Comparison of resection and radiofrequency ablation for treatment of solitary colorectal liver metastases

Hepatocellular carcinoma and liver metastases: clinical data on a new dual-lumen catheter kit for surgical sealant infusion to prevent perihepatic bleeding and dissemination of cancer cells following biopsy and loco-regional treatments

Background

RFA is a safe and effective procedure for treating unresectable primary or secondary liver malignancies, but it is not without complications. The most common reported complications include abdominal hemorrhage, bile leakage, biloma formation, hepatic abscesses, and neoplastic seeding.

The aim of this study is to evaluate the feasibility of percutaneous use of surgical sealant with a new coaxial bilumen catheter, to prevent the perihepatic bleeding and dissemination of cancer cells through the needle-electrode (neoplastic seeding) or along the needle track.

Methods

We designed a novel dual-lumen catheter to facilitate the optimal application of fibrin sealant after diagnostic and therapeutic percutaneous procedures. Percutaneous RFA has been performed using mask ventilation or neuroleptanalgesia. The main aims of this study, after the ablation procedure, in the treatment of unresectable liver cancer were to prevent major adverse events: a) the perihepatic bleeding; b) dissemination of cancer cells through the needle-electrode and or needle track.

Results

A total of 181 patients were evaluated for this study at National Cancer Institute of Naples from January 2012 to January 2014. The association of blood loss (≤1 g/dl; ≥1 g/dl) with age, gender, histological diagnosis were analyzed. No statistical significance was observed between bleeding and age (p = 0.840), gender (p = 0.607) and histological diagnosis (p = 0,571), respectively.

Conclusions

This study demonstrated that fibrin sealant or other surgical sealant injection, after any locoregional procedure such as biopsy or ablation, could make adverse events even more rare.

Optimal management of colorectal liver metastases in older patients: a decision analysis

BACKGROUND

Comparative trials evaluating management strategies for colorectal cancer liver metastases (CLM) are lacking, especially for older patients. This study developed a decision-analytic model to quantify outcomes associated with treatment strategies for CLM in older patients.

METHODS

A Markov-decision model was built to examine the effect on life expectancy (LE) and quality-adjusted life expectancy (QALE) for best supportive care (BSC), systemic chemotherapy (SC), radiofrequency ablation (RFA) and hepatic resection (HR). The baseline patient cohort assumptions included healthy 70-year-old CLM patients after a primary cancer resection. Event and transition probabilities and utilities were derived from a literature review. Deterministic and probabilistic sensitivity analyses were performed on all study parameters.

RESULTS

In base case analysis, BSC, SC, RFA and HR yielded LEs of 11.9, 23.1, 34.8 and 37.0 months, and QALEs of 7.8, 13.2, 22.0 and 25.0 months, respectively. Model results were sensitive to age, comorbidity, length of model simulation and utility after HR. Probabilistic sensitivity analysis showed increasing preference for RFA over HR with increasing patient age.

CONCLUSIONS

HR may be optimal for healthy 70-year-old patients with CLM. In older patients with comorbidities, RFA may provide better LE and QALE. Treatment decisions in older cancer patients should account for patient age, comorbidities, local expertise and individual values.

Liver-directed therapies in metastatic colorectal cancer

Colorectal cancer (CRC) is a major health concern in the United States (US) with over 140,000 new cases diagnosed in 2012. The most common site for CRC metastases is the liver. Hepatic resection is the treatment of choice for colorectal liver metastases (CLM), with a 5-year survival rate ranging from 35% to 58%. Unfortunately, only about 20% of patients are eligible for resection. There are a number of options for extending resection to more advanced patients including systemic chemotherapy, portal vein embolization (PVE), two stage hepatectomy, ablation and hepatic artery infusion (HAI). There are few phase III trials comparing these treatment modalities, and choosing the right treatment is patient dependent. Treating hepatic metastases requires a multidisciplinary approach and knowledge of all treatment options as there continues to be advances in management of CLM. If a patient can undergo a treatment modality in order to increase their potential for future resection this should be the primary goal. If the patient is still deemed unresectable then treatments that lengthen disease-free and overall-survival should be pursued. These include chemotherapy, ablation, HAI, chemoembolization, radioembolization (RE) and stereotactic radiotherapy.

Image-guided interventions in oncology

Interventional oncology, a term commonly used to indicate the minimally invasive procedures performed by interventional radiologists to diagnose and manage cancer, encompasses a broad spectrum of techniques unique to interventional radiology that have been established as a vital part of the multidisciplinary oncologic cancer care team. This article provides an updated overview of the variety of applications of image-guided procedures to distinct clinical scenarios, such as the diagnosis, treatment, and management of complications of malignancies.

Synergistic ablation of liver tissue and liver cancer cells with high-intensity focused ultrasound and ethanol

We investigated the combined effect of ethanol and high-intensity focused ultrasound (HIFU), first, on heating and cavitation bubble activity in tissue-mimicking phantoms and porcine liver tissues and, second, on the viability of HepG2 liver cancer cells. Phantoms or porcine tissues were injected with ethanol and then subjected to HIFU at acoustic power ranging from 1.2 to 20.5 W (HIFU levels 1-7). Cavitation events and the temperature around the focal zone were measured with a passive cavitation detector and embedded type K thermocouples, respectively. HepG2 cells were subjected to 4% ethanol solution in growth medium (v/v) just before the cells were exposed to HIFU at 2.7, 8.7 or 12.0 W for 30 s. Cell viability was measured 2, 24 and 72 h post-treatment. The results indicate that ethanol and HIFU have a synergistic effect on liver cancer ablation as manifested by greater temperature rise and lesion volume in liver tissues and reduced viability of liver cancer cells. This effect is likely caused by reduction of the cavitation threshold in the presence of ethanol and the increased rate of ethanol diffusion through the cell membrane caused by HIFU-induced streaming, sonoporation and heating.

"How we do it" - a practical approach to hepatic metastases ablation techniques

Secondary liver malignancies are associated with significant mortality and morbidity if left untreated. Colorectal cancer is the most frequent origin of hepatic metastases. A multidisciplinary approach to the treatment of hepatic metastases includes medical, surgical, radiation and interventional oncology. The role of interventional oncology in the management of hepatic malignancies continues to evolve and applies to a large and continuous spectrum of metastatic disease, from the relatively small solitary metastasis to larger tumors and multifocal liver disease. Within the past 10 years, several publications of percutaneous image-guided ablation indicated the effectiveness and safety of this minimally invasive therapy for selected patients with limited number (arguably up to 4 metastases) of relatively small (less than 5cm) hepatic metastases. Different image-guided procedures such radiofrequency, microwave, and laser cause thermal ablation and coagulation necrosis or cell death of the target tumor. Cryoablation, causing cell death via cellular freezing, has also been used. Recently, irreversible electroporation, a nonthermal modality, has also been used for liver tumor ablation. In the following section, we review the different liver ablation techniques, as well as indications for ablation, specific patient preparations, and different "tricks of the trade" that we use to achieve safe and effective liver tumor ablation. We also discuss appropriate imaging and clinical patient follow-up and potential complications of liver tumor ablation.

