Prognostic significance of tumor deposits in patients with stage III colon cancer

Objective To investigate the prognostic significance of tumor deposits (TD) in patients with stage Ⅲ colorectal cancer who underwent radical resection. Methods We retrospectively analyzed the clinicopathological data, and the impact of tumor deposits on the disease free survival (DFS) and overall survival (OS) in 206 patients with stage Ⅲ colorectal cancer using Kaplan-Meier and Cox regression analyses. Results Among the 206 patients with stage Ⅲ colorectal cancer, there were 112 (54.4%) tumor deposit-positive (TD+ ) cases and 94 (45.6%) tumor deposit-negative (TD-) cases. The TD- and TD+ cases accounted for 10.6% and 21.4% of patients aged <50 years, 22.3% and 36.6% of patients with poorly differentiated carcinoma, and 16% and 29.5% of patients with neural invasion, respectively (P<0.05 for all). In addition, the neural invasion was more often found along with the increasing number of TD. However, multivariate analysis showed that TD was not significantly associated with DFS and OS of the patients. Among the patients with N1 stage cancer, the 3-year DFS rates of TD+ and TD- groups were 23.0% and 58.8%, and the median disease-free survival durations were 26 months and 43 months, respectively (P=0.002). Meanwhile, in the TD- group, the 3-year DFS rates in the patients with stage N1a~1b without tumor deposit and N1c cancer were 63.5% and 21.2%, and the median disease-free survival durations were 41 and 25 months, respectively (P=0.004). Conclusions Tumor deposit is an independent unfavorable prognostic factor affecting the DFS. The number of tumor deposits may be an important factor affecting prognosis in stage Ⅲ colorectal cancer patients. Tumor deposits after radical resection are associated with neural invasion, and can be used as an independent factor of poor prognostic evaluation in patients with stage N1 colorectal cancer. Key words: Colorectal neoplasms; Neoplasm staging; Prognosis; Tumor deposits