Percutaneous radiofrequency thermal ablation combined with transcatheter arterial embolization in the treatment of large hepatocellular carcinoma

Radiofrequency thermal ablation of liver tumors

Radiofrequency ablation (RFA) of liver tumors was first proposed in 1990. New technologies enable us to produce liver thermal lesions of approximately 3-3.5 cm in diameter; RFA has consequently become an emerging percutaneous therapeutic option both for small hepatocellular carcinoma (HCC) and for non-resectable liver metastases, mainly from colorectal cancer. New devices (for example, triplet of cooled needles, wet needles) and combined therapies (tumor ischemia and RFA) have made it possible to treat large tumors. RFA can be carried out by a percutaneous, laparoscopic or laparotomic approach. Percutaneous RFA can be performed with local anaesthesia and mild sedation; deep sedation or general anaesthesia are also used. The guidance system is generally represented by ultrasound. CT or MR examinations are the more sensitive tests for assessing therapeutic results. The series of patients treated with RFA allow the technique to be considered as effective and safe, achieving a relatively high rate of cure in properly selected cases; it should be classified as curative/effective treatment for HCC, replacing percutaneous ethanol injection. The complication rate of RFA is low but not negligible; key elements in a strategy to minimize them are identified.

Interventional radiology in pediatric oncology

There are many radiological interventions necessary for pediatric oncology patients, some of which may be covered in other articles in this publication. I will discuss a number of interventions including percutaneous biopsy for solid tumor and hematological malignancy diagnosis or recurrence, for the diagnosis of graft versus host disease after stem cell or bone marrow transplantation, and for the diagnosis of complications of immunosuppression such as invasive pulmonary aspergillosis. In the past, tumor localization techniques have been necessary to biopsy or resect small lesions. However improved guidance techniques have allowed for more precise biopsy and the use of thermal ablation instead of excision for local tumor control. A percutaneously placed radio frequency, microwave, laser or cryogen probe can ablate the primary and metastatic tumors of the liver, lung, bone, kidney and other structures in children. This is an alternative treatment for the local control of tumors that may not be amenable to surgery, chemotherapy or radiotherapy. I will also describe how chemoembolization can be used to treat primary or metastatic tumors of the liver that have failed other therapies. This treatment delivers chemotherapy in the hepatic artery infused with emboli to increase the dwell time and concentration of the agents.

Percutaneous radiofrequency ablation for hepatocellular carcinoma

BACKGROUND

Radiofrequency ablation (RFA) was introduced recently as a therapeutic modality for hepatocellular carcinoma (HCC), an alternative to percutaneous ethanol injection therapy (PEIT), which is coming into use worldwide. Previously reported treatment efficacy and complication rates have varied considerably.

METHODS

Between February 1999 and February 2003, the authors performed 1000 treatments of RFA to 2140 HCC nodules in 664 patients with a cooled-tip electrode at the University of Tokyo Hospital (Tokyo, Japan). Short-term and long-term complications were analyzed by treatment and session basis. Cumulative survival was also assessed in 319 patients who received RFA as primary treatment (naive patients) and 345 patients who received RFA for recurrent tumor after previous treatment including resection, PEIT, microwave coagulation therapy, and transarterial embolization (nonnaive patients).

RESULTS

A total of 40 major complications (4.0% per treatment, 1.9% per session) and 17 minor complications (1.7% per treatment, 0.82% per session) were observed during the observation period until March 31, 2004. There were no treatment-related deaths. Surgical intervention was required in one case each of bile peritonitis and duodenal perforation. The cumulative survival rates at 1, 2, 3, 4, and 5 years were 94.7%, 86.1%, 77.7%, 67.4%, and 54.3% for naive patients, whereas the cumulative survival rates were 91.8%, 75.6%, 62.4%, 53.7%, and 38.2% for nonnaive patients, respectively.

CONCLUSIONS

The authors confirmed the safety and efficacy of RFA for HCC in a large-scale series and long-term prognosis was satisfactory.

Metastatic Colorectal Carcinoma: Cost-effectiveness of Percutaneous Radiofrequency Ablation versus That of Hepatic Resection

PURPOSE

To evaluate the relative cost-effectiveness of radiofrequency (RF) ablation and hepatic resection in patients with metachronous liver metastases from colorectal carcinoma (CRC) and compare the outcomes, cost, and cost-effectiveness of a variety of treatment and follow-up strategies.

MATERIALS AND METHODS

A state-transition decision model for evaluating the (societal) cost-effectiveness of RF ablation and hepatic resection in patients with CRC liver metastases was developed. The model tracks the presence, number, size, location, growth, detection, and removal of up to 15 individual metastases in each patient. Survival, quality of life, and cost are predicted on the basis of disease extent. Imaging, ablation, and resection affect outcomes through detection and elimination of individual metastases. Several patient care strategies were developed and compared on the basis of cost, effectiveness, and incremental cost-effectiveness (expressed as dollars per quality-adjusted life-year [QALY]). Extensive sensitivity analysis was performed to evaluate the impact of alternative scenarios and assumptions on results.

RESULTS

A strategy permitting ablation of up to five metastases with computed tomographic (CT) follow-up every 4 months resulted in a gain of 0.65 QALYs relative to a no-treat strategy, at an incremental cost of $2400 per QALY. Compared with this ablation strategy, a strategy permitting resection of up to four metastases, one repeat resection, and CT follow-up every 6 months resulted in an additional gain of 0.76 QALYs at an incremental cost of $24 300 per QALY. Across a range of model assumptions, more aggressive treatment strategies (ie, ablation or resection of more metastases, treatment of recurrent metastases, more frequent follow-up imaging) were superior to less aggressive strategies and had incremental cost-effectiveness ratios of less than $35 000 per QALY. Findings were insensitive to changes in most model parameters; however, results were somewhat sensitive to changes in size thresholds for RF ablation, the number of metastases present, and surgery and treatment costs.

