Exploring the link between liver cirrhosis and liver metastasis in colorectal cancer.

301 Background: Colorectal cancer (CRC) is the third most common cancer and the second most common cause of cancer mortality in the world. Although it is now associated with improved outcomes due to advancements in treatment modalities, CRC continues to be the most common source of liver metastasis. Previous studies have shown cirrhotic livers to be at reduced risk of metastatic disease. Our study aims to investigate the association between colorectal cancer and liver metastasis in the presence of concomitant liver cirrhosis. Methods: The National Inpatient Sample (NIS) was queried to identify all hospitalizations with colorectal cancer utilizing ICD-10 codes C18.x, C19.x, and C20.x from 2016 to 2020 and were further classified based on the presence or absence of cirrhosis. Demographic and clinical data were analyzed using chi-squared tests, independent sample t-tests, and binary logistic regression (adjusted for age, gender, and Charlson comorbidity index or CCI). The primary outcome studied was liver metastasis. Secondary outcomes were hepatic encephalopathy, portal hypertension, and spontaneous bacterial peritonitis. Statistical significance is indicated by a p-value less than 0.05. Results: A total of 255,599 hospitalizations with colorectal cancer were identified. Out of these, 5,370 (2.1%) had liver cirrhosis and 250,229 (97.9%) did not. Hospitalizations with CRC and concomitant cirrhosis had higher comorbidities as per the Charlson Comorbidity Index (10.5 vs 8.1, p-value<0.001) and higher mortality rates (8.5% vs 4.2%, p-value<0.001). Higher rates of liver metastasis (26.5 vs 23.4, p <0.001) and portal hypertension (26.1% vs 0.3%, p<0.001) were observed in the cirrhosis subgroup. This subgroup also has a significantly higher risk of SBP (2.8% vs 0.2%, p <0.001). Conclusions: This is a large retrospective study analyzing the impact of cirrhosis on liver metastasis in patients with colorectal cancer. Patients with concomitant cirrhosis consistently have increased liver metastasis and worse outcomes. The results of this study imply that diligent CRC screening is of utmost importance in patients with cirrhosis. Patients with CRC and coexisting cirrhosis would benefit from routine surveillance such as carcinoembryonic antigen (CEA) screening or CT scans to allow early detection of liver metastases which could potentially improve outcomes. Colorectal Cancer Patients No Cirrhosis (N=250,229) Cirrhosis (N=5,370) p-value Age (in years) 65.79 ± 13.8 65.04 ± 10.9 <.001 Sex (Female) 47.3% 36.8% <.001 Charlson Comorbidity Index 8.1 ± 3.6 10.5 ± 3.7 <.001 Mortality 4.2% 8.5% <.001 Length of Stay 6.6 ± 7.2 7.4 ± 7.2 <.001 Liver Metastasis 23.4% 26.5% <.001 Hepatic Encephalopathy 0.0% 0.2% <.001 Portal hypertension 0.3% 26.1% <.001 Spontaneous Bacterial Peritonitis (SBP) 0.2% 2.8% <.001