Background: Cytokeratin 19 and its soluble fragment CYFRA have been studied as markers that may be associated with response to therapy and survival in non-small-cell lung cancer (NSCLC). As a prospective correlative study of Cancer and Leukemia Group B 30203, a randomized phase II trial of carboplatin/gemcitabine with eicosanoid modulators (celecoxib, zileuton, or both) in advanced NSCLC, serum CYFRA levels were obtained before and during treatment.
Methods: Serum CYFRA levels were measured at baseline and after the first cycle of treatment using an electrochemoluminescent assay. Paired specimens were available from 88 patients. The logarithms of the initial concentration and of the difference in concentrations were analyzed for association with overall survival (OS) and failure-free survival (FFS).
Results: Lower baseline CYFRA levels were associated with both longer OS and FFS (p < 0.0001 and p = 0.0003). In addition, larger reductions in CYFRA levels correlated with longer OS and FFS (p = 0.0255 and p = 0.0068).
Conclusion: CYFRA and change in CYFRA were found to be reliable markers for response to chemotherapy for NSCLC; however, a precise threshold to mark response has yet to be determined.