Clinical impact of K-ras mutation analysis in EUS-guided FNA specimens from pancreatic masses

Takeshi Ogura, Kenji Yamao, Akira Sawaki, Nobumasa Mizuno, Kazuo Hara, Susumu Hijioka, Yasumasa Niwa, Masahiro Tajika, Shinya Kondo, Yasuhiro Shimizu, Vikram Bhatia, Kazuhide Higuchi, Waki Hosoda, Yasushi Yatabe

Research output: Contribution to journalArticlepeer-review

57 Citations (Scopus)


Background: EUS-guided FNA (EUS-FNA) is considered optimal for differentially diagnosing pancreatic masses. However, the sensitivity of EUS-FNA ranges from 65% to 95%, respectively, which requires improvement. Objective: To evaluate clinical impact of K-ras mutation analysis in EUS-FNA specimens from pancreatic masses. Design: Prospective registration, single-center study. Setting: Tertiary referral center. Patients: This study involved 394 consecutive patients with pancreatic masses (307 pancreatic ductal adenocarcinomas [PDACs], 47 pancreatic inflammatory lesions, and 40 other types of tumors) who underwent EUS-FNA and analysis of K-ras mutations. Intervention: EUS-FNA, Cycleave polymerase chain reaction. Main Outcome Measurements: Improvement of the diagnostic accuracy by K-ras mutation analysis; absence of K-ras mutations in non-PDAC masses. Results: K-ras mutations were detected in 266 of 307 PDAC aspirates (87%) and in 3 of 87 non-PDAC masses (3%). K-ras mutations were detected in 18 of 39 patients (46%) who remained cytohistopathologically undiagnosed. The sensitivity, specificity, positive and negative predictive values, and accuracy of cytohistopathological and K-ras mutation analyses alone were 87%, 100%, 100%, 54%, and 89%, respectively, and, when combined, were 93%, 100%, 100%, 68%, and 94%, respectively. Adding K-ras mutation analysis to standard cytohistopathological assessment increased the sensitivity and accuracy of EUS-FNA by 6% (P <.001) and 5% (P <.001), respectively. Limitations: Single-center study. Conclusions: K-ras mutation analysis may be helpful in patients with suspected PDAC yet inconclusive EUS-FNA findings. K-ras mutations were extremely rare in pancreatic inflammation and other pancreatic tumors.

Original languageEnglish
Pages (from-to)769-774
Number of pages6
JournalGastrointestinal endoscopy
Issue number4
Publication statusPublished - 04-2012
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Radiology Nuclear Medicine and imaging
  • Gastroenterology


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