The anatomic localization of circulating tumor cells and the immediate impact of surgery and radiofrequency ablation

Abstract

e22004 Background: 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. Methods: CTCs from consecutive patients with colorectal liver metastases were quantitated prior to 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 portal vein and hepatic vein. Results: A total of 29 consecutive patients with colorectal liver metastases were included with a median age of 55 (range 30 - 88 years). 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 all sites measured (p<0.05). Conversely, RFA, either open or percutaneous was associated with an increase in CTCs. Conclusions: Surgical resection of metastases but not RFA decreases CTC levels. In patients with colorectal liver metastases, CTCs are localized to the hepatic (and probably pulmonary) macrocirculations. This may explain why metastases in sites other than the liver and lungs, are infrequently observed in cancer. No significant financial relationships to disclose.