CONCLUSION

RF ablation is a cost-effective treatment option for patients with CRC liver metastases. However, in most scenarios, hepatic resection is more effective (in terms of QALYs gained) than RF ablation and has an incremental cost-effectiveness ratio of less than $35 000 per QALY.

Radiofrequency ablation of liver tumours: systematic review

Thermal ablation by use of radiofrequency energy can be used to achieve necrosis of liver tumours, and increased availability of this technique is leading to more widespread use. Much of the impetus for the use of radiofrequency ablation has come from cohort series that have provided an evidence base for this technique. Here, we give an overview of the current status of radiofrequency ablation for liver tumours, including its physical properties, to assess the characteristics that make this technique applicable in clinical practice. We review the technical development of probe design and summarise current indications and outcomes of reported clinical use. We also provide a profile of side-effects and information on the integration of this technique into the general management of patients with liver tumours. Current evidence suggests that radiofrequency ablation can be done with few side effects; however, although this technique seems to ablate tumours effectively, it should form part of multidisciplinary care for liver cancer. Crucially, the role of radiofrequency ablation in lengthening the survival of patients with liver tumours remains to be assessed.

Large liver tumors: protocol for radiofrequency ablation and its clinical application in 110 patients--mathematic model, overlapping mode, and electrode placement process

PURPOSE

To establish a preoperative protocol for ultrasonographically guided percutaneous radiofrequency (RF) ablation of large liver tumors that is based on mathematic models and clinical experience and to evaluate the role of this protocol in RF ablation.

MATERIALS AND METHODS

A regular prism and a regular polyhedron model were used to develop a preoperative protocol for liver tumor ablation. This protocol enabled the authors to minimize the number of ablation spheres, optimize the overlapping mode, and determine the electrode placement process. One hundred ten patients with 121 liver tumors were treated by using this protocol. Sixty-nine patients had 74 hepatocellular carcinomas (HCCs), and 41 had 47 metastases to the liver (ie, metastatic liver carcinomas [MLCs]). Patients underwent follow-up helical computed tomography (CT) 1 month and every 2-3 months after RF ablation. Ablation was considered a success if no contrast enhancement was detected in the treated area on the CT scan obtained at 1 month.

RESULTS

A total of 536 ablations were performed in the 121 tumors. The ablation success rate was 87.6% (106 of 121 tumors); the local recurrence rate, 24.0% (29 of 121 tumors); and the estimated mean recurrence-free survival, 17.1 months. Twenty-five patients underwent 38 re-treatments for local tumor recurrence. Major complications occurred in seven patients. Of these patients, only one, who had a tumor close to the colon, had a colon perforation 1 week after RF and required surgical intervention.

CONCLUSION

The described protocol for treatment of large tumors had a success rate of 87.6% and a local recurrence rate of 24.0%.

Transcatheter arterial chemoembolization for unresectable hepatocellular carcinoma fed by the cystic artery

PURPOSE

To evaluate the safety, technical success rate, and effectiveness of transcatheter arterial chemoembolization (TACE) for unresectable hepatocellular carcinoma (HCC) fed by the cystic artery.

MATERIALS AND METHODS

Treatment of 27 tumors in 25 patients fed by the cystic artery was attempted with TACE. Twenty-two patients had previously undergone one to eight TACE sessions (mean, four sessions), and the duration after initiation of treatment of HCC was 4-69 months (mean, 24). In three patients, parasitization of the cystic artery was revealed at initial angiography. TACE was performed only when the microcatheter could be inserted into the tumor feeding branch and the stain of the gallbladder wall disappeared. The therapeutic effects and complications were retrospectively analyzed.

RESULTS

Seventeen tumors were completely fed by the cystic artery and 10 were fed by both the hepatic artery and cystic artery. Attenuation or occlusion of the hepatic artery was observed in 56%. The tumor feeding branch arising from the cystic artery could be successfully embolized in 18 tumors (67%) of 16 patients without severe complications. Adequate iodized oil accumulation was achieved in 14 tumors (52%) of 12 patients. Percutaneous therapy (n = 7), radiation (n = 4), and TACE after cholecystectomy (n = 1) were added for tumors with incomplete or unsuccessful TACE. Local progression was observed in three (21%) of 14 tumors treated by TACE alone during a mean follow-up period of 18 months.

CONCLUSION

TACE via the cystic artery was safe and technically possible in 67% of patients. If adequate iodized oil accumulation is obtained, which was only achieved in 52% of patients, sufficient therapeutic effect may be expected.

Influence of large peritumoral vessels on outcome of radiofrequency ablation of liver tumors

PURPOSE

The effect of large vessels (>/=3 mm) contiguous to hepatic tumors was evaluated with respect to clinical tumor recurrence rates after radiofrequency (RF) ablation.

MATERIALS AND METHODS

The first 105 malignant liver tumors treated by RF ablation therapy at our institution with pathologic analysis or a minimum of 6 months of clinical follow-up were reviewed. The original pretreatment imaging studies were reviewed by a radiologist who was blinded to the cases, and, based on lesion contiguity to vessels of at least 3 mm, the lesions were categorized as perivascular or nonperivascular. Treatment outcomes with respect to local tumor recurrence between these two groups were then compared. Logistic regression analysis was performed to take into account other variables and to determine whether this categorization was an independent predictor of treatment outcome.

