Published online Aug 28, 2013. doi: 10.3748/wjg.v19.i32.5271
Revised: May 15, 2013
Accepted: June 8, 2013
Published online: August 28, 2013
Processing time: 161 Days and 3.4 Hours
AIM: To examine the epidemiology and the morphology of the proximal sessile serrated adenomas (SSAs).
METHODS: We conducted a retrospective study to identify patients with SSAs using a university-based hospital pathology database query from January 2007 to April 2011. Data collected included: age, gender, ethnicity, body mass index, diabetes, smoking, family history of colorectal cancer, aspirin, and statin use. We collected data on morphology of SSAs including site (proximal or distal), size, and endoscopic appearance (flat or protuberant). We also compared proximal SSAs to proximal tubular adenomas detected during same time period.
RESULTS: One hundred and twenty patients with SSAs were identified: 61% were distal and 39% were proximal SSAs. Proximal SSAs were more likely to be flat than distal (100% vs 78% respectively; P = 0.0001). Proximal SSAs were more likely to occur in smokers (OR = 2.63; 95%CI: 1.17-5.90; P = 0.02) and in patients with family history of colorectal cancer (OR = 4.72; 95%CI: 1.43-15.55; P = 0.01) compared to distal. Proximal SSAs were statistically more likely to be ≥ 6 mm in size (OR = 2.94; P = 0.008), and also more likely to be large (≥ 1 cm) (OR = 4.55; P = 0.0005) compared to the distal lesions. Smokers were more likely to have proximal (P = 0.02), flat (P = 0.01) and large (P = 0.007) SSAs compared to non-smokers. Compared to proximal tubular adenomas, proximal SSAs were more likely to be large and occur in smokers.
CONCLUSION: Proximal SSAs which accounted for two-fifths of all SSAs were more likely to present as flat lesions, larger SSAs, and were more likely to occur in smokers and in patients with family history of colorectal cancer. Our data has implications for colorectal cancer screening.
Core tip: Sessile serrated adenomas (SSAs) have been implicated in the alternative pathway for colorectal carcinoma. Proximal SSAs might account for higher incidence of interval colorectal cancers (CRC) on the right side given the fact that these are often flat and difficult to detect. Our study is first to compare the morphology and epidemiology of proximal SSAs with distal SSAs. We found proximal SSAs are more likely to present as flat lesions, larger SSAs, and were more likely to occur in smokers and in patients with family history of CRC. These findings have implications for CRC screening.