Radiofrequency ablation in patients with primary and secondary hepatic malignancies

Local Control Outcomes Using Stereotactic Body Radiation Therapy for Liver Metastases From Colorectal Cancer

PURPOSE

To evaluate the effective dose and patterns of recurrence after stereotactic body radiation therapy (SBRT) for hepatic metastases that arise from colorectal cancer.

METHODS AND MATERIALS

A cohort of 70 patients with 103 colorectal liver metastases were treated with SBRT at a single institution. The prescribed doses were 45 to 60 Gy in 3 to 4 fractions, but these were modified according to the tolerance of the adjacent normal tissue. To allow for dose comparisons, a biological equivalent dose was calculated.

RESULTS

The median follow-up period was 34.2 months (range, 5.3-121.8 months). The 2-year overall survival and progression-free survival rates were 75% and 35%, respectively. In subgroups, the 2-year local control rates for biological equivalent dose ≤80 Gy (group 1), 100 to 112 Gy (group 2), and ≥132 Gy (group 3) were 52%, 83%, and 89%, respectively. Cox proportional hazards model revealed a significant difference between groups (hazard ratio 0.44, P=.03 for group 2; hazard ratio 0.17, P=.17 for group 3; P=.01 for total). The major pattern of failure was a new liver metastasis out of the SBRT field. There was no grade ≥3 toxicity.

CONCLUSIONS

Stereotactic body radiation therapy of liver metastases derived from colorectal cancer offers a locally effective treatment without significant complications. Longer local control can be expected if higher doses are used. Further studies will be needed to compare the efficacies of SBRT with those of surgical resection or radiofrequency ablation.

Liver metastases and SBRT: A new paradigm?

BACKGROUND

The outstanding innovations made by early diagnosis, novel surgical techniques, effective chemotherapy regimens and conformal radiotherapy, have significantly improved patients overall survival and quality of life. Multidisciplinary approach to cancer has also led to an increased prevalence of patients with few, organ-confined metastases, who can experience long-term survival even if their disease is no longer localized. Liver is one of the most common site for metastatic disease from several cancers, and when metastatic disease is confined to liver, given the ability of this organ to regenerate almost to its optimal volume, surgical resection represents the standard of care because is associated with a better prognosis. Approximately 70-90% of liver metastases, however, are unresectable and a safe, effective alternative therapeutic option is necessary for these patients.

MATERIALS AND METHODS

A review of the current literature was performed to analyze the role of SBRT in treating liver metastases from different cancers. A literature search using the terms "SBRT" and "liver metastases" was carried out in PUBMED.

RESULTS

Stereotactic body radiation therapy has shown to provide promising results in the treatment of liver metastases, thanks to the ability of this procedure to deliver a conformal high dose of radiation to the target lesion and a minimal dose to surrounding critical tissues.

CONCLUSION

Stereotactic body radiation therapy is a non-invasive, well-tolerated and effective treatment for patients with liver metastases not suitable for surgical resection.

Prognostic value of circulating tumour cells for early recurrence after resection of colorectal liver metastases

BACKGROUND

Despite good outcomes for many, a substantial group of patients undergoing metastasectomy for isolated liver metastases from colorectal cancer (CRC) experience early recurrence. We have investigated whether circulating tumour cell (CTC) detection can identify patients developing disease recurrence within 1 year after liver metastasectomy.

METHODS

In CRC patients undergoing liver metastasectomy, 30 ml peripheral blood was withdrawn preoperatively. CTCs were detected by the CellSearch system after a density-gradient-based enrichment step.

RESULTS

One hundred and seventy-three samples from 151 individual patients were analysed. In 75 samples (43%), CTCs were detected, 16% had ⩾3 CTCs/7.5 ml of blood. Eighty-two patients (47%) experienced early disease recurrence (<1 year). The 1-year recurrence rate between patients with or without detectable CTCs were similar (47% vs 48%) or with a low or high CTC count (<3 or ⩾3 CTCs/7.5 ml of blood) (50% vs 47%). Also disease-free and overall survival were similar between patients with or without CTCs.

