Diagnosis
New Recommendations from 2022 Focused Guideline Update
Recommendation 1.1
➤ Patients with locally recurrent unresectable or metastatic hormone
receptor-positive and human epidermal growth factor receptor 2 (HER2)
-negative breast cancer who are candidates for a treatment regimen that
includes a PI3K inhibitor and a hormonal therapy, should undergo testing
for PIK3CA mutations using next-generation sequencing of tumor tissue
or ctDNA in plasma to determine their eligibility for treatment with the
PI3K inhibitor alpelisib plus fulvestrant. If no mutation is found in ctDNA,
testing in tumor tissue, if available, should be used since this will detect
a small number of additional patients with PIK3CA mutations. (Strong
recommendation; EB-B-H)
Note: See J Clin Oncol 39:3959-3977, 2021 for the corresponding recommendation
concerning the use of alpelisib in patients with PIK3CA-mutated, advanced or metastatic
breast cancer: https://ascopubs.org/doi/full/10.1200/JCO.21.01392.
Recommendation 2.1
➤ There are insufficient data at present to recommend routine testing for
ESR1 mutations to guide therapy for hormone receptor-positive, HER2-
negative metastatic breast cancer (MBC). Existing data suggest reduced
efficacy of aromatase inhibitors compared to the selective estrogen
receptor degrader (SERD) fulvestrant in patients who have tumor or
ctDNA with ESR1 mutations. (Moderate recommendation; IC-Ins)
Recommendation 3.1
➤ Patients with metastatic HER2-negative breast cancer who are
candidates for treatment with a poly [ADP-ribose] polymerase (PARP)
inhibitor should undergo testing for germline BRCA1 and BRCA2
pathogenic or likely pathogenic mutations to determine their eligibility
for treatment with the PARP inhibitors olaparib or talazoparib. (Strong
recommendation; EB-B-H)
Note: See: J Clin Oncol 39:3959-3977, 2021 for the corresponding recommendation
concerning the use of the use of PARP inhibitors in the treatment of patients with HER2-
negative metastatic breast cancer: https://ascopubs.org/doi/full/10.1200/JCO.21.01392.
