Aims The American Cancer Society reduced the age of CRC screening from 50 to 45 years in 2018 in response to a recent increase in early onset-CRC1. Our primary aim was to analyse the prevalence of colorectal preneoplastic and neoplastic lesions in patients under 50 referred for colonoscopy in our center. The secondary aim was to identify possible risk factors for the development of these lesions.
Methods We retrospectively collected data from 1882 patients under 50 referred for colonoscopy (Jan-2015 and Dec-2018). Of these, 104 (5.5%) were excluded due to the presence of a known diagnosis of CRC hereditary syndrome, for lack of important data, or for poor bowel preparation.
Results The cumulative incidence rate for adenoma was 27.5 per 1000 person-years and 3.8 per 1000 person-years for adenocarcinoma. Notably 13/27 patients (48%) with adenocarcinoma had a metastatic disease at the time of diagnosis. Adenomas have been identified mainly in the colon, while adenocarcinomas arose in most cases in the rectum (13/27,48,15%;p=0,009). Age≥40 was the main risk factor (OR 2.66;CI 1,69-4,18;p=0,000) for both adenoma (160/196 patients, 81.62%; mean age 43,5(± 5,7)) and adenocarcinoma (20/27 patients, 74.07%;mean age 42,5(±6,1)). Smoking seemed to have no role (p=0.772). IBD seemed to be protective for eoCRC. The presence of alarm symptoms was statistically significant at bivariable analysis for adenocarcinoma only (OR 3.60; CI 1,49-9,22; p=0,005). Having multiple gastrointestinal symptoms had a wide 95% confidential interval (OR 19.85; CI 2,64-149,42; p=0,004).
Conclusions We found a high cumulative incidence of both adenomas and eoCRC, this latter occurring more common in patients aged 40-49 without apparent risk factors, and being more aggressive. The presence of alarm symptoms or multiple symptoms generally lead to a late diagnosis. Hence, in the absence of stronger and more convincing evidence, it is reasonable to assume to benefit from an earlier screening strategy.
