Efficacy and safety of radiofrequency ablation of hepatocellular carcinoma in the hepatic dome with the CT-guided extrathoracic transhepatic approach

PURPOSE: The purpose of this study was to determine the efficacy and safety of radiofrequency (RF) ablation for the treatment of hepatocellular carcinoma (HCC) in the hepatic dome with CT-guided extrathoracic transhepatic approach. MATERIALS AND METHODS: Fifteen patients with 15 HCCs (size range: 0.8-4 cm, mean size: 1.8 cm) in the hepatic dome were treated by RF ablation using cooled-tip electrodes and with CT-guided extrathoracic transhepatic approach. Therapeutic response of the tumor to RF ablation and procedure-related complications including hepatic injury, hemoperitoneum, and thermal injury of diaphragm were evaluated. RESULTS: The average number of needle punctures to ensure the correct needle position in the targeted tumor was 3.7 (range: 1-6 punctures). The average ablation time was 14.7 min (range: 8-25 min). Complete necrosis without marginal recurrence after at least 13-month follow-up was attained in 13 tumors (86.7%). There were no major complications related to the procedures. Six patients had shoulder pain that lasted three days to two weeks after the procedures and their symptoms were resolved with conservative treatment. CONCLUSIONS: RF ablation using CT-guided extrathoracic transhepatic approach is an effective and safe technique for the treatment of HCC in the hepatic dome.     

Percutaneous Radiofrequency Ablation for the Hepatocellular Carcinoma Abutting the Diaphragm: Assessment of Safety and Therapeutic Efficacy

Objective

To assess the safety and therapeutic efficacy of a percutaneous radiofrequency (RF) ablation for the hepatocellular carcinoma (HCC) abutting the diaphragm.

Materials and Methods

We retrospectively assessed 80 patients who underwent a percutaneous RF ablation for a single nodular (< 4 cm) HCC over the last four years. Each patient underwent an ultrasound-guided RF ablation using internally cooled electrodes for the first-line treatment. We divided patients into two subgroups based on whether the index tumor was abutting (less than 5 mm) the diaphragm or not: group A (abutting; n = 31) versus group B (non-abutting; n = 49). We compared the two subgroups for complications and therapeutic efficacy using image and the review of medical records. The statistical assessment included an independent t-test, Fisher''s exact test, and chi-square test.

Results

The assessment of the diaphragmatic swelling at CT immediately following the procedure was more severe in group A than group B (mean thickness change:1.44 vs. 0.46 mm, p = 0.00). Further, right shoulder pain was more common in group A than B (p = 0.01). Although minor complications (hemothorax 1 case, pleural effusion 1 case) were noted only in group A, no major thoracic complication occurred in either group. The technical success rate was lower in group A than group B (84% vs. 98%, p = 0.03). As well, the primary and secondary technique effectiveness rates in group A and group B were 90% versus 98% (p = 0.29) and 79% versus 91% (p = 0.25), respectively. The local tumor progression rate was higher in group A than in group B (29% vs. 6%, p = 0.02).

Conclusion

We found that the percutaneous RF ablation for the HCC abutting the diaphragm is a safe procedure without major complications. However, it is less effective with regard to technical success and local tumor control.     

Radiofrequency ablation of hepatic tumors adjacent to the gallbladder: feasibility and safety

OBJECTIVE: This study was performed to assess the feasibility and safety of radiofrequency ablation of hepatic tumors adjacent to the gallbladder. MATERIALS AND METHODS: Of the 83 patients who underwent radiofrequency ablation of hepatic tumors at our institution between December 1997 and August 2000, we identified eight patients--four men and four women who were 42-85 years old (mean age, 67 years)--who had tumors adjacent to the gallbladder. All ablations were performed with curative intent. We reviewed the patients' preablation imaging, radiofrequency ablation parameters, and course after ablation. Follow-up ranged from 3 to 22 months (mean, 8 months). RESULTS: Six patients with colorectal carcinoma and two with hepatocellular carcinoma had a total of 14 tumors adjacent to the gallbladder. Of the 14 tumors, nine (64%) were metastases and five (36%) were hepatocellular carcinoma. Eleven tumors (79%) were located directly adjacent to the gallbladder and three (21%) were located within 1 cm of the gallbladder. Tumor size ranged from 0.9 to 4.5 cm (mean, 3.6 cm). The number of radiofrequency ablations performed on each tumor ranged between one and six (mean, three ablations). Right upper quadrant pain developed in the immediate postablation period (within 7 days after the ablation) in six patients (75%) and ranged in duration from 5 to 21 days (mean, 7 days). Fever developed in four patients (50%), with a mean duration of 5 days. Arthralgia and right shoulder pain developed in one patient (12%). No deaths were noted in the immediate period after ablation. Complete ablation of all tumors visible on CT was achieved in seven patients. Of these, one patient (14%) had local tumor recurrence after 11 months. CONCLUSION: Radiofrequency ablation of tumors adjacent to the gallbladder is feasible and appears to be safe. Self-limited morbidity after ablation is noted in most patients and is probably related to a mild iatrogenic cholecystitis.     

