Circulating Tumor Cells in Patients Undergoing Surgery for Hepatic Metastases from Colorectal Cancer

Abstract

Circulating tumor cells (CTCs) have been detected in patients with a variety of metastatic cancers, including colorectal, and may be a significant prognostic variable in patients with liver metastases. This prospective study involved 20 patients (13 men and 7 women) undergoing surgical excision or ablation of liver metastases from a colon or rectal primary tumor. Four 7.5-mL vials of peripheral blood were drawn preoperatively, 2 weeks postoperatively, and during mobilization of the liver or at the beginning of radiofrequency ablation. The samples were centrifuged, the sera combined to a final volume of 7.5 mL, and the CellSearch system used to identify circulating epithelial cells. A CTC count >2 was defined as clinically significant. Preoperative CTC levels averaged 3.9 (range, 0-56) and were significant in 2 patients (10%). Postoperative CTC levels averaged 1.0 (in 18 patients; range, 0-9) and were significant in 1 patient (5%). Intraoperative CTC levels averaged 28.2 (range, 0-315) and were significant in 10 patients (50%). At a median follow-up of 11.5 months (range, 5-25), 6 patients (30%) were dead of disease, 6 patients (30%) showed no evidence of disease, and 8 patients (40%) were alive with disease. Statistical analysis suggested a correlation between the presence of postoperative CTCs and survival (P = 0.036), as well as with disease-free survival (P = 0.036). Thus, CTCs are present and quantifiable in many patients with colorectal hepatic metastases, and peripheral CTCs are present in greater quantity during intraoperative liver manipulation. This preliminary study suggests a relationship between the presence of postoperative CTCs and outcome. Further accrual and follow-up of this group is needed to confirm these findings.