Background and aim: Serrated lesions (SLs) have attracted attention as precursors of colorectal cancer (CRC). However, their prevalence, risk factors, and clinical significance have not been satisfactorily elucidated. This study used high-quality colonoscopy data to determine the prevalence of SLs and to identify their risk factors and relationship with synchronous advanced colorectal neoplasia (ACN) in asymptomatic screened individuals.
Methods: This study included data for 5,218 individuals who underwent first-time screening colonoscopy by highly experienced endoscopists. The relationships between baseline characteristics and the presence of SLs and those between the presence of SLs and synchronous ACN were assessed using the chi-square test and multivariate logistic regression.
Results: The proportions of individuals with SLs and right-sided SLs were 23.3% and 7.6%, respectively. Age, sex, family history of CRC, smoking, and body mass index were significantly related with the presence of SLs, and current smoking was most strongly associated with SLs (adjusted odds ratio [aOR] 2.6, 95% confidence interval [CI] 2.1-3.2). The aOR (95% CI) of the presence of SLs, SLs sized ≥10 mm, and right-sided SLs ≥5 mm for synchronous ACN was 1.4 (1.1-1.9), 3.5 (1.3-9.6), and 1.9 (1.0-3.8), respectively. The presence of left-sided SLs ≥10 mm (without right-sided SLs) was also significantly associated with ACN (aOR 8.1, 95% CI 2.0-33.7).
Conclusions: The relatively high prevalence of SLs and risk factors in screened individuals were elucidated and the significant relationship between SLs, particularly SLs ≥10 mm and right-sided SLs ≥5 mm, and synchronous ACN was confirmed.
Keywords: Advanced colorectal neoplasia; colonoscopy; colorectal cancer; serrated lesion.