Published online Sep 15, 2022. doi: 10.4251/wjgo.v14.i9.1699
Peer-review started: April 19, 2022
First decision: May 11, 2022
Revised: May 18, 2022
Accepted: July 26, 2022
Article in press: July 26, 2022
Published online: September 15, 2022
Processing time: 143 Days and 2.3 Hours
Tumor deposits (TDs) plays an important role in The American Joint Committee on Cancer (AJCC) tumor, node and metastasis (TNM) staging system. However, the definition of TDs as well as N1c remains controversial. Just taking the quantitative information of TDs into consideration may be suboptimal in the current staging system while adding TDs into lymph node metastases (LNMs) count may improve accuracy and N1c category may represents patients with heterogeneous survival.
AJCC TNM staging system is the standard tool for tumor staging and the treatment strategies for patients mostly depend on tumor stage. To guarantee more appropriate treatment strategies can be received by patients and to predict prognosis of patients better, developing an optimal staging system is crucial.
The main objective of this study is to assess the association between the presence of TDs and overall survival (OS). As exploratory outcomes, the impact of number of TDs on OS was investigated and the N stage was reclassified to the novel N category by the addition of TDs to the LNM count. The outcome indicated that TDs are an independent prognostic factor for OS in colorectal cancer and the addition of TDs to LNM count improved the prognostic accuracy of TNM staging. Therefore, a part of patients staged as N1 previously would be N2 after the addition of TDs to LNM count and the prognosis would change subsequently.
Patients with colorectal cancer including TD-negative and TD-positive subpopulations were derived from Surveillance, Epidemiology, and End Results database (SEER). Cox proportional hazard model was used for survival analysis and the sensitivity analyses were performed to detect outcome robustness. The subgroup analysis was also performed to explore the different profile of risk factors between patients with and without TDs. Comparative effectiveness research was used in current study.
The presence of TDs is an independent prognostic factor for OS in colorectal cancer and there may be more than one way through which TDs influence survival. Both TDs and their numbers should be integrated into N staging and the N1c category in TNM staging was inappropriate. Given that novel adjuvant therapy has already been the standard regimen in some settings and there is no evidence whether TDs in patients with novel adjuvant therapy should be regarded the same as patients without novel adjuvant therapy, further investigations need to be conducted.
The presence of TDs is an independent prognostic factor for OS in colorectal cancer and addition of TDs to the LNM count improves the prognostic accuracy of current TNM staging.
The origin as well as formation of TDs remains ambiguous and further studies are needed to substantiate the definition and demonstrate the pathogenesis of TDs. Patients with and without novel adjuvant therapy need to be investigated separately, especially when patients achieve substantial downstaging.