Unique Localization of Circulating Tumor Cells in Patients With Hepatic Metastases

There are few data on the impact of immediate and differing surgical interventions on circulating tumor cells (CTCs), nor their compartmentalization or localization in different anatomic vascular sites. CTCs from consecutive patients with colorectal liver metastases were quantified before and immediately after open surgery, laparoscopic resection, open radiofrequency ablation (RFA), or percutaneous RFA. For individuals undergoing open surgery, either hepatic resections or open RFA, CTCs were examined in both systemic and portal circulation by measuring CTCs in samples derived from the peripheral vein, an artery, the hepatic portal vein, and the hepatic vein. A total of 29 consecutive patients with colorectal liver metastases with a median age of 55 years (range, 30 to 88 years) were included. CTCs were localized to the hepatic portosystemic macrocirculation with significantly greater numbers than in the systemic vasculature. Surgical procedures led to a statistically significant fall in CTCs at multiple sites measured. Conversely, RFA, either open or percutaneous, was associated with a significant increase in CTCs. Surgical resection of metastases, but not RFA, immediately decreases CTC levels. In patients with colorectal liver metastases, CTCs appear localized to the hepatic (and pulmonary) macrocirculations. This may explain why metastases in sites other than the liver and lungs are infrequently observed in cancer.