CHICAGO – A substantial number of adenomas may be missed by pathologists, but changes in the standard methodology can significantly decrease that amount, according to findings presented at Digestive Disease Week®.
A nondiagnostic result is common in histologic specimens obtained from the colon and occurs in about 9% of biopsies. However, a protocol known as “exhaustive leveling of histologically nondiagnostic specimens” can significantly increase the detection of adenomas.
“In our study, we were answering the question, Are pathologists missing adenomas?” said Lauren Suzanne Cole, MD, of the University of Arizona, Phoenix.
During a standard pathology analysis, 50% of the polyp isn’t analyzed at all, and the remaining half is cut into three different levels that are approximately 2 microns each. “Ultimately, less than 1% is actually reviewed by the pathologist,” she said.
GI physicians may perceive that the pathology review is definitive, Dr. Cole explained. “They believe that the section is viewed in its entirety, when, in reality, 50% of the tissue block is cut and less than 1% is viewed to come up with a diagnosis.”
The term nondiagnostic biopsy generally indicates that a specific diagnosis cannot be made. In their literature review, Dr. Cole and her team looked at eight published studies and found that a nondiagnostic biopsy was a very common result, ranging from 9% to 16%. In addition, the literature also showed that there was a significant conversion rate in nondiagnostic biopsies, from 4% to 20%, when additional leveling was performed.
In the current study, they investigated whether the detection of adenomas is improved when pathologists examine representative levels taken from the entire tissue block of specimens that have been diagnosed as nondiagnostic.
They conducted a retrospective review of pathology results that had been performed by a large GI practice (from November 2012 to November 2016) after implementing a so-called “polyp protocol,” which included an analysis of tissue sections from the entire tissue block (exhaustive leveling) of polyps initially deemed histologically nondiagnostic.
A total of 120,115 polyps had been removed during the study period, and, of this group, 10,768 (9%) were initially found to be nondiagnostic and were selected for exhaustive leveling. After exhaustive leveling, more than one-third (37%; n = 3,964) of the diagnoses converted to adenoma.
When the detection rate for adenomas for exhaustive leveling was compared with that for standard leveling, there was a statistically significant 3.3% increase (P less than .0001) from baseline.
“Our conclusion is that adenomas are missed,” said Dr. Cole. “This is partially because pathologists are not typically evaluating an entire specimen.”
These results support the need for implementing standardized protocols for exhaustive leveling as a means of increasing the adenoma detection rate, she noted. “Our research emphasizes the need for further studies assessing pathology specimen processing and analysis.”
Digestive Disease Week® is jointly sponsored by the American Association for the Study of Liver Diseases (AASLD), the American Gastroenterological Association (AGA) Institute, the American Society for Gastrointestinal Endoscopy (ASGE), and the Society for Surgery of the Alimentary Tract (SSAT).
Dr. Cole declared no relevant disclosures.