Deciding whether small colon polyps were adenomas or less dangerous hyperplastic ones can be done safely during the colonoscopy exam itself. Avoiding the need for an additional pathology test could make diagnosis faster and less expensive.
Adenomas have the potential to develop into colorectal cancer, but not all colon polyps are adenomas. Standard procedure is to remove all polyps seen during a colonoscopy and send them to the pathology lab for testing. However, doctors in London were able to accurately predict which polyps were adenomas more than 9 out of 10 times with colonoscopy alone.
During colonoscopies following up on positive fecal occult blood tests (FOBT) at St. Mark’s Hospital, four endoscopists predicted whether pathology tests would show an adenoma or a hyperplastic polyp based what they saw during the exam.
The optical diagnosis was based on colonoscopy using high-definition white light, followed by narrow-band imaging without magnification and chromoendoscopy, as needed.
In 130 patients, they found 363 polyps smaller than 10 millimeters, 278 of which were diagnosed both during the optical colonoscopy and by histopathology. Of those 80 were not neoplastic, meaning they weren’t the kind that turn into cancer.
Optical colonoscopy accurately diagnosed 186 of 198 adenomas and 55 of 62 hyperplastic polyps or 94 percent of adenomas and 89 percent of hyperplastic polyps. Overall accuracy was 93 percent.
Based on optical colonoscopy alone 82 patients could be told when to return for a follow-up exam, and the pathology report agreed with the follow-up interval for 80 of them or 98 percent.
Dr. Ana Ignjatovic and her team wrote,
For polyps less than 10 mm in size, in-vivo optical diagnosis seems to be an acceptable strategy to assess polyp histopathology and future surveillance intervals. Dispensing with formal histopathology for most small polyps found at colonoscopy could improve the efficiency of the procedure and lead to substantial savings in time and cost.