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

Thermal ablative therapies for secondary hepatic malignancies

Hepatic metastatic disease affects more than half of the patients with colorectal cancer and neuroendocrine cancer. Hepatic resection remains the gold standard for liver metastasis from colorectal and neuroendocrine primaries. Thermal ablative technologies, however, are increasingly being used either alone or in combination with resection to treat this group of patients. Radiofrequency ablation is the most common modality used in the United States, whereas microwave ablation has been more widely used in the East. In addition to being adjuncts to hepatic resection, ablation has gained an increased popularity in the management of patients who are not operative candidates or have unresectable colorectal or neuroendocrine hepatic metastasis. Although radiofrequency ablation seems to have a higher local recurrence than resection, ablation remains an important therapeutic option for many patients with hepatic metastasis.

Thermoablation of colorectal liver metastasis

Thermoablation is a local therapy that is effective in in situ destruction of colorectal liver metastasis while preserving surrounding normal liver tissue. It is less invasive compared to surgery, easy to use, and can be repeated. The therapy provides local control of unresectable disease and is an alternative therapy for small resectable lesions in patients with insufficient hepatic reserve after resection or coexistent comorbid conditions. It can artificially increase the resection margin thus increasing the number of patient candidate for resection. When used in conjunction with liver resection it clears the liver of multiple lesions that are surgically inaccessible or unresectable. Main limitations of the treatment are local recurrence of the disease, treatment-related complications, and questionable impact on patient. Outcome of therapy can be improved when used as part of multimodality treatment.

Advanced hepatic ablation technique for creating complete cell death: irreversible electroporation

PURPOSE

To evaluate the effectiveness of irreversible electroporation (IRE) in hepatic tissue ablation and the radiologic-pathologic correlation of IRE-induced cell death.

MATERIALS AND METHODS

On approval of the animal research committee, 16 Yorkshire pigs underwent ultrasonography (US)-guided IRE of normal liver. A total of 55 ablation zones were created, which were imaged with US, magnetic resonance (MR) imaging, and computed tomography (CT) and evaluated with immunohistochemical analysis, including hematoxylin-eosin (H-E), Von Kossa, and von Willibrand factor (vWF) staining and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay.

RESULTS

At gross section examination, the mean diameter of the ablation zones was 33.5 mm + or - 3.0 (standard deviation) and was achieved in 6.9 minutes (mean total procedure time per ablation), with a mean difference of 2.5 mm + or - 3.6 between US and gross section measurements (r = 0.804). No complications were seen in any of the 16 animals. IRE ablation zones were well characterized with US, CT, and MR imaging, and real-time monitoring was feasible with US. H-E, Von Kossa, and vWF staining showed complete cell death, with a sharply demarcated treatment area. Bile ducts and vessels were completely preserved. Areas of complete cell death were stained positive for apoptotic markers (TUNEL, BCL-2 oncoprotein), suggesting involvement of the apoptotic process in the pathophysiology of cell death caused by IRE.

CONCLUSION

In an animal model, IRE proved to be a fast, safe, and potent ablative method, causing complete tissue death by means of apoptosis. Cell death is seen with full preservation of periablative zone structures, including blood vessels, bile ducts, and neighboring nonablated tissues.

Radiofrequency ablation as first-line treatment in patients with early colorectal liver metastases amenable to surgery

OBJECTIVE

Aiming at avoidance of futile surgery, we have tested whether radiofrequency ablation (RFA) may be used as first-line treatment in patients with colorectal metastases (CRLM) occurring within the first year after colorectal surgery.

SUMMARY BACKGROUND DATA

Surgical resection is the standard treatment in patients with CRLM. Major retrospective analyses have identified the interval between colorectal surgery and the occurrence of CRLM to be of prognostic importance. So far, it is unknown whether survival of the respective patients is hampered if RFA is used as first-line treatment.

METHODS

According to a clinical pathway, we have treated patients with CRLM detected within the first year after colorectal surgery preferentially by RFA (n=28). Resection (n=82) was performed in patients who were deemed not amenable to RFA due to number, size, or location of metastatic lesions. The diameter of lesions differed between the groups. All other characteristics of patients and lesions were comparable. Local recurrence and new hepatic lesions were treated with repeated RFA or surgery whenever possible.

RESULTS

Local recurrence at the site of ablation or resection occurred in 32% and 4% (P<0.001), new metastases apart from the site of previous treatment in 50% and 34% (P=0.179), and systemic recurrence in 32% and 37% (P=0.820) of the patients after RFA and surgery, respectively. Time to progression was significantly shorter in patients primarily treated with RFA (203 vs. 416 days; P=0.017). After primary treatment, 9 RFA patients and 8 surgery patients were amenable to repeated RFA or repeated surgery resulting in identical rates of disease-free patients and identical 3-year overall survival in both treatment groups: 67% and 60%, respectively; P=0.93.

CONCLUSIONS

Despite striking differences in local tumor recurrence and shorter time to progression, survival in patients with early CRLM does not depend on the mode of primary hepatic treatment.

Evolution in surgery: influence of minimally invasive approaches on the hepatobiliary surgeon

BACKGROUND

Advances in technology and in medical knowledge underlie the constant change in paradigms for medical care. Those who understand, anticipate, and plan for these changes will have the greatest impact on future care of patients and education of the next generation of scholars.

METHODS

Review of pertinent literature.

RESULTS

In hepatobiliary surgery, rapid developments in laparoscopic surgery, image-guided interventions, and minimally invasive ablative therapies have combined to produce much improved care for patients with disease of the liver and biliary tract. Laparoscopic procedures of the gallbladder, bile duct, and liver have altered the morbidity of operations on these organs. Major changes in the treatment of liver abscess, gallstone disease, and liver tumors have resulted from recent changes in technology, highlighting the great opportunities the surgeon anticipating these changes may capitalize on to improve, not only patient care, but the field of surgery.

