Diagnostic value of tumor marker pro-gastrin-releasing peptide in patients with small cell lung cancer: a systematic review.

Background: Lung cancer is one of the most common malignancies in the world and one of the leading cancers that result in death. The aim of this study was to evaluate and compare the diagnostic value of the serum tumor marker pro-gastrin-releasing peptide 31-98 (ProGRP31-98) to pathological diagnosis as reference standard in patients with suspected small cell lung cancer (SCLC).

Methods: Literature searches covering 1978 through to 2009 were performed in Pubmed, OVID, MEDLINE, EMbase, Cancerlit, China National Knowledge Infrastructure (CNKI), and CBM using the key search words; 'small cell lung cancer', 'tumor marker', 'ProGRP31-98' and 'diagnostic tests', 'ELISA', 'EIA' and 'diagnostic accuracy'. Studies were collected and data analyzed to evaluate the diagnostic value of serum ProGRP31-98 levels for the diagnosis of SCLC compared with pathology. Eligibility criteria for inclusion in the analysis were based on criteria for diagnostic research published by the Cochrane Screening and Diagnostic Tests

Methods: Group (SDTMG). The characteristics of the included articles were appraised and the data were extracted from the original articles for further statistical analysis of study heterogeneity using Review Manager 4.2 software. Based on study heterogeneity analysis, a suitable 'effect' model was selected to calculate pooled sensitivity and specificity by meta-analysis. A Summary Receiver Operating Characteristic (SROC) curve and the area under the curve (AUC) were generated and sensitivity analysis conducted.

Results: A total of 22 articles were entered into this meta-review, including 11 English articles with a quality at level C. In total, the studies involved 6759 subjects, of which 1470 were diagnosed with SCLC by pathology, and 5289 subjects diagnosed with non-SCLC (NSCLC). The meta-analysis showed that heterogeneity among studies was high (P = 0.00001, I(2) = 86.8%). With ELISA, the pooled sensitivity was 0.72 (0.70 to 0.75 at 95%CI) and the pooled specificity was 0.93 (0.92 to 0.94 at 95%CI); the SROC and the AUC were 0.8817. These data suggest that ProGRP31-98 has a relatively high rate of missed diagnosis (28%), but a relatively low rate of misdiagnosis (7%).

Conclusion: From meta-analysis, we concluded that serum ProGRP31-98 is a valuable marker with a high specificity for diagnosis of SCLC with a similar diagnostic accuracy to pathology.