CYFRA 21-1 in the follow-up of inoperable non-small cell lung cancer patients treated with chemotherapy

The introduction of new regimens in the chemotherapy of inoperable non-smal l cell lung cancer (NSCLC) patients provides a useful extension of survival probability that may now justify the application of turner markers for the disease monitoring. In a prospective study of 48 consecutive NSCLC patient s with TNM stages IIB/IV we compared changes in the serum levels of the cyt okeratin 19 fragment CYFRA 21-1 with the clinical evaluations of response t o therapy. CYFRA 21-1 levels were measured using the enzyme immunoassay of Boehringer, Mannheim (Germany). Clinical response to therapy was evaluated according to standard criteria of the WHO. For the assessment of response t o therapy by changes in the marker levels the difference between two consec utive levels must exceed 30 %. This value is based on the formula: Differen ce = 2 root 2 x CV (CV: inter-assay coefficient of variation of the marker test). CYFRA 21-1 was found to be elevated in 29/48 (60.4 %) patients prior to therapy and in 10/48 (20.8 %) patients at tumor progression. 91 evaluat ions have been recorded in these 39 patients. The overall concordance betwe en changes in the marker levels and the clinical assessment was 59.3 %. The decrease of CYFRA 21-1 levels at remission was rather low resulting in a c oncordance of only 42.9 % i.e. marker assays cannot replace the clinical re staging by imaging modalities. In contrast, changes in the marker levels at progression did exceed the required 30 % in the majority of cases (64.7 %) . Most of discordant results (40.7 %) could be explained by insufficient de crease or increase of CYFRA 21-1 levels or by extended lead-time. The most striking result was the detection of progressive disease by rising marker l evels. Except one case, there was no false-positive elevation of CYFRA 21-1 levels. It is concluded that the detection of progressive disease by risin g CYFRA 21-1 levels may avoid continuation of ineffective treatment.