Association between tumor deposits and liver and lung metastases at diagnosis of colorectal cancer: A SEER-based analysis.

Background: Tumor deposits are a unique histologic feature of colorectal cancer that is associated with adverse survival outcomes. The present study aimed to assess the association between tumor deposits and liver and lung metastases and to describe the characteristics of colorectal cancer associated with tumor deposits.

Methods: The Surveillance, Epidemiology, End Results (SEER) database was screened between 2010 and 2020 for patients with colorectal adenocarcinoma who underwent radical resection with data on tumor deposits. The primary outcome of the study was liver and lung metastases. The secondary outcome was the characteristics of patients with tumor deposits.

Results: A total of 205,294 patients (52% male, mean age 66.5 years) were included in the study. Tumor deposits were detected in 20,059 (9.7%) patients. Patients with tumor deposits were younger and presented more often with larger tumors, T3/T4 tumors, N+ tumors, stage IV disease, left-sided and rectal cancers, signet-ring cell carcinomas, high-grade adenocarcinomas, and perineural invasion. Multivariable binary regression analyses showed that tumor deposits were associated with 72% higher odds of liver metastases (odds ratio 1.72, 95% confidence interval 1.62-1.82, P < .001) and 68% higher odds of lung metastases (1.68, 1.51-1.86, P < .001). The odds of liver metastases increased by 3% (odds ratio 1.03, 95% confidence interval 1.03-1.04, P < .001) and the odds of lung metastases increased by 2% (1.02, 1.01-1.03, P < .001) for each tumor deposit detected.

Conclusions: Tumor deposit-positive colorectal cancers were larger, more often on the left side or in the rectum and presented with more advanced disease and unfavorable histology than tumor deposit-negative cancers. Tumor deposits were independently associated with 72% and 68% higher odds of liver and lung metastases, respectively.