Clinicopathological Factors and Nomogram Construction for Lymph Node Metastasis in Early-Onset Colorectal Cancer

Colorectal cancer (CRC) is the most prevalent malignant tumor of the digestive system globally, ranking third in incidence and second in mortality. The rates among individuals under 50 years (termed early-onset CRC, EO-CRC) have risen by approximately 2% annually over the past decade. We aim to compare clinicopathological profiles between EO-CRC and late-onset CRC (LO-CRC) patients, with a subsequent focus on identifying preoperative predictors of lymph node metastasis (LNM) in EO-CRC.

In this retrospective study, 3920 CRC patients were selected. The preoperative and postoperative clinicopathological features were retrospectively studied. Univariate analysis and multivariate analysis were performed using binary logistic regression to determine the predictive factors for LNM. Odds ratio (OR) and 95% confidence interval (CI) were calculated.

3327 (84.9%) patients were diagnosed with LO-CRC, while 593 (15.1%) patients were identified with EO-CRC. Compared to LO-CRC, EO-CRC patients exhibited significantly more aggressive tumor characteristics, including larger tumor size (p = 0.002), higher rates of poor differentiation(p < 0.001), advanced T stage (p = 0.016), N2 stage (p = 0.004), elevated perineural invasion (p < 0.001) and lymphovascular invasion (LVI) (p = 0.002). Multivariate analysis revealed elevated carbohydrate antigen 19 - 9 (CA19-9) (p < 0.001, OR = 2.433), T3/T4 stage classification (p = 0.001, OR = 2.323), nerve invasion (p = 0.001, OR = 2.482), and LVI (p = 0.003, OR = 2.180) were independent risk factors of LNM. In contrast, high microsatellite instability (MSI-H) (p < 0.001, OR = 0.371) seemed to be an independent protective factor.

These findings refine our understanding of metastatic drivers in EO-CRC and underscore the need for age-specific risk assessment tools. A significant potential of MSI-H status was indicated in the treatment of patients with EO-CRC.