Prognostic value of tumor deposits for long-term oncologic outcomes in patients with stage III colorectal cancer: a systematic review and meta-analysis

Purpose: The presence of tumor deposits (TDs) in colorectal cancer is associated with a poor prognosis. In patients with the concomitant presence of both TDs and lymph nodes (LNs), there is no staging option except for the number of positive LNs alone. Therefore, to determine the prognostic value of TDs in patients with stage III colorectal cancer, meta-analyses of survival outcomes of patients with TDs were performed comparing different subgroups based on the lymph node status. Methods: PubMed, EMBASE, and the Cochrane Library were searched. Data were pooled, and overall effect size was calculated using random-effect models. Outcome measures were 5-year overall survival (OS) and 5-year disease-free survival (DFS). Results: We included in the analysis 18 nonrandomized studies and 1 prospective study that examined 90,455 patients. N1c patients (TD + LN-) had worse 5-year DFS than TDs-negative stage III patients (TD-LN +) with a RR of 1.30 (95% CI 1.06–1.61, I² = 47%). In subgroup analysis, N1c patients had worse 5-year DFS (RR = 1.60, 95% CI = 1.25–2.05, I² = 40%) compared with TDs-negative N1 patients (TD-N1) whereas N1c patients had better 5-year OS (RR = 0.72, 95% CI = 0.62–0.83, I² = 0%) and 5-year DFS (RR = 0.75, 95% CI = 0.57–0.99, I² = 0%) compared with TDs-negative N2 patients (TD-N2). Conclusions: These results may suggest that current nodal staging for colorectal cancer needs modification. The presence of TDs may have more adverse oncologic outcomes than TDs-negative N1 patients. More studies are warranted to further verify these results.