Risk of neoplasia according to age and sex – how to prioritize high-risk groups in colorectal cancer screening

Summary: Background: Early onset colorectal cancer (CRC; cancer in a person younger than 50 years) has increasing incidence in the last few years. Current age limit for population screening in Czech Republic is 50 years of age. Lowering the age limit is necessary, but this collides with limited capacity of endoscopy units. The aim of our study was to evaluate the risk of neoplastic lesions according to age and gender. Methods: It was an observational retrospective study conducted in a non-university hospital Frýdek-Místek between 2017 and 2023. The incidence of all neoplastic lesions was evaluated in age groups 30–34, 35–39, 40–44, 45–49, 50–54, and 55–59 years separately for men and women. Two dichotomous variables were compared using the Chi square test, where P <0.05 was considered significant. Results: During the study period, 13,352 colonoscopies were done in total (7,094 men, 6,258 women); 2,678 in patients <50 years of age, and 10,674 in patients ≥50 years. The incidence of all neoplastic lesions in each age group was always significantly higher than in the previous age group, the results are shown in the tables below in this text. As we determined the reference group of women 50–54 years of age as the group with the lowest risk of neoplastic lesions currently involved in population screening, the comparable risk of all neoplastic lesions was observed for men 45–49 years of age (P = 0.304) and also for men 40–44 years of age (P = 0.086). Women 45–49 years of age (P = 0.001) have a significantly lower risk of advanced neoplastic lesions than women 50–54 years of age. Conclusions: If we do not want to overload the capacity of endoscopy units, we should lower the age limit for population screening by age and gender groups. According to our retrospective data, the highest risk of neoplastic lesions is found in men 45–49 years of age, and after them men 40–44 years of age. Women 45–49 years of age have a significantly lower risk of CRC. Key words: colorectal cancer – diagnosis – mass screening – population groups