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Managing TNBC

CE / CME

Cases and Challenges in the Optimal Treatment of Triple-Negative BC

Physician Assistants/Physician Associates: 1.00 AAPA Category 1 CME credit

Nurse Practitioners: 1.00 Nursing contact hours, includes 1.00 hour of pharmacotherapy credit

Released: May 08, 2023

Expiration: May 07, 2024

Jeremy M. Force
Jeremy M. Force, DO
CME/CE Information

Activity

Progress
1
Course Completed

Recommended Biomarker Testing in Breast Cancer

All patients who are diagnosed with breast cancer at any stage should be tested for estrogen and progesterone receptors using IHC, and for HER2 receptor status using IHC plus dual-probe in situ hybridization assays (ISH) to avoid missed opportunities for effective endocrine or HER2-directed therapy.10 In the 2023 National Comprehensive Cancer Network (NCCN) guidelines, HER2-positive is defined as IHC 3+ or IHC 2+/ISH-positive, HER2-low is defined as IHC 1+ or IHC 2+/ISH-negative, and HER2-negative as IHC 0. The differentiation between IHC 1+, which previously was considered negative, and IHC 0 is clinically relevant because of the availability of effective treatment for patients with HR-negative/HER2-low metastatic disease.10 For patients diagnosed at a young age, germline mutation analysis to determine whether they have BRCA-mutated disease is recommended.10

Patients presenting with recurrent or metastatic TNBC should be tested for PD-L1 expression using IHC reported as a CPS.10,11 As additional targetable mutations are identified, patients also may benefit from NGS to identify targetable mutations, TMB-H (TMB ≥10 mut/MB) and microsatellite instability (MSI) status. Tissue-based IHC is used to identify dMMR.10,11

BRCA1/2 mutation status should be determined if patients have not already had germline mutation sequencing to determine eligibility for treatment with PARP inhibitors.10 A recent study in breast cancer found that 3% of women with TNBC diagnosed after age 65 carried a pathogenic variant of BRCA, contributing to the current guideline for BRCA testing of all patients with TNBC, regardless of age.10,12,13 BRCA1/2 mutation status should automatically be assessed in patients with lobular breast cancer and a personal or family history of diffuse gastric or male breast cancer, or with family history of 1 or more male relative with breast cancer. Other populations known to be enriched with BRCA variants include those diagnosed before age 45; those with 1 or more close relative who had breast, ovarian, pancreatic, or high-risk prostate cancer; and those of Ashkenazi Jewish ancestry.10

All patients with TNBC should be tested for PD-L1 expression and BRCA1/2 mutations at recurrence or metastatic development (if not already done), as these inform treatment decisions.

 

Expert Insights From Dr Force: Importance of Rebiopsying Over Time

 

Which of these is part of the indication for pembrolizumab in early-stage high-risk TNBC?

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