3642 Background: The location and weight of tumor deposit (TD) in the TNM staging system may be seriously underestimated, which affects the accuracy of TNM staging in predicting prognosis. We conducted a study to further clarify the role of TD in predicting the prognosis, the weighting of TD, and the possible value of optimizing the TNM staging system of CRC. Methods: The subject was CRC patients diagnosed by postoperative pathology in our hospital from January 2013 to December 2021, including 2642 TD (+) and 1162 TD (-) patients. TD (-) patients were regarded as the control group according to category matching principle of the diagnosis, treatment and the period as TD (+) patients. Cox univariate and multivariate were analyzed. K-M curve was applied to analyze survival. Results: (1) The clinical and pathological characteristics are as follows: The TD positive rate was 25.3%. In stage I-III, more advanced tumor T and N-stage, primary sites in the left-sided colon or rectum, poorer histologic grade, and more nerve invasion and vascular infiltration (all p<0.05) were observed in TD (+) patients. In stage IV patients, TD (+) patients were more likely to have multiple metastases ( p <0.05). (2) Patients with TD (+) had worse prognosis than patients with TD (-), with shorter DFS and OS in stage I-III (3-y DFS and OS rate, all p <0.05), with shorter PFS in stage IV (3-y PFS rate, p<0.05). The univariate and multivariate analysis showed that TD (+) was one of independent prognosis factors in CRC patients. And the prognosis shows a trend of getting worse as the number of TD increases. (3) The relationship between TD and N staging: Patients with TD (+), LN (-) had similar OS as patients with TD (-), LN (+) (3-y OS rate, p=0.418). Patients with TD (+), LN (-) had similar OS as patients with TD (-), N2 (3-y OS rate, p=0.695). Patients with TD (+), LN (-) had shorter OS than patients with N2a, TD (-) (3-y OS rate, p=0.029) and longer OS than patients with N2b, TD (-) (3-y OS rate, p=0.034). When TD and LN were counted together for N-staging, the OS between patients with new N2 and primary N2 was similar (3-y OS rate, p=0.382). (4) The relationship between TD and M staging: The survival of patients with TD more than 4 was similar to stage IV patients (2-y OS rate , p=0.061); when the number of LN more than 6 and TD (+) coexisted, OS was similar with stage IV patients (2-y OS rate, p=0.554). When TD and M were counted together for M-staging, the OS between patients with new M1 and primary M1 was similar (3-y OS rate: p=0.149). Conclusions: TD (+) patients are related with unfavorable prognostic clinical and pathological factors. TD was one independent prognosis factor in CRC patients. The location and weight of TD in the TNM staging system may be seriously underestimated. The prognostic accuracy of TNM staging may be improved when the weight of the presence and quantity of TD is increased. Clinical trial information: 2023-ks-143.
Wang et al. (2026) studied this question.