RESULTS

There were 74 nonperivascular tumors and 31 perivascular tumors. Mean tumor size was 2.4 cm and mean follow-up was 11.3 months. Residual or locally recurrent tumors were documented in 20 of 105 cases (19%). In the nonperivascular group, five of 74 (7%) had either incompletely treated tumor (manifested within 6 months) or local recurrence beyond 6 months. In the perivascular group, 15 of 31 (48%) had incompletely treated or locally recurrent tumor (P <.001). Subanalysis of lesion size (61 tumors </=2.5 cm, 33 tumors 2.6-4 cm, and 11 tumors >4 cm), tumor type (40 hepatocellular carcinomas, 48 colorectal metastases, and 17 other metastases), access (53 intraoperative, 52 percutaneous), and RF device (45 Radiotherapeutics electrodes, 18 Rita electrodes, and 42 Radionics electrodes) showed similar results. Multivariate logistic regression analysis showed that presence or absence of a large peritumoral vessel is an independent, and the dominant, predictor of treatment outcome.

CONCLUSION

The presence of vessels at least 3 mm in size contiguous to hepatic tumors is a strong independent predictor of incomplete tumor destruction by RF ablation. Modified ablation strategies should be considered to improve destruction of these tumors.

Ultrasound-guided percutaneous thermal ablation of hepatocellular carcinoma using microwave and radiofrequency ablation

AIM

To investigate the therapeutic efficacy of thermal ablation for treatment of hepatocellular carcinoma (HCC) using microwave and radiofrequency (RF) energy application.

MATERIALS AND METHODS

A total of 190 nodules in 97 patients (84 male, 13 female; mean age 53.4 years, range 24-74 years) with HCC were treated with microwave or RF ablation in the last 4 years. The applicators were introduced into the tumours under conscious analgesic sedation by intravenous administration of fentanyl citrate and droperidol and local anaesthesia in both thermal ablation procedures. The patients were then followed up with contrast-enhanced computed tomography (CT) to evaluate treatment response. Survival was analysed using the Kaplan-Meier method.

RESULTS

Complete ablation was obtained in 92.6% (176/190) nodules. The complete ablation rates were 94.6% (106/112) in microwave ablation and 89.7% (70/78) in RF ablation. The complete ablation rates in tumours</=2.0, 2.1-3.9 and >/=4.0 cm were 93.1, 93.8 and 86.4%, respectively. Local recurrence was found in 9.5% nodules and the rates in tumours</=2.0, 2.1-3.9 and >/=4.0 cm in diameter were 3.4, 9.9 and 31.8%, respectively. In the follow-up period, 7.1% nodules ablated by microwave and 12.8% by RF presented local recurrence. The 1, 2 and 3-year distant recurrence-free survivals were 47.2, 34.9 and 31.0%, respectively. Estimated mean survival was 32 months, and 1, 2 and 3-year cumulative survivals were 75.6, 58.5, and 50.0%, respectively. One and 2 years survivals of Child-Pugh class A, B and C patients were 83.8 and 70.4%, 78.2 and 53.2%, 36.3 and 27.3%, respectively.

CONCLUSION

Thermal ablation therapy by means of microwave and RF energy application is an effective and safe therapeutic technique for hepatocellular carcinoma. Large tumours can be completely ablated, but have a significantly higher risk of local recurrence at follow-up.

Radiofrequency ablation in the treatment of small hepatocellular carcinomas: comparison of the radiofrequency effect with and without chemoembolization

OBJECTIVE

The purpose of this study was to determine whether a combination of transcatheter arterial chemoembolization using doxorubicin and radiofrequency ablation can increase tumor destruction compared with radiofrequency alone in the treatment for hepatocellular carcinoma. SUBJECTS AND METHODS. Twenty-one patients with 26 nodules smaller than 3 cm in diameter were treated with radiofrequency ablation. Of these, 10 nodules were treated with a combination of radiofrequency ablation and chemoembolization using doxorubicin. All nodules were evaluated for size of induced coagulation, local recurrence, and complication.

RESULTS

The therapeutic areas averaged 27.6 x 22.3 mm using an electrode with a 2-cm tip and 37.2 x 29.1 mm using an electrode with a 3-cm tip. With respect to the results for 14 nodules treated using an electrode with a 3-cm tip with or without chemoembolization, the greatest dimension of the area coagulated by combined therapy was significantly larger (longest axis dimension, 39.9 +/- 4.4 mm; shortest axis dimension, 32.3 +/- 5.2 mm; n = 7 nodules) than areas without chemoembolization (longest axis dimension, 34.6 +/- 2.6 mm; shortest axis dimension, 26.0 +/- 3.3 mm; n = 7 nodules) (longest and shortest axis dimensions, p < 0.05). No recurrence occurred in the nodules smaller than 2 cm in diameter. Among the nodules larger than 2 cm in diameter, one local recurrence was observed in seven nodules treated by combined therapy, while two local recurrences were observed in seven nodules treated by radiofrequency alone. Minor complications developed in three patients, two with persistent high fever and one with biliary stenosis.

CONCLUSION

The combination of radiofrequency ablation and transcatheter arterial chemoembolization using doxorubicin markedly increased the extent of induced coagulation compared with radiofrequency alone, despite a small number of patients and the preliminary nature of this study.