Radiofrequency ablation of liver tumors

Radiofrequency ablation (RFA) is an alternative therapy for hepatocellular carcinoma and liver metastases when resection cannot be performed or, in the case of hepatocellular carcinoma, when transplant cannot be performed in a timely enough manner to avoid the risk of dropping off the transplant list. RFA has the advantage of being a relatively low-risk minimally invasive procedure used in the treatment of focal liver tumors. This review article discusses the current evidence supporting RFA of liver tumors, as well as the indications, complications, and follow-up algorithms used after RFA.

Radiofrequency ablation for colorectal liver metastases

The management of hepatic metastases from colorectal cancer (HMCRC) is multimodal including chemotherapy, surgical resection, radiation therapy, and focused destruction technologies. Radiofrequency ablation (RFA) is the most commonly used focused destruction technology. It represents a therapeutic option that may be potentially curative in cases where surgical excision is contra-indicated. It also increases the number of candidates for surgical resection among patients whose liver metastases were initially deemed unresectable. This article explains the techniques, indications, and results of radiofrequency ablation in the treatment of hepatic colorectal metastases.

Impact of treatment modality and number of lesions on recurrence and survival outcomes after treatment of colorectal cancer liver metastases

BACKGROUND

Ablative strategies have been used to treat and facilitate hepatic resection (HR) in patients with otherwise unresectable colorectal liver metastases (CLM). We evaluated the efficacy of HR, concomitant HR and ablation and isolated ablation on recurrence and survival outcomes after treatment of CLM in patients with 1-4 and ≥5 lesions, respectively.

METHODS

A retrospective review of a prospectively collected hepatobiliary surgery database was performed on patients who underwent treatment for isolated CLM between 1990 and 2010. Pre-operative and treatment characteristics were compared between patients who underwent HR, concomitant HR and ablation and ablation alone. The impact of treatment modality on survival and recurrence outcomes was determined.

RESULTS

A total of 701 patients met inclusion criteria; 550 patients (78%) had 1-4 lesions and 151 patients (22%) had ≥5 lesions. Overall median survival for the entire cohort was 35 months with 5- and 10-year survival of 33% and 20%, respectively. Overall median and 5-year recurrence-free survival (RFS) was 13 months and 21%, respectively. For patients with 1-4 lesions, median survival was 37 months with 5-year survival of 36%. Stratified by procedure type, 5-year survival was 41% in patients who underwent HR, 35% in patients who underwent concomitant HR and ablation and 13% in patients who underwent ablation alone (P<0.001). For patients with ≥5 lesions, median survival was 28 months with 5-year survival of 23% without difference between treatment groups (P=0.078).

CONCLUSIONS

HR appears to be the most effective strategy for patients with 1-4 lesions. When ≥5 lesions are present, ablative strategies are useful in facilitating HR in otherwise unresectable patients.

Comparative analysis of radiofrequency ablation and resection for resectable colorectal liver metastases

AIM: To evaluate the therapeutic efficacy of radiofrequency ablation (RFA) for resectable colorectal liver metastases (CRLM) compared with that of resection.

METHODS: Between June 2004 and June 2009, we retrospectively analyzed 29 patients with resectable CRLMs; 17 patients underwent RFA, and 12 underwent hepatic resection. All of the patients were informed about the treatment modalities and were allowed to choose either of them. RFA including an intraoperative approach was performed by a radiologist; otherwise, hepatic resection was performed by a surgeon. Comparative analysis of the two groups was performed, including comparisons of gender, age, and clinical outcomes, such as primary tumor stage and survival rates.

RESULTS: The mean tumor size was significantly larger in the resection group (3.59 cm vs 2.02 cm, P < 0.01), and the 5-year overall survival (OS) rate for all patients was 44.7%. There was no difference in the 5-year OS rates between the RFA and resection groups (37.8% vs 66.7%). Univariate analysis indicated significantly lower 5-year OS rates for patients with a tumor size > 3 cm. The 5-year disease-free survival (DFS) rates were 17.6% and 22.2% in the RFA and resection groups, respectively (P = 0.119). Univariate analysis revealed that in cases of male gender, age > 65 years, T stage < IV, absence of lymphatic metastasis, and tumor size > 3 cm, RFA resulted in significantly inferior 5-year DFS rates compared with surgical resection.

CONCLUSION: Surgical resection revealed superior outcomes in the treatment of resectable CRLMs, particularly in cases with a hepatic tumor size > 3 cm.

Radiofrequency ablation technique in the treatment of liver tumours: review and future issues

Thermal ablation is increasingly being used for treatment of liver tumours. Among the techniques of thermal ablation, radiofrequency ablation (RF) is undoubtedly being used most frequently because of its advantages, such as morbidity and mortality rates, effective tumour ablation, as well as being less time-consuming. This paper presents the state of the art of RF ablation technique. This includes the theoretical development, experimental study and clinical application of the radiofrequency ablation technique. First, it introduces the principle of this technique. Second, it shows the development of this technique and valuable achievements. These achievements include the device, strategy of operation and extension to other diseases. Third, it concludes future issues to be addressed in order to further advance this technique.

Percutaneous radiofrequency ablation (RFA) or robotic radiosurgery (RRS) for salvage treatment of colorectal liver metastases

BACKGROUND

Stereotactic radiation therapy is an evolving modality to treat otherwise unresectable liver metastases. In this analysis, two local therapies: 1) single session robotic radiosurgery (RRS) and 2) percutaneous radiofrequency ablation (RFA) were compared in a total of 60 heavily pretreated colorectal cancer patients.

METHODS

Thirty patients with a total of 35 colorectal liver metastases not qualifying for surgery that were treated in curative intent with RRS were prospectively followed. To compare efficacy of both treatment modalities, patients treated with RFA during the same period of time were matched according to number and size of the treated lesions. Local tumor control, local disease free survival (DFS), and freedom from distant recurrence (FFDR) were analyzed for efficacy. Treatment-related side effects were recorded for comparison.

