Hepatocellular carcinoma treated with percutaneous radio-frequency ablation: evaluation with follow-up multiphase helical CT

Radiofrequency ablation: post-ablation assessment using CT perfusion with pharmacological modulation in a rat subcutaneous tumor model

RATIONALE AND OBJECTIVES

Inflammatory reaction surrounding the ablated area is a major confounding factor in the early detection of viable tumor after radiofrequency (RF) ablation. A difference in the responsiveness of normal and tumor blood vessels to vasoactive agents may be used to distinguish these regions in post-ablation follow-up. The goal of this study was to examine longitudinal perfusion changes in untreated viable tumor and the peripheral hyperemic rim of RF-ablated tumor in response to a vasoconstrictor (phenylephrine) or vasodilator (hydralazine) in a subcutaneous rat tumor model.

MATERIALS AND METHODS

Bilateral subcutaneous shoulder tumors were inoculated in 24 BDIX rats and evenly divided into two groups (phenylephrine and hydralazine groups). One tumor in each animal was completely treated with RF ablation (at 90 +/- 2 degrees C for 3 minutes), and the other remained untreated. Computed tomographic perfusion scans before and after phenylephrine (10 microg/kg) or hydralazine (5 mg/kg) administration were performed 2, 7, and 14 days after ablation. Four rats per group were euthanized on each scan day, and pathologic evaluation was performed. The changes of blood flow in the peripheral rim of ablated tumor and untreated viable tumor in response to phenylephrine or hydralazine at each time point were compared. The diagnostic accuracy of viable tumor using the percentage change of blood flow in response to phenylephrine and hydralazine was compared using receiver-operating characteristic analysis.

RESULTS

The peripheral rim of ablated tumor presented with a hyperemic reaction with dilated vessels and congestion on day 2 after ablation, numerous inflammatory vessels on day 7, and granulation tissue formation on day 14. Phenylephrine significantly decreased the blood flow in the peripheral hyperemic rim of ablated tumor on days 2, 7, and 14 by 16.3 +/- 9.7% (P = .001), 24.0 +/- 22.6% (P = .007), and 31.1 +/- 25.4% (P = .045), respectively. In untreated viable tumor, the change in blood flow after phenylephrine was irregular and insignificant. Hydralazine decreased the blood flow in the peripheral rim of both ablated tumor and untreated viable tumor. Receiver-operating characteristic analysis showed that reliable tumor diagnosis using the percentage change of blood flow in response to phenylephrine was noted on days 2 and 7, for which the areas under the curve were 0.82 (95% confidence interval, 0.64-1.00) and 0.81 (95% confidence interval, 0.56-1.00), respectively. However, tumor diagnosis using the blood flow change in response to hydralazine was unreliable.

CONCLUSION

Phenylephrine markedly decreased blood flow in the peripheral hyperemic rim of ablated tumor but had little effect on the untreated viable tumor. Computed tomographic perfusion with phenylephrine may be useful in the long-term treatment assessment of RF ablation.

Fatty hepatocellular carcinoma: radiofrequency ablation--imaging findings

PURPOSE

To describe the imaging features during follow-up after radiofrequency (RF) ablation of fat-containing hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

Institutional review board approval was obtained; informed consent was waived. A retrospective search in an electronic radiologic archive was performed for a 40-month period between February 2004 and May 2007 to identify patients who had undergone RF ablation of fat-containing HCCs. The presence of intratumoral fat was determined at imaging (magnetic resonance or computed tomography) prior to the RF procedure; eight fat-containing HCCs, which had a mean size of 25 mm (range, 20-30 mm), were found. Images during follow-up were reviewed and compared with images prior to RF ablation to determine changes in fat content, complete or partial ablation, and local tumor progression. Tumor response was on the basis of assessment of lesion characteristics and enhancement for a follow-up of at least 6 months.

RESULTS

Persistent fat content was found at imaging in all ablation zones. Six patients were considered to have completely ablated tumors (mean follow-up, 16 months; range, 6-29 months), and two patients had local progression (mean follow-up, 18 months; range, 14-22 months). In the ablation zone of completely ablated tumors, the fat content progressively decreased (n = 4) or was unchanged during follow-up (n = 2). In the two tumors with local progression, the fat portion enlarged (n = 1) or did not change after ablation (n = 1).

CONCLUSION

Persistence of fat in the ablation zone during imaging follow-up after RF ablation of fat-containing HCCs does not necessarily indicate treatment failure. Changes in fat content of the ablation zone during follow-up (increase or decrease in size) could be used as additional criteria to determine success or failure of RF ablation in fat-containing HCC.

Radiofrequency ablation of hepatic tumors: lessons learned from 3000 procedures

Radiofrequency ablation has been accepted as the most popular local ablative therapy for unresectable malignant hepatic tumors. For 9 years from April 1999, we performed 3000 radiofrequency ablation procedures for hepatic tumors in our institution. Our results on the safety (mortality, 0.15%/patient) and therapeutic efficacy (5-year survival rate, 58%) are similar to those of previous studies reported, supporting the growing evidence of a clear survival benefit, excellent results for local tumor control and improved quality of life. The most important lesson learned from our 3000 procedures is that the best planning, safe ablation and complete ablation are key factors for patient outcome. Furthermore, multimodality treatment is the best strategy for recurrent hepatocellular carcinoma encountered after any kind of first-line treatment.

Hepatocellular cancer response to radiofrequency tumor ablation: contrast-enhanced ultrasound

Radiofrequency ablation (RFA) is increasingly being used as percutaneous treatment of choice for patients with early stage hepatocellular carcinoma (HCC). An accurate assessment of the RFA therapeutic response is of crucial importance, considering that a complete tumor ablation significantly increases patient survival, whereas residual unablated tumor calls for additional treatment. Imaging modalities play a pivotal role in accomplishing this task, but ultrasound (US) is not considered a reliable modality for the evaluation of the real extent of necrosis, even when color/power Doppler techniques are used. Recently, newer microbubble-based US contrast agents used in combination with grey-scale US techniques, which are very sensitive to non-linear behavior of microbubbles, have been introduced. These features have opened new prospects in liver ultrasound and may have a great impact on daily practice, including cost-effective assessment of therapeutic response of percutaneous ablative therapies. Technical evolution of CEUS focusing on findings after RFA are illustrated. These latter are detailed, cross-referenced with the literature and discussed on the basis of our personal experience. Timing of CEUS posttreatment assessment among with advantages and limitations of CEUS are also described with a perspective on further technologic refinement.

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.

Treatment outcomes of hepatic and pulmonary metastases from colorectal carcinoma

BACKGROUND AND AIM

The resection of synchronous or metachronous pulmonary and liver metastasis is an aggressive treatment option for patients with stage IV colorectal cancer and has been shown to yield acceptable long-term survival. We reviewed our experience with colorectal cancer patients with both liver and lung resections to determine the efficacy of surgical resections.

METHODS

We performed a single institution, retrospective analysis of all patients who underwent surgical hepatic and pulmonary resection for metastatic colorectal cancer between 1995 and 2004.

RESULTS

A total of 32 patients underwent resection of both hepatic and pulmonary metastases secondary to colorectal cancer. The 5-year overall survival from initial operation was 60.8%. The disease-free interval was 44.3 months (95% confidence interval: 24.7 and 63.8, respectively). Neither the number of pulmonary lesions nor the time interval between the primary surgery and the metastasectomy had a significant impact on survival (P = 0.134).

