Presence of tumor deposits is a strong indicator of poor outcome in patients with stage III colorectal cancers undergoing radical surgery

Background: Tumor deposits (TDs) are emerging as an adverse prognostic factor in colorectal cancers (CRCs). However, TDs are somewhat neglected in the current staging system. It has been proposed either to add the TD count to the number of metastatic lymph nodes or to consider TDs as distant metastases; however, the scientific basis for these proposals seems questionable. This study aimed to investigate a new staging system. Methods: A total of 243 consecutive patients with stage III CRC who were undergoing curative resection and adjuvant chemotherapy were included. Each substage of stage III TNM was split according to the absence or presence of TDs. Receiver operating characteristic (ROC) curves and bootstrap methods were used to compare the current vs the new competing staging system in terms of oncologic outcome prediction. Results: A high rate of TDs was recorded (124 cases [51%]). TDs were correlated with other adverse prognostic indicators, particularly vascular and perineural invasions, and showed a negative correlation with the number of removed lymph nodes, suggesting a possible multimodal origin. In addition, TDs were confirmed to have a negative impact on oncologic outcome, regardless of their counts. Compared with the current staging system, the new classification displayed higher values at survival ROC analysis, a significantly better stratification of patients, and effective identification of patients at high risk of recurrence. Conclusions: TDs negatively affect the prognosis in CRCs. A revision of the staging system could be useful to optimize treatments. The proposed new classification is easy to implement and more accurate than the current one. This study was registered online on the ClinicalTrials.gov website under the following identifier: NCT05923450.