Needle Tract Seeding after Radiofrequency Ablation of Hepatic Tumors

Current status of sonographically guided radiofrequency ablation techniques

OBJECTIVE

The purpose of this article was to review the current clinical applications of sonographically guided radiofrequency ablation (RFA) techniques.

METHODS

Publications regarding RFA extracted from a computerized database (MEDLINE) and from references cited in these articles were reviewed to evaluate the clinical effect and patient outcome.

RESULTS

Radiofrequency ablation has shown some promising effects in the treatment of tumors in various parts of the body. The recent advances in RFA technology enable larger volumes of treatment and make RFA clinically practical. It is most often used for hepatic and renal tumors, and applications for other organs and structures are increasing and rapidly developing. Sonography provides a convenient way to guide and monitor the procedure in most situations.

CONCLUSIONS

Effectiveness of RFA in the treatment of tumors in various body parts has been achieved. Radiofrequency ablation should be considered as an alternative or complementary method in the integration of oncologic management to obtain the greatest benefit to patients.

Does microvascular invasion affect outcomes after liver transplantation for HCC? A histopathological analysis of 155 consecutive explants

Macroscopic vascular invasion (macroVI) is associated with poor outcomes after liver transplantation (LT) for hepatocellular carcinoma (HCC). Whether microvascular invasion (microVI) is associated with the same adverse prognosis is unclear. One hundred and fifty-five consecutive patients with confirmed HCC after LT from March 1991 to 2004 at our institution were reviewed. Patients had to satisfy Milan criteria to be accepted for LT. They were followed with surveillance images every 3 months while on the waiting list. Disease-free survival (DFS) and overall survival (OS) were evaluated by Kaplan-Meier analysis. Demographic, tumor, and histopathologic characteristics were tested for their prognostic significance. Median follow-up after LT was 30 months. Overall graft survival rates were 87, 74, and 65% at 1, 3, and 5 years, respectively. All recurrences (22/155, 14%) developed within 4 years after LT with an overall 5-year DFS of 79%. Vascular invasion, either microVI or macroVI, was more likely in patients with multicentric HCC (n>or=3, p<0.001) and larger tumor size>4 cm (p=0.04). Tumor size>5 cm (p=0.04), advanced pathological TMN stage (p=0.007), microVI (p=0.001), and macroVI (p<0.001) predicted poor tumor-free survival on univariate analysis, but only macroVI was significant in multivariate analysis (hazard ratio 54.2, 95% confidence interval 11, 266). Furthermore, only macroVI was a significant predictor of mortality after LT (p=0.01). Macrovascular invasion is strongly associated with high rates of recurrence and diminished survival after LT whereas microVI is not an independent risk factor.

Obesity did not diminish the efficacy of percutaneous ablation for hepatocellular carcinoma

BACKGROUND

Overweight and hepatic steatosis can increase the risk of hepatocarcinogenesis. In addition, overweight may affect the treatment efficacy of ultrasound-guided percutaneous ablation. We evaluated the impact of overweight on the safety and efficacy of percutaneous ablation to hepatocellular carcinoma (HCC).

METHODS

We enrolled 743 patients with naïve HCC who were treated by percutaneous ablation including ethanol injection, microwave coagulation, and radiofrequency ablation (RFA) between 1995 and 2003. Patients were divided into two groups by body mass index (BMI): 219 overweight patients with BMI>25 kg/m2 and 524 control patients with BMI<or=25 kg/m2. The effects of BMI on complications of percutaneous ablation, HCC recurrence, and overall survival were analyzed, together with others including tumor and liver function-related factors.

RESULTS

The overweight group required a significantly larger number of sessions by RFA (P=0.01). Major complications were identified in 8.7% in the overweight group and 7.6% in the control group (P=0.94). There was no significant difference in cumulative recurrence rate and local tumor-progression rate between the two groups (P=0.63 and 0.44). Cumulative survival rates at 1, 3, and 5 years were 95.4%, 75.7%, and 57.8%, respectively, in the overweight group and 94.1%, 78.0%, and 58.8% in the control group (P=0.99).

CONCLUSIONS

The results indicated that overweight did not increase complications nor affect HCC recurrence and overall survival. However, the number of sessions of RFA was significantly greater in overweight patients, suggesting that overweight was associated with minor technical difficulties.

Image-guided multipolar radiofrequency ablation of liver tumours: initial clinical results

The local effectiveness and clinical usefulness of multipolar radiofrequency (RF) ablation of liver tumours was evaluated. Sixty-eight image-guided RF sessions were performed using a multipolar device with bipolar electrodes in 53 patients. There were 45 hepatocellular carcinomas (HCC) and 42 metastases with a diameter < or =3 cm (n = 55), 3.1-5 cm (n = 29) and >5 cm (n = 3); 26 nodules were within 5 mm from large vessels. Local effectiveness and complications were evaluated after RF procedures. Mean follow-up was 17 +/- 10 months. Recurrence and survival rates were analysed by the Kaplan-Meier method. The primary and secondary technical effectiveness rate was 82% and 95%, respectively. The major and minor complication rate was 2.9%, respectively. The local tumour progression at 1- and 2-years was 5% and 9% for HCC nodules and 17% and 31% for metastases, respectively; four of 26 nodules (15%) close to vessels showed local progression. The survival at 1 year and 2 years was 97% and 90% for HCC and 84% and 68% for metastases, respectively. Multipolar RF technique creates ablation zones of adequate size and tailored shape and is effective to treat most liver tumours, including those close to major hepatic vessels.

Incidence of needle tract seeding and responses of soft tissue metastasis by hepatocellular carcinoma postradiotherapy

AIM

To determine the incidence of needle tract seeding after fine needle aspiration (FNA) or percutaneous ethanol injection (PEI) and compare iatrogenic or spontaneous soft tissue metastasis (STM) by hepatocellular carcinoma (HCC) postradiotherapy (RT) in responses.

