Clinical usefulness of KRAS mutational analysis in the diagnosis of pancreatic adenocarcinoma by means of endosonography-guided fine-needle aspiration biopsy

Authors


Dr A. Castells, Department of Gastroenterology, Institut de Malalties Digestives, Hospital Clínic, Villarroel 170, 08036 Barcelona, Catalonia, Spain.
E-mail: acastell@medicina.ub.es

Summary

Aim : To establish the usefulness of KRAS mutational analysis in the diagnosis of pancreatic adenocarcinoma by comparing this technique with conventional cytology in aspirates obtained by endosonography-guided fine-needle aspiration.

Methods : All consecutive patients with pancreatic focal lesions undergoing endosonography-guided fine-needle aspiration were included. Samples were obtained with the concourse of an attendant cytopathologist. Detection of codon-12 KRAS mutations was performed by the restriction fragment length polymorphism-polymerase chain reaction method. The effectiveness of conventional cytology, KRAS mutational analysis and their combination was established with respect to the definitive diagnosis. A cost-effectiveness analysis was also performed.

Results : Thirty-three patients had pancreatic adenocarcinoma and 24 patients had other lesions. A total of 136 samples was obtained. In patients in whom specimens were adequate (93% for cytology; 100% for mutational analysis), the specificity of both techniques was 100%, whereas the sensitivity favoured cytology (97% vs. 73%). When inadequate samples were considered as misdiagnosed, a combination of both techniques reached the highest overall accuracy (cytology, 91%; mutational analysis, 84%; combination of both, 98%).

Conclusions : Cytology from aspirates obtained by endosonography-guided fine-needle aspiration is the most precise single technique for the diagnosis of pancreatic adenocarcinoma. However, when adequate specimens are not available to reach a cytological diagnosis, the addition of KRAS mutational analysis represents the best strategy.

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