High levels of fibrotic tumor components are associated with recurrence and intratumoral immune status in advanced colorectal cancer patients.

The importance of collagen and elastin remains incompletely understood concerning tumor immunity in cancer tissues. This study explored the clinical significance of collagen and elastin deposition on tumor immunity in advanced colorectal cancer patients. The collagen and elastin contents were assessed simultaneously using elastic van Gieson (EVG) histochemical staining. Immunohistochemical staining was performed to measure the immune cell markers CD3, CD8, CD86, and CD163 in surgically resected primary tumors from 78 pT4 colorectal cancer patients. High collagen, elastin, and EVG scores are associated with aggressive characteristics and short disease-free survival. A high EVG score was identified as an independent predictor of poor disease-free survival. Furthermore, tumors with high collagen and EVG scores exhibited significantly fewer intratumoral CD3 + and CD8 + cells. Evaluating tumor fibrosis using the classical and straightforward EVG staining method could be a reliable predictor of recurrence in high-risk colorectal cancer patients with tumor immune tolerance.