METHODS

From November 1997 to January 2006, those who presented with STM by HCC after our invasive procedures or developed spontaneously were enrolled into this retrospective study. Metastatic lesions could be divided into procedure related (PR), which were located at the liver span and were related to invasive procedures, and non-procedure related (NPR), which were in extrahepatic areas. STM was treated with an electron or photon beam.

RESULTS

A total of 39 HCC cases with developed STM were referred for RT, including 17 in the PR group and 22 in the NPR group. During the same period, a total of 18,227 person-times of FNA or PEI were performed on these HCC patients. The overall incidence of HCC with STM that was caused by invasive procedures was estimated at 0.13%. According to the Cox' regression model, the initial treatment modality influences the time duration after the initial diagnosis of HCC when STM has not occurred. None of these patients' soft tissue tumor increased in size during RT. The PR group had lower rates of bone metastasis (P=0.003) and coexisting extrahepatic metastasis (P=0.011) and a longer survival rate (P=0.003) than the NPR group. The estimated rates of 18-gauge and 22-gauge needle-induced HCC-related STM were 0.60% and 0.11%, respectively (P=0.064).

CONCLUSION

The PR group bears a better prognosis than the NPR group post-RT.

Technology insight: Image-guided therapies for hepatocellular carcinoma--intra-arterial and ablative techniques

Locoregional techniques have become the mainstay of therapy for patients with unresectable hepatocellular carcinoma (HCC). Such image-guided interventions include catheter-based approaches (transarterial chemoembolization and yttrium-90 radiotherapy) and locoregional ablative techniques, either chemical (percutaneous ethanol injection), or thermal (radiofrequency ablation, laser ablation, microwave ablation and cryoablation). These therapies are mainly utilized for palliation, but have also been used with curative intent. In selected cases, percutaneous interventional treatments have shown good results (5-year survival 40-50%), but, even when chosen as first-line treatment, have not been able to achieve the response rates and outcomes achieved by surgical options (resection or transplantation). New promising image-guided therapies are continuously emerging, as we attempt to improve tumor targeting, minimize hepatic toxicity and ultimately improve quality of life and survival of patients with HCC. With new technologies in imaging and drug delivery becoming available, it is likely that, in the future, patients with HCC will be best treated by a multidisciplinary team approach, utilizing a combination of techniques to improve patient survival. This review outlines the current status of the most commonly used image-guided locoregional interventions in the treatment of patients with HCC, and describes recent research and advances related to image-guided interventions for liver cancer.

Radiofrequency ablation of lung tumours

Radiofrequency ablation (RFA) is a well-established local therapy for hepatic malignancies. It is rapidly emerging as an effective treatment modality for small lesions elsewhere in the body, in particular, the kidney and the lung. It is a relatively safe and minimally invasive treatment for small lung malignancies, both primary and secondary. In particular, it is the preferred form of treatment for non-surgical candidates.

This paper describes the technique employed for radiofrequency ablation of lung tumours, as well as the protocol established, at the Mount Elizabeth Hospital, Singapore.

Complications of percutaneous radiofrequency ablation for hepato-cellular carcinoma: imaging spectrum and management

Percutaneous radiofrequency (RF) ablation is feasible for the treatment of unresectable hepatocellular carcinoma, and experience at the authors' institution during 5 years indicates that percutaneous RF ablation can be performed safely in most cases. However, early or late complications related to mechanical or thermal damage may be observed at follow-up examination. Complications may be classified in three groups: vascular (eg, portal vein thrombosis, hepatic vein thrombosis with partial hepatic congestion, hepatic infarction, and subcapsular hematoma), biliary (eg, bile duct stenosis and biloma, abscess, and hemobilia), and extrahepatic (eg, injury to the gastrointestinal tract, injury to the gallbladder, pneumothorax and hemothorax, and tumor seeding). Most complications can be managed with conservative treatment, percutaneous or endoscopic drainage, or surgical repair. Because an early and accurate diagnosis is necessary for proper management, radiologists should be familiar with the imaging features of each type of complication.

Hepatocellular carcinoma: overcoming challenges in disease management

Hepatocellular carcinoma is the third most frequent cause of death from cancer and the eighth most commonly occurring cancer in the world. In the United States, hepatocellular carcinoma appears to be increasing along with evolution of chronic hepatitis infection, especially in the immigrant population, a major risk group. A disease of multifactorial etiology, hepatocellular carcinoma confers many management challenges. Hepatocarcinogenesis is a multistep process involving different genetic alterations that ultimately lead to malignant transformation of the hepatocyte. Early hepatocellular carcinoma is characteristically silent and slow growing with few symptoms until late in disease. Early and accurate diagnosis of hepatic tumors relies on clinical suspicion, screening protocols, serologic testing, radiologic imaging, and tissue confirmation. Lack of clinically validated biomarkers and clinical identification of hepatocellular carcinoma at advanced disease make diagnosis and treatment difficult. Advances in computed tomography and magnetic resonance imaging have markedly increased the sensitivity and specificity of testing, yet they are still flawed with a relatively high false-positive rate. Several surgical and nonsurgical therapies have been developed and used with varying degrees of success. Options include surgical resection, liver transplantation, local ablation therapies, and pharmaceutical interventions. At 5 years after resection, in those patients who are surgical candidates, the recurrence rate ranges between 30% and 60%. In patients with nonresectable disease, the prognosis is dismal, with a median survival of less than 12 months even with chemotherapy. The medical community faces numerous challenges in hepatocellular carcinoma and must work toward better management and multidisciplinary care of this complex disease.