A new comparative analysis, published in the Journal of the National Cancer Institute, suggests that early-onset colorectal cancer (EO-CRC) does not seem to be biologically different from, or more aggressive than, average-onset CRC (AO-CRC).

Researchers stated that EO-CRCs are more often left-sided and present with rectal bleeding and abdominal pain. However, they cannot be otherwise clinically and genomically distinguished from AO-CRCs. The researchers also stated that more aggressive treatment based on age is not required or effective. While obesity, diabetes, and a Western diet have been found to be the risk factors in older individuals, they do not seem to be definitively linked with the increasing incidence of EO-CRC.

Rectal bleeding was found to be more common in the early-onset subgroups (≤35 years: 41.1%, 36-49 years: 41.0%) in comparison with the average-onset group (25.9%). The results were similar for abdominal pain (37.1%, 34.0%, and 26.8%, respectively), left-sided tumors (80.8%, 83.7%, and 63.9%, respectively), and rectal cancer (33.7%, 33.7%, and 22.6%, respectively). Anemia was more common in the AO-CRC cohort (14.6%) compared with the EO-CRC subgroups (≤35 years: 2.0%, 36-49 years: 3.6%)… (Medpage Today)