The potential role of tumor deposits in the prognosis and TNM staging for colorectal cancer

Background: Tumor deposits (TDs) can impact proper staging of cancer, which is crucial for discussing prognosis and determining the appropriate treatment plan. Our study aimed to correlate how TDs influence prognosis of resected colorectal cancer (CRC) and how to optimize tumor-node-metastasis (TNM) staging with respect to TDs for clinical decision-making.

Methods: A retrospective analysis was performed on 611 patients with CRC treated in Jiangsu Cancer Hospital from January 1, 2010 to December 31, 2020 among whom 197 had TDs. The influence and distribution characteristics of TDs on the median overall survival (mOS) of patients with CRC were quantitatively and qualitatively analyzed, and the differences in mOS between different subgroups were also analyzed.

Results: Patients with TDs had a shorter mOS (only 60.3±3.9 months) than did patients without TDs. TDs had a more significant association with the survival of M0 patients, and there were significant differences in the prognosis of M0 patients with stage pN0 and pN1c or stage pN0, pN1, and pN2. The combination of lymph node metastases (LNMs) and TDs was associated with mOS. The proportion of rectal cancer, papillary tissue type, and nerve invasion was higher in the TD-positive group, and proportion of metastasis to the brain, spleen, lung, and bone in this groups was also higher. Subgroup analysis showed that the degree of tumor differentiation, the depth of tumor invasion, vascular invasion, nerve invasion, liver metastasis, lung metastasis, bone metastasis, peritoneal metastasis, ovarian metastasis, pelvic and abdominal metastasis, and the number of distant metastases were associated with the prognosis of patients with CRC.

Conclusions: TDs were closely correlated with the poor prognosis of patients with CRC. Greater attention should be paid to improving the quality of pathological reports in clinical decision-making and the comprehensive assessment of patients' baseline characteristics so that accurate prognosis and corresponding treatment plan can be properly communicated with patients.