CONCLUSIONS

The presence of CTCs in preoperative peripheral blood samples does not identify patients at risk for early disease recurrence after curative resection of colorectal liver metastases. Other parameters are needed to better identify patients at high risk to relapse after liver metastasectomy for CRC.

Selecting patients for a second hepatectomy for colorectal metastases: an systemic review and meta-analysis

BACKGROUND

Opinions on the suitability of repeat hepatectomy for patients with recurrent colorectal liver metastases (CRLMs) vary among studies. We conducted a meta-analysis to establish the criteria for selecting the best candidates for a second hepatectomy.

METHODS

Database and manual searches were performed to identify comparative or prognostic studies published up to October 2013. Outcomes of interest included disease characteristics, perioperative outcomes, and long-term survival after initial and second hepatectomies for patients with CRLM. Study quality was appraised using the Newcastle-Ottawa scale and a modified Hayden's score.

RESULTS

A total of 7226 patients from 27 studies were included. Recurrent CRLMs after initial hepatectomy were more likely to be solitary (RR = 0.86, P = 0.045), unilobar (RR = 0.60, P < 0.001), and smaller (WMD = -0.66, P < 0.001). Postoperative morbidity and mortality were comparable between initial and second hepatectomies (RR = 1.10, P = 0.191; RR = 0.78, P = 0.678, respectively). In high-quality studies, patients showed better survival after a second hepatectomy than those after a single hepatectomy (HR = 0.68, P = 0.022). Patients meeting the following six predictors survived longer after second hepatectomy: disease-free survival after initial hepatectomy >1 y (P = 0.034); solitary CRLM at second hepatectomy (P < 0.001); unilobar CRLM at second hepatectomy (P = 0.009); maximal size of CRLM at second hepatectomy ≤ 5 cm (P = 0.035); lack of extrahepatic metastases at second hepatectomy (P < 0.001); and R0 resection at second hepatectomy (P < 0.001).

CONCLUSIONS

Second hepatectomy is a safe and feasible procedure for patients with recurrent CRLM. In fact, in well-selected patients it improves overall survival. The established criteria can help clinicians to select the best candidates for second hepatectomy and to achieve better long-term outcomes after resection.

Stereotactic body radiation therapy for liver metastases

Over the years, early diagnosis of metastatic disease has improved and the prevalence of oligometastatic patients is increasing. Liver is a most common site of progression from gastrointestinal, lung and breast cancer and in the setting of oligometastatic patients, surgical resection is associated with increased survival. Approximately 70-90% of liver metastases, however, are unresectable and an effective and safe alternative therapeutic option is necessary for these patients. The role of stereotactic body radiation therapy (SBRT) was investigated in the treatment of oligometastatic patients with promising results, thanks to the ability of this procedure to deliver a conformal high dose of radiation to the target lesion and a minimal dose to surrounding critical tissues. This paper was performed to review the current literature and to provide the practice guidelines on the use of stereotactic body radiotherapy in the treatment of liver metastases. We performed a literature search using Medical Subject Heading terms "SBRT" and "liver metastases", considering a period of ten years.

MR-guided focused ultrasound surgery, present and future

MR-guided focused ultrasound surgery (MRgFUS) is a quickly developing technology with potential applications across a spectrum of indications traditionally within the domain of radiation oncology. Especially for applications where focal treatment is the preferred technique (for example, radiosurgery), MRgFUS has the potential to be a disruptive technology that could shift traditional patterns of care. While currently cleared in the United States for the noninvasive treatment of uterine fibroids and bone metastases, a wide range of clinical trials are currently underway, and the number of publications describing advances in MRgFUS is increasing. However, for MRgFUS to make the transition from a research curiosity to a clinical standard of care, a variety of challenges, technical, financial, clinical, and practical, must be overcome. This installment of the Vision 20∕20 series examines the current status of MRgFUS, focusing on the hurdles the technology faces before it can cross over from a research technique to a standard fixture in the clinic. It then reviews current and near-term technical developments which may overcome these hurdles and allow MRgFUS to break through into clinical practice.

