Clinical usefulness of KRAS mutational analysis in the diagnosis of pancreatic adenocarcinoma by means of endosonography-guided fine-needle aspiration biopsy.
OBJECTIVE
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 concurrence 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.
Pellisé
M
M
Department of Gastroenterology, Institut de Malalties Digestives, Hospital Clínic, Barcelona, Spain.
Castells
A
A
Ginès
A
A
Solé
M
M
Mora
J
J
Castellví-Bel
S
S
Rodríguez-Moranta
F
F
Fernàndez-Esparrach
G
G
Llach
J
J
Bordas
J M
JM
Navarro
S
S
Piqué
J M
JM
D000230:Adenocarcinoma / Q000175:diagnosis*; D001707:Biopsy, Needle / Q000379:methods; D003362:Cost-Benefit Analysis; D004252:DNA Mutational Analysis / Q000379:methods / Q000592:standards*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000235:genetics; D010190:Pancreatic Neoplasms / Q000175:diagnosis*; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D018084:Ultrasonography, Interventional