Understanding lymph node metastasis in early-onset colorectal cancer is crucial for surgical decision-making and patient management.

• Early-onset patients show more aggressive tumor features vs. late-onset: larger size, poorer differentiation, and higher lymphovascular invasion rates.
• Key predictors for lymph node metastasis include elevated CA19-9, T3/T4 stage, nerve invasion, and lymphovascular invasion, with odds ratios over 2.4 for some factors.
• High microsatellite instability is identified as a protective factor against metastasis.

These findings highlight the importance of age-specific assessment tools to tailor surgical approaches and improve outcomes for younger patients.