S1 Data -

Background
The prognostic value of tumor deposits (TDs) in stage III colorectal cancer (CRC) patients is poorly described based on the current tumor node metastasis (TNM) stage system.
Materials and methods
Based on the data from the Surveillance, Epidemiology, and End Result (SEER) database between 2010 to 2020 and local hospital between 2006 to 2022, the clinicopathological features of stage III CRC patients with TDs were screened by Chi-square test. Kaplan-Meier curves were performed to describe the significant difference in overall survival (OS) among the different groups, and log-rank tests were used to compare the cumulative survival distributions.
Result
Patients with TDs exhibited more aggressive tumors, characterized by advanced T staging (T3&T4), N staging (N2), perineural invasion, and more advanced TNM stage. The presence of TDs was identified as a negative prognostic factor in stage III CRC patients, with the co-existence of TDs and lymph node metastasis associated the poorest prognosis. A pairwise comparison revealed no statistically significant difference between TD+N1a/b and N1c groups, while the OS of TD-LN+ (TD- N1a/b) patients was the most favorable within the N1 stage. Notably, patients with a single lymph node positive had a significantly better OS than those with a single TD positive.
Conclusion
The presence of tumor deposits was a negative prognostic factor in stage III colorectal cancer patients, and the significance of tumor deposits was underestimated in the current TNM staging system.