CONCLUSIONS

Active investigation and developments in education in these areas to improve the training of the next generation of surgeons undoubtedly will improve patient care.

Long-term outcomes following hepatic resection and radiofrequency ablation of colorectal liver metastases

Recently some have called for randomized controlled trials comparing RFA to hepatic resection, particularly for patients with only a few small metastases. The objectives were to compare local recurrence and survival following RFA and hepatic resection for colorectal liver metastases. This was a retrospective review of open RFA and hepatic resection for colorectal liver metastases between January 1998 and May 2007. All patients who had RFA were considered to have unresectable disease. 58 patients had hepatic resection and 43 had RFA. A 5-year survival after resection was 43% compared to 23% after RFA. For patients with solitary lesions, a 5-year survival was 48% after resection and 15% after RFA. Sixty percent of patients suffered local recurrences after RFA compared to 7% after hepatic resection. RFA is inferior to resection. The results observed in this study support the consensus that RFA cannot be considered an equivalent procedure to hepatic resection.

Surgical resection versus non-surgical treatment for hepatic node positive patients with colorectal liver metastases

BACKGROUND

Involvement of hepatic lymph node in patients with colorectal liver metastases is associated with poor prognosis.

OBJECTIVES

To determine the benefits and harms of curative liver resection with lymphadenectomy versus other treatments for colorectal liver metastases with hepatic node involvement.

SEARCH STRATEGY

We searched The Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, Science Citation Index Expanded, and LILACS until September 2009 for identifying the randomised trials.

SELECTION CRITERIA

We considered only randomised clinical trials (irrespective of language, blinding, or publication status) comparing liver resection (alone or in combination with radiofrequency ablation or cryoablation) versus other treatments (neo-adjuvant chemotherapy, chemotherapy, or radiofrequency ablation) in patients with colorectal liver metastases with hepatic node involvement.

DATA COLLECTION AND ANALYSIS

Two authors independently identified trials for inclusion.

MAIN RESULTS

We were unable to identify any randomised clinical trial fulfilling the inclusion criteria of this review. We were also unable to identify any quasi-randomised or cohort studies, which could meaningfully answer this important issue.

AUTHORS' CONCLUSIONS

There is no evidence in the literature to assess the role of surgery versus other treatments for patients with colorectal liver metastases with hepatic node involvement. High quality randomised clinical trials are feasible and are necessary to determine the optimal management of patients with colorectal liver metastases with hepatic node involvement.

Perioperative mortality for management of hepatic neoplasm: a simple risk score

OBJECTIVES

To develop a population-based risk score for stratifying patients by risk of in-hospital mortality following procedural intervention for hepatic neoplasm.

BACKGROUND

There has been growing support for the value of surgical management of hepatic neoplastic disease, both primary and metastatic. Advances in surgical and ablative technologies have contributed to a decrease in the mortality associated with these procedures. However, multiple patient-, disease- and treatment-related factors can contribute to perioperative morbidity and mortality.

METHODS

Using the Nationwide Inpatient Sample from 1998 to 2005, a retrospective cohort of patient-discharges for hepatic procedures with a concurrent diagnosis of hepatic primary or metastatic neoplasm to the liver was assembled. Procedures were categorized as lobectomy, wedge resection, or enucleation/ablation. Logistic regression and bootstrap methods were used to create an integer score for estimating the risk of in-hospital mortality using patient demographics, comorbidities, procedure type, tumor type, and hospital characteristics. A randomly selected sample of 80% of the cohort was used to create the risk score. Testing was conducted in the remaining 20% validation-set.

RESULTS

In total, 12,969 patient-discharges were identified. Overall in-hospital mortality was 3.45%. Predictive characteristics incorporated into the model included: age, sex, Charlson comorbidity score, procedure type, hospital type, and type of neoplasm. Integer values were assigned to these, and used to calculate an additive score. Five clinically relevant groups were assembled to stratify risk, with a 36-fold gradient in mortality. Rates in the groups were as follows: 0.9%, 2.5%, 6.8%, 17.6%, and 35.9%. In the derivation set, as well as in the validation set, the simple score discriminated well, with c-statistics of 0.76 and 0.70, respectively.

CONCLUSIONS

An integer-based risk score can be used to predict in-hospital mortality after hepatic procedure for neoplasm, and may be useful for preoperative risk stratification and patient counseling.

[Intraoperative radiofrequency ablation of liver metastases: age of reason]

Intraoperative radiofrequency ablation (IORA) is a surgical technique used to destroy liver metastases by heat. It is performed by a surgeon experienced in intraoperative ultrasounds. It has been officially registered in the French nomenclature of medical acts in 2009. Indications and results of IORA are very different from those of the percutaneous route used by radiologists. Ten years of experience have allowed to define IORA indications in complement to resection which remains the gold standard of liver surgery: 1) lesion no greater than 30 mm in diameter; 2) no proximity to a major portal structure; 3) use of a straight needle with overlapping heat volumes; 4) complete vascular exclusion (portal and sus-hepatic circulation) to treat para-sus-hepatic lesions; 5) requirement to spare parenchymal liver volume. Positive preliminary data of two prospective studies, the EORTCC CLOCC study and the ARF2003 study confirm that IORA complements surgery to obtain complete resection in a larger proportion of patients after chemotherapy induction.

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.