RESULTS

The median diameter of the treated lesions was 33 mm (7-53 mm). Baseline characteristics did not differ significantly between the groups. One- and two-year local control rates showed no significant difference but favored RRS (85% vs. 65% and 80% vs. 61%, respectively). A significantly longer local DFS of patients treated with RRS compared to RFA (34.4 months vs. 6.0 months; p < 0.001) was found. Both, median FFDR (11.4 months for RRS vs. 7.1 months for RFA p = 0.25) and the recurrence rate (67% for RRS and 63% for RFA, p > 0.99) were comparable.

CONCLUSION

Single session RRS is a safe and effective method to treat colorectal liver metastases. In this analysis, a trend towards longer DFS was seen in patients treated with RRS when compared to RFA.

Advances in treatment of liver metastases of colorectal cancer

Liver metastasis of colorectal cancer has a high incidence and mortality and is the main factor affecting prognosis, which necessitates the development of more reasonable therapeutic strategy for this condition. Nowadays, surgical resection is the only probable curative method; however, surgical intervention is indicated in only a few patients. The development of medical technology and accumulation of clinical experience have led to the wide use of multimodal treatment for liver metastases of colorectal cancer. Multimodal treatment includes surgical resection, neoadjuvant chemotherapy, transcatheter hepatic arterial chemoembolization, radiation therapy, radiofrequency ablation, cryotherapy, percutaneous ethanol injection, and Chinese medicine treatment. The combined application of the above treatments can improve the survival rate and the quality of life of patients. This article summarizes the advances in comprehensive treatment for colorectal liver metastases.

Radiofrequency ablation of liver metastases from colorectal cancer: a literature review

Liver metastases occur in up to 60% of patients with colorectal cancer, and the control of liver metastases is considered to be of primary importance because it is a critical factor in determining prognosis. Radiofrequency ablation (RFA) therapy is one of the least invasive techniques for unresectable hepatic malignancies and can be performed safely using percutaneous, laparoscopic, or open surgical techniques. The local tumor progression rates after RFA for colorectal liver metastases range from 8.8% to 40.0%, and 5-year survival rates range from 20.0% to 48.5%. No prospective, randomized trials comparing the efficacy of RFA with that of surgical resection for colorectal liver metastases are currently available. However, some retrospective studies have reported that patients who received RFA had a survival rate similar to that observed in surgically treated groups, while other studies have reported better survival among patients who underwent surgical resection. The use of a laparoscopic or open surgical approach allows the repeated placement of RFA electrodes at multiple sites to ablate larger tumors. An accurate evaluation of treatment response is very important for the success of RFA therapy because a sufficient safety margin (at least 0.5 cm) can prevent local tumor progression. This review critically summarizes the current status of RFA for liver metastases from colorectal cancer.

Combined Hepatic Arterial Embolization and Hepatic Ablation for Unresectable Colorectal Metastases to the Liver

Liver-directed therapy for hepatic metastases includes: intra-arterial techniques such as trans-arterial chemoembolization (TACE) and yttrium-90 resin (90Y) microsphere radioembolization and ablative technologies: cryoablation, radiofrequency ablation, and microwave ablation. Combining embolization techniques with liver ablation may enhance the therapeutic benefit of each and result in improved patient survival. We retrospectively reviewed our experience with combined intra-arterial therapies and ablation for unresectable hepatic colorectal metastases from 1996 to 2011. Patient demographics, tumor characteristics, specific liver-directed treatments, procedure-related morbidity and mortality, and overall survival were recorded. There were 17 (53%) males and 15 (47%) females. Average age for the group was 74.1 years (median, 75.5 years). Fifteen patients (46.9%) had a single hepatic metastasis. Eleven (34%) patients had bilobar tumor distribution and seven (22%) patients had vascular invasion of the portal vein or hepatic/caval venous structures. Seven (21%) tumors were greater than 5 cm in diameter. Twenty-seven (84.4%) patients received TACE and five (15.6%) received 90Y. Fourteen (43%) were embolized before any ablation. Fifty-three per cent of patients required multiple hepatic ablation sessions. Median length of hospital stay was 1 day. There were no procedure-related mortalities and complications occurred in six (18.8%) patients. Mean follow-up for the group was 33 months. Kaplan-Meier 1-, 3-, and 5-year estimated survival was 93.8, 50.0, and 10.1 per cent, respectively. Median survival for the group was 46 months. Hepatic ablation and embolization techniques can be combined safely with minimal morbidity. In our series, we observed 5-year survival in 10 per cent of patients.

Comparison of FDG-PET, MRI and CT for post radiofrequency ablation evaluation of hepatic tumors

PURPOSE

Treatment effect of radiofrequency ablation (RFA) is traditionally accomplished with MRI and/or CT. The aim of the study was to assess the role of FDG-PET in post RFA hepatic tumor evaluation, in comparison with MRI and CT.

MATERIALS AND METHODS

28 patients (33 hepatic RFA lesions) who had post RFA FDG-PET within 8 weeks of abdominopelvic MRI or CT were retrospectively reviewed. Accuracy of FDG-PET on post hepatic RFA evaluation was compared with MRI and/or CT based on clinical and imaging follow-up.

RESULTS

Among total of 33 RFA-treated lesions, 17 had residual or recurrent tumor (positive). PET identified 16 with a sensitivity of 94.1 %. Of these 17 lesions, 12 had concurrent MRI and 8 were positive with a sensitivity of 66.7 %. Similarly, 6 out of the 17 lesions had CT and 4 were positive with a sensitivity of 66.7 %. Sixteen lesions were successfully ablated (negative). Among them FDG-PET was negative in 13 with a specificity of 81.3 %; MRI was performed in 8 and 7 were negative with a specificity of 87.5 %; CT was performed in 8 and 5 were negative with a specificity of 62.5 %. The overall accuracy of PET, MRI and CT was 87.9, 75.0, and 64.3 %, respectively. The average scan numbers for PET, MRI and CT to achieve a final accurate diagnosis were 1.121, 1.316 and 1.250, with a corresponding cost of $1455.2, $1845.8, and $933.8, respectively.

CONCLUSIONS

The study suggests that FDG-PET is superior to MRI and/or CT and is more cost-effective in post RFA hepatic tumor assessment.

Radiofrequency ablation versus resection for colorectal cancer liver metastases: a meta-analysis

BACKGROUND

No randomized controlled trial (RCT) has yet been performed to provide the evidence to clarify the therapeutic debate on liver resection (LR) and radiofrequency ablation (RFA) in treating colorectal liver metastases (CLM). The meta-analysis was performed to summarize the evidence mostly from retrospective clinical trials and to investigate the effect of LR and RFA.

