Past

Tumor deposits (TDs) are defined as isolated tumor foci found in the pericolic or perirectal fat or adjacent mesenteric fat without histologic evidence of residual lymph nodes or identifiable vascular or neural structures in the nodule.1 According to the American Joint Committee on Cancer (AJCC) tumor-node-metastasis (TNM) staging system, patients with tumor deposits are classified as stage N1c in the absence of lymph node metastasis. Recently, many studies have shown that tumor deposits are a poor prognostic indicator.2,3,4 In this context, ignoring the number of TDs in patients with lymph node metastasis and patients with stage N1c is not conducive to assessing the patient’s prognosis.

Present

This study investigated the impact of TDs on two independent cohorts of stage III colorectal cancer (CRC) patients from the Surveillance, Epidemiology, and End Results (SEER) database (n = 8232) and the First Affiliated Hospital of Wenzhou Medical University (n = 423).5 In multivariable Cox models, the independent prognostic effect of TDs was validated. The TD-positive patients with different N stages all had worse 5-year overall survival (OS) and 5-year cause-specific survival (CSS) than the TD-negative patients. Further, the number of TDs had a linear, negative effect on OS and CSS in the N2 group. In the N2 subgroup, a prognostic cutoff value of 5 for the patients’ tumor deposits was observed in both 5-year OS and 5-year CSS.

Future

According to current research findings, prospective clinical studies are needed to further validate the impact of TDs on prognosis. At the same time, studies need to consider how to better incorporate the influence of TDs into the existing TNM staging system, thereby assisting patients in making more informed choices regarding suitable chemotherapy regimens and treatment durations.