It is believed that blood from the superior mesenteric vein and splenic vein mixes incompletely in the portal vein and maintains a streamline flow influencing its anatomic distribution. Although several experimental studies have demonstrated the existence of streamlining, clinical studies have shown conflicting results. We investigated whether streamlining of portal vein affects the lobar distribution of colorectal liver
metastases and estimated its impact on survival.
METHODS: Data of patients who underwent
hepatectomy for colorectal liver
metastases were retrospectively collected. The chi-square test was used for analyzing the distribution of
metastasis. Cox analysis was used to identify risk factors of survival. Fisher exact test was used for subgroup analysis comparing hepatic recurrence.
RESULTS: A total of 410 patients were included. The right-to-left ratio of liver
metastases were 2.20:1 in right-sided
colon cancer and 1.39:1 in left-sided
cancer (P = 0.017). Cox analyses showed that margin < 5 mm (P < 0.001; 95% confidence interval [CI], 1.648-4.884; hazard ratio [HR], 2.837), age ≥ 60 years (P = 0.004; 95% CI, 1.269-3.641; HR, 2.149), N2 status (P < 0.001, 95% CI, 1.598-4.215; HR, 2.595),
tumor size ≥ 45 mm (P = 0.014; 95% CI, 1.159-3.758; HR, 2.087) and other
metastasis (P = 0.012; 95% CI, 1.250-5.927; HR, 2.722) were risk factors of survival. However, in 70 patients who underwent right hemihepatectomy for solitary
metastasis, left-sided
colorectal cancer was a risk factor (P = 0.019; 95% CI, 1.293-17.956; HR, 4.818), and was associated with higher recurrence than right-sided
cancer (43.1% and 15.8%, respectively, P = 0.049).
CONCLUSION: This study showed significant difference in lobar distribution of liver
metastases between right
colon cancer and left colorecral
cancer. Furthermore, survival of left-sided
colorectal cancer was poorer than that of right-sided
cancer in patients who underwent right hemihepatectomy for solitary
metastasis. These findings can be helpful for clinicians planning treatment strategy.