Radio-frequency thermal ablation with hypertonic saline solution injection of the lung: ex vivo and in vivo feasibility studies

The aim of this study was to assess the effects of simultaneous instillation of NaCl solutions during radio-frequency ablation (RFA) on the dimension of the ablated lesion in ex vivo bovine lung tissue and in vivo rabbit lung tissue. The RFA was induced in ex vivo bovine lung tissue which was inflated with room air and in vivo rabbit lung tissue by a 500-kHz RF generator and a 17-G cooled-tip electrode. In in vivo experiments, RFA was performed using CT guidance. The RF energy was applied for 5 min with or without instillation of 0.9 or 36% NaCl solutions. The changes in tissue impedance, current, power output, and temperature of the electrode tip were automatically measured. The maximum diameter of all thermal lesions was measured perpendicular to the electrode axis by two observers. In an ex vivo study, the mean lesion diameters using 36 and 0.9% NaCl solutions were larger than those of the control group: 51+/-8, 34+/-6, and 5+/-2 mm ( p<0. 05). In in vivo rabbit lung tissue, the mean lesion diameter with NaCl solution (15.3+/-3.1 mm) was larger than that of the lesion without NaCl solution (8.5+/-1.4 mm; p<0.05). With instillation of NaCl solutions, a marked decrease of tissue impedance (>100 Omega) and corresponding increase of current flow occurred in both ex vivo and in vivo studies. This experimental study demonstrates that RF ablation with simultaneous NaCl solution infusion of the lung is more effective in achieving coagulation necrosis than conventional RFA procedure.

Radiofrequency thermal ablation with expandable needle of focal liver malignancies: complication report

The aim of this study was to describe type and rate of complications in a series of patients with liver tumors treated by the radiofrequency (RF) expandable system. A total of 166 patients, 114 with hepatocellular carcinoma (HCC; 92 small HCC, 22 large) and 52 with liver metastasis, were treated by the percutaneous RF expandable system. In large HCCs, RF ablation was performed after tumor ischemia (TAE or balloon stop flow of the hepatic artery). Major complications were those that delayed hospital discharge, with or without additional medical procedures or treatments. Minor complications did not require an additional hospital stay. No deaths occurred. Among 151 patients followed, there were 7 (4.6%) early major complications-severe pain with session interruption in 3 cases, capsular necrosis in 1 case, 1 abdominal wall necrosis, 1 dorsal burning, 1 peritoneal hemorrhage-and 3 (1.9%) delayed major complications: sterile fluid collection at the site of the treated tumor in 2 cases and cutaneous seeding in 1 case. There were 49 (32.5%) minor complications. The complication rate is similar to that observed after percutaneous alcohol injection (PEI). With the cooled system, the complication rate is seemingly lower but that may well be due to a different definition of major complications. The seeding rate after expandable system ablation is lower than after PEI. It is the same as or lower than that in other series of patients treated by the cooled system.

Combined interventional therapies of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common malignancies in the world, responsible for an estimated one million deaths annually. It has a poor prognosis due to its rapid infiltrating growth and complicating liver cirrhosis. Surgical resection, liver transplantation and cryosurgery are considered the best curative options, achieving a high rate of complete response, especially in patients with small HCC and good residual liver function. In nonsurgery, regional interventional therapies have led to a major breakthrough in the management of unresectable HCC, which include transarterial chemoembolization (TACE), percutaneous ethanol injection (PEI), radiofrequency ablation (RFA), microwave coagulation therapy (MCT), laser-induced thermotherapy (LITT), etc. As a result of the technical development of locoregional approaches for HCC during the recent decades, the range of combined interventional therapies has been continuously extended. Most combined multimodal interventional therapies reveal their enormous advantages as compared with any single therapeutic regimen alone, and play more important roles in treating unresectable HCC.

Image-guided percutaneous chemical and radiofrequency tumor ablation in an animal model

PURPOSE

To determine whether combining acetic acid instillation before radiofrequency (RF) ablation can improve local tissue electrical conductivity, RF energy deposition, intratumoral heating, and tumor necrosis in a large animal model.

MATERIALS AND METHODS

Multiple hypovascular canine venereal sarcomas were implanted in 11 mildly immunosuppressed dogs (25 mg/kg cyclosporin A twice daily). Tumors were incubated for 8-12 weeks to 4.2 cm +/- 0.6 in diameter. Treatment strategies included 10% and 15% acetic acid diluted in distilled water, 10% and 15% acetic acid diluted in saturated NaCl solution, 50% acetic acid, and 100% ethanol, with 6 mL of each injected alone or in combination with RF ablation (internally cooled, 1-cm tip; 12 minutes). Two additional control groups were studied in which tumors received either RF alone or distilled water injected alone. Comparisons were also made with groups treated with 36% NaCl with and without RF ablation. Resultant coagulation for these ablative strategies, along with local temperatures and RF parameters such as impedance, current, and power, were compared.

RESULTS

Increasing coagulation was observed with increasing acetic acid concentrations (1.7 cm +/- 0.4, 2.8 cm +/- 0.6, and 3.5 cm +/- 0.3 for 10%, 15%, and 50% acetic acid alone, respectively; P <.01). The combination of RF ablation with acetic acid resulted in greater coagulation than with either therapy alone (P <.05). However, maximum heating and coagulation were observed with 10% acetic acid diluted in NaCl, with which the entire tumor (diameter, 4.5 cm +/- 0.4) was completely ablated in every case. This was equivalent to results for tumors treated with 36% NaCl combined with RF. RF with a 50% acetic acid concentration resulted in coagulation measuring only 3.7 cm +/- 0.3 (P <.01). Significantly greater RF heating (89.7 degrees C +/- 12.3 at 10 mm) was observed when the tumors were pretreated with 10% or 15% acetic acid in saturated NaCl, compared with 67.9 degrees C +/- 13.7 observed when acetic acid was diluted in water (P <.02). RF combined with ethanol produced less coagulation (2.8 cm +/- 0.3) than combinations with acetic acid because rapid and irreversible impedance increases were observed.