CONCLUSION

An aggressive surgical treatment of selected colorectal cancer patients with lung and liver metastases resulted in prolonged survival. The 5-year survival rate of 60.8% with no perioperative mortality was observed in our study.

Hepatocellular carcinoma treated with radio frequency ablation: an early evaluation with magnetic resonance imaging

PURPOSE

To determine the usefulness of nonenhanced T1-weighted spoiled gradient-recalled acquisition in the steady-state (SPGR) MRI in the early assessment of the efficacy of radio frequency (RF) therapy for hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

A total of 23 patients with 28 HCC nodules treated with percutaneous RF ablation underwent nonenhanced MRI within two days after the RF procedure and contrast-enhanced computed tomography (CT) one week after. MR assessment of ablation efficacy according to the concentric zonal pattern on T1-weighted SPGR imaging was compared with the one-week CT and presence of local recurrence by means of follow-up study for 12 months or more.

RESULTS

In 18 of 28 ablated nodules, SPGR images revealed a central hyperintense zone covering the entire tumor, CT showed a nonenhanced area covering the entire tumor, and no local recurrence was demonstrated in the follow-up studies. In nine of 28 nodules, the central hyperintense zone did not cover the entire tumor; and local recurrence was demonstrated in three nodules. In the remaining one nodule, no signal change was seen in the treated area on SPGR images and CT showed the presence of residual viable tumor.

CONCLUSION

Nonenhanced T1-weighted MRI was considered useful for early assessment of the efficacy of RF therapy for HCC.

Radiofrequency ablation of hepatocellular carcinoma: value of virtual CT sonography with magnetic navigation

OBJECTIVE

Virtual CT sonography with magnetic navigation yields cross-sectional images of CT volume data that correspond to the angle of the transducer in the magnetic field in real time. The purpose of this study was to evaluate the efficiency and feasibility of virtual CT sonography for radiofrequency ablation of hypervascular hepatocellular carcinoma poorly defined on B-mode sonography.

MATERIALS AND METHODS

One hundred one patients enrolled in the study were separated into two groups. Fifty-one patients with 65 hepatocellular carcinomas underwent prospective virtual CT sonography as guidance for radiofrequency ablation. Fifty patients with 63 hepatocellular carcinomas managed with B-mode sonographic guidance were retrospectively selected under the same conditions as the virtual CT sonography group to act as a historical control group.

RESULTS

In the virtual CT sonography group, technically successful ablation was achieved in a single session in 92% (47/51) of the patients and in two sessions in 8% (4/51). In the B-mode sonography group, technical success was achieved in a single session in 72% (36/50) of the patients, in two sessions in 24% (12/50), and in three sessions in 4% (2/50). Treatment analysis showed that the technical success rate after a single treatment session was significantly (p = 0.017) higher for the virtual CT sonography group. The number of treatment sessions was significantly (p = 0.021) lower for the virtual CT sonography group (mean, 1.1 +/- 0.1 vs 1.3 +/- 0.3 sessions).

CONCLUSION

Virtual CT sonographically assisted radiofrequency ablation is an efficient treatment of patients with hepatocellular carcinoma that is poorly defined on B-mode sonography.

Effect of artificial ascites on thermal injury to the diaphragm and stomach in radiofrequency ablation of the liver: experimental study with a porcine model

OBJECTIVE

The purpose of this study was to evaluate the effect of artificial ascites on thermal injury to the diaphragm and stomach in a porcine model of radiofrequency ablation of the liver.

MATERIALS AND METHODS

We performed this study using eight pigs in experimental and control groups of four pigs each. Artificial ascites was produced before radiofrequency ablation to separate the liver from the diaphragm and the stomach in the experimental group. Using a 1-cm exposed internally cooled radiofrequency electrode for 5 minutes, we performed 74 hepatic ablations abutting the diaphragm and stomach. CT was performed on the day of the procedure and 7 days after ablation. The pigs were sacrificed, and necropsy was performed. We performed pathologic and CT examinations to compare the frequency and extent of thermal injury to the two organs.

RESULTS

The mean number of radiofrequency ablations in each pig was 9.3 (range, 6-12). The mean number of ablation zones adjoining the diaphragm was 5.5 (range, 3-8) and of zones contiguous with the stomach was 3.8 (range, 3-4). Thermal injury to the adjacent organs occurred more frequently in the control group than in the experimental group (p < 0.05). The major complications of diaphragmatic hernia and gastric perforation occurred only in the control group. No major complications were identified in the experimental group at necropsy. The sizes of the radiofrequency ablation zone of the liver did not differ between the two groups (p > 0.05). The mean diameters of the diaphragmatic and gastric lesions did differ (p < 0.05). Histopathologic examination revealed a significant difference in the depths of thermal injury in the two groups (p < 0.05).

CONCLUSION

Artificial ascites may be a simple and useful technique for reducing the frequency and severity of collateral thermal injury to the diaphragm and stomach during radiofrequency ablation of subcapsular hepatic tumors.

Spectrum of CT findings after radiofrequency ablation of hepatic tumors

Image-guided radiofrequency (RF) ablation has been used to treat both resectable and nonresectable hepatic tumors. A precise imaging assessment of the therapeutic response and of any complications is mandatory after ablation. Contrast material-enhanced ultrasonography, computed tomography (CT), and magnetic resonance imaging all may be useful for this assessment. At most institutions, a three-phase contrast-enhanced CT examination is performed immediately or within 1 month after RF ablation to assess the technical success of treatment. If ablation was technically successful, three-phase CT may be repeated at 3-month intervals for evaluation of tumor recurrence. The typical CT finding in the zone subjected to RF ablation is an area of low attenuation that encompasses the tumor and an ablative margin. However, the appearance of the ablative zone may vary greatly, depending on the success of treatment and the time elapsed after the procedure. Ringlike enhancement representing benign reactive hyperemia around the ablation zone, central high-attenuation areas representing greater cellular disruption, and tiny air bubbles frequently are seen at immediate follow-up CT but usually have disappeared by the first or second follow-up examination. The successfully ablated zone gradually involutes. The appearance of the zone differs when residual tumor tissue or local tumor progression is present. Immediate or delayed complications also may be seen at follow-up CT. Radiologists must be familiar with both typical and atypical CT findings and their clinical significance. (c) RSNA, 2008.

Laparoscopic radiofrequency of hepatocellular carcinoma using ultrasound-guided selective intrahepatic vascular occlusion

BACKGROUND

The optimal treatment for hepatocellular carcinoma (HCC) is surgical resection. However, only a small percentage of patients are operative candidates. The authors aimed to assess a novel operative combination of laparoscopic radiofrequency (LRF) with a selective intrahepatic vascular occlusion (SIHVO) to obtain an increased rate of total necrosis and a reduced rate of local HCC recurrences.

METHODS

For this study, 37 patients with HCC in liver cirrhosis were submitted to LRF with SIHVO. An LRF was indicated for patients not amenable to liver resection who evidenced at least one of the following criteria: severe impairment of the coagulation tests, large tumors (but <5 cm) or multiple lesions requiring repeated punctures, superficial lesions adjacent to visceral structures, deep-sited lesions with a very difficult or impossible percutaneous approach, and short-term recurrence of HCC after percutaneous loco-regional therapies.

