Comparison of the short- and long-term prognosis of early-onset colorectal cancer compared with later-onset colorectal cancer: A systematic review and meta-analysis.

Background and Aims: The annual incidence of early-onset colorectal cancer (EOCRC) is increasing at an alarming rate. The prognosis of EOCRC remains controversial, and whether the early onset is a risk factor for colorectal cancer remains unclear. Methods: We searched four electronic bibliographic databases from database inception to April 25, 2022 for studies that included both early- and later-onset patients and performed a prognostic analysis. Random-effects models were used to summarize the prognostic information extracted by the investigators, including overall survival (OS), cancer-special survival (CSS), and disease-free survival (DFS). Network meta-analysis (NMA) was used to compare patients' long-term prognoses in different age subgroups. Results: After 694 reports were screened, 13 studies were included in the final analysis, with a total of 448,781 CRC cases. In the meta-analysis of the 5-year OS, EOCRC had a better prognosis compared to LOCRC (hazard ratio [HR] 0.87, 95% confidence interval [CI], 0.74-0.99; relative risk [RR] 0.83, 95% CI, 0.78-0.89). No difference in prognosis was found between the two groups in terms of 5-year CSS (RR 0.99, 95% CI, 0.93-1.05), 5-year DFS (RR 0.90, 95% CI, 0.74-1.09), and short-term OS. In the NMA, patients aged <30 years had the worst outcome (surface under the cumulative ranking curve [SUCRA], 15.8%) in 5-year OS; consistent results were observed in the analysis of 5-year CSS (<30 years, SUCRA 4.5%), but the difference was not statistically significant. Conclusion: Although patients with early-onset CRC had better OS than those with later-onset CRC, there was no difference in the CSS. Meanwhile, the trend for survival was worse in younger patients, especially in those ages 18-29 years. Thus, more attention should be paid to early diagnosis and treatment of EOCRC. Systematic Review and Meta­Analysis Registration: The systematic review and Meta-analysis protocol was registered with PROSPERO (registration number CRD42022334697).