Lymphovascular invasion affects prognosis of colorectal cancer liver metastasis underwent primary resection: a propensity score matching analysis

Abstract Background: Lymphovascular invasion (LVI) is associated with poor prognosis in a variety of malignancies; however, its prognostic value has not been fully defined in patients with colorectal cancer with liver metastases (CRCLM). The aim of this study was to investigate the impact of lymphovascular invasion on long-term postoperative recurrence and survival in patients with CRCLM. Methods：Clinicopathologic data were retrospectively collected from patients who underwent primary resection for CRCLM at Wuhan Union Hospital from 2013 to 2018. To reduce potential confounders and selection bias, we used propensity score matching (PSM) to compare the clinicopathologic characteristics and long-term prognostic outcomes of patients in the LVI(+) and LVI(-) groups. Cox unifactorial and multifactorial analyses were used to screen relevant factors affecting patient prognosis, and Kaplan-Meier curves were plotted to compare differences in patient OS and DFS. The predictive power of independent factors on patients' long-term prognosis was assessed using receiver operating characteristic ROC) curves and area under the curve (AUC). Results: After PSM, 230 patients were enrolled in the study (n=115 per group). Multifactorial analysis revealed that LVI was an independent prognostic factor for OS and DFS (hazard ratio [HR], 1.424; 95% confidence interval [CI], 1.004–2.022; P=0.048 and HR, 1.452; 95% CI, 1.020–2.069; p=0.039, respectively). In the LVI(-) group, postoperative chemotherapy did not significantly improve OS or DFS; however, in the LVI(+) group, those who received chemotherapy had significantly improved OS (HR: 2.424 , 95% CI: 1.471−3.992; P=0.00034) and DFS (HR: 2.164, 95% CI. 1.328−3.525; P=0.0014) compared with patients not treated with chemotherapy. In the LVI(+) group, the AUC for the OS AUROC curves was more favorable compared with after PSM (AUC at 3 years: 0.786 vs 0.903; AUC at 5 years: 0.744 vs 0.889). For DFS, the area under the AUROC curve was also better in the LVI(+) subgroup compared with after PSM (AUC at 3 years: 0.874 vs 0.786; AUC at 5 years: 0.863 vs 0.744). Conclusions: LVI significantly impacts long-term survival and prognosis in patients with CRLM undergoing primary resection and is an independent prognostic factor for OS and DFS. Postoperative chemotherapy significantly improved the long-term prognosis of patients with LVI(+).