Update and review of the multidisciplinary management of stage IV colorectal cancer with liver metastases

Background

The management of stage IV colorectal cancer with liver metastases has historically involved a multidisciplinary approach. In the last several decades, there have been great strides made in the therapeutic options available to treat these patients with advancements in medical, surgical, locoregional and adjunctive therapies available to patients with colorectal liver metastases(CLM). As a result, there have been improvements in patient care and survival. Naturally, the management of CLM has become increasingly complex in coordinating the various aspects of care in order to optimize patient outcomes.

Review

A review of historical and up to date literature was undertaken utilizing Medline/PubMed to examine relevant topics of interest in patients with CLM including criterion for resectability, technical/surgical considerations, chemotherapy, adjunctive and locoregional therapies. This review explores the various disciplines and modalities to provide current perspectives on the various options of care for patients with CLM.

Conclusion

Improvements in modern day chemotherapy as allowed clinicians to pursue a more aggressive surgical approach in the management of stage IV colorectal cancer with CLM. Additionally, locoregional and adjunctive therapies has expanded the armamentarium of treatment options available. As a result, the management of patients with CLM requires a comprehensive, multidisciplinary approach utilizing various modalities and a more aggressive approach may now be pursued in patients with stage IV colorectal cancer with CLM to achieve optimal outcomes.

Society of Interventional Radiology position statement on percutaneous radiofrequency ablation for the treatment of liver tumors

Focal tumor ablation--whether applied percutanously, laparoscopically, or by means of open surgery--is an effective therapy for selected liver tumors. The choice of liver ablation as well as the choice between percutaneous and surgical approaches is dependent on tumor factors, patient factors, and other viable treatment options. Currently, the largest cumulative reported experience is with radiofrequency (RF) ablation of hepatocellular carcinoma and colorectal metastases. This document is a position statement of the Interventional Oncology Task Force and the Standards Division of the Society of Interventional Radiology regarding the use of percutaneous RF ablation for the treatment of liver tumors.

Radiofrequency ablation for metachronous hepatic metastases from gastric cancer

The objective of this study was to evaluate the results of radiofrequency ablation (RFA) for the treatment of metachronous hepatic metastases from gastric adenocarcinoma. Between January 2000 and February 2008, we retrospectively reviewed 7 cases for which RFA was performed for treating metachronous hepatic metastases after resection of the primary gastric adenocarcinoma. The median period between curative gastrectomy and metachronous hepatic metastasis was 14 months (range: 6 to 48 mo). The median survival of the patients was 11.0 months (range: 5.5 to 39.2) after the first detection of hepatic metastases and 10.0 months (range: 5 to 38.2) after the first RFA. Hepatic metastases recurred 3 to 21 months after RFA in all patients. A second RFA was performed for a single recurrent hepatic metastasis in 1 patient and this patient survived more than 3 years without recurrence until the time of this study. In conclusion, the efficacy of RFA alone for metachronous hepatic metastases from gastric adenocarcinoma was disappointing due to multiple intrahepatic recurrences. Combination therapy such as systemic chemotherapy or hepatic arterial infusion chemotherapy adjuvant to RFA would more reasonable for treating hepatic metastases from gastric cancer.

Open surgical is superior to percutaneous access for radiofrequency ablation of hepatic metastases

PURPOSE

This study was designed to determine the best approach to radiofrequency ablation (RFA) in the liver.

METHODS

From a total of 41 procedures, 37 patients with 47 tumors were treated with RFA for metastatic disease. Indications included colorectal cancer (n=28, 68%), neuroendocrine tumors (n=2, 5%), gynecological primaries (n=4, 10%), pancreatic/duodenal cancer (n=2, 5%), and miscellaneous entities (n=5, 12%). Mean follow-up period was 18 (median, 18) months. All ways of approach to RFA were applied: percutaneous was chosen in 17 (41.5%), laparoscopic and hand-assisted laparoscopic in 5 (12.2%), and open surgical in 19 cases (46.3%), and in 10 cases, RFA was combined with hepatic resection. The average maximum tumor size was 2.3 (range, 0.8-6) cm, and the mean number of nodules treated per patient in a single session was 1.3 (range, 1-3).

RESULTS

Overall survival was 59.5% at 2 years, recurrence-free 2-year survival was 12.6%, local tumor recurrence rate was 34%, and overall recurrence was 75.6%. Local tumor recurrence and disease-free survival were significantly improved in the open surgically treated patients compared with the percutaneous treatment group (15.8% [n=3] vs. 58.8% [n=10] and 11.5 vs. 7.9 months, p<0.01 [chi2 test] and p<0.05 [log-rank test], respectively).

CONCLUSIONS

Open surgical approach is superior to percutaneous access for RFA in metastatic hepatic disease.

Liver ablation techniques: a review

BACKGROUND

Ablation techniques for unresectable liver carcinomas have evolved immensely since their introduction. Results of studies involving these techniques are restricted to reports of patient case series, which are often not presented in a standardised manner. This review aims to summarise the major studies in ablation technologies and present them in a way that may make comparison between the major modalities easier.

METHODS

All major databases (Medline, Cochrane, Embase and Pubmed) were searched for studies using microwave, radiofrequency or cryoablation to treat unresectable liver tumours. Only studies with at least 30 patients and 3-year follow-up were included. Complication, recurrence and survival rates of all studies are summarised and presented.

RESULTS AND CONCLUSION

It is difficult to compare ablation modalities, as probe design and energy sources have evolved rapidly over the last decade. Ablation offers an invaluable palliative option and in some cases it may offer rates of cure approaching that of surgical resection with lower morbidity and mortality. Perhaps the time has come, therefore, for prospective large-scale randomised control trials to take place comparing ablation modalities to each other and surgical resection.