Percutaneous radiofrequency ablation of hepatic tumors: postablation syndrome

OBJECTIVE: Our objective was to define the spectrum and possible predictors of symptoms that occur in patients after percutaneous radiofrequency ablation of hepatic tumors. SUBJECTS AND METHODS: We performed 50 consecutive percutaneous radiofrequency ablation sessions on 39 patients with a total of 89 liver tumors. All patients had pre- and postablation laboratory studies and CT or MRI scans. After treatment, patients were followed for 3 weeks with a standardized questionnaire to assess for postablation symptoms. Comparisons of the presence or absence of symptoms were made for the laboratory test values, liver volumes, and pre- and postablation tumor volumes. RESULTS: Postablation symptoms occurred in 14 of 39 (36%) patients after 17 of 50 (34%) ablation sessions. Symptoms consisted of fever (16/17), malaise (12/17), chills (6/17), delayed pain (5/17), and nausea (2/17). On average, the symptoms presented 3 days after ablation and lasted 5 days. Statistically significant (p < 0.01) predictors of symptoms were tumor volumes > 50 cm3 (4.5 cm diameter), ablated tissue volumes > 150 cm3 (6.5 cm diameter), a difference between preablation tumor volume and the volume of tissue ablated > 125 cm3, or postablation aspartate aminotransferase levels > 350 IU/L. CONCLUSION: Approximately one third of patients undergoing percutaneous radiofrequency ablation of hepatic tumors develop delayed, transient flulike symptoms that can be treated conservatively and are significantly related to the volume of tissue ablated. Familiarity with this postablation syndrome should facilitate appropriate management of affected patients.     

Minimizing diaphragmatic injury during radio-frequency ablation: efficacy of subphrenic peritoneal saline injection in a porcine model

PURPOSE: To investigate if a targeted subphrenic peritoneal infusion of normal saline to separate liver from diaphragm before radio-frequency (RF) ablation could minimize or eliminate diaphragmatic injury. MATERIALS AND METHODS: With a 2-cm-diameter, eight-prong RF needle electrode, 37 hepatic dome RF lesions were created in 10 pigs. Seventeen lesions were created before (non-saline group) and 20 lesions after (post-saline group) intraperitoneal infusion of approximately 500 mL of normal saline. Ten non-saline lesions were created deep (centered 1-2 cm from the liver surface) and seven superficially (centered within 1 cm of the capsule). All 20 post-saline lesions were created superficially. Helical enhanced computed tomography was performed 24-48 hours after ablation. The pigs were killed immediately, and the diaphragm was visually inspected and sectioned. Diaphragmatic injury was graded as 0, no injury; 1, injury up to one-third thickness; 2, injury to two-thirds thickness; 3, full-thickness injury. Representative grade 3 injuries and all partial injuries underwent gross and histologic analysis. RESULTS: All 10 deep non-saline RF lesions caused grade 0 injury. All seven superficial non-saline lesions caused grade 3 injury. Of the 20 superficial post-saline lesions, 13 (65%) caused grade 0 injury; four (20%), grade 1; and three (15%), grade 3. The post-saline group caused significantly less diaphragmatic injury (P <.05). CONCLUSION: Intraperitoneal saline infusion may reduce the frequency and severity of diaphragmatic injury when adjacent liver is treated with RF ablation.     

Radiofrequency ablation of hepatocellular carcinoma: treatment success as defined by histologic examination of the explanted liver

