Patterns of recurrence after ablation of colorectal cancer liver metastases.

Kingham, T Peter; Tanoue, Michael; Eaton, Anne; Rocha, Flavio G; Do, Richard; Allen, Peter; De Matteo, Ronald P; D'Angelica, Michael; Fong, Yuman; Jarnagin, William R

PURPOSE To determine the local recurrence rate and factors associated with recurrence after intraoperative ablation of colorectal cancer liver metastases. METHODS A retrospective analysis of a prospectively maintained database was performed for patients who underwent ablation of a hepatic colorectal cancer metastasis in the operating room from April 1996 to March 2010. Kaplan-Meier survival curves and Cox models were used to determine recurrence rates and assess significance. RESULTS Ablation was performed in 10% (n = 158 patients) of all cases during the study period. Seventy-eight percent were performed in conjunction with a liver resection. Of the 315 tumors ablated, most tumors were ≤ 1 cm in maximum diameter (53%). Radiofrequency ablation was used to treat most of the tumors (70%). Thirty-six tumors (11%) had local recurrence as part of their recurrence pattern. Disease recurred in the liver or systemically after 212 tumors (67%) were ablated. On univariate analysis, tumor size greater than 1 cm was associated with a significantly increased risk of local recurrence (hazard ratio 2.3, 95% confidence interval 1.2-4.5, P = 0.013). The 2 year ablation zone recurrence-free survival was 92% for tumors ≤ 1 cm compared to 81% for tumors >1 cm. On multivariate analysis, tumor size of >1 cm, lack of postoperative chemotherapy, and use of cryotherapy were significantly associated with a higher local recurrence rate. CONCLUSIONS Intraoperative ablation appears to be highly effective treatment for hepatic colorectal tumors ≤ 1 cm.