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Editorial |
Department of Surgical Oncology, University of Texas M. D. Anderson Cancer Center, Unit 444, P.O. Box 301402 Houston, Texas 77230-1402
Correspondence: Address correspondence and reprint requests to: Eddie K. Abdalla, MD, FACS; E-mail: eabdalla{at}mdanderson.org
A timely and important analysis of the "Factors Influencing the Local Failure Rate of Radiofrequency Ablation of Colorectal Liver Metastases" is presented by van Duijnhoven et al.1 based on follow-up imaging of 158 colorectal liver metastases (CLM) treated with radiofrequency ablation (RFA). With systematic radiological follow-up, the authors indicated a local recurrence rate of 47%. This finding is, in fact, in keeping with other large series, which have reported local recurrence or persistence rates up to 40% after RFA of CLM,2,3 and it brings to light two critical issues that must be considered by physicians who treat CLM and by oncologists who refer patients for RFA of CLM—survival after hepatic resection of CLM is increasing, and RFA is not equivalent to hepatic resection.
First, results from hepatic resection for CLM must be reiterated. Despite expanding indications for resection for this disease, including patients with multiple, bilateral lesions, limited extrahepatic disease, and small liver remnants, several studies have shown marked improvement in survival compared with historical series. Three single-institution series4–6 and one multi-institutional series7 reported on patients who underwent complete hepatic resection for CLM since 1990—all four revealed 5-year overall survival of 58%.
Second, local recurrence is common after RFA of virtually all tumor types. We recently reported the results of surgical treatment of a homogenous population of patients with solitary CLM.8 Our findings further clarify and complement the findings of van Duijnhoven et al.1 First, we found that the 5-year overall survival after hepatic resection for solitary CLM was 71%, with disease-free survival of 50% among 150 patients with resected disease. This survival rate is nearly double the historical rate reported in series from the early 1990s,9 when the outcome for resection of solitary versus multiple tumors was reported to be similar, and it underscores the improving outcome for resection among all patients with CLM.
Furthermore, we systematically reviewed follow-up imaging in all patients with resected disease and in all patients treated with RFA for solitary lesions. Our findings confirm those of van Duijnhoven1—37% of all treated lesions recurred locally after RFA (vs. 5% after hepatic resection; P = .0001). van Duijnhoven et al.1 noted the high failure rate of RFA in treatment of large tumors (
5 cm), and we showed that local recurrence after RFA is not better as a local control modality for small tumors when all treated small tumors are confirmed to be malignant lesions (31% local recurrence for RFA of tumors 
3 cm vs. 3% after hepatic resection; P = .001). In addition, we found that the local recurrence rate was similar among patients with tumors in contact with main hepatic veins (27% local recurrence) versus tumors remote from major vessels (47% local recurrence; P = NS).
The implications of these studies are important. We and others have shown a modest (and probably diminishing) survival benefit to treatment by RFA in patients with unresectable CLM in the face of steadily improving survival in similar cohorts of patients treated with modern systemic chemotherapy.4 Authors who propose that RFA and resection are similar3,10 simply ignore the wide difference in disease-free and overall survival among patients treated with hepatic resection versus RFA. The difference in recurrence rates between resection and RFA cannot be attributed to biological differences in the tumors treated; thus, the difference in disease-free survival is likely related to the treatment, not the disease. The two treatments are not similar, do not provide similar local control rates, and do not provide similar long-term outcomes. Because there is no equipoise between RFA and resection, even in patients with solitary CLM, we feel that a randomized study between the two techniques for resectable lesions would be unethical.
This new gold standard survival after resection is likely the result of many factors, including better staging and patient selection, improved intraoperative technique, and improved adjuvant systemic therapy. At this time, the role of RFA for CLM is limited to the treatment of patients with comorbid conditions that preclude safe resection. More patients might benefit from improved outcomes after hepatic resection for CLM if more patients had access to multidisciplinary assessment for hepatic resection for CLM. Evaluation by a team experienced in the treatment of hepatic colorectal metastases, which must include oncologists and radiologists—and, importantly, surgeons with significant experience in hepatic surgery—is required to assess treatment options in complex cases. Only when patients are deemed unresectable by an appropriate multidisciplinary team can the decision to apply less effective therapies such as RFA be made.
Received for publication November 29, 2005. Accepted for publication December 9, 2005.
REFERENCES
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