title: Clinical impact of K-ras mutation analysis in EUS-guided FNA specimens from pancreatic masses.
abstract: 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.
  
  
  METHODS
  Prospective registration, single-center study.
  
  
  METHODS
  Tertiary referral center.
  
  
  METHODS
  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.
  
  
  METHODS
  EUS-FNA, Cycleave polymerase chain reaction.
  
  
  METHODS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Gastroenterology, Aichi Cancer Center Hospital, Nagoya, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Ogura
authors.forename: Kenji
authors.initials: K
authors.lastname: Yamao
authors.forename: Akira
authors.initials: A
authors.lastname: Sawaki
authors.forename: Nobumasa
authors.initials: N
authors.lastname: Mizuno
authors.forename: Kazuo
authors.initials: K
authors.lastname: Hara
authors.forename: Susumu
authors.initials: S
authors.lastname: Hijioka
authors.forename: Yasumasa
authors.initials: Y
authors.lastname: Niwa
authors.forename: Masahiro
authors.initials: M
authors.lastname: Tajika
authors.forename: Shinya
authors.initials: S
authors.lastname: Kondo
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Shimizu
authors.forename: Vikram
authors.initials: V
authors.lastname: Bhatia
authors.forename: Kazuhide
authors.initials: K
authors.lastname: Higuchi
authors.forename: Waki
authors.initials: W
authors.lastname: Hosoda
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Yatabe
mesh_terms: D000230:Adenocarcinoma / Q000235:genetics* / Q000473:pathology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D044963:Biopsy, Fine-Needle; D004252:DNA Mutational Analysis; D003937:Diagnosis, Differential; D019160:Endosonography; D005260:Female; D011905:Genes, ras / Q000235:genetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D018358:Neuroendocrine Tumors / Q000235:genetics* / Q000473:pathology; D010183:Pancreatic Ducts; D010190:Pancreatic Neoplasms / Q000235:genetics* / Q000473:pathology; D050500:Pancreatitis, Chronic / Q000235:genetics / Q000276:immunology / Q000473:pathology; D011237:Predictive Value of Tests; D018084:Ultrasonography, Interventional; D055815:Young Adult