RESULTS

Laparoscopic ultrasound identified seven new malignant lesions (19%) undetected by preoperative imaging. There was no operative mortality. Of the 37 patients, 31 experienced no complications (84%). Computed tomography (CT) evaluation 1 month after treatment showed that a complete response with 100% necrosis had been achieved for all the patients (100%). During the follow-up period (mean, 11.8 +/- 8.2 months), new malignant nodules developed in 14 patients (42%), and 36% of these recurrences were located in the same treated segment of the HCC.

CONCLUSIONS

The combined LRF and SIHVO procedure proved to be a safe and effective technique at least in the short and mid term. In fact, it permitted the treatment of lesions not treatable using the percutaneous approach with a complete clearance, and it had a low morbidity rate.

Percutaneous radiofrequency ablation of sonographically unidentifiable liver tumors. Feasibility and usefulness of a novel guiding technique with an integrated system of computed tomography and sonographic images

OBJECTIVE

The purpose of this study was to evaluate the safety and feasibility of a real-time integrated system with computed tomography (CT) and sonographic images for radiofrequency (RF) ablation of hepatic malignancies poorly defined on B-mode sonography, and to clarify the suitable phase of CT images for using this virtual sonography.

METHODS

Between September 2004 and December 2004, 12 patients with 16 hepatocellular carcinomas and two metastatic lesions arising from colorectal adenocarcinoma (n = 1) and rectal carcinoid (n = 1) were treated. The maximum diameter of nodules ranged from 1.0 to 2.5 cm (mean +/- SD; 1.5 +/- 0.6 cm) on CT images.

RESULTS

Complete tumor necrosis was achieved in a single session in 19 lesions (90%), while a second session was required for the remaining two lesions (10%). Portal phase multi-planar reconstruction images were displayed under a suitable position corresponding to the ultrasound images in 9 patients (HCC = 7, metastasis = 2), and arterial phase multi-planar reconstruction images were displayed in the 3 remaining patients with hepatocellular carcinoma.

CONCLUSION

Percutaneous RF ablation guidance using virtual sonography is an effective treatment for patients with hepatic malignancies. The portal phase of CT images may be the most suitable to indicate the 3-dimensional relationship between the liver vasculature and tumors on virtual sonography.

Comparison of contrast enhanced ultrasound and contrast enhanced CT or MRI in monitoring percutaneous thermal ablation procedure in patients with hepatocellular carcinoma: a multi-center study in China

To evaluate the ability of contrast enhanced ultrasound (CEUS) in monitoring percutaneous thermal ablation procedure in patients with hepatocellular carcinoma (HCC) in comparison with contrast enhanced computed tomography (CECT) and/or magnetic resonance imaging (CEMRI). A total of 151 patients were enrolled in the study. Before the radio-frequency (RF) or microwave ablation treatment, tumor vascularity was assessed in 139 patients with three imaging modalities i.e., US (139 exams), CEUS (139 exams) and CECT (103 exams)/CEMR (36 exams). CEUS examination was performed using a sulphur hexafluoride-filled microbubble contrast agent (SonoVue((R)), Bracco, Milan, Italy) and real-time contrast-specific imaging techniques. Within 30 +/- 7 d after the ablation procedure, 118/139 patients were monitored to assess the tumor response to treatment. Before ablation, contrast enhancement within tumor was observed in 129/139 (92.8%) patients with CEUS and 133/139 (95.7%) patients with CECT/CEMRI. Compared with CECT/CEMRI, CEUS sensitivity and accuracy in detecting tumor vascularity were 97.0% and 94.2%, respectively. One month after treatment, no enhancement was seen in 110/118 (93.2%) both on CEUS and CECT/CEMRI. Concordance between CEUS and CECT/CEMR on the presence of residual vascularization was obtained in four patients (true positive). The specificity and accuracy of CEUS in detecting tumor vascularity were 98.2% and 96.6%, respectively. The periprocedural impact of SonoVue administration on the assessment of treatment extent was also evaluated in a subgroup of patients and CEUS showed its superiority compared with baseline US in defining treatment outcome. In conclusion, in the detection of HCC tumor vascularity and assessment of response to thermal ablation after 1 month, real time CEUS provided results comparable to those obtained with CECT/CEMRI. CEUS examination proved to be a safe and easy to access procedure, with potential for diagnostic impact in the clinical practice.

The use of contrast-enhanced ultrasonography in the selection of patients with hepatocellular carcinoma for radio frequency ablation therapy

OBJECTIVE

The purpose of this study was to evaluate the use of contrast-enhanced ultrasonography (CEUS) in selecting patients with hepatocellular carcinoma (HCC) for radio frequency ablation (RFA).

METHODS

One hundred seventy-nine patients with HCC were divided into 2 groups before receiving RFA: a CEUS group and a control group. The patients were concatenated and alternately apportioned into these 2 groups. In the CEUS group, 92 patients underwent pre-RFA CEUS using the contrast agent sulfur hexafluoride and enhanced computed tomography or magnetic resonance imaging before RFA for selecting suitable cases for RFA, and in the control group, conventional ultrasonography and enhanced computed tomography or magnetic resonance imaging were performed in 87 patients for selecting patients.

RESULTS

In the CEUS group, 9 patients (9.8%) were excluded for RFA therapy by CEUS. The other 83 patients (90.2%), with a total of 114 lesions, were treated by RFA. In the control group, 5 patients (5.7%) were excluded for RFA. The other 82 patients (94.3%), with a total of 107 lesions, were treated by RFA. During the follow-up period of 18 to 50 months, the primary technique effectiveness rates in the CEUS and control groups were 94.7% and 87.9%, respectively (P = .1182). The local tumor progression rate, the new HCC rate, and the repeated RFA rate of the CEUS group were significantly lower than those of the control group (P = .033, .004, and .001, respectively).

CONCLUSIONS

Pre-RFA CEUS provides important information for selecting suitable patients for RFA. The use of CEUS in selecting patients with HCC can decrease post-RFA local tumor progression and improve the efficacy of RFA therapy.

Recurrence of Hepatocellular Carcinoma After Liver Transplantation: Patterns and Prognostic Factors Based on Clinical and Radiologic Features

OBJECTIVE

The purpose of this study was to elucidate on the basis of clinicoradiologic features the patterns of and prognostic factors for recurrence of hepatocellular carcinoma after liver transplantation.

MATERIALS AND METHODS

Institutional review board approval and informed consent were waived for this retrospective study. The subjects were 119 patients (102 men, 17 women; mean age, 49.8 years) with unresectable hepatocellular carcinoma who underwent liver transplantation from September 1996 to May 2005 and survived more than 2 months. We evaluated the incidence, imaging features, cumulative disease-free survival rate, and prognosis for recurrence of hepatocellular carcinoma. We examined clinical, therapeutic, and pretransplantation contrast-enhanced CT findings as prognostic factors and analyzed them with multivariate analysis. The median follow-up period was 17.2 months (range, 2.0-102.4 months).

RESULTS

Recurrence was found in 16 (13.4%) of 119 patients and was most frequent in the liver, with no specific pattern. A multivariate stepwise Cox hazard model showed that the presence of portal venous thrombosis, more than 3-cm diameter of the largest tumor, and a viable tumor volume ratio greater than 10% were statistically independent prognostic factors. The 3- and 5-year cumulative disease-free survival rates for the entire cohort were 82.1% and 76.6%, respectively. Despite local therapy for a solitary metastatic lesion, recurrences were common. The mortality rate among patients with recurrent disease was 56.3%.