METHODOLOGY/PRINCIPAL FINDINGS

Systematic literature search of clinical studies was carried out to compare RFA and LR for CLM in Pubmed, Embase and the Cochrane Library Central databases. The meta-analysis was performed using risk ratio (RR) and random effect model, in which 95% confidence intervals (95% CI) for RR were calculated. Primary outcomes were the overall survival (OS) and disease-free survival (DFS) at 3 and 5 years plus mortality and morbidity. 1 prospective study and 12 retrospective studies were finally eligible for meta-analysis. LR was significantly superior to RFA in 3 -year OS (RR 1.377, 95% CI: 1.246-1.522); 5-year OS (RR: 1.474, 95%CI: 1.284-1.692); 3-year DFS (RR 1.735, 95% CI: 1.483-2.029) and 5-year DFS (RR 2.227, 95% CI: 1.823-2.720). The postoperative morbidity was higher in LR (RR: 2.495, 95% CI: 1.881-3.308), but no significant difference was found in mortality between LR and RFA. The data from the 3 subgroups (tumor<3 cm; solitary tumor; open surgery or laparoscopic approach) showed significantly better OS and DFS in patients who received surgical resection.

CONCLUSIONS/SIGNIFICANCES

Although multiple confounders exist in the clinical trials especially the bias in patient selection, LR was significantly superior to RFA in the treatment of CLM, even when conditions limited to tumor<3 cm, solitary tumor and open surgery or laparoscopic (lap) approach. Therefore, caution should be taken when treating CLM with RFA before more supportive evidences for RFA from RCTs are obtained.

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.

Comparison of radiofrequency ablation and resection for hepatic metastasis from colorectal cancer

BACKGROUND/AIMS

Radiofrequency ablation (RFA) has been mostly used as a therapeutic alternative to hepatic resection for treating liver metastasis of colorectal cancer. The purpose of the present study was to determine whether there were differences in outcome between RFA and surgical resection in the treatment of colorectal cancer with liver metastases.

METHODS

We performed a retrospective analysis of 53 patients who underwent only hepatic resection or only RFA for colorectal liver metastases. Twenty-five patients who underwent hepatic resection were compared with 28 patients who underwent RFA for synchronous or metachronous liver metastases.

RESULTS

The median CEA level at the time of diagnosis of liver metastases was significantly higher in the resection group (14.2 ng/mL vs. 2.8 ng/mL, p=0.002). The median size of main liver metastases was significantly larger in the resection group (4.0 cm vs. 2.05 cm, p=0.002). There was no difference in the percentage of patients experiencing major complication (one patient in each group). The marginal recurrence rate was significantly higher in the RFA group (p=0.004). Disease-free and overall survival were longer in the resection group (p=0.008 and 0.017, respectively). In multivariate analysis, only the type of treatment was a factor associated with disease-free and overall survival (p=0.004 and 0.007, respectively).

CONCLUSIONS

Because of the high marginal recurrence rate, RFA shows an inferior outcome in comparison with surgical resection. Therefore, RFA should be considered for only selected patients with unresectable (by any means) disease or with high operative risk.

Radiofrequency ablation in the treatment of liver metastases from colorectal cancer

BACKGROUND

Colorectal cancer (CRC) is the most common malignant tumour and the third leading cause of cancer deaths in USA. For advanced CRC, the liver is the first site of metastatic disease; approximately 50 % of patients with CRC will develop liver metastases either synchronously or metachronously within 2 years after primary diagnosis. Hepatic resection (HR) is the only curative option, but only 15-20% of patients with liver metastases from CRC (CRLMs) are suitable for surgical standard treatment. In patients with unresectable CRLMs downsizing chemotherapy can improve resectability (16%). Modern systemic chemotherapy represents the only significant treatment for unresectable CRLMs. However several loco-regional treatments have been developed: hepatic arterial infusion (HAI), cryosurgical ablation (CSA), radiofrequency ablation (RFA), microwave ablation and selective internal radion treatment (SIRT). During the past decade RFA has superseded other ablative therapies, due to its low morbidity, mortality, safety and patient acceptability.

OBJECTIVES

The objective of this study was to systematically review the role of radiofrequency ablation (RFA) in the treatment of CRLMs.

SEARCH METHODS

We performed electronic searches in the following databases:CENTRAL, MEDLINE and EMBASE. Current trials were identified through the Internet using the Clinical-Trials.gov site (to January 2, 2012) and ASCO Proceedings. The reference lists of identified trials were reviewed for additional studies.

SELECTION CRITERIA

Randomized clinical trials (RCTs), quasi-randomised or controlled clinical trials (CCTs) comparing RFA to any other therapy for CRLMs were included. Observational study designs including comparative cohort studies comparing RFA to another intervention, single arm cohort studies or case control studies have been included if they have: prospectively collected data, ten or more patients; and have a mean or median follow-up time of 24 months. Patients with CRLMs who have no contraindications for RFA. Patients with unresectable extra-hepatic disease were also included.Trials have been considered regardless of language of origin.

DATA COLLECTION AND ANALYSIS

A total of 1144 records were identified through the above electronic searching. We included 18 studies: 10 observational studies, 7 Clinical Controlled Trials (CCTs) and an additional 1 Randomized Clinical Trial (RCT) (abstract) identified by hand searching in the 2010 ASCO Annual Meeting. The most appropriate way of summarizing time-to-event data is to use methods of survival analysis and express the intervention effect as a hazard ratio. In the included studies these outcome are mostly reported as dichotomous data so we should have asked authors research data for each participant and perform Individual Patient Data (IPD) meta-analysis. Given the study design and low quality of included studies we decided to give up and not to summarize these data.

MAIN RESULTS

Seventeen studies were not randomised and this increases the potential for selection bias. In addition, there was imbalance in the baseline characteristics of the participants included in all studies. All studies were classified as having a elevate risk of bias. The assessment of methodological quality of all non-randomized studies included in meta-analysis performed by the STROBE checklist has allowed us to identify several methodological limits in most of the analysed studies. At present, the information from the single RCT included (Ruers 2010) comes from an abstract of 2010 ASCO Annual Meeting where the allocation concealment was not reported; however in original protocol allocation concealment was adequately reported (EORTC 40004 protocol). The heterogeneity regarding interventions, comparisons and outcomes rendered the data not suitable.

AUTHORS' CONCLUSIONS

This systematic review gathers information from several controlled clinical trials and observational studies which are vulnerable to different types of bias. The imbalance between characteristics of patients in the allocated groups appears to be the main concern. Only one randomised clinical trial (published as an abstract), comparing 60 patients receiving RFA plus CT versus 59 patients receiving CT alone, was identified. This study showed that PFS was significantly higher in the group that received RFA. However, it was not able to provide information on overall survival. In conclusion, evidence from the included studies are insufficient to recommend RFA for a radical oncological treatment of CRLMs.

