Detection of circulating tumor cells in non-small cell lung cancer

Lung cancer represents the second most common type of cancer in both men and women in the Western world and is a leading cause of mortality (1). Approximately 80% of all lung cancers are classed as NSCLC, 15% are small cell lung cancer (SCLC) and other histological variants account for about 5% (2). Although NSCLC comprises different histological types, prognosis and therapy for the approximately 40% adenocarcinomas, 25% to 30% squamous cell carcinomas (SCCs) and 10% to 15% large cell carcinomas (LCC) is often comparable. For patients with early-stage disease, surgery followed by adjuvant chemotherapy is the optimal treatment (3). However, over 50% of patients are initially diagnosed with advanced or metastatic disease with worse outcomes. For patients with locally advanced disease, the standard approach is chemoradiotherapy since it offers a small but statistically significant prolongation in survival. For patients with metastatic disease, chemotherapy represents the mainstay of treatment resulting in a median survival of approximately 10 months. The 5-year survival rate for metastatic disease is a low as 3%, whereas the 5-year survival rate for all stages is approximately 15%. Therefore, early detection of tumor dissemination and further improvement in diagnostics and treatments are required.