Multicenter retrospective study of incidence and characteristics of metastatic colorectal cancer diagnosed before age 35 years

The incidence of early-onset colorectal cancer (EOCRC), diagnosed before the age of 50 years, is increasing. Studies of patients diagnosed prior to age 35 years as a distinct subset of EOCRC have yielded inconsistent results. A multicenter retrospective analysis of prospectively collected data in the Treatment of Recurrent and Advanced Colorectal Cancer (TRACC) Australasian registry ompared demographic and clinicopathologic characteristics of metastatic CRC patients diagnosed < 35Y with remaining metastatic EOCRC patients diagnosed 35-49Y and older patients (≥50Y) as reference. From July 2009 to December 2023, the authors identified 4399 patients with mCRC, including 133 (3.0%) <35Y and 537 (12%) 35-49Y. The proportion of < 25Y among newly diagnosed mCRC increased per calender year (OR 1.07; 95% CI 1.02-1.11). Gender, ECOG performance status, and primary tumor location were similar for xtagstartz35Y and 35-49Y. Compared to 35-49Y, <35Y had more de novo metastatic disease (79% versus 70%; p=0.04),