HER2 status is positively associated with vessel invasion of colorectal cancer: a retrospective large cohort study

Purpose HER2-positive colorectal cancer was drawn increasing attention in recent years. Accumulating evidence showed HER2-positive metastatic colorectal cancer could benefit from HER2-targeted therapy. While HER2 expression and the relationship between HER2 status and clinicopathological characteristics of overall colorectal cancer remains largely unknown. The aim of this study was to evaluate HER2 expression in colorectal cancer and compare the clinicopathological features between HER2-positive and HER2-negative colorectal cancer. Methods We retrospectively analyzed 3910 primary colorectal cancer patients treated in our institution from January 2016 to December 2019. Medical records and pathology reports after surgery were collected to provide information about HER2 status and other clinicopathological characteristics. Results We identified 3347 HER2-negative and 79 HER2-positive colorectal cancer patients in our cohort. The chi-square test showed that vessel invasion was significantly more common in HER2-positive colorectal cancer patients. Crude analysis showed HER2 positive was associated with vessel invasion in colorectal cancer [OR and 95% CI 0.534 (0.341, 0.835), p = 0.006]. After adjusting for N stage, a significant association was still observed between HER2 status and vessel invasion in colorectal cancer [OR and 95% CI 0.550 (0.322, 0.941), p = 0.029]. Survival analysis showed that there was no significant difference in 3-year overall survival rate between HER2 positive and HER2 negative group ( p = 0.603). Conclusion Our findings indicate that the rate of HER2 positivity in colorectal cancer was relatively low, and HER2 status was strongly associated with vessel invasion while having no significant influence on the 3-year overall survival rate in colorectal cancer patients.