A systematic review on the clinical benefit and role of radiofrequency ablation as treatment of colorectal liver metastases

AIM

To evaluate the role of radiofrequency ablation (RFA) as treatment of colorectal cancer liver metastases (CLMs).

METHOD

A PubMed literature search for original articles published until August 2008 was performed. Studies with 40 patients, 18 month median follow-up and reported 3 year overall survival (OS) rates after RFA of CLM were selected for analysis.

RESULTS

Thirteen clinical series and 8 non-randomised comparative studies were analysed. Median progression free survival after RFA ranged between 6 and 13 months. Median and 5-year OS after RFA (RFA plus resection) ranged between 24-59 months and 18-40% (36-46 months and 27-30%). Comparative studies indicated significantly improved OS after RFA versus chemotherapy alone, RFA plus chemotherapy versus RFA alone and up-front RFA versus RFA following second-line chemotherapy.

CONCLUSION

Our findings support that RFA prolongs time without toxicity and survival as an adjunct to hepatectomy and/or chemotherapy in well-selected patients, but not as an alternative to resection.

Radiofrequency ablation vs. resection for hepatic colorectal metastasis: therapeutically equivalent?

INTRODUCTION

The role of ablation for hepatic colorectal metastases (HCM) continues to evolve as ablation technology changes and systemic chemotherapy improves. Our aim was to evaluate the therapeutic efficacy of radiofrequency ablation (RFA) of HCM compared to surgical resection.

METHODS

A retrospective review of our 1,105 patient prospective hepatic database from August 1995 to July 2007 identified 192 patients with only hepatic resection or only ablation for HCM.

RESULTS

Patients who underwent RFA were similar to resection patients based on a similar Fong score (1.8 vs. 2.1 p = 0.28), presence of extrahepatic disease (15% vs. 9% p = 0.19), mean number of hepatic lesions (2.8 vs. 2.1 p = 0.14), and prior chemotherapy (67% vs. 60% p = 0.33). Median time to recurrence was shorter with ablation than resection (12.2 vs. 31.1 months; p < 0.001). Recurrence at the ablation-resection site was more common with ablation than resection occurring 17% vs. 2% (p < or = 0.001) of the time, respectively. Distant recurrence in the liver was also more common with ablation occurring in 33% of patients vs. 14% for resection (p = 0.002).

CONCLUSIONS

Surgical resection is associated with a lower chance of recurrence and a longer disease-free interval than RFA and should remain the treatment of choice in resectable HCM.

Resection versus laparoscopic radiofrequency thermal ablation of solitary colorectal liver metastasis

PURPOSE

There is scant data in the literature regarding radiofrequency thermal ablation (RFA) versus resection of colorectal liver metastases. The aim of this study is to compare the clinical profile and survival of patients with solitary colorectal liver metastasis undergoing resection versus laparoscopic RFA.

METHODS

Between 1996 and 2007, 158 patients underwent RFA (n = 68) and open liver resection (n = 90) of solitary liver metastasis from colorectal cancer. Patients were evaluated in a multidisciplinary fashion and allocated to a treatment type. Data were collected prospectively for the RFA patients and retrospectively for the resection patients.

RESULTS

Although the groups were matched for age, gender, chemotherapy exposure and tumor size, RFA patients tended to have a higher ASA score and presence of extra-hepatic disease (EHD) at the time of treatment. The main indication for referral to RFA included technical reasons (n = 25), patient comorbidities (n = 24), extra-hepatic disease (n = 10) and patient decision (n = 9). There were no peri-operative mortalities in either group. The complication rate was 2.9% (n = 2) for RFA and 31.1% (n = 28) for resection. The overall Kaplan-Meier median actuarial survival from the date of surgery was 24 months for RFA patients with EHD, 34 months for RFA patients without EHD and 57 months for resection patients (p < 0.0001). The 5-year actual survival was 30% for RFA patients and 40% for resection patients (p = 0.35).

CONCLUSIONS

This study shows that, although patients in both groups had a solitary liver metastasis, other factors including medical comorbidities, technically challenging tumor locations and extra-hepatic disease were different, prompting selection of therapy. With a simultaneous ablation program, higher risk patients have been channeled to RFA, leaving a highly selected group of patients for resection with a very favorable survival. RFA still achieved long-term survival in patients who were otherwise not candidates for resection.

[Metastases of colorectal carcinoma]

Metastases of colorectal cancer represent an interdisciplinary therapeutic challenge. Evidence-based guidelines are supportive of treatment decisions in specific situations with the objective to improve the therapeutic outcome for patients. Interventional tumor therapies are increasingly applied therapeutic options in the treatment of colorectal metastases. The current literature indicates that thermoablation of colorectal liver metastasis can lead to an improved survival in selected patients. However, recommendation of thermoablation as a part of guidelines for the therapy of colorectal metastases is restricted due to a shortcoming of randomized controlled trials. Therefore, interventional tumor therapies have to be evaluated in comparison with standard therapies, particularly with regard to surgical resection and chemotherapy. Moreover, the interdisciplinary combination of tumor ablation, surgical resection, and chemotherapy is a promising approach for the optimization of oncological therapy strategies in the treatment of colorectal metastases.

Society of Interventional Radiology position statement on percutaneous radiofrequency ablation for the treatment of liver tumors

Focal tumor ablation--whether applied percutanously, laparoscopically, or by means of open surgery-is an effective therapy for selected liver tumors. The choice of liver ablation as well as the choice between percutaneous and surgical approaches is dependent on tumor factors, patient factors, and other viable treatment options. Currently, the largest cumulative reported experience is with radiofrequency (RF) ablation of hepatocellular carcinoma and colorectal metastases. This document is a position statement of the Interventional Oncology Task Force and the Standards Division of the Society of Interventional Radiology regarding the use of percutaneous RF ablation for the treatment of liver tumors.