PURPOSE: To retrospectively evaluate the effectiveness of radiofrequency (RF) ablation of hepatocellular carcinoma (HCC) by using histologic examination of the explanted liver. MATERIALS AND METHODS: The study was approved by the medical center Institutional Review Board, with waiver of informed consent. Forty-seven HCC nodules in 24 patients (18 men, six women; age range, 33-71 years; mean age, 56 years) were treated with single or double RF ablation sessions prior to liver transplantation. Histologic data from hematoxylin-eosin staining of explanted liver specimens were retrospectively reviewed to determine treatment success, which was defined as the absence of residual or recurrent viable carcinoma cells at treatment site. Tumor size and the presence of large (> or =3 mm) abutting vessels that were observed during imaging were tested as potential predictors of treatment success or failure (Fisher exact test). In patients who underwent postablation computed tomographic (CT) or magnetic resonance (MR) imaging within 3 months prior to transplantation (21 patients with 44 tumors), imaging results were analyzed for sensitivity and specificity of residual or recurrent tumor by using histologic data as the reference standard. RESULTS: Thirty-five (74%) of 47 ablated tumors, including 29 (83%) of 35 tumors less than 3 cm, were found to be successfully treated on the basis of histologic findings after a mean interval of 7.5 months between RF ablation and transplantation. Nodules that were successfully treated had mean maximal diameter of 2.0 cm, and nodules that were unsuccessfully treated had mean maximal diameter of 3.1 cm (P=.014). Seven (47%) of 15 perivascular lesions were successfully treated whereas 28 (88%) of 32 nonperivascular lesions were successfully treated (P <.01). Imaging correlation showed 100% (33 of 33) specificity and 36% (four of 11) sensitivity of postablation CT and MR imaging for the depiction of residual or recurrent tumor. CONCLUSION: Histologic evidence directly validates RF ablation as an effective treatment of small (<3 cm) HCC.     

Major complications after radio-frequency thermal ablation of hepatic tumors: spectrum of imaging findings.

Although radio-frequency (RF) ablation has been accepted as a promising and safe technique for treatment of unresectable hepatic tumors, investigation of its complications has been limited. According to the multicenter (1,139 patients in 11 institutions) survey data of the Korean Study Group of Radiofrequency Ablation, a spectrum of complications occurred after RF ablation of hepatic tumors. The prevalence of major complications was 2.43%. The most common complications were hepatic abscess (0.66%), peritoneal hemorrhage (0.46%), biloma (0.20%), ground pad burn (0.20%), pneumothorax (0.20%), and vasovagal reflex (0.13%). Other complications were biliary stricture, diaphragmatic injury, gastric ulcer, hemothorax, hepatic failure, hepatic infarction, renal infarction, sepsis, and transient ischemic attack. One procedure-related death (0.09%) occurred (due to peritoneal hemorrhage). Three important strategies for decreasing the rate of complications are prevention, early detection, and proper management. A physician who performs RF ablation of hepatic malignancies should be aware of the broad spectrum of major complications so that these strategies can be used. Copyright RSNA, 2003.     

Percutaneous radiofrequency ablation of symptomatic giant hepatic cavernous hemangiomas: report of two cases and review of literature

The presented cases detail percutaneous radiofrequency (RF) ablation of multiple giant hepatic hemangiomas in two patients who presented with right upper-quadrant pain and fullness and chose not to undergo surgical resection. Treatment of two hemangiomas per patient, 7 cm and 6 cm in one and 9 cm and 2 cm in the other, was accomplished in single ablation sessions with 12 and nine cycles, respectively. Patients had durable resolution of symptoms with reduction of lesion size by 68%-82% at a mean follow-up of 13 months. These cases, along with promising results in the current literature, support RF ablation as a safe and effective surgical alternative.     

Radiofrequency ablation of the liver in a rabbit model: creation of artificial ascites to minimize collateral thermal injury to the diaphragm and stomach

PURPOSE: To assess whether the creation of artificial ascites during radiofrequency (RF) ablation of the subcapsular portion of the liver can minimize collateral thermal injury to the diaphragm and stomach. MATERIALS AND METHODS: A total of 20 percutaneous RF ablation procedures were performed in the livers of 10 rabbits (control, n = 5; experimental, n = 5) with use of an internally cooled electrode (1-cm active tip). In the experimental group, artificial ascites was established before RF ablation by dripping 320 mL of normal saline solution via a 20-gauge sheathed needle to separate the liver from the diaphragm and stomach. In each rabbit, two subcapsular ablation zones were made in the inferior tip of the left lobe of the liver adjacent to the stomach and in the far dome of the right lobe next to the diaphragm consecutively. After the animals were killed 3 days after the procedure, the frequency, size, and degree of thermal injury were compared between the experimental and control groups. The degree of thermal injury was graded by visual inspection according to a four-point scoring system. Representative cases underwent gross and histologic analysis. RESULTS: Artificial ascites was achieved successfully with a single puncture in all rabbits in the experimental group. Mean procedure time for the formation of artificial ascites was 9 minutes. There was no difference in the size of the RF ablation zones in the liver between the two groups (P > .05). Thermal injury in the adjacent organs was observed significantly more frequently in the control group compared with the experimental group (diaphragm, 100% vs 0; stomach, 80% vs 20%; P < .05). CONCLUSION: Creation of artificial ascites may be a simple and useful technique that can be used to reduce the frequency and severity of thermal injury during RF ablation of subcapsular hepatic tumors.     