CONCLUSION

Addition of acetic acid injections to RF ablation substantially increases tumor destruction compared with RF or injection therapy alone. However, lower acetic acid concentrations in saturated NaCl produced greater tumor coagulation, suggesting that, in this hypovascular tumor model, alterations in electrical conductivity play a more important role in increasing tumor ablation efficiency than do the additional ablative effects of acetic acid.

Percutaneous radiofrequency ablation of liver metastases in potential candidates for resection: the "test-of-time approach"

BACKGROUND

Some surgeons have advocated delaying resection of liver metastases to allow additional metastases which may be present, but are undetected, to be identified. This "test-of-time" approach can limit the number of resections performed on patients who ultimately will develop additional metastases. The current study evaluated the potential role and possible advantages of performing radiofrequency (RF) ablation during the interval between diagnosis and hepatic metastasectomy as part of a test-of-time management approach.

METHODS

Eighty-eight consecutive patients with 134 colorectal carcinoma liver metastases were potential candidates for hepatic metastasectomy. They were treated with percutaneous RF ablation using single (101 treatments) or triple-probe cluster (22 treatments) 18-gauge internally cooled electrodes. Treatment was performed under conscious sedation (22 of 119 treatments), anesthesia (14 of 119 treatments), or general anesthesia (83 of 119 treatments). At the time of the initial RF ablation procedure, 49 of 88 patients (56%) were found to have 1 metastasis, 32 of 88 patients (36%) had 2 metastases, and 7 of 88 patients (8%) had 3 metastases. Metastases ranged from 0.6 to 4.0 cm in greatest dimension (mean, 2.1 cm). Follow-up with serial computed tomography scans scans ranged from 18 to 75 months (median, 33 months) after the initial RF ablation.

RESULTS

A total of 119 RF ablations were performed. Complete necrosis was obtained in 53 of 88 patients (60%) and in 85 of 134 lesions (63%). During follow-up of these 53 patients, 16 (30%) remained free of disease and 37 (70%) developed new lesions. New lesions were intrahepatic in 26 of 37 patients (70%), extrahepatic in 4 patients (11%), and both intrahepatic and extrahepatic in 7 patients (19%). Of 26 patients whose new lesions were intrahepatic only, 15 (58%) were retreated with RF and 7 were free of disease at the time of last follow-up (median follow-up, 28 months). Ten additional patients with only intrahepatic new lesions were deemed untreatable and 1 patient underwent resection. Overall, among the 53 patients in whom complete tumor necrosis was achieved after RF ablation therapy, 52 (98%) were spared surgical resection: 23 (44%) because they have remained free of disease and 29 (56%) because they developed disease progression. Among all 88 patients, 21 (24%) underwent resection after RF ablation (8 were free of disease at the time of last follow-up), 23 (26%) remained free of disease after successful RF ablation, and 56 (64%) developed untreatable disease progression (44 after RF alone, 12 after RF and surgery). Lesions in 35 of 88 patients (40%) demonstrated local tumor recurrence on follow-up imaging studies. Twenty of these 35 patients (57%) underwent surgical resection, whereas the remaining 15 patients (43%) developed additional, untreatable metastases. New lesions were intrahepatic in 9 of 15 patients (60%), extrahepatic in 1 of 15 patients (7%), and both intrahepatic and extrahepatic in 5 of 15 patients (33%). No patient who had been treated with RF ablation became unresectable due to the growth of metastases and there was no evidence of needle track seeding in any patient after RF ablation. Overall, among the 35 patients in whom complete tumor necrosis was not achieved after RF ablation therapy, 15 (43%) were spared surgical resection.

CONCLUSIONS

The results of the current study suggest that current RF ablation techniques, when used as part of a test-of-time management approach, can decrease the number of resections performed. The approach results in complete tumor necrosis in some patients and provide an interval for others who ultimately will develop new intrahepatic and/or extrahepatic metastases to do so.

Thermal ablative therapy for malignant liver tumors: a critical appraisal

The management of primary and secondary malignant liver tumors poses a great challenge to clinicians. Although surgical resection is the gold-standard treatment, most patients have unresectable malignant liver tumors. Over the past decade, various modalities of loco-regional therapy have gained much interest. Among them, thermal ablative therapy, including cryotherapy, microwave coagulation, interstitial laser therapy, and radiofrequency ablation (RFA), have been proven to be safe and effective. Despite the effective tumor eradication achieved within cryotherapy, the underlying freeze/thaw mechanism has resulted in serious complications that include bleeding from liver cracking and the 'cryoshock' phenomenon. Thermal ablation using microwave and laser therapy for malignant liver tumors is curative and is associated with minimal complications. However, this treatment modality is effective only for tumors <3 cm diameter. Radiofrequency ablation seems to be the most promising form of thermal ablative therapy in terms of a lower complication rate and a larger volume of ablation. However, its use is restricted by the difficulty encountered when using imaging studies to monitor the areas of ablation during and after the procedure. Moreover, the techniques of RFA need to be refined in order to achieve the same oncological radicality of malignant liver tumors as achieved by surgical resection. As each of the loco-regional therapies has its own advantages and limitations, a multidisciplinary approach using a combination of therapies will be the future trend for the management of malignant liver tumors.

Risk factors for local recurrence of small hepatocellular carcinoma tumors after a single session, single application of percutaneous radiofrequency ablation

BACKGROUND

The objectives of this study were to clarify risk factors for local tumor recurrence and to determine which patients with hepatocellular carcinoma (HCC) are most suitable for a single session, single application of percutaneous radiofrequency (RF) ablation.