Comparative study of resection and radiofrequency ablation in the treatment of solitary colorectal liver metastases

BACKGROUND

We compared outcomes in patients with solitary colorectal liver metastases treated by either hepatic resection (HR) or radiofrequency ablation (RFA).

METHODS

A retrospective analysis from a prospective database was performed on 67 consecutive patients with solitary colorectal liver metastases treated by either HR or RFA.

RESULTS

Forty-two patients underwent HR and 25 patients underwent RFA. The 5-year overall and local recurrence-free survival rates after HR (50.1% and 89.7%, respectively) were higher than after RFA (25.5% and 69.7%, respectively) (P = .0263 and .028, respectively). In small tumors less than 3 cm (n = 38), the 5-year survival rates between HR and RFA were similar, including overall (56.1% vs 55.4%, P = .451) and local recurrence-free (95.7% vs 85.6%, P = .304) survival rates. On multivariate analysis, tumor size, metastases treatment, and primary node status were significant prognostic factors.

CONCLUSIONS

HR had better outcomes than RFA for recurrence and survival after treatment of solitary colorectal liver metastases. However, in tumors smaller than 3 cm, RFA can be recommended as an alternative treatment to patients who are not candidates for surgery because the liver metastases is poorly located anatomically, the functional hepatic reserve after a resection would be insufficient, the patient's comorbidity inhibits a major surgery, or extrahepatic metastases are present.

Clinical outcomes of hepatic resection and radiofrequency ablation in patients with solitary colorectal liver metastasis

BACKGROUND

The role of the radiofrequency ablation (RFA) in treatment of solitary liver metastasis has not been established yet. Both hepatic resection (HR) and RFA have been used increasingly in the treatment of colorectal liver metastases.

STUDY

A systemic review was performed to determine the impact of treatment modality of solitary liver metastasis on recurrence patterns, disease-free survival, and overall survival (OS) rates.

RESULTS

Solitary liver metastases were treated by HR in 116 patients (75.8%) and 37 patients (24.2%) were treated with RFA. Prognostic factors, recurrence rate, recurrence patterns, and survival rates were analyzed. The cumulative 3-year and 5-year local recurrence free survival rates were markedly higher in the HR group (88.0% and 84.6%) as compared with those in the RFA group [53.3% and 42.6%, respectively (P</=0.001)]. The 5-year OS rate was lower in the RFA group as compared with the HR group without statistical significance (5-year OS, 65.7% in the HR, 48.5% in the RFA group, P=0.227).

CONCLUSIONS

Despite of higher local recurrence rate, RFA may be considered as a therapeutic option for patients who are considered unsuitable for conventional surgical treatment. Randomized prospective controlled trials comparing the therapeutic outcome of RFA and HR are definitely warranted.

Impact of whole-body imaging on treatment decision to radio-frequency ablation in patients with malignant liver tumors: comparison of [18F]fluorodeoxyglucose-PET/computed tomography, PET and computed tomography

OBJECTIVE

The correct staging of patients with malignant liver tumors before radio-frequency ablation (RFA) is mandatory for successful treatment. Our study aimed to compare the influence on decision to perform RFA of whole-body fluorodeoxyglucose (FDG)-PET/computed tomography (CT) with whole-body contrast-enhanced CT (CE-CT) and PET alone.

METHODS

Fifty-eight patients with known hepatic malignancies (23, liver metastases 35) received FDG-PET/CT before RFA planned with curative intention. CT and PET data were each read separately, PET/CT fusion data were read in consensus afterward by a third reader group. The diagnostic accuracy of CE-CT, PET alone, and PET/CT to identify patients eligible for RFA was compared and the impact on decision was analyzed. The McNemar test with Bonferroni correction was used to test for significant differences.

RESULTS

The accuracy and sensitivity to detect correctly intrahepatic and extrahepatic tumor were 94 and 97% for CT, 75 and 54% for PET, and 97 and 95% for PET/CT. The differences between CT and PET, as well as between PET/CT and PET, were statistically significant, but there was no significant difference between PET/CT and CT alone (P>0.65). PET alone, CE-CT, and PET/CT correctly identified 32, 55, and 57 patients, respectively. Again, PET/CT showed no significant advantage over CE-CT. Both imaging methods performed significantly better than PET alone (P<0.0001). Forty-three (74%) of 58 patients underwent RFA with curative intention.

CONCLUSION

Whole-body imaging changed patient management in 26% of the patients planned for curative intended RFA, yet there was no significant difference between CE-CT and PET/CT.

Image-guided radiotherapy for liver cancer using respiratory-correlated computed tomography and cone-beam computed tomography

PURPOSE

To evaluate a novel four-dimensional (4D) image-guided radiotherapy (IGRT) technique in stereotactic body RT for liver tumors.

METHODS AND MATERIALS

For 11 patients with 13 intrahepatic tumors, a respiratory-correlated 4D computed tomography (CT) scan was acquired at treatment planning. The target was defined using CT series reconstructed at end-inhalation and end-exhalation. The liver was delineated on these two CT series and served as a reference for image guidance. A cone-beam CT scan was acquired after patient positioning; the blurred diaphragm dome was interpreted as a probability density function showing the motion range of the liver. Manual contour matching of the liver structures from the planning 4D CT scan with the cone-beam CT scan was performed. Inter- and intrafractional uncertainties of target position and motion range were evaluated, and interobserver variability of the 4D-IGRT technique was tested.

