On-site cytopathology falls short for pancreatic biopsy

Last Updated: 2015-09-17

By Will Boggs MD

NEW YORK (Reuters Health) - The immediate availability of on-site cytopathology evaluation during fine needle aspiration (FNA) of pancreatic masses does not increase the diagnostic accuracy of the biopsy, according to a multicenter study.

"The major impetus for this study was the lack of level 1 evidence with regards to the impact on an on-site cytopathologist during endoscopic ultrasound (EUS)-FNA of pancreatic masses," Dr. Sachin Wani, from the University of Colorado Anschutz Medical Center, Aurora, told Reuters Health by email.

EUS-guided FNA is integral to the diagnosis and staging of pancreatic cancer, which accounts for more than 37,000 deaths annually in the United States. The goal of on-site cytopathology evaluation (OCE) is to ensure the content and adequacy of a specimen in order to make the most accurate diagnosis.

Dr. Wani and colleagues from three tertiary referral centers compared the diagnostic yield of malignancy and the proportion of inadequate specimens in patients undergoing EUS-FNA of pancreatic masses with and without OCE.

Among the 241 patients included in their final analysis, there was no significant difference between the diagnostic yield of malignancy in the 120 with OCE absent (71.6%) and in the 121 with OCE present (75.2%; p=0.45).

There was also no difference between the groups in the proportion of inadequate specimens (13.3% with OCE absent versus 9.8% with OCE present, p=0.31), according to the September 8 online report in the American Journal of Gastroenterology.

Procedures with OCE present required fewer EUS-FNA passes (median, four versus seven with OCE absent) but took longer (mean, 23.7 minutes versus 19.3 minutes with OCE absent).

The two groups did not differ in the sensitivity or accuracy of the biopsy or in the need for repeat procedures, and the cost per patient for EUS-FNA was comparable with OCE ($2053) and without OCE ($2090).

"These results in conjunction with the cost analysis suggest that OCE may not change outcomes in patients with pancreatic masses undergoing EUS-FNA at tertiary care centers," the researchers concluded.

"It is critical to recognize that this study was conducted at tertiary care centers by experienced endosonographers," Dr. Wani said. "The generalizability of these results needs to be confirmed in future studies that include community practitioners and less experienced endosonographers."

Dr. Ji Young Bang, from Indiana University, Indianapolis, told Reuters Health by email, "The most surprising aspect of the study was that the proportion of inadequate specimens with or without onsite cytopathology evaluation was 9.8% and 13.3%, respectively. One would expect the rate of non-diagnostic specimens to be less than 5% when expert onsite cytopathology evaluation is available."

"Some tumors require additional tissue for specialized specimen processing that can be undertaken only off-site (pancreatic lymphoma: flow cytometry, neuroendocrine tumors: immunohistochemistry studies)," she explained. "The presence of onsite evaluation will facilitate procurement of additional tissue during the procedure in specialized collection media for these ancillary studies. Otherwise the patients may have to undergo a repeat EUS examination for procurement of additional tissue in specialized collection medium."

"On-site evaluation definitely decreases the rates of non-diagnostic sampling," Dr. Bang said. "All prior studies have shown that the presence of onsite cytopathology services improves diagnostic yield, decreases rates of indeterminate diagnosis, and lowers unsatisfactory specimen procurement."

This research was partially supported by an American College of Gastroenterology Clinical Research Award. The authors reported no disclosures.

SOURCE: http://bit.ly/1QIAx7q

Am J Gastroenterol 2015.