Thermal tumor ablation therapy for colorectal cancer hepatic metastasis

Surgical resection for colorectal hepatic metastases (CRHM) is the preferred treatment for suitable candidates, and the only potentially curative modality. However, due to various limitations, the majority of patients with CRHM are not candidates for liver resection. In recent years, there has been an increasing interest in the role of thermal tumor ablation (TTA) as a component of combined resection-ablation strategies, staged hepatic resections, or as standalone adjunct treatment for patients with CRHM. Thus, ablative approaches have expanded the group of patients with CRHM that may benefit from liver-directed treatment strategies.

Long-term outcome of radiofrequency thermal ablation (RFA) of liver metastases from colorectal cancer (CRC): size as the leading prognostic factor for survival

PURPOSE

The aim of this study was to review some prognostic factors for survival after radiofrequency ablation (RFA) of metastases from colorectal cancer (CRC).

MATERIALS AND METHODS

From 1996 to 2009, 262 patients with metastases from CRC were treated with RFA. Fourteen were lost to follow-up. The following predictors were analysed in the remaining 248: synchronous/metachronous metastases, single/multiple metastases, diameter of largest metastasis and absence/presence of extrahepatic metastases. Survival was measured from the date of metastasis diagnosis and from the date of RFA.

RESULTS

Survival at 1, 2, 3 and 5 years was 93%, 78%, 62% and 35% from metastasis diagnosis, and 84%, 59%, 43% and 23% from the date of RFA. Median survival was 41 months in patients with largest metastasis ≤3 cm and 21.7 months for those with metastases >3 cm (p=0.0001); survival increased to 45.2 months in patients with largest metastasis ≤2.5 cm and fell to 18.5 months in those with metastasis >3.5 cm. Median survival of patients with extrahepatic metastases was significantly lower than that of patients without extrahepatic disease (23.3 vs. 32.6 months, p=0.018).

CONCLUSIONS

In light of our long-term results obtained with commonly used equipment, small lesion size (diameter of largest lesion ≤3 or 2.5 cm) proved to be the most favourable prognostic factor for survival in patients with CRC metastases to the liver treated with RFA. This conclusion is probably related to the possibility of obtaining radical ablation and points to the usefulness of devices allowing ablation of larger volumes. In the presence of extrahepatic metastases, RFA has less impact on survival, even though it is potentially useful in patients at a higher risk of death due to hepatic rather than extrahepatic metastases.

Multi-modality treatment of colorectal liver metastases

Liver metastases synchronously or metachronously occur in approximately 50% of colorectal cancer patients. Multimodality comprehensive treatment is the best therapeutic strategy for these patients. However, the optimal pattern of multimodality therapy is still controversial, and it raises several significant concerns. Liver resection is the most important treatment for colorectal liver metastases. The definition of resectability has shifted to focus on the completion of R0 resection and normal liver function maintenance. The role of neoadjuvant and adjuvant chemotherapy still needs to be clarified. The management of either progression or complete remission during neoadjuvant chemotherapy is challenging. The optimal sequencing of surgery and chemotherapy in synchronous colorectal liver metastases patients is still unclear. Conversional chemotherapy, portal vein embolization, two-stage resection, and tumor ablation are effective approaches to improve resectability for initially unresectable patients. Several technical issues and concerns related to these methods need to be further explored. For patients with definitely unresectable liver disease, the necessity of resecting the primary tumor is still debatable, and evaluating and predicting the efficacy of targeted therapy deserve further investigation. This review discusses different patterns and important concerns of multidisciplinary treatment of colorectal liver metastases.

Interventional radiology and the care of the oncology patient

Interventional Radiology (IR) is occupying an increasingly prominent role in the care of patients with cancer, with involvement from initial diagnosis, right through to minimally invasive treatment of the malignancy and its complications. Adequate diagnostic samples can be obtained under image guidance by percutaneous biopsy and needle aspiration in an accurate and minimally invasive manner. IR techniques may be used to place central venous access devices with well-established safety and efficacy. Therapeutic applications of IR in the oncology patient include local tumour treatments such as transarterial chemo-embolisation and radiofrequency ablation, as well as management of complications of malignancy such as pain, organ obstruction, and venous thrombosis.