RESULTS

The workflow of 4D-IGRT was successfully practiced in all patients. The absolute error in the liver position and error in relation to the bony anatomy was 8 +/- 4 mm and 5 +/- 2 mm (three-dimensional vector), respectively. Margins of 4-6 mm were calculated for compensation of the intrafractional drifts of the liver. The motion range of the diaphragm dome was reproducible within 5 mm for 11 of 13 lesions, and the interobserver variability of the 4D-IGRT technique was small (standard deviation, 1.5 mm). In 4 patients, the position of the intrahepatic lesion was directly verified using a mobile in-room CT scanner after application of intravenous contrast.

CONCLUSION

The results of our study have shown that 4D image guidance using liver contour matching between respiratory-correlated CT and cone-beam CT scans increased the accuracy compared with stereotactic positioning and compared with IGRT without consideration of breathing motion.

Radiofrequency ablation of colorectal liver metastases: small size favorably predicts technique effectiveness and survival

The objective of this study was to analyze long-term results of radiofrequency thermal ablation (RFA) for colorectal metastases (MTS), in order to evaluate predictors for adverse events, technique effectiveness, and survival. One hundred ninety-nine nonresectable MTS (0.5-8 cm; mean, 2.9 cm) in 122 patients underwent a total of 166 RFA sessions, percutaneously or during surgery. The technique was "simple" or "combined" with vascular occlusion. The mean follow-up time was 24.2 months. Complications, technique effectiveness, and survival rates were statistically analyzed. Adverse events occurred in 8.1% of lesions (major complication rate: 1.1%), 7.1% with simple and 16.7% with combined technique (p = 0.15). Early complete response was obtained in 151 lesions (81.2%), but 49 lesions (26.3%) recurred locally after a mean of 10.4 months. Sustained complete ablation was achieved in 66.7% of lesions < or = 3 cm versus 33.3% of lesions > 3 cm (p < 0.0001). Survival rates at 1, 3, and 5 years were 91%, 54%, and 33%, respectively, from the diagnosis of MTS and 79%, 38%, and 22%, respectively, from RFA. Mean survival time from RFA was 31.5 months, 36.2 in patients with main MTS < or = 3 cm and 23.2 in those with at least one lesion > 3 cm (p = 0.006). We conclude that "simple" RFA is safe and successful for MTS < or = 3 cm, contributing to prolong survival when patients can be completely treated.

Five-year survival following radiofrequency ablation of small, solitary, hepatic colorectal metastases

PURPOSE

Radiofrequency (RF) ablation is an increasingly accepted treatment for nonsurgical candidates with a limited number of colorectal hepatic metastases. RF ablation is most effective in tumors smaller than 4.0 cm. This report describes 5-year survival in patients with single tumors with a maximum diameter of 4 cm.

MATERIALS AND METHODS

Forty of 291 patients (14%; 24 men, 16 women; mean age, 67 years; age range, 34-86 y) with no or treated extrahepatic disease were identified who were not candidates for resection and who had a minimum follow-up of 6 months. Sixteen had undergone hepatic resection and two had undergone lung resection and lung ablation. Thirty-two (80%) received chemotherapy. Thirty-five were treated under general anesthesia and five under conscious sedation. Our standard ablation protocol used internally water-cooled electrodes introduced percutaneously with ultrasonography and computed tomography guidance and monitoring. Follow-up data were obtained from primary care physicians or oncologists.

RESULTS

Mean tumor diameter was 2.3 cm (range, 0.8-4.0 cm). There were two successfully treated systemic complications: a chest infection and an exacerbation of asthma. There were no local complications. Mean follow-up was 38 months (range, 6-132 months). The median survival duration and 1-, 3-, and 5-year survival rates were 59 months and 97%, 84%, 40%, respectively, after ablation; and 63 months, 100%, 88%, and 54%, respectively, from the diagnosis of liver metastases. History of liver resection did not impact survival.

CONCLUSIONS

RF ablation of solitary liver metastases 4 cm or smaller can be performed with minimal morbidity and results in excellent long-term survival, approaching that of surgical resection, even in patients who are not surgical candidates.

Optimizing the approach to patients with potentially resectable liver metastases from colorectal cancer

Liver metastases are a common event in colorectal carcinoma. Significant advances have been made in managing these patients in the last decade, including improvements in staging and surgical techniques, an increasing armamentarium of chemotherapeutics and multiple local ablative techniques. While combination chemotherapy significantly improves median patient survival, surgical resection provides the only prospect of cure and is the focus of this review. Interpretation of published work in this field is challenging, particularly as there is no consensus to what is resectable disease. Of particular interest recently has been the use of neoadjuvant treatment for downstaging and downsizing disease in patients with initially unresectable liver metastases, in the hope of response leading to potentially curative surgery. This review summarizes the recent developments and consensus guidelines in the areas of staging, chemotherapy, local ablative techniques, radiation therapy and surgery, emphasizing the multidisciplinary approach to this disease and ongoing controversies in this field and examines the changing paradigms in the management of colorectal hepatic metastases.

Which patients will benefit from percutaneous radiofrequency ablation of colorectal liver metastases? Critically appraised topic

In clinical radiology, there are numerous examples of new techniques that were initially enthusiastically promoted and then subsequently abandoned when early promise was not realized in routine patient care. Appropriateness of new or established interventional radiology techniques to specific clinical conditions must be determined from clinical experience, from communication with experts in the field and/or careful review of available medical literature, and on an individual patient basis by means of review of clinical notes and diagnostic imaging studies. For patients with liver neoplasms, regional techniques such as radiofrequency ablation (RFA) have been developed and are now the subject of ongoing research. This article describes the utilization of Evidence-Based Practice (EBP) techniques as a means of deciding the appropriateness of percutaneous RFA in treating colorectal liver metastases (CLM).

