High infiltration of mast cells positive to tryptase predicts worse outcome following resection of colorectal liver metastases

Abstract

Background

Accumulation of tumor-infiltrating mast cells (MCs) predicts poor survival in several cancers after resection. However, its effect on the prognosis of patients with colorectal liver metastases (CRLM) is not known.

Methods

Our retrospective study included 135 patients who underwent potentially curative resection for CRLM between 2001 and 2010. Expression of tryptase, MAC387, CD83, and CD31, which are markers for MCs, macrophages, mature dendritic cells, and vascular endothelial cells, respectively, was determined via immunohistochemistry of resected tumor specimens. The relationship between immune cell infiltration and long-term outcome was investigated.

Results

The median follow-up time was 48.4 months for all patients and 57.5 months for survivors. Overall survival (OS) rates at 1, 3, and 5 years were 91.0, 62.4, and 37.4 %, respectively. Five-year disease-free survival (DFS) and OS rates were 21.6 and 38.1 %, respectively, in patients with high MC infiltration, and 42.6 and 55.6 %, respectively, in patients with low MC infiltration (p < 0.01 for both DFS and OS). Infiltration of other types of immune cells did not correlate with survival. Multivariate analyses indicated that hypoalbuminemia and high peritumoral MC infiltration were significant predictors of unfavorable OS.

Conclusion

High peritumoral MC infiltration predicts poor prognosis in patients who underwent hepatectomy for CRLM. The number of MCs in metastatic lesions is important for predicting the prognosis of CRLM patients and as an indication of therapy.