Does the Site of the Primary Affect Outcomes When Ablating Colorectal Liver Metastases with Radiofrequency Ablation?

Purpose: To determine whether primary tumor side was a predictor of radiofrequency ablation (RFA) outcome in colorectal liver metastases (CRLM).

Materials And Methods: The institutional review board approved this retrospective study. Written informed consent was obtained from all patients. From January 2007 to December 2013, 102 patients underwent RFA of metachronous CRLM were enrolled in this study with propensity score matching method. Recurrence rate (RR) and overall survival (OS) were analyzed between two patients cohorts with primary left-side colorectal cancer (LSCRC) or primary right-side colon cancer (RSCC).

Results: The total RR was 59.8% in all patients. Patients in LSCRC cohort had lower RR and non-local recurrence (NLR) rate than those in RSCC patients' cohort (49.0 vs 70.6%, p = 0.026 and 21.6 vs 41.2%, p = 0.033). Five-year OS was 14 and 30% for RSCC and LSCRC, respectively. There was a significant difference between two cohorts in median OS (29.4 vs 40.3 months for RSCC and LSCRC, respectively, p = 0.042). Univariate analysis showed that primary tumor side, the number of liver metastases, tumor size, carcinoembryonic antigen level, differentiation, TNM stage, active chemotherapy and RFA boundary were significant in predicting OS. When these variables were subsequently entered in a multivariate model, RSCC (p < 0.001; hazard ratio [HR], 6.2) and tumor size (> 3 cm) (p = 0.006; HR, 3.9) were significant.

Conclusion: LSCRC and tumor size (≤ 3 cm) are independent predictors of RFA in CRLM and yield the better oncologic outcomes.