Diagnosis and predictors of sessile serrated adenoma

Post written by Dan Li, MD, from the Department of Gastroenterology, Kaiser Permanente Northern California, Santa Clara, California, USA.

In this retrospective cohort study, we sought to investigate whether educational training significantly improved the diagnosis rate of sessile serrated adenoma (SSA) among community gastroenterologists and pathologists. In addition, we also examined patient-level predictors of SSA and the correlation between the adenoma detection rate (ADR) and SSA detection rate (SDR).

Approximately 15-30% of colorectal cancers develop through the serrated pathway in which the precursor lesions are serrated lesions and, in particular, SSAs. SSAs are more commonly found in the proximal colon and can be difficult to detect during colonoscopy due to their flat appearance and subtle endoscopic features. Although the prevalence and predictors of SSAs have been increasingly studied, data from community-based settings are still limited. This knowledge gap has important implications for colorectal cancer prevention since patients with SSAs are recommended to have more frequent surveillance colonoscopies than patients with hyperplastic polyps (HPs). In addition, recent studies reported a correlation between the serrated polyp detection rate and conventional adenoma detection rate–a colonoscopy quality metric–but this deserves further investigation in community-based settings.

Our study presents a detailed evaluation of SSA prevalence and predictors in a community-based, integrated healthcare setting. We found that the annual average SDR increased significantly after implementing SSA diagnosis training for gastroenterologists and pathologists. The increase in the detection of proximal SSAs was accompanied by a decrease in the detection of HPs. Our data also demonstrated race/ethnicity as an independent predictor of SSA detection. SSA detection was lower among Asians (adjusted odds ratio [aOR] 0.46, 95% confidence interval [CI] 0.31-0.69) and Hispanics (aOR 0.59, 95% CI 0.36-0.95) compared with non-Hispanic whites. In addition, the SSA detection was higher among patients with synchronous conventional adenoma (aOR 1.46, 95% CI 1.15-1.86), HP (aOR 1.74, 95% CI 1.30-2.34), and current smokers (aOR 1.78, 95% CI 1.17-2.72). Lastly, there was a moderately-strong correlation between SDR and ADR (r=0.64, P=0.0003).


Figure 1. Average annual detection rates of proximal serrated polyps before and after training. Time of sessile serrated adenoma (SSA) diagnosis training for gastroenterologists and pathologists at 3 KPNC medical centers: 2012. Detection rates reflect average detection rates across 3 medical centers. Proximal colon includes the colonic segments from the cecum to the splenic flexure. Trend analysis: P < .0001 in all 3 lines. HP, Hyperplastic polyp; KPNC, Kaiser Permanente Northern California.

The moderately-strong correlation between the SDR and ADR suggests the latter can be used as a surrogate for the detection of SSAs in community settings, particularly given the relatively low prevalence of SSA, making SDR a challenging quality metric in clinical practice. On the other hand, more investigations will be beneficial to assess the feasibility and necessity of establishing a quality benchmark for the detection of clinically significant serrated polyps. In addition, further studies are necessary to determine the longitudinal impact of enhanced SSA detection on colorectal cancer incidence and mortality.

Read the full article online.

The information presented in Endoscopedia reflects the opinions of the authors and does not represent the position of the American Society for Gastrointestinal Endoscopy (ASGE). ASGE expressly disclaims any warranties or guarantees, expressed or implied, and is not liable for damages of any kind in connection with the material, information, or procedures set forth.

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