The Diagnostic Value Of Pro-gastrin-releasing Peptide For Small Cell Lung Cancer

Objective:To evaluate the clinical value of pro-gastrin-releasing peptide (ProGRP) for small cell lung ancer (SCLC).Methods:Serum levels of ProGRP,neuron-specific enolase(NSE),(carcino embryonic antigen) CEA,(cytokeratin19fragment) CYFRA21-1and (squamous cell carcinoma antigen) SCC were measured by chemiluminescent immunoassay and electrochemiluminescent immunoassay in46patients with SCLC (26patients limited disease LD,20patients extensive disease ED),51patients with non-small cell lung cancer (NSCLC),45patients with benign pulmonary diseases and56healthy subjects. The serum levels of ProGRP, NSE, CEA, CYFRA21-1and SCC shew the skewness distribution,so the results of tumor makers in patients were expressed as dedians and the variation as interquartile range.The serum levels of ProGRP and NSE in SCLC patients, NSCLC patients, benign pulmonary diseases patients and healthy subjects were compared by the non-parameteic Kruskal-wallis H test. And serum levels of ProGRP and NSE in LD-SCLC patients, NSCLC patients, benign pulmonary diseases patients and healthy subjects were also compared by the non-parameteic Kruskal-wallis H test. The serum levels of ProGRP and NSE between SCLC group and healthy subjects, SCLC group and benign pulmonary diseases group, SCLC group and NSCLC group,were analyzed by the non-parameteic Mann-Whitney Utest. The size of test (0.05) was divided by6because of4times of group comparson,so P<0.008were considered statistically significant.The serum levels of ProGRP and NSE between LD-SCLC group and healthy subjects, LD-SCLC group and benign pulmonary diseases group, LD-SCLC group and NSCLC group were analyzed by the non-parameteic Mann-Whitney U test. The size of test (0.05) was divided by6because of4times of group comparson,so P<0.008were considered statistically significant. The size of test (0.05) was divided by6because of4times of group comparson,so P<0.008were considered statistically significant.The serum levels of ProGRP and NSE between ED-SCLC group and LD-SCLC group were analyzed by the non-parameteic Mann-Whitney U test.Using the receiver oprerating characterisitic curve (ROC) to set cut-off value and the areas under receiver oprerating characterisitic curve (ROC-AUC) of ProGRP and NSE. Z test was used to compared ROC-AUC and Chi square test was used to analyze the sensitivity and specificity.Results:(1) The serum levels of ProGRP in healthy subjects,benign pulmonary diseases,NSCLC and SCLC groups were22.9(19.5～28.7) pg/ml,23.7(20.0～27.8) pg/ml,28.9(23.8～34.7)pg/ml and370.9(129.4～1951.6)pg/ml; serum levels of NSE were14.1(12.5～15.7) ng/ml,13.3(10.3～15.3)ng/ml,16.8(11.7～22.1)ng/ml and39.9(16.1～93.9)ng/ml,respectively.The Kruskal-Wallis test showed significantly statistical difference in different groups of ProGRP and NSE (H=92.116and55.481,P<0.001).(2) Serum level of ProGRP in SCLC group was significantly increased than those in the healthy group,benign pulmonary diseases group and NSCLC group (U value of ProGRP were106,110and226, P<0.001; U value of NSE were368.5、242and561.5, P<0.001).Serum level of ProGRP in LD-SCLC group was significantly increased than those in the healthy group(U=57,P<0.001),benign pulmonary diseases group(U=70,P<0.001) and NSCLC group (U=144,P<0.001). Serum level of NSE in LD-SCLC group was significantly increased than those in the healthy group(U=303,P<0.001) and benign pulmonary diseases group(U=199,P<0.001).The differences between LD-SCLC group and NSCLC group were not significantly for NSE(U=433.5,P=0.013).In ED-SCLC group,ProGRP and NSE were higher than those in LD-SCLC group (U=119and153,P<0.05).(3) Analysing the receiver operating curves result showed that: whatever using healthy,benign pulmonary diseases and NSCLC groups as controls,the areas under receiver operating characteristic curves(ROC-AUC)of ProGRP was statistically higher than that of NSE in the SCLC group(Z=2.57,1.99and2.90,P<0.05,respectively). The ROC-AUC of combining detection of ProGRP and NSE was equal to ProGRP itself.(4) Using healthy,benign pulmonary diseases and NSCLC groups as controls respectively, the sensitivity of ProGRP were statistically higher than that of NSE in the SCLC group(χ2=4.90,4.00and4.00,P<0.05).(5) Using NSCLC group as control,the specificity of it was also higher than that of NSE in the SCLC group (χ2=6.13,P<0.05). The sensitivity of combining detection of ProGRP and NSE (parallel test) were increased and the specificity decreased when compared with that of ProGRP itself. At the same time,using heathy subjects,benign pulmonary diseases and NSCLC groups as controls respectively,the sensitivity of ProGRP was higher than that of NSE in LD-SCLC (χ2=6.13,5.14and5.14,P<0.05).Conclusion ProGRP has a higher diagnostic value than NSE in SCLC.