Smaller tumor size is associated with poor survival in T4b colon cancer

AIM: To hypothesize that in patients with colon cancer showing heavy intestinal wall invasion without distant metastasis(T4b N0-2M0), small tumor size would correlate with more aggressive tumor behaviors and therefore poorer cancer-specific survival(CSS).METHODS: We analyzed T4 b N0-2M0 colon cancer patients in the Surveillance, Epidemiology and End Results(SEER) database. A preliminary analysis of T4 b N0-2M0 colon cancer patients at the Fudan University Shanghai Cancer Center is also presented.RESULTS: A total of 1734 T4 b N0-2M0 colon cancer patients from the SEER database were included. Kaplan-Meier analysis revealed decreasing CSS with decreasing tumor size(P < 0.001). Subgroup analysis showed a significant association between poorer CSS with smaller tumor size in T4 b N0 patients(P = 0.024), and a trend of association in T4 b N1(P = 0.182) and T4 b N2 patients(P = 0.191). Multivariate analysis identified tumor size as an independent prognostic factor for CSS in T4 b N0-2M0 patients(P = 0.024). Preliminary analysis of Fudan University Shanghai Cancer Center samples suggested the 5-year CSS was 50.0%, 72.9% and 77.1% in patients with tumors ≤ 4.0 cm, 4.0-7.0 cm and ≥ 7.0 cm.CONCLUSION: Smaller tumor size is associated with poorer CSS in the T4 b N0-2M0 subset of colon cancer, particularly in the T4 b N0M0 subgroup.