METHODS

Fifty-six consecutive patients with 65 HCC tumors measuring <or= 3 cm in greatest dimension who received a single session, single application of percutaneous RF ablation and who achieved optimal tumor ablation, as assessed by an immediate computed tomography scan, were enrolled in this study. Six possible factors for local recurrence were analyzed using a Cox proportional hazards regression model: tumor size, tumor location, proximity of the tumor to intrahepatic large vessels, types of electrodes used, prior treatment, and observation of impedance rises. Local recurrence free intervals were estimated using the Kaplan-Meier method, and differences between groups were compared using the log-rank test.

RESULTS

The Kaplan-Meier estimates of overall cumulative local recurrence free intervals after a single RF ablation treatment were 76% (95% confidence interval [95%CI], 70.9-81.7%) at 12 months and 74% (95%CI, 68.2-79.6%) at 15 months. The log-rank test revealed a statistically significant difference between the local recurrence free intervals according to tumor size (P = 0.001) and tumor location (P < 0.001). Further investigation with a Cox regression analysis indicated that a greatest tumor dimension > 2 cm (risk ratio [RR], 4.9; 95%CI, 1.3-16.4; P = 0.019) and subcapsular location (RR, 5.2; 95%CI, 1.7-16.6; P = 0.005) were associated independently with local recurrence. The other four factors were not associated with local recurrence in this study.

CONCLUSIONS

A single session, single application of RF ablation produced favorable local control. Patients who have nonsubcapsular HCC tumors measuring <or= 2 cm in greatest dimension may be the most suitable candidates for a single-session, single application of RF ablation.

Radiofrequency ablation combined with chemoembolization in hepatocellular carcinoma: treatment response based on tumor size and morphology

PURPOSE

To evaluate local therapeutic efficacy of radiofrequency (RF) ablation after chemoembolization for hepatocellular carcinoma (HCC) based on tumor size and morphology.

MATERIALS AND METHODS

Sixty-four patients underwent RF ablation under ultrasonographic or real-time computed tomographic (CT) fluoroscopic guidance within 2 weeks after chemoembolization. One hundred eight lesions were treated. Sixty-five lesions were small (<or=3 cm), 32 were intermediate in size (3.1-5 cm), and 11 were large (5.1-12 cm). Seventy-four of the HCCs were nodular lesions and the other 34 were nonnodular (multinodular and infiltrative) lesions. Response to treatment was evaluated by dynamic enhanced CT and magnetic resonance imaging. Tumor necrosis was considered to be complete when no foci of enhancement were seen within the tumor and at its periphery.

RESULTS

Complete necrosis was achieved in all lesions regardless of tumor size or morphology. There have been no local recurrences in small and intermediate-sized lesions regardless of tumor morphology during a mean follow-up of 12.5 months. In large HCCs, nodular lesions showed no recurrence, but two of six of nonnodular lesions recurred beyond the thermal lesions created around the tumor. The estimated 1-year survival rate was 98.0% in all patients.

CONCLUSIONS

This combined therapy has a therapeutic effect on small and intermediate-sized HCCs regardless of tumor morphology and is a promising treatment option for large nodular lesions. Control of large nonnodular lesions is still a challenging problem.

Complications of radiofrequency coagulation of liver tumours

BACKGROUND

Radiofrequency coagulation (RFC) is being promoted as a novel technique with a low morbidity rate in the treatment of liver tumours. The purpose of this study was to assess critically the complication rates of RFC in centres with both large and limited initial experience, and to establish causes and possible means of prevention and treatment.

METHODS

This is an exhaustive review of the world literature (articles and abstracts) up to 31 December 2001; 82 independent reports of RFC of liver tumours were analysed.

RESULTS

In total, 3670 patients were treated with percutaneous, laparoscopic or open RFC. The mortality rate was 0.5 per cent. Complications occurred in 8.9 per cent: abdominal bleeding in 1.6 per cent, abdominal infection in 1.1 per cent, biliary tract damage in 1.0 per cent, liver failure in 0.8 per cent, pulmonary complications in 0.8 per cent, dispersive pad skin burn in 0.6 per cent, hepatic vascular damage in 0.6 per cent, visceral damage in 0.5 per cent, cardiac complications in 0.4 per cent, myoglobinaemia or myoglobinuria in 0.2 per cent, renal failure in 0.1 per cent, tumour seeding in 0.2 per cent, coagulopathy in 0.2 per cent, and hormonal complications in 0.1 per cent. The complication rate was 7.2, 9.5, 9.9 and 31.8 per cent after a percutaneous, laparoscopic, simple open and combined open approach respectively. The mortality rate was 0.5, 0, 0 and 4.5 per cent respectively.

CONCLUSION

The morbidity and mortality of RFC, while low, is higher than previously assumed. With adequate knowledge, many complications are preventable.

Minimally invasive image-guided therapies for hepatocellular carcinoma

Minimally invasive therapies are gaining increasing attention as an alternative to standard surgical therapies in the treatment of primary hepatocellular carcinoma. These include therapies administered transcatheterally (arterial embolization, intraarterial chemoinfusion, and combination chemoembolization) and percutaneously (chemical ablation with ethanol or acetic acid, and thermal ablation with radiofrequency, microwave, or laser energies). Benefits over surgical resection include the anticipated reduction in morbidity and mortality, low cost, suitability for real time image guidance, the ability to perform ablative procedures on outpatients, and the potential application in a wider spectrum of patients, including nonsurgical candidates. This review examines reported clinical success, potential complications, current limitations, and future directions of development of chemoembolization, ethanol and acetic acid instillation, and radiofrequency, microwave, and laser thermal ablation.

Satellite lesions in patients with small hepatocellular carcinoma with reference to clinicopathologic features

BACKGROUND

It is not rare to find satellite lesions in patients with small hepatocellular carcinoma (HCC). The purpose of this study was to elucidate the factors associated with satellite lesions in these patients.