Use heat with caution! Pleurobiliary fistula after hepatocellular carcinoma microwave ablation in lymphoma patient: A case study

Thermal ablation by microwave ablation (MWA) or radiofrequency ablation (RFA) is a frequently used technique for hepatic lesion treatment due to its low rate of complications. Surgery, transarterial chemoembolization (TACE), and yttrium-90 (Y-90) transarterial radioembolization (TARE) are other ways to treat hepatic lesions. Thoracobiliary fistula (TBF) is a rare side effect of thermal ablation. Other side effects include vascular injury, damage to the biliary system, and infection. We present the case of a 62-year-old male patient who has a history of lymphoma and was diagnosed with a hepaticellular carcinoma lesion on follow-up CT in segment VII, which appeared in close relation to the right diaphragm. The patient had been through several interventional procedures, including Y-90 therapy, TACE, and MWA with thermal impact, which resulted in a biloma forming and ramping up the progression of pleurobiliary fistula, which is confirmed by HIDA scan, this case highlights the significance of monitoring patients after thermal ablation, particularly in cases of large justa-diaphragmatic tumors, to detect any diaphragmatic or biliary tree injuries.     

Radio-frequency ablation of hepatic metastases: postprocedural assessment with a US microbubble contrast agent--early experience.

PURPOSE: To evaluate contrast agent-enhanced ultrasonography (US) in the detection of untreated tumor after radio-frequency (RF) ablation of hepatic metastases. MATERIALS AND METHODS: Twenty patients with solitary colorectal liver metastases underwent percutaneous RF tumor ablation. Pre- and postablation imaging was performed with nonenhanced and enhanced color and power Doppler US and contrast-enhanced helical computed tomography (CT). Initial follow-up CT and US were performed 24 hours after ablation. The findings at US and CT were compared. RESULTS: Nonenhanced US demonstrated intratumoral signal in 15 of 20 metastases before ablation. This signal increased after contrast agent administration. Contrast-enhanced US performed 24 hours after ablation demonstrated residual foci of enhancement in three tumors, whereas no US signals were seen in any tumor on nonenhanced scans. CT demonstrated small (< 3-mm) persistent foci of residual enhancement in these three tumors and in three additional lesions that were not seen at US (US sensitivity, 50%; specificity, 100%; diagnostic agreement with CT, 85%). All six patients with evidence of residual tumor underwent repeat RF ablation. CONCLUSION: Contrast-enhanced US may depict residual tumor after RF application and thereby enable additional directed therapy. The potential reduction in treatment sessions and/or ancillary imaging procedures might increase the ease and practicality of percutaneous ablation of focal hepatic metastases.     

Recurrent hepatocellular carcinoma: percutaneous radiofrequency ablation after hepatectomy

PURPOSE: To evaluate the therapeutic efficacy and safety of percutaneous radiofrequency (RF) ablation for recurrent hepatocellular carcinoma (HCC) in the liver after hepatectomy. MATERIALS AND METHODS: Forty-five patients with 53 recurrent HCC tumors in the liver underwent percutaneous RF ablation with ultrasonographic guidance. All patients had a history of hepatic resection for HCC. The mean diameter of recurrent tumors was 2.1 cm (range, 0.8-4.0 cm). All patients were followed up for at least 10 months after ablation (range, 10-40 months; mean, 23 months). Therapeutic efficacy and complications were evaluated with multiphase helical computed tomography (CT) at regular follow-up visits. Overall and disease-free survival rates were calculated. RESULTS: At follow-up CT after initial RF ablation, 11 (21%) of 53 ablated HCC tumor sites showed residual tumor or local tumor progression. After additional RF ablation, complete ablation of 46 (87%) of 53 tumors was attained. Also at initial follow-up CT, before either additional RF ablation or other treatment was performed, 21 (47%) of 45 patients were found to have 41 new HCC tumors at other liver sites. Of these, nine tumors in eight patients were treatable with a second application of RF ablation. Overall survival rates at 1, 2, and 3 years were 82%, 72%, and 54%, respectively. No deaths or complications requiring further treatment occurred as a result of RF ablation. CONCLUSION: Percutaneous RF ablation is an effective and safe method for treating recurrent HCC in the liver after hepatectomy, with a good overall patient survival rate.     

