The role of tumor deposits (TDs) in staging remains debated. We have assessed the relation of TDs with metastatic pattern to evaluate whether TDs might add significant new information to staging.

A literature review of TDs in the prognosis of CRC using the databases of PubMed, Embase, Medline databases, Web of Science, Library, Wanfang, and China Zhiwang from its establishment to 2021. The literature was screened by inclusion and exclusion criteria, and data on tumor staging, histological features, and follow-up outcomes were extracted from the literature, as well as lymph node metastases (LNMs), extramural vascular invasion (EMVI), and their correlation with metastatic patterns.

A total of 18 publications involving 13 383 colorectal cancer patients were included in the study, and 20.3% presented with TDs. TDs are invariably associated with poor outcome. Presence of TDs was associated with presence of LNMs and EMVI (Z=4.79, P＜0.01; Z=6.19, P＜0.01, respectively). In a pairwise comparison, effects of TD were stronger than those of both LNMs and EMVI. In terms of risk ratios (RR), TDs and LNMs provided similar results; however, liver and lung metastases were significantly more common when TDs and LNMs were combined (RR=3.74, 95%CI: 2.96~4.71; RR=4.38, 95%CI: 3.29~5.83, respectively).

CRC patients with TD have a significantly worse prognosis than those without TD, including those with N1a and N1b. It is possible to misjudge the prognosis of patients with TDs in the absence of LNMs by simply defining them as N1c.