METHODS

We investigated the prevalence of satellite lesions, the relationship of clinicopathologic factors to satellite lesions, and the distance from the main tumor to the satellite lesion in 149 patients. Patients, who had a solitary HCC of 3.0 cm or less in diameter but no satellite lesions on preoperative imaging procedures, underwent potentially curative resection. The main tumors were macroscopically classified into four groups: early HCC, a vaguely nodular type showing preservation of the preexisting liver structure; single nodular type; single nodular type with extranodular growth; and confluent multinodular type.

RESULTS

Of 149 resected specimens, 28 (19%) showed satellite lesions. Of the clinicopathologic factors investigated, the macroscopic type and tumor differentiation were significantly associated with the prevalence of satellite lesions. Both the single nodular type with extranodular growth and the confluent multinodular type showed satellite lesions more frequently than the early HCC and the single nodular type. A significantly higher prevalence of satellite lesions was observed in poorly differentiated HCC than in well and moderately differentiated HCC. The satellite lesions were located 0.5 cm or less from the main tumor in 8 (33%) specimens, 0.6-1.0 cm in 12 (50%), and 1.1-2.0 cm in 4 (17%). No identifiable factors were significantly related to the distance from the main tumor to the satellite lesion. However, all satellite lesions located more than 1.0 cm from the main tumor coexisted with poorly differentiated HCC, which were the single nodular type with extranodular growth or the confluent multinodular type.

CONCLUSION

In the single nodular type with extranodular growth, confluent multinodular type, and poorly differentiated HCC, extensive treatment achieving a large safety margin and/or frequent posttreatment follow-up examinations may be needed because of the high prevalence of satellite lesions.

Hepatocellular carcinoma: therapeutic experience with percutaneous ethanol injection under real-time contrast-enhanced color Doppler sonography with the contrast agent Levovist

OBJECTIVE

To describe our experience with percutaneous ethanol injection under real-time contrast-enhanced color Doppler sonography with Levovist (SH U 508A; Nihon Schering, Osaka, Japan) for hepatocellular carcinoma after transcatheter arterial infusion.

METHODS

Twenty patients (17 men and 3 women; mean age, 58.4 years) with 23 hepatocellular carcinoma nodules (mean +/- SD, 2.7 +/- 1.5 cm) underwent percutaneous ethanol injection under real-time contrast-enhanced color Doppler sonography 1 week after transcatheter arterial infusion. Therapeutic effects were assessed by contrast-enhanced computed tomography and posttreatment fine-needle biopsy. This study was performed on a prospective basis.

RESULTS

After the transcatheter arterial infusion, contrast-enhanced color Doppler sonography showed intense intratumoral color signals in all 23 hepatocellular carcinomas. After the percutaneous ethanol injection, contrast-enhanced color Doppler sonography, fine-needle biopsy, and contrast-enhanced computed tomography showed no color signals, no viable tumor tissues, and no enhancement in any of the 23 hepatocellular carcinomas. Three to 5 (mean, 3.3) percutaneous ethanol injection sessions with a 5.2- to 15.6-mL (mean, 12.8-mL) total volume of ethanol per tumor were required for complete disappearance of color signals on contrast-enhanced color Doppler sonography.

CONCLUSIONS

Percutaneous ethanol injection under real-time contrast-enhanced color Doppler sonography has considerable efficacy in treating hepatocellular carcinoma.

Thermal ablation therapy for hepatocellular carcinoma

Thermal ablation strategies, including the use of radiofrequency, microwaves, lasers, and high-intensity focused ultrasound, are gaining increasing attention as an alternative to standard surgical therapies in the treatment of primary hepatocellular carcinoma. Benefits over surgical resection include the anticipated reduction in morbidity and mortality, low cost, suitability for real-time imaging guidance, ability to perform ablative procedures on an outpatient basis, and the potential application in a wider spectrum of patients-including those who are not surgical candidates. In this review, the authors examine the reported clinical success of each of these four therapies, potential complications, current limitations, and future directions of development.

Locoregional therapies for hepatocellular carcinoma: a critical review from the surgeon's perspective

OBJECTIVE

This article reviews the current results of various locoregional therapies for hepatocellular carcinoma (HCC), with special reference to the implications for surgeons.

SUMMARY BACKGROUND DATA

Resection or transplantation is the treatment of choice for HCC, but most patients are not suitable candidates. The past decade has witnessed the development of a variety of locoregional therapies for HCC. Surgeons are faced with the challenge of adopting these therapies in the management of patients with resectable or unresectable HCC.

METHODS

A review of relevant English-language articles was undertaken based on a Medline search from January 1990 to August 2001.

RESULTS

Retrospective studies suggested that transarterial chemoembolization is an effective treatment for inoperable HCC, but its perceived benefit for survival has not been substantiated in randomized trials, presumably because its antitumor effect is offset by its adverse effect on liver function. Nonetheless, it remains a widely used palliative treatment for HCC not amenable to resection or ablative therapies, and it also plays an important role as a treatment of postresection recurrence and as a pretransplant therapy for transplantable HCC. Better patient selection, selective segmental chemoembolization, and treatment repetition tailored to tumor response and patient tolerance may improve its benefit-risk ratio. Transarterial radiotherapy is a less available alternative that produces results similar to those of chemoembolization. Percutaneous ethanol injection has gained wide acceptance as a safe and effective treatment for HCCs 3 cm or smaller. Uncertainty in tumor necrosis limits its potential as a curative treatment, but its repeatability allows treatment of recurrence after ablation or resection of HCC that is crucial to prolongation of survival. Cryotherapy affords a better chance of cure because of predictable necrosis even for HCCs larger than 3 cm, but its use is limited by a high complication rate. There has been recent enthusiasm for heat ablation by microwave, radiofrequency, or laser, which provides predictable necrosis with a low complication rate. Preliminary data indicated that radiofrequency ablation is superior to ethanol injection in the radicality of tumor ablation. The advent of more versatile radiofrequency probes has allowed ablation of HCCs larger than 5 cm. Recent studies have suggested that combined transarterial embolization and heat ablation is a promising strategy for large HCCs. Thus far, no randomized trials comparing various thermoablative therapies have been reported. It is also uncertain whether a percutaneous route, laparoscopy, or open surgery affords the best approach for these therapies. Thermoablative therapies have been combined with resection or used to treat postresection recurrence, and they have also been used as a pretransplant therapy. However, the value of such strategies requires further evaluation.

