Prevalence of colorectal neoplasms in young, average risk individuals: A turning tide between East and West.

Aim: To determine the prevalence of colorectal neoplasia in average risk persons 40-59 years of age in Israel and to compare the results with other populations.

Methods: We reviewed the results of asymptomatic average-risk subjects, aged 40 to 59 years, undergoing their first screening colonoscopy between April 1994 and January 2014. The detection rates of adenoma, advanced adenoma (AA) and colorectal cancer (CRC) were determined in the 40's and 50's age groups by gender. The prevalence of lesions was compared between age groups. After meticulous review of the literature, these results were compared to published studies addressing the prevalence of colorectal neoplasia in similar patient groups, in a variety of geographical locations.

Results: We included first screening colonoscopy results of 1750 individuals. The prevalence of adenomas, AA and CRC was 8.3%, 1.0% and 0.2% in the 40-49 age group and 13.7%, 2.4% and 0.2% in the 50-59 age group, respectively. Age-dependent differences in adenoma and AA rates were significant only among men (P < 0.005). Literature review disclosed 17 relevant studies. As expected, in both Asian and Western populations, the risks for overall adenoma and advanced adenoma was significantly higher in the 50's age group as compared to the 40's age group in a similar fashion. The result of the current study were similar to previous studies on Western populations. A substantially higher rate of adenoma, was observed in studies conducted among Asian populations in both age groups.

Conclusion: The higher rate of colorectal neoplasia in Asian populations requires further investigation and reconsideration as to the starting age of screening in that population.