18F-FDG PET/CT in evaluation of radiofrequency ablation of liver metastasis

Image-guided radiofrequency ablation (RFA) is a minimally invasive therapy option in the treatment of primary and secondary hepatic malignancies, which are not suitable for surgery/chemotherapy, and more recently, for tumors with limited hepatic involvement and solitary liver metastasis. Accurate assessment of treatment response after RFA remains a concern. Conventional imaging modalities have limitations of differentiation between residual/recurrence from post-RFA changes. We illustrate images of 3 patients in whom (18)F-FDG PET/CT was used for response assessment and restaging after RFA in liver tumors.

Margin size is an independent predictor of local tumor progression after ablation of colon cancer liver metastases

PURPOSE

This study was designed to evaluate the relationship between the minimal margin size and local tumor progression (LTP) following CT-guided radiofrequency ablation (RFA) of colorectal cancer liver metastases (CLM).

METHODS

An institutional review board-approved, HIPPA-compliant review identified 73 patients with 94 previously untreated CLM that underwent RFA between March 2003 and May 2010, resulting in an ablation zone completely covering the tumor 4-8 weeks after RFA dynamic CT. Comparing the pre- with the post-RFA CT, the minimal margin size was categorized to 0, 1-5, 6-10, and 11-15 mm. Follow-up included CT every 2-4 months. Kaplan-Meier methodology and Cox regression analysis were used to evaluate the effect of the minimal margin size, tumor location, size, and proximity to a vessel on LTP.

RESULTS

Forty-five of 94 (47.9 %) CLM progressed locally. Median LTP-free survival (LPFS) was 16 months. Two-year LPFS rates for ablated CLM with minimal margin of 0, 1-5 mm, 6-10 mm, 11-15 mm were 26, 46, 74, and 80 % (p < 0.011). Minimal margin (p = 0.002) and tumor size (p = 0.028) were independent risk factors for LTP. The risk for LTP decreased by 46 % for each 5-mm increase in minimal margin size, whereas each additional 5-mm increase in tumor size increased the risk of LTP by 22 %.

CONCLUSIONS

An ablation zone with a minimal margin uniformly larger than 5 mm 4-8 weeks postablation CT is associated with the best local tumor control.

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.

Effects of tirapazamine on experimental colorectal liver metastases after radiofrequency ablation1

Background

Radiofrequency ablation (RFA) is a common procedure for the management of colorectal liver metastases. RFA-generated lesions are surrounded by a rim of hypoxia that is associated with aggressive outgrowth of intrahepatic micrometastases. Hypoxia-activated prodrugs such as tirapazamine are designed selectively to induce apoptosis in tumour cells under hypoxic conditions. Therefore, it was hypothesized that tirapazamine may have therapeutic value in limiting hypoxia-associated tumour outgrowth following RFA.

Methods

Murine C26 and MC38 colorectal cancer cells were grown under hypoxia and normal oxygenation in vitro, and treated with different concentrations of tirapazamine. Apoptosis and cell cycle distribution were assessed by western blot and fluorescence-activated cell sorting analysis. Proliferative capacity was tested by means of colony-formation assays. Mice harbouring microscopic colorectal liver metastases were treated with RFA, followed by a single injection of tirapazamine (60 mg/kg) or saline. Tumour load was assessed morphometrically 7 days later.

Results

Tirapazamine induced apoptosis of colorectal tumour cells under hypoxia in vitro. Under normal oxygenation, tirapazamine caused a G2 cell cycle arrest from which cells recovered partly. This reduced, but did not abolish, colony-forming capacity. A single dose of tirapazamine largely prevented accelerated outgrowth of hypoxic micrometastases following RFA. Tirapazamine administration was associated with minimal toxicity.

Conclusion

Tirapazamine induced apoptosis in colorectal cancer cells in a hypoxia-dependent manner and potently suppressed hypoxia-associated outgrowth of liver metastases with limited toxicity. This warrants further study to assess the potential value of tirapazamine, or other hypoxia-activated prodrugs, as adjuvant therapeutics following RFA treatment of colorectal liver metastases.

Laparoscopic thermoablation of colorectal cancer metastases to the liver - new experience of the centre

Aim of the study

Thermoablation of metastatic lesions in the liver is very commonplace. At present there are 3 essential techniques of access to carry out the procedure: open surgery, percutaneous technique and laparoscopic method. Percutaneous thermoablation is criticised due to the possible lack of radicalism. On the other hand, thermoablation during open surgery is a big perioperative trauma for the patient. The laparoscopic technique seems to be a compromise between the aforementioned techniques. The aim of this study was to present the technique and preliminary results of thermoablation of the liver carried out by means of the laparoscopic technique.

Material and methods

Laparoscopic thermoablation was carried out in 4 patients with colorectal cancer metastases to the liver. In order to precisely locate the tumour and guarantee radicalism of the surgery, laparoscopic probe ultrasonography was carried out during the procedure.

Results

All the patients underwent the procedure without any difficulties. All the patients left the hospital department as soon as 3 or 4 days after the surgery. This was about 7 days earlier in comparison with the open surgery procedure, which had been carried out before. The patients required a supply of analgesics only during the first 48 hours – non-steroid anti-inflammatory drugs, which made a substantial difference between them and the patients treated with the open surgical technique. Thanks to the laparoscopic ultrasound technique one patient had an additional lesion located, which had not been described in preoperative examinations.

Conclusions

In combination with ultrasonography, laparoscopic access, which does not have a very invasive character, seems to be relatively simple and effective to carry out the procedure of thermoablation.

The management of solitary colorectal liver metastases

Surgical resection of solitary colorectal liver metastases is associated with long-term survival. Radiofrequency ablation used as the primary treatment option of solitary resectable colorectal liver metastases is associated with an increased risk of local recurrence that generally leads to worse survival compared to resection. In contrast with treatment of other hepatic malignancies, radiofrequency ablation is not equivalent to resection for colorectal liver metastases and should not be used as an alternative but limited to inoperable patients. Although overall survival rate after resection can be up to 71% at 5 years, the majority of patients develop recurrence. Preoperative chemotherapy contributes to decrease the risk of recurrence after resection of colorectal liver metastases. In patients with advanced solitary colorectal liver metastasis initially non suitable for resection, chemotherapy and portal vein embolization contribute to increase the number of surgical candidates whereas radiofrequency is rarely an option.