CONCLUSION

Recurrence of hepatocellular carcinoma after liver transplantation is common, and the prognosis is not favorable. The presence of portal venous thrombosis and tumor size greater than 3 cm on baseline CT are significant risk factors. Aggressive interventional therapy seems to be helpful as a bridge to liver transplantation.

Combined hepatectomy and radiofrequency ablation for multifocal hepatocellular carcinomas: long-term follow-up results and prognostic factors

BACKGROUND

For multifocal hepatocellular carcinomas (HCCs) that are untreatable with resection only, locoregional therapies added to hepatectomy have been introduced. However, some preliminary reports have documented average survival results and relatively high complication rates. We evaluated the long-term survival results and safety of combined hepatectomy and radiofrequency ablation (RFA) in patients with HCCs and assessed the prognostic factors affecting their survival.

METHODS

A total of 53 patients who had 148 HCCs in their livers underwent hepatectomy combined with ultrasound-guided intraoperative RFA. The mean diameter of the 82 resected tumors was 4.8 cm (range 1.3-21.0 cm) and that of 66 ablated tumors was 1.5 cm (range 0.8-3.5 cm). We evaluated the primary effectiveness rates, survival rates, and complications. In addition, we assessed the prognostic factors associated with the survival rates using Cox proportional hazard models.

RESULTS

The primary effectiveness rate of RFA was 98% (65 of 66). Local tumor progression was observed in two (3%) ablation zones of 65 tumors with complete primary effectiveness. The cumulative survival rates at 1, 2, 3, 4, and 5 years were 87, 83, 80, 68, and 55%, respectively. Patients with smaller resected tumors (< or = 5 cm) demonstrated better survival results (P = 0.004). No procedure-related deaths occurred. We observed hepatectomy-related complications in 4 patients (8%, 4 of 53) and an RFA-related complication in 1 patient (2%, 1 of 53).

CONCLUSIONS

Combined hepatectomy and RFA is an effective and safe treatment modality for multifocal HCCs. Resected tumor size was a significant prognostic predictor of long-term survival.

Radiofrequency ablation of recurrent hepatocellular carcinoma after hepatectomy: therapeutic efficacy on early- and late-phase recurrence

OBJECTIVE

Our objective was to assess the efficacy and safety of radiofrequency ablation of recurrent hepatocellular carcinoma (HCC) after hepatectomy and to compare the effects on early- and late-phase recurrence.

SUBJECTS AND METHODS

We studied 41 patients with 76 recurrent HCC tumors (diameter range, 2.0-6.6 cm; mean, 3.8 +/- 1.3 [SD] cm) after hepatectomy who underwent sonography-guided percutaneous radiofrequency ablation in our hospital (recurrent-HCC group). The interval between surgery and recurrence ranged from 1 to 96 months (mean, 24.5 months). These patients were divided into an early-recurrence group (20 patients with 41 recurrent HCC tumors) and a late-recurrence group (21 patients with 35 recurrent HCC tumors). Early recurrence was defined as that occurring within 1 year after surgery, and late recurrence was defined as that occurring after 1 year. Another 116 patients with 172 primary HCC tumors (diameter range, 1.2-7.0 cm; mean, 3.9 +/- 1.1 cm) treated by radiofrequency ablation were regarded as a control group. No other therapies were given before radiofrequency ablation in any group. Regular follow-up with enhanced CT was performed to evaluate the treatment results. Ablation was considered successful if no contrast enhancement was detected in the treated area on 1-month CT scans. Indexes including ablation success rate, local recurrence rate, distant recurrence rate, and survival were obtained for analysis and comparison.

RESULTS

The ablation success rate, local recurrence rate, distant recurrence rate, and mean overall survival time of the recurrent-HCC group were 93.4% (71/76 tumors), 9.2% (7/76 tumors), 36.6% (15/41 patients), and 30.9 +/- 3.7 months, respectively. The incidence of distant recurrence in the early-recurrence group was significantly higher than that in the late-recurrence group (55.0% vs 19.0%, p = 0.017). The early-recurrence group had a shorter overall survival than did the late-recurrence group (mean overall survival, 16.4 +/- 2.4 vs 42.9 +/- 4.4 months, p < 0.001) or the control group (16.4 +/- 2.4 vs 45.9 +/- 2.5 months, p < 0.001). The survival time of the late-recurrence group was similar to that of the control group (42.9 +/- 4.4 vs 45.9 +/- 2.5 months, p > 0.05). Serious hemorrhage after radiofrequency ablation occurred in one patient in the late-recurrence group and was controlled with conservative treatment.

CONCLUSION

Radiofrequency ablation is generally effective and safe in treating recurrent HCC after hepatectomy and is more effective in late recurrence than in early recurrence.

Percutaneous radiofrequency ablation of hepatocellular carcinoma: effect of histologic grade on therapeutic results

OBJECTIVE

The purpose of our study was to assess the therapeutic results of radiofrequency ablation of hepatocellular carcinoma (HCC) based on the histologic grades of the tumors.

SUBJECTS AND METHODS

Between April 1999 and December 2003, 95 patients with nodular HCC were treated with percutaneous radiofrequency ablation. All tumors were histologically proven by sonography-guided percutaneous biopsy and were classified as Edmondson-Steiner grade I HCC (n = 38) (mean, 2.3 cm) (group 1), grade II HCC (n = 50) (mean, 2.4 cm) (group 2), or grade III HCC (n = 7) (mean, 2.8 cm) (group 3). All patients underwent contrast-enhanced three-phase helical CT examination before and after radiofrequency ablation. After retrospective review of the medical records and follow-up CT examinations, the rates of technique effectiveness, local tumor progression, cumulative survival, and cancer-free survival using a Kaplan-Meier method were calculated and compared among the groups.

RESULTS

Technique effectiveness rates in groups 1, 2, and 3 were 87% (27/31), 71% (30/42), and 43% (3/7), respectively, with statistical significance (p = 0.032). Local tumor progression rates in groups 1, 2, and 3 were 16% (5/31), 36% (15/42), and 71% (5/7), respectively, with statistical significance (p = 0.013). Five-year cumulative survival rates in groups 1, 2, and 3 were 71%, 44%, and 43%, respectively, with no statistical significance (p > 0.05). Four-year cancer-free survival rates in groups 1, 2, and 3 were 39%, 10%, and 0%, respectively (p < 0.05 for groups 1 vs 2; p > 0.05 for groups 1 vs 3 and groups 2 vs 3).

CONCLUSION

The histologic grade of HCC is an important factor influencing therapeutic results with survival after radiofrequency ablation.

Percutaneous Radiofrequency Ablation for Recurrent Hepatocellular Carcinoma After Hepatectomy: Long-term Results and Prognostic Factors

BACKGROUND

We evaluated the long-term survival results and safety of percutaneous radiofrequency ablation (RFA) for recurrent hepatocellular carcinoma (HCC) after hepatectomy, and assessed the prognostic factors that can influence its long-term therapeutic results.

METHODS

One hundred and two patients, who had 119 recurrent HCC in their livers, underwent ultrasound-guided percutaneous RFA. All the patients had a history of hepatic resection as a first-line treatment modality for HCC. The mean diameter of the recurrent tumors was 2.0 cm (range, 0.8-5.0 cm). We evaluated the effectiveness rates, local tumor progression rates, survival rates, and complications. We also assessed the prognostic factors of the survival rates by using Cox proportional hazard models.