Anatomical versus nonanatomical resection of colorectal liver metastases: is there a difference in surgical and oncological outcome?

BACKGROUND

The increased use of neoadjuvant chemotherapy and minimally invasive therapies for recurrence in patients with colorectal liver metastases (CLM) makes a surgical strategy to save as much liver volume as possible pivotal. In this study, we determined the difference in morbidity and mortality and the patterns of recurrence and survival in patients with CLM treated with anatomical (AR) and nonanatomical liver resection (NAR).

METHODS

From January 2000 to June 2008, patients with CLM who underwent a resection were included and divided into two groups: patients who underwent AR, and patients who underwent NAR. Patients who underwent simultaneous radiofrequency ablation in addition to surgery and patients with extrahepatic metastasis were excluded. Patient, tumor, and treatment data, as well as disease-free and overall survival (OS) were compared.

RESULTS

Eighty-eight patients (44%) received AR and 113 patients (56%) underwent NAR. NAR were performed for significant smaller metastases (3 vs. 4 cm, P < 0.001). The Clinical Risk Score did not differ between the groups. After NAR, patients received significantly less blood transfusions (20% vs. 36%, P = 0.012), and the hospital stay was significantly shorter (7 vs. 8 days, P < 0.001). There were no significant differences in complications, positive resection margins, or recurrence. For the total study group, estimated 5-year disease-free and OS was 31 and 44%, respectively, with no difference between the groups.

CONCLUSIONS

Our study resulted in no significant difference in morbidity, mortality, recurrence rate, or survival according to resection type. NAR can be used as a save procedure to preserve liver parenchyma.

Planning and follow-up after ablation of hepatic tumors: imaging evaluation

CTs or MRIs are essential for preablative therapy planning of hepatic tumors to identify accurate size, number, and location of tumors. Tumors larger than 5 cm and located near the major branches of the portal vein and hepatic vein have a higher potential for incomplete ablation. Postablative imaging studies are needed to determine if the entire tumors are included in the treatment zone to minimize the risk of local tumor recurrences. Complications of ablative therapy can be identified on post-treatment imaging studies.

Stereotactic body radiation therapy for colorectal liver metastases

BACKGROUND

Stereotactic body radiation therapy (SBRT) is a treatment option for colorectal liver metastases. Local control, patient survival and toxicity were assessed in an experience of SBRT for colorectal liver metastases.

METHODS

SBRT was delivered with curative intent to 20 consecutively treated patients with colorectal hepatic metastases who were candidates for neither resection nor radiofrequency ablation (RFA). The median number of metastases was 1 (range 1-3) and median size was 2.3 (range 0.7-6.2) cm. Toxicity was scored according to the Common Toxicity Criteria version 3.0. Local control rates were derived on tumour-based analysis.

RESULTS

Median follow-up was 26 (range 6-57) months. Local failure was observed in nine of 31 lesions after a median interval of 22 (range 12-52) months. Actuarial 2-year local control and survival rates were 74 and 83 per cent respectively. Hepatic toxicity grade 2 or less was reported in 18 patients. Two patients had an episode of hepatic toxicity grade 3.

CONCLUSION

SBRT is a treatment option for patients with colorectal liver metastases who are not candidates for resection or RFA.

Optimizing the outcome of surgery in patients with rectal cancer and synchronous liver metastases

BACKGROUND

This study evaluated the outcome of patients treated for rectal cancer and synchronous hepatic metastases in the era of effective induction radiotherapy and chemotherapy.

METHODS

All patients undergoing surgical treatment of rectal cancer and synchronous liver metastases between 2000 and 2007 were identified retrospectively from a prospectively collected database. Three approaches were followed: the classical staged, the simultaneous and the liver-first approach.

