Biomarker-driven therapies superior to standard care in breast cancer

Patients with breast cancer may gain greater therapeutic advantages from biomarker-driven than standard-of-care therapies, suggests a study.

Using key terms (ie, breast cancer, clinical practice guidelines, gene mutations, genomic assay, immune cancer therapy, predictive and/or prognostic biomarkers, and targeted therapies), the authors carried out a literature search from January 2015 to March 2022. They then identified, reviewed, and assessed relevant trials, meta-analyses, seminal articles, and clinical practice guidelines in the English language.

“Breast cancer is a biologically heterogeneous disease, leading to wide variability in treatment responses and survival outcomes,” the authors said.

Biomarkers for breast cancer evolved from traditional biomarkers in immunohistochemistry such as oestrogen receptor, progesterone receptor, and epidermal growth factor receptor type 2 (HER2) to genetic biomarkers with therapeutic implications (eg, breast cancer susceptibility gene 1/2, oestrogen receptor α gene mutation, HER2 gene mutation, microsatellite instability, phosphatidylinositol 3-kinase catalytic subunit 3Cα gene mutation, neurotrophic tyrosine receptor kinase gene mutation).

Current data were strongest for biomarkers in immunotherapy (eg, programmed cell death receptor ligand-1, microsatellite instability-high, or deficient mismatch repair). Additionally, oncotype DX assay continued to be the best validated gene expression assay, being both predictive and prognostic, while MammaPrint was prognostic for genomic risk.

“The purported survival benefits associated with biomarker-driven therapies should be weighed against their potential harms,” the authors said.