Comparison of early-onset and average-onset colorectal cancer in Saudi Arabia: A multicenter retrospective cohort study

Background: Although overall colorectal cancer (CRC) incidence has stabilized or declined in some regions, early-onset CRC (EO-CRC) is increasing in many countries. We aimed to compare EO-CRC with average-onset CRC (AO-CRC) to inform screening and care policies in Saudi Arabia. Methods: This retrospective study included patients with newly diagnosed CRC from, January 2017 to December 2023, at two referral centers in Saudi Arabia. We compared patient and tumor characteristics between EO-CRC and AO-CRC. Kaplan–Meier curve with log-rank test was used to compare overall survival up to 36 months after diagnosis. Results: Of 1365 patients with confirmed CRC, 406 (29.7%) had EO-CRC and 959 (70.3%) had AO-CRC, with more males in both groups (56% in EO-CRC and 53% in AO-CRC; P = 0.373). Hypertension and type 2 diabetes were more common in AO-CRC (both P < 0.001), while smoking history was more frequently documented in EO-CRC (16.7% vs. 12.0%; P = 0.054), although this difference did not reach statistical significance. Late-stage diagnosis was more frequent in EO-CRC (stage IV: 53.0% vs. 42.3%; P = 0.009), while tumor location was similar across groups, predominantly left-sided (87% vs. 89%; P = 0.391). Symptom profiles were broadly comparable between groups. Abdominal pain was more common in EO-CRC (60.3% vs. 53.6%; P = 0.015), whereas rectal bleeding occurred at similar frequencies in both groups (45.3% vs. 46.7%; P = 0.860). At 36 months, estimated survival probabilities were 0.75 for EO-CRC and 0.78 for AO-CRC, with no significant difference between groups on unadjusted analysis (log-rank P = 0.40). In multivariable Cox regression adjusting for sex and stage, EO-CRC was not associated with a difference in hazard of death than AO-CRC (adjusted hazard ratio 1.04, 95% confidence interval 0.80–1.37). Conclusion: EO-CRC comprised approximately one-third of CRC diagnoses in our cohort. Patients with EO-CRC had higher rates of late-stage diagnosis and more commonly presented with abdominal pain, whereas rectal bleeding, a well-recognized alarm symptom, occurred at similar frequencies in both groups. Despite later-stage presentation, short-term survival up to 36 months was similar between EO-CRC and AO-CRC. These findings highlight the need for tailored screening and early detection in younger populations.