Neoadjuvant Chemotherapy and Biomarkers

Abstract

Neoadjuvant or presurgical therapy refers to the administration of therapy before surgery and has been used for over two decades to downstage locally advanced and unresectable primary breast cancers to make them operable. The goal of neoadjuvant therapy is to improve surgical outcomes by causing tumor shrinkage by providing effective systemic therapy. Neoadjuvant chemotherapy is preferred frequently in women with aggressive breast cancers like luminal B, triple-negative, and HER2-positive subtypes. The efficacy is monitored by the extent of tumor shrinkage measured by the RECIST (Response Evaluation Criteria in Solid Tumors).

It has been demonstrated that some breast cancer cells have receptors on their outer wall that catch specific hormone and stimulate unrestricted tumor growth. The commonly tested immunohistochemistry (IHC) biomarkers are estrogen receptors, progesterone receptors, and HER2. Other biomarkers such as Ki 67, p53, and C kit overexpression are also used in clinical practice where available. Genomic testing provides tests such as Oncotype Dx, MammaPrint, etc., which are predictive biomarkers and can help calculate risk of recurrence. Gene expression profiling tests analyze a number of different genes within cancer cells to predict risk of cancer recurrence. Women with a high score of risk of recurrence potentially benefit from adjuvant chemotherapy and those with low risk of recurrence may forgo adjuvant chemotherapy.