ProGRP and NSE in therapy monitoring in patients with small cell lung cancer.

The usefulness of serum pro-gastrin-releasing peptide (ProGRP) as a tumor marker in patients with small cell lung cancer has recently drawn the attention of many research centers. The aim of the study was the evaluation of ProGRP, neuron-specific enolase (NSE), soluble fragment of cytokeratin 19 (CYFRA 21-1) and lactate dehydrogenase (LDH) levels at the time of diagnosis and during chemo- and radiotherapy of small cell lung cancer patients with limited disease (SCLC-LD). The studies were performed on a group of 64 patients with SCLC-LD who had received no prior therapy. All the patients were given the same treatment regimen. ProGRP, NSE, CYFRA 21-1 and LDH were measured before each course of chemotherapy and then at 3 and 6 months after the end of treatment. Prior to therapy, elevated levels of ProGRP, NSE, CYFRA 21-1 and LDH were found in 79.7%, 57.8%, 23.4%, and 12.5% of the patients respectively. Before the second chemotherapy course, all the tumor marker levels except LDH decreased significantly in comparison with the pretreatment concentrations. However, only ProGRP levels showed a progressive drop during consecutive courses of therapy, while NSE and CYFRA 21-1 fluctuated within reference ranges. When the study group was divided with respect to the effect of treatment evaluated six months from its termination, significant differences in ProGRP levels were found between both subgroups throughout all therapy and follow-up, except for the fifth course of chemotherapy. Differences in NSE levels were only significant for the first two courses and follow-up. Univariate analysis showed significant relationships between disease-free survival and the initial levels of NSE and CYFRA 21-1 as well as between overall survival and prophylactic cranial irradiation (PCI) and the initial ProGRP, NSE and CYFRA 21-1 levels. Changes of ProGRP level seem to be more precise than NSE as a tool for monitoring therapy in SCLC patients with limited disease, but for prediction of relapse, in addition to NSE determinations of ProGRP seem to be optimal.