Association between the histopathologic measurement of tumor–visceral peritoneal distance and prognosis in T3 colon adenocarcinoma

Objective To investigate the relationship between microscopic tumor–visceral peritoneal distance (T-VPD) and histopathological markers of aggressiveness in pT3 colon adenocarcinoma and to assess its prognostic significance. Methods A total of 329 resection specimens were retrospectively analyzed. T-VPD was defined as the shortest distance between the deepest invasive tumor front and the true serosal surface. Cut-off values of ≤0.01 cm, ≤0.05 cm, ≤0.1 cm, and ≤0.5 cm were evaluated. Associations with adverse histopathological features were examined using multivariable logistic regression. Overall survival (OS) and disease-free survival (DFS) were analyzed in 181 patients with available follow-up using Kaplan–Meier curves and Cox regression. Results T-VPD ≤0.5 cm was independently associated with lymphovascular invasion, whereas T-VPD ≤0.05 cm correlated with poor differentiation and tumor deposits. In OS analysis, advanced age, nodal metastasis, lymphovascular invasion, and perineural invasion were adverse prognostic factors, while a strong peritumoral lymphocytic response was protective. Tumor deposits predicted worse DFS, and peritumoral lymphocytic response remained protective. T-VPD was not an independent predictor of survival. Conclusion T-VPD reflects aggressive tumor behavior but lacks independent prognostic value. Combined with established adverse features, it may provide additional information for risk stratification in pT3 colon cancer.