[Regional therapy of liver tumors]

Malignant liver tumors are either originating from the liver, such as the primary liver tumors hepatocellular carcinoma and the cholangiocellular carcinoma, or metastases from extrahepatic malignancies. Apart from surgical procedures (resection, liver transplantation) percutaneous local-ablative (ethanol injection, radiofrequency thermal ablation as well as radiation therapy) and transarterial interventions are non-surgical therapeutic options. While these regional therapies have been shown in randomised controlled studies to be effective for hepatocellular carcinoma, their therapeutic efficacy in cholangiocellular carcinoma and liver metastases has not been shown. In the following we will summarize the regional therapeutic options in primary and secondary liver tumors.

Mid-term outcome of positron emission tomography/computed tomography-assisted radiofrequency ablation in primary and secondary liver tumours--a single-centre experience

AIMS

To determine the mid-term results of percutaneous radiofrequency ablation (RFA) of malignant liver tumours when using FDG-positron emission tomography (FDG-PET)/computed tomography for tumour evaluation and follow-up.

MATERIALS AND METHODS

Between January 2002 and June 2006, 55 patients (mean age 63 years) with 78 liver lesions (39 colorectal metastases, 39 hepatocellular carcinoma [HCC] nodules) were treated with RFA. All patients received PET/computed tomography before intervention. RFA was performed under computed tomography guidance with conscious sedation. Post-interventional PET/computed tomography was carried out in PET-positive patients 24h after the ablation and was repeated at 1, 3 and 6 months and every 6 months after the intervention. PET-negative patients received contrast-enhanced computed tomography at the same time points. The rate of local tumour progression (LTP) and survival rates were assessed for the whole patient population.

RESULTS

The 78 lesions (mean size 2.3 cm, range 0.8-5 cm) were treated with 101 consecutive ablation procedures resulting in a technical success rate of 96%. The mean time of follow-up was 25+/-12 months. Thirty-five of 78 tumours (45%) developed LTP. At the end of follow-up, LTP was found in 22 patients (40%), with intra- and extrahepatic recurrence in 11 patients. Twenty-two patients remained free of hepatic tumours. The 1-, 2- and 3-year survival rates were 85, 74 and 58%, respectively. Tumour entity, lesion size and localisation were significant risk factors for LTP.

CONCLUSIONS

Computed tomography-guided RFA of malignant liver tumours is effective, but shows a high rate of LTP. PET/computed tomography supports RFA by early identification of residual tumour or LTP.

Imaging guided percutaneous irreversible electroporation: ultrasound and immunohistological correlation

Preliminary results of percutaneous irreversible electroporation (PIE) on swine liver as a novel non-thermal ablation are presented. The goal of this study was to evaluate the feasibility of using irreversible electroporation in more clinically applicable manner, a percutaneous method, and to investigate a possible role of apoptosis in PIE-induced cell death. We performed PIE on four swine livers under real-time ultrasound guidance. The lesions created by PIE were imaged with ultrasound and were correlated with histology data, including pro-apoptotic marker. A total of 11 lesions were created with a mean size of 16.8 cm(3) in 8.4 +/- 1.8 minutes. Real-time monitoring was performed and a correlation of (+) 2 +/- 3.2 mm in measurement comparison between ultrasound and gross pathologic measurements was demonstrated. Complete hepatic cell death without structural destruction, unaffected by heat-sink effect, and with a sharp demarcation between the ablated zone and the non-ablated zone were observed. Immunohistological analysis confirmed complete apoptotic cell death by PIE on Von Kossa, BAX, and H&E staining. In summary, PIE can provide a novel and unique ablative method with real-time monitoring capability, ultra-short procedure time, non-thermal ablation, and well-controlled and focused apoptotic cell death.

Risk factor stratification after simultaneous liver and colorectal resection for synchronous colorectal metastasis

BACKGROUND/AIM

This study was conducted to devise a prognostic model for patients undergoing simultaneous liver and colorectal resection.

MATERIALS AND METHODS

A retrospective analysis was performed on 138 colorectal patients who underwent simultaneous liver and colorectal resection between September 1994 and September 2005. The primary endpoint of the study was overall survival. Three patients with positive liver resection margin were excluded from the analysis.

RESULTS

At multivariate level, poor prognostic factors were liver resection margin < or =5 mm (P = 0.047; relative risk, 1.684; 95% CI = 1.010-2.809), CEA greater than 5 ng/ml (P = <0.001; relative risk, 2.507; 95% CI = 1.499-4.194), number of liver metastasis > 1 (P = <0.042; relative risk, 1.687; 95% CI = 1.020-2.789), and lymph node > or = 4 (P = <0.012; relative risk, 1.968; 95% CI = 1.158-3.347). The risk stratification grouping of the 135 patients was performed according to the following criteria: low risk group, 0-1 factor; intermediate risk group, 2 factors; high-risk group, 3-4 factors. Of 135 patients, 86 patients (63.0%) were categorized as low-risk group, 36 patients (26.6%) as intermediate risk group, and 14 patients (10.4%) as high-risk group. Median survival times for low, intermediate, high-risk groups were 68.0, 43.6 (95% CI, 24.7-62.4), and 23.5 months (95% CI, 9.4-31.5), respectively. The high-risk group demonstrated an approximately threefold (relative risk, 3.1; 95% CI, 1.6-6.0) increased risk of death.

CONCLUSIONS

A simple risk factor stratification system was proposed to evaluate the chances of cure of patients after simultaneous resection of liver metastases and primary colorectal carcinoma. The risk factor stratification showed three groups with distinct survival. The risk stratification may help to predict patient survival after simultaneous liver and colorectal resection. This system needs further prospective validation.

