Gene Expression-Based Prognostic and Predictive Markers for Breast Cancer: A Primer for Practicing Pathologists (Report)

Gene Expression-Based Prognostic and Predictive Markers for Breast Cancer: A Primer for Practicing Pathologists (Report)

CLINICAL BACKGROUND The identification of molecular markers with prognostic significance may help cancer patients avoid treatment that is unlikely to be successful. In breast cancer, for example, clinical studies have shown that adding adjuvant chemotherapy to tamoxifen in the treatment of node-negative, hormone receptor (HR)-positive breast cancer improves disease outcome. (1) However, treatment with tamoxifen alone is associated with a 15% likelihood of distant recurrence at 10 years in this population, suggesting that 85% of these patients would do well without the addition of cytotoxic chemotherapy and could avoid the adverse events inherent to such treatment.1 Nevertheless, the current National Comprehensive Cancer Network (NCCN) (2) and St. Gallen (3) clinical practice guidelines, using classical histopathology and immunohistochemical prognostic markers, categorize less than 10% of patients with nodenegative, HR-positive disease at low enough risk of recurrence to forgo adjuvant chemotherapy. These treatment guidelines assume that patients will derive the same degree of benefit from chemotherapy regardless of their baseline risk.

Gene Expression-Based Prognostic and Predictive Markers for Breast Cancer: A Primer for Practicing Pathologists (Report)

Gene Expression-Based Prognostic and Predictive Markers for Breast Cancer: A Primer for Practicing Pathologists (Report) | | 4.5