Performance of K-ras mutation analysis plus endoscopic ultrasound-guided fine-needle aspiration for differentiating diagnosis of pancreatic solid mass: a meta-analysis.

Background: Difficulties persist in differentiating pancreatic ductal adenocarcinomas (PDAC) from pancreatic inflammatory masses (PIM). Auxiliary diagnostic techniques which enhance the endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) diagnostic yield have been attempted, for example, K-ras mutation analysis. We aimed to evaluate the accuracy of K-ras mutation analysis combined with EUS-FNA for the differential diagnosis of PDAC and PIM by pooling data of existing trials.

Methods: We systematically searched the Medline, PubMed, Web of Science, Embase, and Cochrane Central Trials databases for relevant published studies. Meta-analysis was performed. Pooling was conducted in fixed-effect model or random-effect model.

Results: In total eight studies, with 696 cases of PDAC and 138 cases of PIM, met our inclusion criteria. The pooled sensitivity, specificity, positive likely ratio and negative likely ratio of K-ras mutation analysis combined with cytopathology for diagnosis of PDAC versus PIM were 90%, 95%, 13.45, and 0.13, respectively. Especially, among total 123 patients whose EUS-FNA results were inconclusive or negative, fifty-nine had K-ras mutations and were finally diagnosed with PDAC (48%, 59/123). Publication bias was not present.

Conclusions: Combining K-ras mutation analysis with routine cytology moderately improves the ability of EUS-FNA to differentially diagnose between PDAC and PIM, especially for patients with suspected PDAC yet inconclusive EUS-FNA findings, and may prove to be a valuable supplemental method to EUS-FNA.