Understanding the behavior and progression of sessile serrated adenomas
As pathologists, diagnostic excellence is always our goal. Even so, we are often stymied by differences in terminology, inconsistent application of microscopic criteria and insufficient large-scale studies. These differences make it difficult to answer important questions in pathology. A good example is a relatively newly recognized colon polyp known as sessile serrated adenomas (SSAs). Not enough is known about these in comparison to other polyps of the colon and rectum, especially conventional adenomas (the well-known polyps that can lead to cancer). However, important work performed by the scientists at Inform Diagnostics resulted in interesting and compelling information.
SSAs are recognized as precursors to adenocarcinomas – a type of cancerous tumor. The common belief is that the development of cancer in SSAs is rapid. Some authors have recently suggested that these polyps explain the phenomenon of ‘interval’ cancers, or cancers arising between scheduled surveillance colonoscopies, and therefore should be treated aggressively.
A study in the Journal of Clinical Pathology authored by some of our Inform Diagnostics pathologists examined 290,810 colonoscopic specimens from 179,111 patients. Among those, SSAs were identified in 2,416 specimens from 2,139 patients. The majority of the affected patients were women. Based on significant age differences between patients with SSAs showing no precancerous change (“dysplasia”) compared to those with dysplasia and cancer, there appears to be a stepwise progression of dysplasia and carcinoma that averages 10 to 15 years, a period two to three times longer than that for conventional adenomas.
In the last several years, it has been suggested that SSAs progress to adenocarcinoma more rapidly than conventional adenomas. Inform Diagnostics research demonstrated the opposite – that this type of polyp appears to grow more slowly than is the current understanding, although further controlled follow-up studies are needed.
An accompanying editorial appearing in the Journal of Clinical Pathology critiquing the Inform Diagnostics study of sessile serrated adenomas (SSAs) highlighted Inform Diagnostics’ unique practice model.
The Inform Diagnostics approach ensures that each patient gets the benefit of the experience and knowledge of top gastrointestinal pathology experts. Variability is minimized through the company’s use of consensus terminology and microscopic criteria, lectures, journal reviews, and daily multi-headed microscope sessions. In addition, the large sample volumes analyzed by Inform Diagnostics has led to the development of a nationally-recognized GI database that fuels research at a remarkable speed.