Prognostic significance of tumor deposit counts in stage III colorectal cancer based on T/N staging and chemotherapy status: A retrospective cohort study

Background

We aimed to evaluate the impact of tumor deposit (TD) count on cancer-specific survival (CSS) and disease-free survival (DFS) in stage III colorectal cancer (CRC) patients stratified by T and N staging, and further explore its impact on chemotherapy effect.

Method

We determined the optimal TD cut-off value for stage III CRC patients from the SEER database utilizing X-tile analysis, and retrospectively analyzed the clinicopathological data of 443 patients from the First Affiliated Hospital of Wenzhou Medical University from 2019 to 2020. Chi-square (χ2) tests compared categorical variables. Kaplan–Meier assessed CSS and DFS. Cox regression model evaluated prognostic factors on CSS and DFS.

Results

2TD is the optimal cutoff value for prognosis in Stage III CRC, in the low-risk group (T1-T3 and N1), ≥3TD patients faced higher cancer-specific mortality (HR = 3.445, 95%CI = 1.254–9.465, P = 0.017) and recurrence risks (HR = 1.934, 95%CI = 1.095–3.416, P = 0.024) vs. 1-2TD, while 1-2TD and no-TD patients showed no difference in survival. In the high-risk group (T4 or N2), both ≥3TD and 1-2TD patients had poor prognosis. Chemotherapy reduced cancer-specific mortality in both groups (1-2TD: HR = 0.347, 95%CI = 0.138–0.870, P = 0.024; ≥3TD: HR = 0.272, 95%CI = 0.077–0.960, P = 0.043) but did not significantly improve recurrence risk (1-2TD: P = 0.177; ≥3TD: P = 0.058).

Conclusion

TD indicates poor prognosis in stage III CRC, with ≥3 TD significantly worsening survival, yet the prognosis remains poor in TD-positive patients with high-risk (T4 or N2) regardless of TD count. Moreover, TD count does not influence chemotherapy's mortality benefit.