Clinical scenarios associated with local recurrence after laparoscopic radiofrequency thermal ablation of colorectal liver metastases.

BACKGROUND

Over the last decade, radiofrequency thermal ablation (RFA) has been incorporated into the treatment algorithm of patients with unresectable colorectal liver metastases (CLM). For this population, the local recurrence (LR) rate is a key parameter used to assess the success of RFA. LR is defined as development of new tumor abutting and/or in 1 cm of an ablation zone. The aim of this study is to correlate LR with other hepatic or extrahepatic recurrence and patient survival.

METHODS

Between 2000 and 2011, 252 patients with CLM underwent laparoscopic RFA of 883 lesions. These patients were followed under a prospective protocol with quarterly liver computed tomography and blood work, including carcinoembryonic antigen levels quarterly for the first 2 years and then biannually. Clinical scenarios associated with LR were identified and categorized as being "isolated LR," "LR associated with new liver disease," or "LR associated with systemic disease." Demographic, clinical, and survival data were assessed using analysis of variance, Chi-square test, and univariate and multivariate Kaplan-Meier analysis.

RESULTS

One hundred eighteen patients (47%) developed LR after their initial laparoscopic RFA. These were 85 men (72%) and 33 women (28%), with a mean age of 70 ± 8 years. For this cohort, the mean of number of lesions was 3.1 ± 0.2 cm (range, 1-11) and dominant tumor size 2.9 ± 0.1 cm (range, 0.7-6.5) at the time of initial RFA. The LR rate per lesion was 29%. Of the patients who developed treatment failure at the RFA site, this was an isolated LR in 31 (26%) patients, associated with new liver disease in 51 (43%) and systemic metastases in 36 patients (31%). When patients with different clinical scenarios associated with LR were compared, no clinical predictors were identified to differentiate these subgroups. At a median follow up of 30 months (range, 3-113), the Kaplan-Meier median overall survival (OS) for patients with and without LR were 28 vs 31 months, respectively (P = .103). The OS for patients whose LR was isolated, associated with new liver and systemic recurrences was 39, 26, and 22 months, respectively (P = .009).

CONCLUSION

This study shows that, although the presence of LR does not negatively impact on survival, the pattern of recurrent disease does. LR after RFA for CLM is most often associated with new liver and systemic recurrences, reflecting the aggressive biology of cancer in patients channeled to this treatment modality.