CONCLUSIONS

Advances in locoregional therapies have led to a major breakthrough in the management of unresectable HCC, but the exact role of the various modalities needs to be defined by randomized studies. Novel thermoablative techniques provide the surgeon with an exciting opportunity to participate actively in the management of unresectable HCC. Locoregional therapies are also useful adjuncts in the management of patients with resectable or transplantable disease. Hence, surgeons must be equipped with the latest knowledge and techniques of ablative therapy to provide the most appropriate treatment for the wide spectrum of patients with HCC.

Percutaneous tumor ablation with radiofrequency

BACKGROUND

Radiofrequency thermal ablation (RFA) is a new minimally invasive treatment for localized cancer. Minimally invasive surgical options require less resources, time, recovery, and cost, and often offer reduced morbidity and mortality, compared with more invasive methods. To be useful, image-guided, minimally invasive, local treatments will have to meet those expectations without sacrificing efficacy.

METHODS

Image-guided, local cancer treatment relies on the assumption that local disease control may improve survival. Recent developments in ablative techniques are being applied to patients with inoperable, small, or solitary liver tumors, recurrent metachronous hereditary renal cell carcinoma, and neoplasms in the bone, lung, breast, and adrenal gland.

RESULTS

Recent refinements in ablation technology enable large tumor volumes to be treated with image-guided needle placement, either percutaneously, laparoscopically, or with open surgery. Local disease control potentially could result in improved survival, or enhanced operability.

CONCLUSIONS

Consensus indications in oncology are ill-defined, despite widespread proliferation of the technology. A brief review is presented of the current status of image-guided tumor ablation therapy. More rigorous scientific review, long-term follow-up, and randomized prospective trials are needed to help define the role of RFA in oncology.

Small hepatocellular carcinoma: therapeutic effectiveness of percutaneous radio frequency ablation therapy with a LeVeen needle electrode

OBJECTIVE

To evaluate the therapeutic effectiveness of percutaneous radio frequency ablation of small (< or =3-cm) hepatocellular carcinoma with a LeVeen needle electrode.

METHODS

Thirty patients (mean age, 65.7 years) with 32 hepatocellular carcinomas (range, 1.2-3.0 cm; mean, 2.3+/-0.5 cm) underwent percutaneous radio frequency ablation to the center of the hepatocellular carcinoma after expansion of the inner needles. The manufacturer's recommended radio frequency ablation protocol was used. Posttreatment contrast-enhanced color Doppler sonography, contrast-enhanced computed tomography, and fine-needle biopsy were performed to assess the radio frequency ablation-induced coagulated necrosis.

RESULTS

Severe intratreatment pain made us abort radio frequency ablation in 2 patients. Complete tumor necrosis was achieved in 1 treatment session with 1 needle electrode insertion in 28 (93.4%) of 30 nodules (28 patients). We found no residual focus on both color Doppler sonography and computed tomography after any of the sessions. In follow-ups ranging from 3 to 15 months (mean, 8.4 months), no local recurrence was found in cases with complete tumor ablation.

CONCLUSIONS

Radio frequency ablation with the LeVeen needle electrode was effective, obtaining complete coagulated necrosis with a safety margin when used for the treatment of small hepatocellular carcinomas.

Rapid progression of hepatocellular carcinoma after transcatheter arterial chemoembolization and percutaneous radiofrequency ablation in the primary tumour region

We report one patient who showed rapid progression of hepatocellular carcinoma (HCC) after undergoing transcatheter arterial chemoembolization (TACE) and percutaneous radiofrequency ablation (PRFA) for a small HCC measuring 2.5 cm in diameter. Enhanced magnetic resonance imaging (MRI) following treatment showed complete tumour necrosis and did not reveal the presence of a tumour around the treated area. Furthermore, the serum alpha-fetoprotein (AFP) level decreased at the completion of therapy. However, the HCC advanced in a very short time. Numerous tumours around the treated area were observed on enhanced computed tomography (CT) 50 days after PRFA. It is strongly suspected that the tumour was disseminated through the portal system because of the presence pattern of tumours. We believe this to be the first case illustrating a hepatic cancer that progressed rapidly following TACE and PRFA.

Tumor ablation with radio-frequency energy

Tumor ablation by using radio-frequency energy has begun to receive increased attention as an effective minimally invasive approach for the treatment of patients with a variety of primary and secondary malignant neoplasms. To date, these techniques have been used to treat tumors located in the brain, musculoskeletal system, thyroid and parathyroid glands, pancreas, kidney, lung, and breast; however, liver tumor ablation has received the greatest attention and has been the subject of a large number of published reports. In this article, the authors review the technical developments and early laboratory results obtained with radio-frequency ablation techniques, describe some of the early clinical applications of these techniques, and conclude with a discussion of challenges and opportunities for the future.