Accuracy and other quality indicators of solid pancreatic mass endoscopic ultrasound-guided fine needle aspiration and biopsy in two academic endoscopy centers

K-ras mutation detected by peptide nucleic acid-clamping polymerase chain reaction, Ki-67, S100P, and SMAD4 expression can improve the diagnostic accuracy of inconclusive pancreatic EUS-FNB specimens

OBJECTIVES

We aimed to assess the diagnostic utility of an immunohistochemical panel including calcium-binding protein P, p53, Ki-67, and SMAD family member 4 and K-ras mutation for diagnosing pancreatic solid lesion specimens obtained by endoscopic ultrasound-guided fine-needle biopsy and to confirm their usefulness in histologically inconclusive cases.

METHODS

Immunohistochemistry and peptide nucleic acid-clamping polymerase chain reaction for K-ras mutation were performed on 96 endoscopic ultrasound-guided fine-needle biopsy specimens. The diagnostic efficacy of each marker and the combination of markers was calculated. The diagnostic performances of these markers were evaluated in 27 endoscopic ultrasound-guided fine-needle biopsy specimens with histologically inconclusive diagnoses. A classification tree was constructed.

RESULTS

K-ras mutation showed the highest accuracy and consistency. Positivity in more than two or three of the five markers showed high diagnostic accuracy (94.6 % and 93.6 %, respectively), and positivity for more than three markers showed the highest accuracy for inconclusive cases (92.0 %). A classification tree using K-ras mutation, Ki-67, S100P, and SMAD4 showed high diagnostic performance, with only two misclassifications in inconclusive cases.

CONCLUSIONS

K-ras mutation detection via peptide nucleic acid-clamping polymerase chain reaction is a stable and accurate method for distinguishing between pancreatic ductal adenocarcinoma and non-pancreatic ductal adenocarcinoma lesions. A classification tree using K-ras mutation, Ki-67, S100P, and SMAD4 helps increase the diagnostic accuracy of cases that are histologically difficult to diagnose.

Essential reading from the editor’s desk

Quality measures are becoming increasingly important in clinical practice, not only as a monitoring tool in the hospital for internal quality purposes but more and more also in communication with the general community as publicly available indicators of quality (1-3). Especially for technical subspecialties such as endoscopy, it is key that outcome and complications are closely monitored. This is also reflected in a multitude of quality initiatives of national and international endoscopy societies (4). In the current edition of the Acta, Moreels and colleagues evaluated the accuracy of self-reported adverse events by the endoscopists by comparing it to a retrospective analysis of the medical records (5). The total adverse events rate was 1.95% with only half of the events being voluntarily reported by the endoscopist. Even if 2/3 of the unreported events were mild, this important study still highlights that the current reporting methods are flawed and a more user-friendly ad-hoc registration system, integrated in the electronic medical records, should be developed.