Predictive and Prognostic Biomarkers in Non-Small Cell Lung Cancer

Therapy of non-small cell lung cancer (NSCLC) patients has evolved over the past few years with the incorporation of targeted therapy and immune therapy. These changes have increased the importance of prognostic and predictive biomarkers to enable practicing physicians in making the most appropriate treatment decisions for NSCLC patients. A variety of prognostic factors based on clinical and pathologic features determine the overall outcome of the patient and these factors do influence decisions regarding initiation of therapy. The most important prognostic factors remain stage of the disease at diagnosis and performance status. For years, the only approved systemic therapy for NSCLC patients was chemotherapy. Despite attempts at defining factors that influence efficacy of chemotherapeutic agents, pemetrexed is the only chemotherapy drug that has differential activity based on a specific factor. In recent years, there is increasing focus on defining the molecular alterations critical to the oncogenic phenotype of NSCLC and targeting these alterations for therapeutic benefit. In addition, there is increasing use of immune-modulating drugs, specifically anti-PD-1 drugs, in advanced NSCLC patients. Several studies have shown that the probability of clinical benefit from these agents is greater in patients with NSCLCs that express PD-L1. The totality of these data suggests that determination of predictive markers prior to initiation of therapy is critical.