RESULTS

The primary effectiveness rate was 93.3% (111 of 119). The cumulative rates of local tumor progression at 1, 3, and 5 years were 6.0, 8.6, and 11.9%, respectively. The cumulative survival rates at 1, 2, 3, 4, and 5 years were 93.9, 83.7, 65.7, 56.6, and 51.6%, respectively. Patients with a lower serum alpha-fetoprotein (AFP) level (<or=100 microg/L) before RFA or with small resected tumors (<or=5 cm) demonstrated better survival results (P < .05). There was only one major complication (liver abscess, 1.0% per treatment) during the follow-up period. There were no procedure-related deaths.

CONCLUSIONS

Percutaneous RFA is an effective and safe treatment modality for intrahepatic recurrent HCC after hepatectomy. Serum AFP level before RFA and resected tumor size were significant prognostic predictors of long-term survival.

Multidetector-row computed tomography of focal liver lesions treated by radiofrequency ablation: spectrum of findings at long-term follow-up

OBJECTIVE

To assess serial changes in liver tumors after percutaneous radiofrequency ablation at follow-up multidetector-row computed tomography.

MATERIALS AND METHODS

Forty patients with 65 malignant lesions underwent multidetector-row computed tomography immediately, 1 month and every 3 months, up to a maximum of 15 months after radiofrequency ablation. The computed tomography (CT) appearance of the treated lesions (non-enhanced attenuation, enhancement pattern, shape and size) was assessed at each follow-up. The relationship between each CT finding and the treatment outcome was evaluated by chi2 test (P < 0.05).

RESULTS

No significant differences were found in lesion shape and in non-enhanced CT attenuation between successfully and unsuccessfully treated lesions, whereas over time change of lesion size was significantly different. The no enhancement and nodular enhancement pattern prevalence was significantly (P < 0.0001) different between successfully and unsuccessfully treated lesions, whereas non-nodular enhancement pattern did not show any relationship with the treatment outcome.

CONCLUSIONS

Lesion size increase and nodular enhancement pattern resulted significantly related to the treatment failure.

Therapeutic response assessment of high intensity focused ultrasound therapy for uterine fibroid: utility of contrast-enhanced ultrasonography

PURPOSE

To assess the utility of contrast-enhanced ultrasonography (ceUS) in the assessment of the therapeutic response to high intensity focused ultrasound (HIFU) ablation in patients with uterine fibroid.

MATERIALS AND METHODS

Sixty-four patients with a total of 64 uterine fibroids (mean: 5.3+/-1.2 cm; range: 3.2-8.9 cm) treated with HIFU ablation under the ultrasound guidance were evaluated with ceUS after receiving an intravenous bolus injection of a microbubble contrast agent (SonoVue) within 1 week after intervention. We obtained serial ceUS images during the time period from beginning to 5 min after the initiation of the bolus contrast injection. All of the patients underwent a contrast enhanced MRI (ceMRI) and ultrasound guided needle puncture biopsy within 1 week after HIFU ablation. And as a follow-up, all of the patients underwent US at 1, 3, 6 and 12 months after HIFU treatment. The volume change was observed and compared to pre- and post-HIFU ablation. The results of the ceUS were compared with those of the ceMRI in terms of the presence or absence of residual unablated tumor and pathologic change in the treated lesions.

RESULTS

On ceUS, diagnostic accuracy was 100%, while residual unablated tumors were found in three uterine fibroids (4.7%) and failed treatment was found in eight uterine fibroids (12.5%). All the 11 fibroids were subjected to additional HIFU ablation. Of the 58 ablated fibroids without residual tumors on both the ceUS and ceMRI after the HIFU ablation, the volumes of all the fibroids decreased in different degrees during the 1 year follow-up USs. And histologic examinations confirmed findings of necrotic and viable tumor tissue, respectively.

CONCLUSION

CEUS is potentially useful for evaluating the early therapeutic effect of percutaneous HIFU ablation for uterine fibroids.

MR-guided radiofrequency ablation in a 0.2-T open MR system: Technical success and technique effectiveness in 100 liver tumors

PURPOSE

To evaluate the feasibility and technique effectiveness of magnetic resonance (MR)-guided radiofrequency (RF) ablation of hepatic malignancies.

MATERIALS AND METHODS

In 64 patients, 100 primary (N = 19) or secondary (N = 81) liver tumors (mean diameter = 24.7 mm; range = 4-60 mm) were treated with 87 sessions of MR-guided RF ablation. The entire ablation procedure was carried out at an 0.2-T open MR system by using MR-compatible internally cooled electrodes. T2-weighted turbo spin echo sequences (TR/TE = 3500 msec/110 msec) were used to monitor thermally induced coagulation. Technique effectiveness was assessed four months after the last RF ablation by dynamic MR imaging at 1.5-T.

RESULTS

MR-guided RF ablation procedures were technical successful in 85 of 87 (97.7%) assessed at the end of each session. Complete coagulation was intended in 99 of 100 tumors. Technique effectiveness was observed in 92 of 99 (92.9%) of these tumors. To achieve complete coagulation 82 of 92 (89.1%) tumors required a single session. T2-weighted sequences were accurate to monitor the extent of coagulation and were supportive to guide overlapping ablation. There were two of 87 (2.3%) major and seven of 87 (8.0%) minor complications.

CONCLUSION

MR-guided RF ablation is a safe and effective therapy in the treatment of hepatic malignancies. MR imaging offers an accurate monitoring of thermally-induced coagulation, thus enabling complete tumor coagulation in a single session.

Hemobilia after radiofrequency ablation of hepatocellular carcinoma

OBJECTIVE

The purpose of this study was to report on the clinical course and imaging findings of hemobilia after radiofrequency (RF) ablation in four patients with hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

From July 2000 to December 2005, we experienced four cases of hemobilia after 1574 sessions of ultrasonography (US)-guided RF ablation in 1037 patients with HCCs. All ablation procedures were percutaneously performed with an internally cooled RF electrode system. The diagnosis of hemobilia was made if the patient complained of melena after RF ablation and biliary dilatation with high attenuating bile was noted at CT obtained immediately after RF ablation. We evaluated the clinical course and imaging findings of hemobilia caused by RF ablation.

RESULTS

All patient well tolerated RF ablation procedures without any incident during the procedure. Three of four patients complained of melena with an interval from 1 day to 4 days after RF ablation. One patient was asymptomatic. The melena symptom in all symptomatic patients spontaneously improved in 2 days. None of the patients showed substantial change in vital sign and the level of hemoglobin during the admission period. In all four patients, biliary (including GB) dilatation with high attenuating bile was noted at immediate follow-up CT. The CT findings in all four patients disappeared at 1 month follow-up CT.

CONCLUSION

Hemobilia is a rare potential complication of RF ablation with a favorable prognosis. Clinicians who use this technique should be aware of the characteristic CT findings and clinical course of hemobilia after RF ablation for liver tumors.