Radiofrequency ablation vs hepatic resection for solitary colorectal liver metastasis: A meta-analysis

AIM: To evaluate the comparative therapeutic efficacy of radiofrequency ablation (RFA) and hepatic resection (HR) for solitary colorectal liver metastases (CLM).

METHODS: A literature search was performed to identify comparative studies reporting outcomes for both RFA and HR for solitary CLM. Pooled odds ratios (OR) with 95% confidence intervals (95% CI) were calculated using either the fixed effects model or random effects model.

RESULTS: Seven nonrandomized controlled trials studies were included in this analysis. These studies included a total of 847 patients: 273 treated with RFA and 574 treated with HR. The 5 years overall survival rates in the HR group were significantly better than those in the RFA group (OR: 0.41, 95% CI: 0.22-0.90, P = 0.008). RFA had a higher rate of local intrahepatic recurrence compared to HR (OR: 4.89, 95% CI: 1.73-13.87, P = 0.003). No differences were found between the two groups with respect to postoperative morbidity and mortality.

CONCLUSION: HR was superior to RFA in the treatment of patients with solitary CLM. However, the findings have to be carefully interpreted due to the lower level of evidence.

Ablative therapies for colorectal liver metastases: a systematic review

AIM

The standard treatment for colorectal liver metastases (CRLM) is surgical resection. Only 20-30% of patients are deemed suitable for surgery. Recently, much attention has focused on ablative therapies either to treat unresectable CRLM or to extend the margins of resectability. This review aims to assess the long-term outcome and complication rates of various ablative therapies used in the management of CRLM.

METHOD

A literature search was performed of electronic databases including Medline, Cochrane Collaboration Library and the National Library of Medicine's ClinicalTrials.gov. Inclusion criteria were ablation for CRLM with minimum 1 year follow-up and >10 patients, published between January 1994 and January 2010.

RESULTS

In all, 226 potentially relevant studies were identified, of which 75 met the inclusion criteria. Cryotherapy (26 studies) had local recurrence rates of 12-39%, with mean 1-, 3- and 5-year survival rates of 84%, 37% and 17%. The major complication rate ranged from 7% to 66%. Microwave ablation (13 studies) had a local recurrence rate of 5-13%, with a mean 1-, 3- and 5-year survival of 73%, 30% and 16%, and a major complication rate ranging from 3% to 16%. Radiofrequency ablation (36 studies) had a local recurrence rate of 10-31%, with a mean 1-, 3- and 5-year survival of 85%, 36% and 24%, with major complication rate ranging from 0% to 33%.

CONCLUSION

Ablative therapies offer significantly improved survival compared with palliative chemotherapy alone with 5-year survival rates of 17-24%. Complication rates amongst commonly used techniques are low.

[Percutaneous radiofrequency and other liver ablation techniques: 2011 update]

Percutaneous ablation of liver tumors was initially limited to patients that were not surgical candidates and with a limited number of relatively small liver lesions. Because of the diversification of techniques and technologies, percutaneous liver ablation has progressively been integrating to more and more complex therapeutic strategies available to a wider group of patients. Local knowledge and expertise with these techniques, largely dominated by radiofrequency ablation, often dictate the role of these techniques in the management of patients with liver tumors. We will review the clinical indications of percutaneous ablation techniques for liver tumors based on clinical considerations as well as ablation techniques.

Radiofrequency ablation for treating liver metastases from a non-colorectal origin

Objective

We wanted to assess the safety and efficacy of performing radiofrequency ablation (RFA) in patients with non-colorectal liver metastases.

Materials and Methods

In this retrospective study, 25 patients with 40 hepatic metastases (M:F = 17:8; mean age, 57 years; tumor size, 0.5-5.0 cm) from a non-colorectal origin (stomach, biliary, breast, pancreas, kidney and skin) were treated with RFA. The RFA procedures were performed using either an internally cooled electrode or a clustered electrode under ultrasound or CT guidance. Contrast-enhanced CT scans were obtained immediately after RFA and follow-up CT scans were performed within three months after ablation and subsequently at least every six months. The intrahepatic disease-free interval was estimated and the overall survival from the time of the initial RFA was analyzed using the Kaplan-Meier method.

Results

No intraprocedural deaths occurred, but four major complications developed, including abscesses (n = 3) and pneumothorax (n = 1). Technical effectiveness was determined on the initial follow-up images. During the follow-up period (range, 5.9-68.6 months; median time, 18.8 months) for 37 tumors in 22 patients where technical effectiveness was achieved, 12 lesions (32%, 12 of 37) showed local tumor progression and new intrahepatic metastases occurred in 13 patients (59%, 13 of 22). The median intrahepatic disease-free interval was 10.1 months. The 1-year, 3-year and 5-year overall survival rates after RFA were 86%, 39% and 19%, respectively.

Conclusion

RFA showed intermediate therapeutic effectiveness for the treatment of non-colorectal origin liver metastases.

Percutaneous radiofrequency thermal ablation of primary and metastatic hepatic tumors: current concepts and review of the literature

The liver is a common site for primary malignancy and hematogenous metastasis. Although surgical resection of primary or metastatic hepatic tumors is generally regarded as first-line therapy, the majority of patients with hepatic malignancy have disease that is not amenable to surgical resection because of tumor location, poor hepatic reserve, or medical comorbidities. This has led to significant interest in the development of nonsurgical image-guided therapies, including radiofrequency ablation (RFA). RFA is appealing as a minimally invasive therapy that may be performed on an outpatient basis. It enables ablation of an area 3 to 5 cm in diameter, with relatively low morbidity and mortality rates. The results concerning the use of percutaneous RFA in the treatment of hepatocellular carcinoma, colorectal metastases, and other hepatic metastases are reviewed in this article. Clinical and technical considerations and complications are also discussed.

Comparative analysis of radiofrequency ablation and surgical resection for colorectal liver metastases

PURPOSE

To evaluate the comparative therapeutic efficacy of radiofrequency ablation (RFA) and hepatic resection for the treatment of colorectal liver metastasis (CRLM).

METHODS

Between 1996 and 2008, 177 patients underwent RFA, 278 underwent hepatic resection and 27 underwent combination therapy for CRLM. Comparative analysis of clinical outcomes was performed including number of liver metastases, tumor size, and time of CRLM.

RESULTS

Based on multivariate analysis, overall survival (OS) correlated with the number of liver metastases and the use of combined chemotherapy (P < 0.001, respectively). Disease-free survival (DFS) also correlated with the number of liver metastases (P < 0.001). In the 226 patients with solitary CRLM < 3 cm, OS and DFS rates did not differ between the RFA group and the resection group (P = 0.962 and P = 0.980). In the 70 patients with solitary CRLM ≥ 3 cm, DFS was significantly lower in the RFA group as compared with the resection group (P = 0.015).

