The importance of circulating tumor markers in lung cancer in clinical practice

We have reviewed the available publications about circulating tumor markers (CTM) - CYFRA 21-1, CEА, SCC, NSE and proGRP, in patients with small-cell (SCLC) and non-small cell lung cancer (NSCLC). Elevated levels of at least one of them (CEA, CYFRA 21-1 и SCC) were seen in 100 % of patients with stage III-IV NSCLC. CEA, CYFRA 21-1 and SCC could have prognostic and predictive value. Their decrease during chemotherapy or immunotherapy correlates with better overall survival. For SCLC the main CTM are NSE and proGRP. Together with CTM for NSCLC these markers could predict correctly histological subtype of lung cancer in 79-97 % of patients. Levels of proGRP after 1, 2 and 3 cycles of chemotherapy in SCLC correlated with response to treatment and were associated with prognosis. Thus, it can be used as an additional response criterion, for example in patients with non-measurable disease. CTM provide additional easy-to-use predictive and prognostic data for patients with lung cancer.