Percutaneous radiofrequency ablation for early-stage hepatocellular carcinoma as a first-line treatment: long-term results and prognostic factors in a large single-institution series

The purpose of this study was to evaluate the long-term survival results and complications of percutaneous radiofrequency ablation (RFA) in patients with early-stage hepatocellular carcinoma (HCC). Between April 1999 and May 2005, 570 patients with 674 early-stage HCCs underwent percutaneous RFA as a first-line treatment option in a single institution. We evaluated the effectiveness rates, local tumor progression rates, survival rates, and complications. We also assessed the prognostic values of survival rates by using Cox proportional hazard models. The primary technique effectiveness rate was 96.7% (652 of 674). The cumulative rates of local tumor progression at 1, 2, and 3 years were 8.1%, 10.9%, and 11.8%, respectively. The cumulative survival rates at 1, 2, 3, 4, and 5 years were 95.2%, 82.9%, 69.5%, 60.8%, and 58.0%, respectively. Patients with Child-Pugh class A cirrhosis, of younger age (<or=58 years), or having lower AFP level (<or=100 microg/L) demonstrated better survival results (P < 0.05). A total of 11 major complications (1.9% per treatment) were found during the follow-up period. There was no procedure-related death. Percutaneous RFA can be used successfully as a first-line treatment modality for early-stage HCCs. Child-Pugh class, age, and AFP level before RFA were significant prognostic predictors of long-term survival.

Imaging features of hepatocellular carcinoma after transcatheter arterial chemoembolization and radiofrequency ablation

OBJECTIVE

The purpose of this pictorial essay is to show the imaging features of hepatocellular carcinoma (HCC) after transcatheter arterial chemoembolization (TACE) and radiofrequency thermal ablation on CT, MRI, and contrast-enhanced sonography and to describe the advantages and limitations of each imaging technique in evaluating the therapeutic effect on HCC.

CONCLUSION

CT is the standard imaging technique for monitoring the effectiveness of TACE and radiofrequency ablation. Contrast-enhanced sonography and MRI can complement CT in evaluating the therapeutic response.

Radiofrequency ablation of rabbit liver in vivo: effect of the pringle maneuver on pathologic changes in liver surrounding the ablation zone

Objective

We wished to evaluate the effect of the Pringle maneuver (occlusion of both the hepatic artery and portal vein) on the pathologic changes in the hepatic vessels, bile ducts and liver parenchyma surrounding the ablation zone in rabbit livers.

Materials and Methods

Radiofrequency (RF) ablation zones were created in the livers of 24 rabbits in vivo by using a 50-W, 480-kHz monopolar RF generator and a 15-gauge expandable electrode with four sharp prongs for 7 mins. The tips of the electrodes were placed in the liver parenchyma near the porta hepatis with the distal 1 cm of their prongs deployed. Radiofrequency ablation was performed in the groups with (n=12 rabbits) and without (n=12 rabbits) the Pringle maneuver. Three animals of each group were sacrificed immediately, three days (the acute phase), seven days (the early subacute phase) and two weeks (the late subacute phase) after RF ablation. The ablation zones were excised and serial pathologic changes in the hepatic vessels, bile ducts and liver parenchyma surrounding the ablation zone were evaluated.

Results

With the Pringle maneuver, portal vein thrombosis was found in three cases (in the immediate [n=2] and acute phase [n=1]), bile duct dilatation adjacent to the ablation zone was found in one case (in the late subacute phase [n=1]), infarction adjacent to the ablation zone was found in three cases (in the early subacute [n=2] and late subacute [n=1] phases). None of the above changes was found in the livers ablated without the Pringle maneuver. On the microscopic findings, centrilobular congestion, sinusoidal congestion, sinusoidal platelet and neutrophilic adhesion, and hepatocyte vacuolar and ballooning changes in liver ablated with Pringle maneuver showed more significant changes than in those livers ablated without the Pringle maneuver (p < 0.05)

Conclusion

Radiofrequency ablation with the Pringle maneuver created more severe pathologic changes in the portal vein, bile ducts and liver parenchyma surrounding the ablation zone compared with RF ablation without the Pringle maneuver. Therefore, we suggest that RF ablation with the Pringle maneuver should be performed with great caution in order to avoid unwanted thermal injury.

Treatment of small hepatocellular carcinoma: a comparison of techniques and long-term results

OBJECTIVE

The aim of this study was to compare the results over time of transcatheter arterial chemoembolization (TACE), percutaneous ethanol injection (PEI), laser thermal ablation (LTA) and combined therapy in the treatment of small hepatocellular carcinoma.

METHODS

Between 1998 and 2004, 131 cirrhosis patients (99 Child-Pugh class A, 32 Child-Pugh class B) with a small hepatocellular carcinoma were included in the study; 34 were treated with PEI, 46 with LTA, 18 with TACE and 33 with combined therapy.

RESULTS

No major complication occurred during any procedure. Computed tomography scan showed that complete necrosis was achieved in 81% of treated nodules (120 out of 148); as a whole, the disease relapsed in 42 (32.0%) patients (with a disease-free interval of 17.0+/-13.7 months). The cumulative survival rates were 81.9, 35.7 and 20.8% at 12, 36 and 60 months respectively. A univariate analysis of survival showed statistically significant differences in the comparison between Child-Pugh class A with respect to Child-Pugh class B (P<0.0001) and between nodules with a diameter of 20 mm or less as opposed to larger than 20 mm (P=0.001). Patients subjected to LTA showed a statistically significant longer survival than those treated with TACE and PEI.

CONCLUSIONS

LTA proves to be the most effective treatment, affording reduced invasiveness, a limited number of sessions, complete necrosis in almost all cases and better total survival in the treated patients.

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.

Therapeutic response assessment of percutaneous radiofrequency ablation for hepatocellular carcinoma: utility of contrast-enhanced agent detection imaging

PURPOSE

To assess the utility of contrast-enhanced agent detection imaging (ADI) in the assessment of the therapeutic response to percutaneous radiofrequency (RF) ablation in patients with hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

Ninety patients with a total of 97 nodular HCCs (mean, 2.1+/-1.3 cm; range, 1.0-5.0 cm) treated with percutaneous RF ablation under the ultrasound guidance were evaluated with contrast-enhanced ADI after receiving an intravenous bolus injection of a microbubble contrast agent (SH U 508A). We obtained serial contrast-enhanced ADI images during the time period from 15 to 90 s after the initiation of the bolus contrast injection. All of the patients underwent a follow-up four-phase helical CT at 1 month after RF ablation, which was then repeated at 2-4 month intervals during a period of at least 12 months. The results of the contrast-enhanced ADI were compared with those of the follow-up CT in terms of the presence or absence of residual unablated tumor and local tumor progression in the treated lesions.

RESULTS

On contrast-enhanced ADI, technical success was obtained in 94 (97%) of the 97 HCCs, while residual unablated tumors were found in three HCCs (3%). Two of the three tumors that were suspicious (was not proven) for incomplete ablation were subjected to additional RF ablation. The remaining one enhancing lesion that was suspicious of a residual tumor on contrast-enhanced ADI was revealed to be reactive hyperemia at the 1-month follow-up CT. Therefore; the diagnostic concordance between the contrast-enhanced ADI and 1-month follow-up CT was 99%. Of the 94 ablated HCCs without residual tumors on both the contrast-enhanced ADI and 1-month follow-up CT after the initial RF ablation, five (5%) had CT findings of local tumor progression at a subsequent follow-up CT.

CONCLUSION

Despite its limitations in predicting local tumor progression in the treated tumors, contrast-enhanced ADI is potentially useful for evaluating the early therapeutic effect of percutaneous RF ablation for HCCs.

