Presence of advanced preneoplastic lesions in patients diagnosed with early onset colorectal cancer: Are they different from those found in older patients?

Aims The incidence of early colorectal cancer (CRC), with diagnosis before 50 years old, is increasing. It has been described that these tumours may exhibit differente biological behaviour than those occurring at an older age. However, it has not been evaluated whether these differences might also exist in the incidence of advanced preneoplastic lesions.

The aim of the study is to evaluate differences in CRC location and type of advanced lesions (advanced adenomas or serrated polyps and synchronous or metachronous) in early and elder-age CRC groups

Methods Retrospective observational study of patients diagnosed with colorectal cancer (CRC) between 2021-2022 in our hospital. Initial and follow-up endoscopic findings are compared between patients diagnosed before and after the age of 50.

Results During the study period, 276 patients with colorectal cancer were included. Of these, 93.1% were over 50 years old (n=257, 72.43±10.38 years) and 6.9% were younger (n=19, 44.11±5.17 years). In the group over 50, the most common locations were the rectum (27.2%) and sigmoid colon (26.5%). In the group under 50, nearly half of the cases were in the rectum (42.1%, p=0.9). In the late-onset CRC group, 16.7% had advanced lesions (AL), with 93% of these being advanced adenomas (AA) and 7% advanced serrated lesions (ASL). While, in the early CRC group, 15.8% of patients had advanced lesions, but ASL were more frequent (66.4%) than advanced adenomas (33.4%). The presence of advanced adenomas were significantly higher in the older patients group (15.2% vs 5.3%, p=0.041). In both groups, synchronous lesions (87.5%) and a non-coincident location with the tumor (70%) were the most frequent findings. Advanced serrated lesions (ASL) were synchronous in all cases and more frequent among younger patients (10.5% vs 1.9%) although this difference was not statistically significant.The ASL location was coincident with original tumour (57.1%) without differences between groups.

Conclusions Differences in advanced polyps frequency and CRC location between groups were not found. However, advanced adenomas were significantly more frequent in older group. Moreover, in both groups, advanced preneoplastic lesions were mostly synchronous and their location was different from the original tumour.