Differences in pathology and mutational status among colorectal cancer patients younger than, older than and of screening age

ABSTRACT Background Screening protocols for colorectal cancer (CRC) are broadly recommended and effective in reducing mortality. However, populations from different age groups can harbor distinct pathological and molecular profiles that can also be influenced by screening and polyp resection, especially in older ages. Methods We retrospectively analyzed tumors from stage IV CRC patients from a central pathology laboratory in Brazil that is a reference for mutational profiling countrywide. Patients were classified into age groups as follows: pre-screening age (PrSA; 75yo). Every tumor was centrally reviewed by the pathologist. Groups were compared regarding clinicopathologic features and the presence of RAS and BRAF mutations. Results We included 1,635 patients (215 PrSA, 1,213 SA and 207 PoSA). There was no difference among groups regarding sidedness (p=0.65) and KRAS mutations (p=0.57). Stage IV disease at diagnosis (p=0.04), the presence of a signet-ring cell component (p Conclusion BRAF mutations are more frequent among PoSA patients, and this seems to be a continuous trend. PrSA and PoSA patients seem to present a distinct profile from SA, including differences in molecular and pathological aspects. These findings could impact the frequency of screening tests among different age groups.