommendation; EB/CB-B-H).
➤ Endocrine therapy should be recommended as initial treatment for
patients with HR+ metastatic breast cancer (MBC), except for patients
with immediately life-threatening disease or for those who experience
rapid visceral recurrence during adjuvant endocrine therapy (Strong
Recommendation; EB-B-I).
➤ The use of combined endocrine therapy and chemotherapy is NOT
recommended (Strong Recommendation; EB-B-H).
➤ Treatment should be administered until there is unequivocal evidence of
disease progression as documented by imaging, clinical examination, or
disease-related symptoms (Strong Recommendation; EB-B-H).
• Tumor markers or circulating tumor cells should not be used as the sole criteria for
determining progression.
➤ Fulvestrant should be administered using the 500 mg dose and with a
loading schedule (Strong Recommendation; EB-B-H).