Colorectal cancer: the role of PET/CT in recurrence

Many imaging modalities and scanning techniques, such as contrast enhanced CT, MRI and FDG-PET, are available for assessment of recurrent colorectal carcinoma. In addition, integrated PET/CT is becoming increasingly available. Intuitively, a synergistic combination of scanning characteristics sounds promising. However, the exact clinical value has not yet been fully established. The role of PET/CT image fusion must be weighed carefully against other available modalities. In this review we evaluate the potential of combined PET/CT in recurrent colorectal carcinoma. When available, PET/CT currently appears the diagnostic tool of choice. In the near future, combined PET/MRI may further enhance the diagnostic algorithm.

Pre-, peri-, and posttreatment imaging of liver lesions

This article provides an overview of current treatment approaches in patients with primary or secondary liver diseases. Emphasis is placed on MR imaging prior, during, and after various treatments, including liver resection, systemic chemotherapy, transcatheter arterial chemoembolization, ablative therapies, and liver transplantation. Findings described for MR imaging are directly applicable to findings for CT and potentially contrast-enhanced ultrasound. The authors' description, however, will deal mainly with MR imaging as this is the their preferred approach due to diagnostic accuracy and patient safety, and the findings are most demonstrative on MR imaging.

The combined effect of radiofrequency and ethanol ablation in the management of large hepatocellular carcinoma

Only a small percentage of patients with large hepatocellular carcinoma (HCC) may benefit out of surgical resection. Thus, most of these patients are in need of a form of local control, such as ethanol ablation, transarterial chemoembolization (TACE), radiofrequency thermal ablation (RF), or laser induced thermotherapy (LITT). The purpose of this study was to assess the short-term effect of sequential RF and ethanol ablation in the management of large HCC (>5 cm). Our series included 40 patients with large HCC tumors (>5 cm in diameter). We adopted a protocol of overlapping RF applications, followed by repeated ethanol ablation sessions. Our results showed that the volume of tumor coagulative necrosis initially induced by RF has significantly risen after adjuvant ethanol ablation sessions (P < 0.001). Patients who achieved complete tumor necrosis after RF ablation were 52.5% of the series. This percent has jumped to 80% of the series at the end of the protocol. This indicates that such combined protocol is more effective than RF alone. Besides, it is valuable in reducing the number of RF sessions.

Percutaneous ultrasound-guided radiofrequency ablation of intrahepatic cholangiocarcinoma

This study evaluated the clinical applications, treatment effects, and complications of percutaneous ultrasound (US)-guided radiofrequency ablation (RFA) of intrahepatic cholangiocarcinoma. Ten patients (6 men and 4 women) with histologically proven cholangiocarcinoma underwent US-guided percutaneous RFA. Tumor diameters ranged from 1.9 to 6.8 cm. There were 12 sessions of RFA for 10 solitary cholangiocarcinomas. Eight patients were treated at a single session and two patients had two treatment sessions. The efficacy of RFA was evaluated using contrast-enhanced dynamic computed tomography 1 month after treatment and then every 3 months. Complete necrosis was defined as lack of contrast enhancement of the treated region. There was complete necrosis in eight tumors. In two patients with large tumors (4.7 and 6.8 cm in diameter), enhancement of residual tissue was observed after RFA treatment, indicating residual tumor. Complete necrosis was seen in all five tumors (100%) with diameters of 3.0 cm or less, two of three tumors (67%) with diameters of 3.1-5.0 cm, and one of two tumors (50%) with diameters of more than 5.0 cm. A large biloma was found in one patient after treatment. No serious complications occurred in the other nine patients. In conclusion, percutaneous RFA is effective and successful in the treatment of intrahepatic cholangiocarcinoma of 3 cm or less and satisfactory for tumors of 3-5 cm. The rate of serious complications after RFA is low. Further follow-up is necessary to determine long-term efficacy.

Local recurrence after hepatic radiofrequency coagulation: multivariate meta-analysis and review of contributing factors

OBJECTIVE

The purpose of this study was to analyze the factors that influence local recurrence after radiofrequency coagulation of liver tumors.

SUMMARY BACKGROUND DATA

Local recurrence rate varies widely between 2% and 60%. Apart from tumor size as an important risk factor for local recurrence, little is known about the impact of other factors.

METHODS

An exhaustive literature search was carried out for the period from January 1, 1990 to January 1, 2004. Only series with a minimal follow-up of 6 months and/or mean follow-up of 12 months were included. Univariate and multivariate meta-analyses were carried out.

RESULTS

Ninety-five independent series were included, allowing the analysis of the local recurrence rate of 5224 treated liver tumors. In a univariate analysis, tumor-dependent factors with significantly less local recurrences were: smaller size, neuroendocrine metastases, nonsubcapsular location, and location away from large vessels. Physician-dependent favorable factors were: surgical (open or laparoscopic) approach, vascular occlusion, general anesthesia, a 1-cm intentional margin, and a greater physician experience. In a multivariate analysis, significantly less local recurrences were observed for small size (P < 0.001) and a surgical (versus percutaneous) approach (P < 0.001).

CONCLUSIONS

Radiofrequency coagulation by laparoscopy or laparotomy results in superior local control, independent of tumor size. The percutaneous route should mainly be reserved for patients who cannot tolerate a laparoscopy or laparotomy. The short-term benefits of less invasiveness for the percutaneous route do not outweigh the longer-term higher risk of local recurrence.

Liver transplantation for malignancy

Liver transplantation for hepatic malignancies has emerged from an exotic and desperate approach to a well-documented and proven treatment modality for these unfortunate patients. However, early unsatisfactory results emphasized that only a highly selected patient population would benefit from transplantation. Currently, <10% of all liver transplants performed are for hepatocellular cancer (HCC). There is no controversy that hepatoblastoma is an excellent indication in pediatric patients with unresectable tumors. Similarly, liver transplantation for HCC in the adult population yields good results for patients whose tumor masses do not exceed the Milan criteria. It remains to be determined whether patients with more extensive tumors can be reliably selected to benefit from the procedure. Adjunctive procedures like radiofrequency ablation, chemoembolization, or cryotherapy might be indicated to limit tumor progression for patients on waiting lists. Epitheloid hemangioendothelioma is also an appropriate indication for liver transplantation, unlike angiosarcoma. Metastatic liver disease is not an indication for liver transplantation, with the exception of cases in which the primary is a neuroendocrine tumor, for which liver transplantation can result in long-term survival and even cure in a number of patients. And finally, while gallbladder cancers are never an indication for liver transplantation, rare cases of cholangiocellular cancer might qualify if aggressive combination therapies, including chemotherapy and radiotherapy followed by OLT, are carried through. Survival in these selected patients can approach that for patients with cholestatic liver disease.

Liver abscess after percutaneous radiofrequency ablation for hepatocellular carcinomas: frequency and risk factors

OBJECTIVE

The purpose of this study was to clarify the frequency and risk factors of liver abscess formation after percutaneous radiofrequency ablation in patients with hepatocellular carcinoma.

MATERIALS AND METHODS

Over a 4-year period, 603 patients with 831 hepatocellular carcinomas measuring 5 cm or less in maximum diameter who underwent a total of 751 percutaneous radiofrequency ablation procedures were enrolled in this study. We retrospectively reviewed the medical records and analyzed the overall frequency of liver abscess, risk factors for abscess, and clinical features of the patients. The relationships between liver abscess and potential risk factors were analyzed using either generalized estimating equations or multiple logistic regression analysis.

