Multicenter cohort study of incidence and survival of early-onset metastatic colorectal adenocarcinoma

There is evidence of increasing incidence of early-onset (EO; diagnosed before age 50 years) colorectal metastatic adenocarcinoma (mADC). A multicenter cohort study in France investigated incidence and survival according to metastatic characteristics of colorectal mADC in EO compared with older patients. Among 37,297 patients with a diagnosis of invasive colorectal adenocarcinoma between 2004 and 2021, 1558 (4.2%) received the diagnosis before age 50 years, and 9995 (26.8%) had mADC. The incidence of single-site metastases did not increase in any age class or sex, whereas the incidence ofmultiple-site metastases among patients aged 15 to 39 years increased annually by 9.5% in male and 10.3% in females. The increase in the EO mainly concerned metastasis in the peritoneum and to a lesser extent in the liver. Net survival of mADC improved over time, except for peritoneal metastasis, and was consistently higher among patients aged 15 to 49 years than among those aged 50 to 75 years. The authors conclude that in this cohort study the incidence of EO mADC increased mainly among patients with multiple metastatic sites and those with peritoneum than liver or lung involvement, whereas net survival improved over time except for peritoneal involvement.