RESULTS

Of 57 patients identified, the primary tumour was resected first in 29 patients (group 1), simultaneous resection was performed in eight patients (group 2), and 20 patients underwent a liver-first approach (group 3). The overall morbidity rate was 24.6 per cent; there was no in-hospital mortality. Median in-hospital stay was significantly shorter for the simultaneous approach (9 days versus 18 and 15 days for groups 1 and 3 respectively; P < 0.001). The overall 5-year survival rate was 38 per cent, with an estimated median survival of 47 months.

CONCLUSION

Long-term survival can be achieved using an individualized approach, with curative intent, in patients with rectal cancer and synchronous liver metastases. Simultaneous resections as well as the liver-first approach are attractive alternatives to traditional staged resections.

American Society of Clinical Oncology 2009 clinical evidence review on radiofrequency ablation of hepatic metastases from colorectal cancer

PURPOSE

To review the evidence about the efficacy and utility of radiofrequency ablation (RFA) for hepatic metastases from colorectal cancer (CRHM).

METHODS

The American Society of Clinical Oncology (ASCO) convened a panel to conduct and analyze a comprehensive systematic review of the RFA literature from Medline and the Cochrane Collaboration Library.

RESULTS

Because data were considered insufficient to form the basis of a practice guideline, ASCO has instead published a clinical evidence review. The evidence is from single-arm, retrospective, and prospective trials. No randomized controlled trials have been included. The following three clinical issues were considered by the panel: the efficacy of surgical hepatic resection versus RFA for resectable tumors; the utility of RFA for unresectable tumors; and RFA approaches (open, laparoscopic, or percutaneous). Evidence suggests that hepatic resection improves overall survival (OS), particularly for patients with resectable tumors without extrahepatic disease. Careful patient and tumor selection is discussed at length in the literature. RFA investigators report a wide variability in the 5-year survival rate (14% to 55%) and local tumor recurrence rate (3.6% to 60%). The reported mortality rate was low (0% to 2%), and the major complications rate was commonly reported to be between 6% and 9%. RFA is currently performed with all three approaches.

CONCLUSION

There is a compelling need for more research to determine the efficacy and utility of RFA to increase local recurrence-free, progression-free, and disease-free survival as well as OS for patients with CRHM. Clinical trials have established that hepatic resection can improve OS for patients with resectable CRHM.

Radiofrequency ablation combined with KS-IL2 immunocytokine (EMD 273066) results in an enhanced antitumor effect against murine colon adenocarcinoma

PURPOSE

Radiofrequency ablation (RFA) is a common treatment modality for surgically unresectable tumors. However, there is a high rate of both local and systemic recurrence.

EXPERIMENTAL DESIGN

In this preclinical study, we sought to enhance the antitumor effect of RFA by combining it with huKS-IL2 immunocytokine [tumor-specific monoclonal antibody fused to interleukin-2 (IL2)] in mice bearing CT26-KS colon adenocarcinoma. Mice were treated with RFA, huKS-IL2 via intratumoral injection, or combination therapy.

RESULTS

Treatment of mice bearing s.c. tumors with RFA and huKS-IL2 resulted in significantly greater tumor growth suppression and enhanced survival compared with mice treated with RFA or huKS-IL2 alone. When subtherapeutic regimens of RFA or huKS-IL2 were used, tumors progressed in all treated mice. In contrast, the combination of RFA and immunocytokine resulted in complete tumor resolution in 50% of mice. Treatment of a tumor with RFA and intratumoral huKS-IL2 also showed antitumor effects against a distant untreated tumor. Tumor-free mice after treatment with RFA and huKS-IL2 showed immunologic memory based on their ability to reject subsequent challenges of CT26-KS and the more aggressive parental CT26 tumors. Flow cytometry analysis of tumor-reactive T cells from mice with complete tumor resolution showed that treatment with RFA and huKS-IL2 resulted in a greater proportion of cytokine-producing CD4 T cells and CD8 T cells compared with mice treated with RFA or huKS-IL2 alone.

CONCLUSIONS

These results show that the addition of huKS-IL2 to RFA significantly enhances the antitumor response in this murine model, resulting in complete tumor resolution and induction of immunologic memory.