RESULTS

Liver abscess developed in 14 tumors of 13 patients after 13 (13/751 [1.7%]) ablation procedures. Generalized estimating equations and multiple logistic regression analysis of various potential risk factors revealed that preexisting biliary abnormality prone to ascending biliary infection (p = 0.0088), tumor with retention of iodized oil from previous transcatheter arterial chemoembolization (p = 0.040), and treatment with an internally cooled electrode system (p = 0.016) were associated with a significant risk of liver abscess formation. No patient died of liver abscess, and all successfully recovered from liver abscess with parenteral antibiotics and percutaneous clearance of pus.

CONCLUSION

Although liver abscess formation was infrequent in patients who underwent percutaneous radiofrequency ablation for hepatocellular carcinoma, the patients with significant risk factors-preexisting biliary abnormality prone to ascending biliary infection, tumor with retention of iodized oil, and treatment with an internally cooled electrode system-for liver abscess formation should be closely monitored after treatment.

Detection of residual tumor after radiofrequency ablation of liver metastasis with dual-modality PET/CT: initial results

The aim of this study was to determine the accuracy of dual-modality positron emission tomography(PET)/computed tomography (CT) in the detection of residual tumor after radiofrequency ablation (RFA) of liver metastasis of colorectal cancer. Eleven patients with 16 hepatic metastases (mean size 2.9 cm) from colorectal cancer were enrolled in this study, and 19 RFA procedures and 32 PET/CT examinations were performed. The patients had PET/CT before and after RFA using [18F]-2-fluoro-2-deoxy-D: -glucose. CT images alone were read by two radiologists, PET images alone were evaluated by two nuclear physicians. Fused images were read by one physician of each speciality in consensus. The accuracy for detection of residual tumor by the different imaging modalities following RFA was assessed. Eleven patients with a mean age of 63 (range 55-71) years were evaluated. The mean follow-up period was 393 days. The overall procedure-based sensitivity for detection of residual tumor was 65% for PET and PET/CT and 44% for CT alone. The accuracies were 68% and 47%, respectively. Four patients had residual tumor after RFA, six patients total developed local recurrence. PET/CT therefore possibly proved superior to CT alone when assessing the liver for residual tumor after RFA.

Perfusion imaging of the liver: current challenges and future goals

Improved therapeutic options for hepatocellular carcinoma and metastatic disease place greater demands on diagnostic and surveillance tests for liver disease. Existing diagnostic imaging techniques provide limited evaluation of tissue characteristics beyond morphology; perfusion imaging of the liver has potential to improve this shortcoming. The ability to resolve hepatic arterial and portal venous components of blood flow on a global and regional basis constitutes the primary goal of liver perfusion imaging. Earlier detection of primary and metastatic hepatic malignancies and cirrhosis may be possible on the basis of relative increases in hepatic arterial blood flow associated with these diseases. To date, liver flow scintigraphy and flow quantification at Doppler ultrasonography have focused on characterization of global abnormalities. Computed tomography (CT) and magnetic resonance (MR) imaging can provide regional and global parameters, a critical goal for tumor surveillance. Several challenges remain: reduced radiation doses associated with CT perfusion imaging, improved spatial and temporal resolution at MR imaging, accurate quantification of tissue contrast material at MR imaging, and validation of parameters obtained from fitting enhancement curves to biokinetic models, applicable to all perfusion methods. Continued progress in this new field of liver imaging may have profound implications for large patient groups at risk for liver disease.

Changes in bile ducts after radiofrequency ablation of hepatocellular carcinoma: frequency and clinical significance

OBJECTIVE

The purpose of our study was to determine the frequency of bile duct changes after radiofrequency ablation for hepatocellular carcinoma and to evaluate their clinical significance.

MATERIALS AND METHODS

Between April 1999 and August 2003, 389 patients with 521 hepatocellular carcinomas underwent a total of 571 sessions of radiofrequency ablation. The maximum dimension of the tumors measured on sonography was 2.4 +/- 0.9 cm (mean +/- SD) (range, 0.5-5.0 cm). The frequency and type of bile duct changes resulting from radiofrequency ablation, the time interval between radiofrequency ablation and the first appearance of bile duct changes, and the serial changes at follow-up CT were analyzed. Complications related to bile duct changes were also evaluated by reviewing medical records and CT scans.

RESULTS

Bile duct changes occurred in 69 (12%) of 571 sessions and 66 (17%) of 389 patients. Bile duct changes seen on CT included mild dilatation of upstream bile ducts surrounding the ablation zone in 57 patients (82.6%), biloma in the ablation zone in four patients (5.8%), and both in eight patients (11.6%). The mean time interval between radiofrequency ablation and the initial appearance of bile duct change was 1.6 months (range, immediate-9 months). Most (87%) of the 69 patients with bile duct changes showed no progression on follow-up CT, and only nine (13%) had slight progression. All patients but one, in whom cholangitis developed, had no major complications requiring specific treatment during the follow-up period.

CONCLUSION

Although bile duct changes were frequent after the radiofrequency ablation of hepatocellular carcinoma, most were of no clinical significance, and major complications requiring additional treatment were rare.

Survival and intra-hepatic recurrences after laparoscopic radiofrequency of hepatocellular carcinoma in patients with liver cirrhosis

BACKGROUND

The optimal treatment for hepatocellular carcinoma (HCC) is surgical resection. However, only a small percentage of patients are operative candidates. Percutaneous radiofrequency interstitial thermal ablation proved to be effective, too. Our objective was to assess a novel operative combination of laparoscopic ultrasound (LUS) with laparoscopic radiofrequency (LRF) in the treatment of HCC not amenable to liver resection.

METHODS

One hundred and four patients with HCC in liver cirrhosis were submitted to laparoscopic LRF. A LRF was indicated in patients not amenable to liver resection that had at least one of the following criteria: (a) severe impairment of the coagulation tests; (b) large tumors (but <5 cm) or multiple lesions requiring repeated punctures; (c) superficial lesions adjacent to visceral structures; (d) deep-sited lesions with a very difficult or impossible percutaneous approach; (e) short-term recurrence of HCC following percutaneous loco-regional therapies.

RESULTS

The LRF procedure was completed in 102 out of 104 patients (98% feasibility rate). LUS identified 26 new malignant lesions (25%) undetected by pre-operative imaging. There was no operative mortality. Seventy-six patients had no complication (73%). At 1-month computed tomography (CT) evaluation, a complete response with a 100% necrosis was achieved in 88 out of 101 patients (87%). During the follow-up (mean follow-up: 22.5 +/- 15.9 months), 55 patients (54%) developed new malignant nodules (42% of these recurrences were localized in the same segment of the HCC treated).

CONCLUSIONS

LRF of HCC proved to be a safe and effective technique at least in the short and mid-term: in fact it permits to treat lesions not treatable with the per cutaneous approach, to detect 25% of new HCC nodules and it has a low morbidity rate.

Assessment of renal cell carcinoma after cryoablation using contrast-enhanced gray-scale ultrasound

We performed contrast-enhanced gray-scale harmonic ultrasound (CUS) in three patients with renal cell carcinoma after cryoablation. CUS showed the decreased enhancement similar to the findings of CT or MRI. It identified feeding vessels more distinctly and found a larger number compared with CT or MRI. A persistent feeder in one case was related to recurrence. CUS may potentially be an alternative to CT and MRI and a useful method in the prediction of recurrent and residual tumors.