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.

Radiofrequency ablation for metachronous liver metastasis from colorectal cancer after curative surgery

BACKGROUND

We compared outcomes of surgery and radiofrequency thermal ablation (RFA) in patients with metachronous liver metastases.

METHODS

Between October 1995 and December 2005, 59 patients underwent hepatic resection and 30 underwent RFA for metachronous liver metastases. Patients with extra-hepatic metastases, those who underwent both types of treatment, and those with synchronous hepatic metastasis were excluded.

RESULTS

The two groups had similar mean age, sex ratio, comorbid medical conditions, primary disease stage, and frequency of solitary metastases. Preoperative mean serum carcinoembryonic antigen (CEA) level was significantly higher in the RFA group (13.4 ng/mL vs. 7.7 ng/mL; p = 0.02). Mean diameter of hepatic metastases was significantly greater in the resection than in the RFA group (3.1 cm vs. 2.0 cm; p = 0.001). Recurrence after treatment of metastasis was observed in 18 of 30 (60.0%) RFA and 33 of 59 (56%) resection patients. Local recurrence at the RFA site was observed in 7 of 30 (23%) patients. Time to recurrence (15 vs. 8 months, p = 0.02) and overall survival (56 vs. 36 months, p = 0.005) were significantly longer in the resection than in the RFA group. In the 69 patients with solitary metastases of diameter </=3 cm, time to recurrence (p = 0.004) and overall survival were significantly greater in the resection group.

CONCLUSIONS

Compared with hepatic resection, RFA for metachronous hepatic metastases from colorectal cancer was associated with higher local recurrence and shorter recurrence-free and overall survival rates, even in patients with solitary, small (</=3 cm) lesions.

Surgical therapy of liver metastases

The liver is the most common site of metastatic disease from both gastrointestinal and extra-intestinal malignancies. Historically, only a minority of patients with colorectal liver metastases were candidates for resection. However, over the past several decades, liver resection has evolved as a safe and potentially curative treatment for hepatic colorectal metastases. The development of active chemotherapy and molecular targeted therapies, together with newer modalities like radiofrequency ablation, have expanded the indications for hepatic resection and improved survival. Selected patients with isolated liver metastases from neuroendocrine tumors, germ cell cancers, ocular melanoma, gastrointestinal stromal tumors (GIST), and breast cancer also may be considered for hepatic surgery.

Radiofrequency ablation of colorectal liver metastases

RFA of liver metastases is promising despite variable results. The differences in reported success rates may be explained by the difference in tumour types/vascularity/aggressiveness, patient selection, operator's expertise and the equipment used. Current limits relate to the small volume of consistent ablation that can be achieved with current equipment. Further technical refinements yielding more reliable ablation with larger surgical margin may reduce local recurrence rate. Although numerous studies have shown effective treatment responses after RFA, the precise impact of RFA on survival of colorectal cancer patients with liver metastases remains unclear. Resection remains the gold standard for patients with liver metastases. In patients with limited number of unresectable lesions and in cases, which are unresectable on the basis of lesional number and localization, RFA is an attractive approach to obtain tumour clearance. Randomised control trials evaluating the value of combined adjuvant systemic chemotherapy are still urgently needed.

Curative in situ ablation of colorectal liver metastases-experimental and clinical implementation

INTRODUCTION

In situ ablation of colorectal liver metastases is frequently assessed for palliative treatment only. The establishment of clinically relevant lesion size and a lack of long-term survival data were regarded as main limitations to using them with curative intention. In contrast to surgical liver resection, whose oncological findings seem to have remained unchanged over the years, the in situ ablation methods have considerably changed technically and clinically in the last few years.

OBJECTIVE

The aim of the paper was to point out experimental and clinical data underlining the impact of in situ ablation for potentially curative treatment of colorectal liver metastases.

DISCUSSION

On the basis of experimental data, the aim of complete local tumor control (R0 ablation) can only be obtained if additional energy is applied after reaching the tumor-adapted maximal coagulation volume. Analogous to the oncological safety margin in surgical resection, we defined this decisive energy difference as the "energy safety margin" for in situ ablation. The energy safety margin is the energy that must be additionally applied after reaching the plateau in the energy/volume curve to achieve complete tumor coagulation. In addition to that, in situ ablation should be combined with temporary interruption of hepatic perfusion whenever possible to prevent intralesional recurrences. In this way, the thermoprotective mechanism of hepatic perfusion can be effectively eliminated. With restrictions, the survival data after ablation in specialized centers is comparable to surgical resection with concomitantly lower morbidity and mortality. Based on recent findings and with the corresponding expertise in the field of ablation and state-of-the-art equipment, ablation is, thus, an alternative to surgical resection. The combined application of surgical resection and ablation is also a suitable method for increasing the R0 rate and thus helps improve the prognosis of treated patients. In summary, it can be said that in situ ablation is a useful expansion of the therapeutic spectrum of liver metastases and can be applied as an alternative to or in combination with surgical resection.

Initial Report of PET/CT–guided Radiofrequency Ablation of Liver Metastases

Computed tomography (CT) and ultrasonography (US) are commonly employed to guide positioning of radiofrequency electrodes within target tumors. However, this technique cannot be used when the tumor is detectable only by positron emission tomography (PET). In such cases, even the use of intraprocedural coregistered PET/CT will not prevent malpositioning of the electrode tip relative to a lesion visualized only on PET as a result of patient breathing and organ shifts during CT-guided electrode placement. The present report describes a single case of successful targeting and complete ablation of a lesion invisible on CT and US with the use of a method to visualize electrode tip positioning by PET.