Treatment
➤ Patients with metastatic hormone receptor-positive (HR-positive)
breast cancer with disease progression on a prior endocrine agent
with or without targeted therapy may be offered treatment with
either endocrine therapy with or without targeted therapy (refer to the
companion ASCO guideline on Endocrine Therapy and Targeted Therapy
for Hormone Receptor-Positive, HER2-negative Metastatic Breast Cancer
[Burstein et al. J Clin Oncol. doi: 10.1200/JCO.21.01392] for details) or
single-agent chemotherapy. (Strong recommendation; EB-B-M)
Practical Information: Treatment choice should be based on individualized patient
and provider assessment of preferences, risks, and benefits.
➤ Patients with metastatic HR-positive but HER2-negative breast cancer
with germline BRCA1 or 2 mutations who are no longer benefiting
from endocrine therapy may be offered an oral PARP inhibitor in the
first- through to third-line setting rather than chemotherapy. (Strong
recommendation; EB-B-M)
Practical Information: Small single-arm studies show that oral PARP inhibitor
therapy demonstrates high response rates in metastatic breast cancer encoding DNA
repair defects, such as germline PALB2 mutation carriers and somatic BRCA
mutations. It should also be noted that the randomized PARP inhibitor trials made
no direct comparison with taxanes, anthracyclines, or platinums. Comparative
efficacy against these compounds is unknown.
➤ Patients with HR-positive HER2-negative metastatic breast cancer
no longer benefiting from endocrine therapy should be offered
single agent chemotherapy rather than combination therapy,
although combination regimens may be offered for symptomatic or
immediately life-threatening disease for which time may allow only
one potential chance for therapy. (Strong recommendation; EB-B-M)
Practical Information: Choice of chemotherapy agent should be based on
individualized patient and provider assessment of preferences, risks, and benefits.
➤ No recommendation regarding at which point a patient's care should
be transitioned to hospice or best supportive care only is possible at
this time. (Strong recommendation; CB-U-n/a)
Practical Information: Given the heterogeneity of breast cancer and the treatment
goals of patients with breast cancer, it is not possible to identify a universal optimal
time to transition to hospice or best supportive care. When to transition is a decision
that should be shared between the patient and clinician in the context of an
ongoing conversation regarding goals of care. The conversation about integration of
supportive care and eventual consideration of hospice care should start early in the
management of metastatic breast cancer.
