Clinicopathological features and risk stratification for lymph node metastasis in early-stage colorectal cancer (from intramucosal carcinoma to SM2): a large-scale retrospective study based on a Chinese population.

Lymph node metastasis rates increased with cumulative adverse indicators (0-4 indicators: 4.4%、11.8%、17.0%、27.1%、30.3%; P < 0.001).

In the SM2 subgroup, high-grade histology and lymphovascular invasion were independent risk factors.

Notably, SM2 patients with ≥ 2 risk factors (high-grade histology / lymphovascular invasion / intermediate and high-grade tumor budding) had significantly higher lymph node metastasis rates (20.5%-33.3%) (P < 0.05), whereas SM1 tumors could not be further stratified.