Phase II feasibility study on the combination of two different regional treatment approaches in patients with colorectal "liver-only" metastases: hepatic interstitial brachytherapy plus regional chemotherapy

The aim of this study was to evaluate the feasibility, safety, and efficacy of combined treatment with hepatic interstitial brachytherapy (HIB) and hepatic arterial infusion (HAI) of chemotherapy after interventional implantation of port catheter systems. Thirty-three patients with unresectable "liver-only" metastases of colorectal cancer were treated with both HIB and HAI during the course of their disease. All 33 patients had recurrent disease and 27 had received previous chemotherapy. Of these, 15 received HAI first and were then consolidated with HIB, 9 started with HIB and were continued with HAI, and 9 received first HIB and subsequently HAI after hepatic disease progression. Patients were evaluated for treatment characteristics, side effects, and efficacy. Comparisons between treatment groups were also performed. The median tumor diameter of metastases treated with brachytherapy was 4.6 cm (range: 1-12 cm). The median minimal irradiation dose inside the tumor margin was 18 Gy administered to a mean of two metastases in 69 interventions. Minor (n = 4) and major (n = 3) complications occurred in 10% of interventions. WHO grade III adverse events of the regional chemotherapy were observed in seven patients; grade IV, in one patient. At a median follow-up of 28 months (range: 7-74 months), the median time to disease progression after first treatment was 10.5 months (range: 1-35 months). Of 138 metastases treated by brachytherapy, 16 local recurrences were seen (mean, 12.3 months; range, 3-45 months). No signs of hepatic failure were observed in any of our patients. In conclusion, combinations of two minimally invasive therapeutic methods are feasible, with acceptable complication rates, and provide promising results in colorectal cancer patients with unresectable hepatic metastases.

Local treatment for recurrent colorectal hepatic metastases after partial hepatectomy

OBJECTIVE

The objective of the study was to identify patients who may benefit from local treatment in recurrent colorectal liver metastases.

MATERIALS AND METHODS

A total of 51 consecutive patients were treated for hepatic recurrence(s) after an initial partial hepatic resection. Surgery was considered as the primary treatment option for eligible patients. Patients with a small liver remnant after major hepatectomy were treated with radiofrequency ablation (RFA) or stereotactic body radiation therapy (SRx). SRx was given as an outpatient, emerging local treatment option for patients with intra-hepatic recurrences not eligible for surgery or RFA. Partial liver resection was performed in 36 patients (70%), RFA in ten patients (20%), and SRx in five patients (10%).

RESULTS

Median hospital stay was 7 (range, 3-62) days with a morbidity of 16% without in-hospital death. None of the patients received adjuvant chemotherapy. There was no difference in recurrence or survival between the three treatment modalities. Overall 5-year survival was 35% with an estimated median survival of 37 months. Patients with a disease-free interval between first hepatectomy and hepatic recurrence less than 6 months did not survive 3 years.

CONCLUSIONS

Resection, RFA, and SRx can be performed safely in patients with recurrent colorectal liver metastases and offer a survival that seems comparable to primary liver resections of colorectal liver metastases.

The change in dimension of the masseter muscle in rabbits after radiofrequency therapy

PURPOSE

The objective of this study was to evaluate the change in muscle dimension after administering radiofrequency (RF) therapy.

MATERIALS AND METHODS

This study used 6 male New Zealand rabbits. Groups were divided by number of applications of RF (eg, 1 to 4 points). The dimension of the masseter muscle was measured using a computerized tomogram scan before operation, and at 1, 2, 3, and 4 weeks after RF therapy was administered under the same conditions. Two horizontal cuts were selected for measurement.

RESULTS

The size of the measured areas for each group at 1 week after RF therapy was significantly increased compared with the preoperative value (P< .05). When the measurements of each group at 3 and 4 weeks after RF therapy were compared with the preoperative value, they were significantly decreased (P< .05). The dimensional change was significantly different among groups at 1 and 3 weeks post RF therapy (P< .05). The swelling at 1 week after RF therapy was increased in terms of the number of RF applications. The ratio of dimension was decreased at 3 weeks after RF therapy in terms of the number of RF applications.

