Estimation of prognosis by circulating biomarkers in patients with non-small cell lung cancer

Prognostic information on the course of cancer disease is highly relevant for the accurate decision of the most effective treatment strategy for an individual patient. In early stage disease, the application of adjuvant chemo- or radiotherapy after surgery depends on the risk of the patient to early suffer from tumor recurrence. In advanced stage disease, risk stratification of the patients influences the choice of more aggressive or mild therapy alternatives. Besides tumor related parameters like tumor stage and individual factors, additional information by biomarkers is needed to better characterize patients prognosis in both situations. Although there are plenty of studies dealing on the prognostic relevance of diverse biomarkers in non-small cell lung cancer (NSCLC), the results are quite heterogeneous and sometimes conflicting. Reasons for this situation may be found in the design, the performance, the evaluation and the quality of result reporting of the studies. In this review, we focus on the prerequisites of informative prognostic trials, spot on the general shortcomings of studies published so far, and summarize the results of the prognostic studies available for early and advanced stages of NSCLC.