CONCLUSION

The results indicate that RFA may be a safe alternative treatment for solitary CRLM less than 3 cm, with outcomes equivalent to those achieved with hepatic resection. A randomized controlled study comparing RFA and resection for patients with single small metastasis would help to determine the most efficient treatment modalities for CRLM.

CT-guided radiofrequency ablation as a salvage treatment of colorectal cancer hepatic metastases developing after hepatectomy

PURPOSE

To evaluate the clinical outcomes of percutaneous radiofrequency (RF) ablation of colorectal cancer liver metastases (CLMs) that recur after hepatectomy.

MATERIALS AND METHODS

From December 2002 to December 2008, 71 CLMs that developed after hepatectomy were ablated in 56 patients. Medical records and imaging were reviewed to determine technique effectiveness/complete ablation (ie, ablation defect covering the entire tumor on 4-6-week postablation computed tomography [CT]), complications, and local tumor progression (LTP) at the site of ablation. LTP-free and overall survival were calculated by using Kaplan-Meier methodology. A modified clinical risk score (CRS) including nodal status of the primary tumor, time interval between diagnoses of the primary tumor and liver metastases, number of tumors, and size of the largest tumor was assessed for its effect on overall survival and LTP.

RESULTS

Tumor size ranged between 0.5 and 5.7 cm. Complete ablation was documented in 67 of 71 cases (94%). Complications included liver abscess (n = 1) and pleural effusion (n = 1). Median overall survival time was 31 months. One-, 2- and 3-year overall survival rates were 91%, 66%, and 41%, respectively. CRS was an independent factor for overall survival (74% for CRS of 0-2 vs 42% for CRS of 3-4 at 2 y; P = .03) and for LTP-free survival (66% for CRS of 0-2 vs 22% for CRS of 3-4 at 1 y after a single ablation; P <.01).

CONCLUSIONS

CT-guided RF ablation can be used to treat recurrent CLM after hepatectomy. A low CRS is associated with better clinical outcomes.

Radiofrequency ablation as a treatment tool for liver metastases of colorectal origin

At diagnosis 10–25% of patients with colorectal liver metastases (CRLM) present as resectable disease. Liver resection is the gold standard treatment, resulting in a 5-year overall survival (OS) of 22–58%, local recurrence rates of 1.2–10.4% and a perioperative mortality of less than 5%. Multiple attempts have been made to assess the possible contribution of radiofrequency ablation (RFA) to improve OS and progression-free survival (PFS) in patients with unresectable colorectal liver metastases. The aim of this paper is to review the RFA literature in the setting of colorectal liver metastases: RFA with and without chemotherapy, RFA with and without resection, RFA for solitary unresectable CRLM, surgical and percutaneous imaging-guided RFA, RFA compared with chemotherapy. The reported OS, PFS, local recurrence rates, morbidity and mortality in these different settings are analyzed. This paper reflects on a possible role of RFA in resectable CRLM.

Radiofrequency ablation versus resection for liver tumours: an evidence-based approach to retrospective comparative studies

BACKGROUND

Recently randomized controlled trials have been advocated to compare radiofrequency ablation (RFA) and hepatic resection (HR) in resectable tumours and determine whether differences in observed survivals result from the heterogeneity in previous studies between RFA (treating unresectable lesions) and HR (treating lesions deemed resectable). We reviewed the literature that directly compares the treatments and employed an evidence-based approach to examine the data.

MATERIALS AND METHODS

All studies comparing RFA and HR were included. Primary outcomes were the overall survival (OS) and disease-free survival (DFS) at 3 and 5 years. A subgroup analysis was conducted for solitary or small tumors (<4 cm for colorectal metastases (CRM) or <5 cm for hepatocellular carcinoma (HCC)).

RESULTS

Most studies were retrospective. For CRM, HR was markedly superior to RFA in respect of 3- and 5-year OS as well as 5-year DFS including tumours smaller than 4 cm and solitary lesions. For HCC, HR was markedly superior to RFA for 3- and 5-year OS as well as 3-year DFS, and produced a better OS at 3 years for solitary lesions and DFS at 3 years for small tumours.

CONCLUSIONS

Multiple factors determine outcomes following treatment of liver tumours. Small or solitary lesions seem the most appropriate ones to study as this reduces the number of confounding variables, but even in these cases HR confers a better OS and DFS than RFA for both CRM and HCC. If our data are confirmed it will be important to examine other factors influencing the response.

Efficacy and feasibility of radiofrequency ablation for liver metastases from gastric adenocarcinoma

PURPOSE

Optimal treatment for liver metastases from gastric cancer remains a matter of debate. The aim of our study is to evaluate the efficacy of radiofrequency ablation (RFA) for the treatment of liver-only metastases from gastric adenocarcinoma.

MATERIALS AND METHODS

We retrospectively reviewed medical records of 29 patients who developed liver-only metastases from gastric adenocarcinoma and subsequently underwent gastric resection and RFA (n = 20) or gastric resection and systemic chemotherapy (n = 9) between January 1995 and February 2008. Overall survival was estimated using the Kaplan-Meier method, and was compared using the log rank test to evaluate RFA efficacy.

RESULTS

Twenty patients who underwent RFA showed a median overall survival of 30.7 months (range: 2.9 to 90.9 months), a median progression-free survival of 6.8 months (range: 0.8 to 45.2 months), and median overall one-, three-, and five-year survival rates were 66.8%, 40.1%, and 16.1% respectively. The RFA group showed a 76% decreased death rate compared to the chemotherapy-only group (30.7 months versus 7 months, hazard ratio, 0.24; p = 0.004). Most patients tolerated RFA well, and complications were found to be minor (transient fever (20%) and/or right upper quadrant pain (25%)). One case of treatment-related death occurred due to sepsis that originated from a liver abscess at the ablation site.

CONCLUSIONS

The data suggest that a use of RFA as a liver-directed treatment may provide greater survival benefit than chemotherapy and is an alternative option for the treatment of liver-only metastases from gastric cancer.

Treatment of liver colorectal metastases: role of laparoscopy, radiofrequency ablation, and microwave coagulation

Up to 50% of patients with colorectal cancer will develop metastatic disease in the liver. While surgical extirpation remains the best option for long-term survival, several complementary modalities such as laparoscopy, radiofrequency ablation, and microwave coagulation have gained wide acceptance as primary and adjunct therapies for both resectable and unresectable disease. This review will focus on the application and outcome of these techniques in patients with colorectal liver metastases.