CONCLUSION

There was an increase in muscle dimension because of swelling in the early stages of RF therapy. However, this dimension decreased at 3 weeks post-RF administration compared with the preoperative value. Therefore, it can be concluded that the change in the masseter muscle dimension was dependent on the number of RF applications.

Isolated hepatic perfusion for the treatment of liver tumors: sunset or sunrise?

Experience with isolated hepatic perfusion (IHP) is limited to a few centers in the world because of the technical difficulties, surgery-related morbidity, and unproved efficacy in randomized trials. Experimental animal IHP models have led to exploring new ways of improving efficacy, reducing technical difficulties, and minimizing regional and systemic toxicity. Future research should be directed to the identification of suitable biologic or chemotherapeutic agents, defining clinical indications, and development of technical modifications to make it more generally applicable and even repeatable.

Subcapsular liver tumors treated with percutaneous radiofrequency ablation: a prospective comparison with nonsubcapsular liver tumors for safety and effectiveness

PURPOSE

To assess the safety and effectiveness of percutaneous radiofrequency (RF) ablation of subcapsular liver tumors.

MATERIALS AND METHODS

The study protocol was approved by the institutional review board, and all patients gave written informed consent. One hundred eighty-one patients (79 men, 102 women; age range, 36-85 years) underwent ultrasonographically (US) guided percutaneous RF ablation of 361 primary or secondary (metastatic) liver tumors. Forty-four patients had one or more subcapsular nodules (group 1), and 137 had nonsubcapsular nodules only (group 2). Overall, 80 nodules were subcapsular and 281 were nonsubcapsular. The completeness of the ablation was assessed with contrast material-enhanced computed tomography (CT) 1 month after RF ablation. If residual tumor was documented, RF ablation was repeated. All patients in whom the ablation was complete after the first or second ablation session were monitored with CT or contrast-enhanced US every 3 months. Major complication, complete ablation, and local tumor progression rates were compared by using the chi(2) test or Fisher exact test.

RESULTS

Three (7%) major complications (intraperitoneal bleeding, skin burn, and tumor seeding) occurred in group 1, and two (1.5%) cases of tumor seeding occurred in group 2 (P = .093). No RF ablation-related deaths occurred. The complete ablation rate was 98% (43 of 44 patients) in group 1 and 98.5% (135 of 137 patients) in group 2 (P = .756). The local tumor progression rate after a median follow-up of 25 months (range, 13-54 months) was 16% (seven of 43 patients) in group 1 and 9.6% (13 of 135 patients) in group 2 (P = .355).

CONCLUSION

The difference in major complication rate between the subcapsular and nonsubcapsular liver tumors was not significant. The safety of RF ablation of subcapsular tumors seems acceptable, and the effectiveness is comparable to that of RF ablation of nonsubcapsular tumors.

Radiofrequency ablation versus resection for resectable colorectal liver metastases: time for a randomized trial?

BACKGROUND

Surgical resection is the gold standard in the treatment of resectable colorectal liver metastases (CRLM). In several centers, resection is being replaced by radiofrequency ablation (RFA), even though there is no evidence yet from randomized trials to support this. The aim of this study was to critically review the oncological evidence for and against the use of RFA for resectable CRLM.

METHODS

An exhaustive review of RFA of colorectal metastases was carried out.

RESULTS

Five-year survival data after RFA for resectable CRLM are not available. Percutaneous RFA is associated with worse local control, worse staging, and a small risk of electrode track seeding when compared with resection (level V evidence). For tumors </=3 cm, local control after surgical RFA is equivalent to resection, especially if applied by experienced physicians to nonperivascular tumors (level V evidence). There is indirect evidence for profoundly different biological effects of RFA and resection.

CONCLUSIONS

A subgroup of patients has been identified for whom local control after RFA might be equivalent to resection. Whether this is true, and whether this translates into equivalent survival, remains to be proven. The time has come for a randomized trial.