The value of tumor deposits in evaluating colorectal cancer survival and metastasis: a population-based retrospective cohort study

BACKGROUND: The role of tumor deposits (TDs) in TNM staging of colorectal cancer is controversial, especially the relationship with distant metastasis. PURPOSE: This study aimed to determine the effect of TDs on the survival of colorectal cancer and the occurrence of distant metastasis and to determine whether TDs (+) patients behaved similarly to stage IV patients. METHODS: A retrospective analysis of CRC patients from two large independent cohorts from the Surveillance Epidemiology and End Results (SEER) database (n = 58775) and the First Affiliated Hospital of Dalian Medical University (n = 742). RESULTS: Univariate logistic analyses revealed that TDs are an independent predictor of liver metastasis [p < 0.001; odds ratio (OR): 5.738; 95% confidence interval (CI): 3.560–9.248] in the First Affiliated Hospital of Dalian Medical University’s patients. Meanwhile, TDs are also an independent predictor of isolated organ metastasis [p <0.001; odds ratio (OR): 3.028; 95% confidence interval (CI): 2.414–3.79; multiple organ metastases [p < 0.001; odds ratio (OR): 4.778; 95% confidence interval (CI): 4.109–5.556]; isolated liver metastasis [p < 0.001; odds ratio (OR): 4.395; 95% confidence interval (CI): 4.099–4.713] and isolated lung metastasis [p < 0.001; odds ratio (OR): 5.738; 95% confidence interval (CI): 3.560–9.248] in the SEER database. Multivariate analyses suggested TDs are an independent poor prognostic factor for distant metastasis (p <0.001). CONCLUSIONS: Our results have shown that compared with patients with negative TDs, CRC patients with positive TDs are more likely to develop distant metastasis. Patients categorized as T4aN2bM0 TDs (+) and T4bN2M0 TDs (+) have a similar prognosis as those with stage IV, and hence these patients should be classified as stage IV. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12957-022-02501-9.