Complications of intraoperative radiofrequency ablation of liver metastases

BACKGROUND

Intraoperative radiofrequency ablation (IRFA) of liver metastases can be used to treat patients with complex tumours that are unsuitable for parenchymal resection alone. This systematic review assesses the frequency, patterns and severity of complications associated with this procedure.

METHODS

We carried out a bibliographic search on MEDLINE focused on IRFA for liver metastases, excluding hepatocarcinomas, and on intraoperative use, excluding percutaneous application.

RESULTS

Thirty papers published between 1999 and 2007 were analysed. They covered a total of 2822 patients and 1755 IRFA procedures. The indications and techniques for IRFA differ from those for percutaneous treatment, as do associated results and complications. Specific complications associated with IRFA, such as liver abscesses, biliary stenoses and vascular thromboses, are directly correlated with the indications and associated procedures. Published results should be interpreted with caution as IRFA can be used alone or combined with parenchymal resection.

CONCLUSIONS

Specific complications related to IRFA are rare, especially for lesions of <35 mm in size located far from a main biliary duct, when additional septic procedures are not used. A lesion-by-lesion approach based on the benefit : risk ratio should therefore be used in the process of making surgical decisions. Combining resection with IRFA leads to higher morbidity, especially in difficult patients with numerous bilateral lesions, but may be necessary to achieve R0 (microscopically negative margins) outcomes.

Colorectal liver metastases

BACKGROUND

Despite major advances in therapies for liver metastases, colorectal cancer remains one of the commonest causes of cancer-related deaths in the UK.

SOURCES OF DATA

The international literature on the management of colorectal liver metastases (CLM) was reviewed.

AREAS OF AGREEMENT

Due to a combination of highly active systemic agents and low perioperative mortality achieved by high-volume centres, a growing number of patients are being offered liver resection with curative intent. Patients with bilobar and/or extrahepatic disease who would previously have received palliative treatment only, are undergoing major surgery with good results. This review focuses on preoperative evaluation, surgical planning and the role of adjuvant therapies in the management of patients with CLM.

AREAS OF CONTROVERSY

Can ablative therapies match the outcomes of surgical resection? How can even more patients be rendered resectable?

GROWING POINTS

The use of other therapies, such as radiofrequency ablation and selective internal radiation therapy.

AREAS TIMELY FOR DEVELOPING RESEARCH

New chemotherapy regimens for neo-adjuvant therapy and the development of new modalities of liver tumour ablation.

Long-term results of radiofrequency ablation for unresectable colorectal liver metastases: a potentially curative intervention

OBJECTIVE

The long-term results and prognostic factors of radiofrequency ablation (RFA) for unresectable colorectal liver metastases (CRLM) in a single centre with >10 years of experience were retrospectively analysed.

METHODS

A total of 100 patients with unresectable colorectal liver metastases (CRLM) (size 0.2-8.3 cm; mean 2.4 cm) underwent a total of 126 RFA sessions (237 lesions). The mean follow-up time was 29 months (range 6-93 months). Lesion characteristics (size, number and location), procedure characteristics (percutaneous or intra-operative approach) and major and minor complications were carefully noted. Local control, mean survival time and recurrence-free and overall survival were statistically analysed.

RESULTS

No direct procedure-related deaths were observed. Major complications were present in eight patients. Local RFA site recurrence was 12.7% (n = 30/237); for tumour diameters of <3 cm, 3-5 cm and >5 cm, recurrence was 5.6% (n = 8/143), 19.5% (n = 15/77) and 41.2% (n = 7/17), respectively. Centrally located lesions recurred more often than peripheral ones, at 21.4% (n = 21/98) vs 6.5% (n = 9/139), respectively, p = 0.009. Including additional treatments for recurring lesions when feasible, lesion-based local control reached 93%. The mean survival time from RFA was 56 (95% confidence interval (CI) 45-67) months. Overall 1-, 3-, 5- and 8-year survival from RFA was 93%, 77%, 36% and 24%, respectively.

CONCLUSIONS

RFA for unresectable CRLM is a safe, effective and potentially curative treatment option; the long-term results are comparable with those of previous investigations employing surgical resection. Factors determining success are lesion size, the number of lesions and location.

Hepatectomy is superior to thermal ablation for patients with a solitary colorectal liver metastasis

INTRODUCTION

Hepatic resection is the mainstay of treatment for solitary colorectal liver metastases (mCRC); however, some patients are not ideal candidates. The aim of this study was to compare outcomes for patients with solitary mCRC who underwent resection or ablation.

METHODS

A retrospective review of a hepatobiliary database identified patients with solitary mCRC. Patients who were treated with hepatectomy were compared to patients who underwent thermal ablation.

RESULTS

The median follow-up time was 25.9 months. Ninety-four patients (67.1%) underwent resection whereas 46 patients (32.8%) underwent ablation. Of the resected patients, most (60%) required a major hepatectomy. Tumor ablation was a significant predictor of overall survival (p = 0.002, OR 3.75, 95% CI 1.696-8.284). Overall, the median disease-free survival was 55.2 months for patients undergoing resection vs. 42.6 months for ablated patients (p = 0.073). Median overall survival was 112.7 months for patients undergoing resection vs. 50.2 months for patients undergoing ablation (p = 0.005).

CONCLUSION

Patients with solitary hepatic colorectal cancer metastases should be considered for hepatic resection as this provides superior survival when compared to thermal ablation.

[Interventional procedures for hepatic metastases]

The therapeutic concept for hepatic metastases is mainly based on surgical resection and systemic chemotherapy. Considering technical respectability, oncological significance and limiting comorbidities, only 10-30% of patients with hepatic metastases can undergo surgery with a curative intention. Patients assessed as being non-resectable qualify in general for (palliative) chemotherapy. However, for many patients surgical therapy of the liver is no longer possible due to medical or technical reasons, nevertheless, the total tumor load is still limited, which makes an interventional, local ablative therapy approach promising, with and without chemotherapy. Thus, various interventional-radiological, minimally invasive techniques could be successfully established as oncological therapy components besides surgery and chemotherapy. These types of intervention encompass mainly chemotherapy (percutaneous alcohol instillation, transarterial chemoembolization and transarterial chemotherapy), thermotherapy (radiofrequency, laser and microwave ablations) and radio-ablative procedures (radio-embolization, selective internal radiation therapy SIRT, interstitial and catheter-guided brachytherapy). Incorporating these procedures into therapeutic multimodal concepts inaugurates a significantly broadened therapy spectrum with a clear additional improvement in patient prognosis.