Treatment strategy to optimize radiofrequency ablation for liver malignancies

PURPOSE: The purposes of this study were to investigate a treatment strategy to increase liver tumor necrosis and minimize complications with ultrasound-guided percutaneous radiofrequency (RF) ablation and to evaluate its therapeutic efficacy. MATERIALS AND METHODS: A total of 332 patients with 503 liver malignancies underwent RF ablation according to a mathematical protocol with adjunctive measures. In the 332 patients, 205 had 308 hepatocellular carcinomas (HCCs) with a mean largest diameter of 4.1 cm and 127 had 195 metastatic liver carcinomas (MLCs) with a mean largest diameter of 3.9 cm. In patients with HCC, 60 (29.3%) had stage I/II disease and 145 (70.7%) had stage III/IV disease. Depending on tumor size, shape, and location, a defined treatment strategy was adopted that consisted of a mathematical protocol, an individualized protocol, and adjunctive measures. The mathematical protocol was followed for tumors larger than 3.5 cm. The individualized protocol was used for tumors located adjacent to the diaphragm, gastrointestinal tract, or gallbladder. Some adjunctive measures such as supplementary fine needle localization, local saline solution injection, and feeding vessel ablation were used to deal with different features of these liver tumors. Patients were followed regularly to assess treatment efficiency, and the tumor was considered to have early complete necrosis if no viability was found on enhanced computed tomography 1 month after RF ablation. RESULTS: In this series, the early necrosis rates were 95.8% for HCC (295 of 308 tumors), 94.9% for MLC (185 of 195 tumors), 91.3% for tumors larger than 3.5 cm (189 of 207 tumors), 90.7% for tumors near the gastrointestinal tract (49 of 54 tumors), 91.5% for tumors near the diaphragm (86 of 94 tumors), and 90.6% for tumors near the gallbladder (48 of 53 tumors). The local recurrence rates were 10.7% for HCC (33 of 308 tumors) and 14.9% for MLC (29 of 195 tumors). The 1-, 2-, and 3-year overall survival rates were 89.6%, 69.4%, and 59.6%, respectively, for HCC and 80.3%, 52.8%, and 30.9%, respectively, for MLC. The 1-, 2-, and 3-year survival rates in 60 patients with stage I/II HCC were 93.7%, 87.1%, and 76.2%, respectively. The incidence of major complications was 1.4% (eight of 574 sessions), which included of three hemorrhages, four injuries to adjacent structures, and one case of needle tract seeding. CONCLUSION: In RF ablation of hepatic tumors, application of a proper protocol and adjunctive measures play important roles in improving tumor necrosis rate and minimizing potential complications.     

Percutaneous Microwave Ablation of Hepatic Tumors: Prospective Evaluation of Postablation Syndrome and Postprocedural Pain

PurposeTo prospectively investigate the frequency and severity of postablation syndrome (PAS) and postprocedural pain in a cohort of patients undergoing hepatic microwave ablation.Materials and MethodsFrom March 2009 to November 2011, 54 consecutive patients undergoing microwave ablation for liver tumors were enrolled. A questionnaire was administered to investigate PAS and pain at 1, 7, and 40 days after ablation. Four patients did not complete all three questionnaires and were excluded from the analysis. Additionally, laboratory tests with results known to significantly increase or decrease after ablation were performed, and ablation parameters were recorded. Potential predictors of PAS and pain at 1 and 7 days were evaluated by a logistic regression model.ResultsFifty patients underwent a single microwave ablation session, 33 for hepatocellular carcinoma (HCC) and 17 for liver metastasis. Median ablation volumes on computed tomography were 31 cm³ for HCC and 42 cm³ for metastasis. Sixty percent of patients experienced PAS in the first week. Aspartate aminotransferase (AST) levels after ablation were significantly associated with PAS during postprocedure days 1–7. Median visual analog scale scores for pain at the puncture site were 1 and 0.24 at 1 and 7 days, respectively. The risk of having at least moderate pain in the first week was significantly related to ablation volume and time and postablation increase in AST level.ConclusionsThe incidence and severity of PAS with hepatic microwave ablation is similar to that reported for radiofrequency ablation, with the best predictive factor being postablation AST level elevation. Postablation pain was best predicted by total ablation volume and AST level.     

Infectious complications after percutaneous radiofrequency ablation of renal cell carcinoma in patients with ileal conduit

Percutaneous renal radiofrequency (RF) ablation is a safe and minimally invasive treatment for renal cell carcinoma. The most common minor complications are pain, self-limiting hematuria, and postablation syndrome. Major complications are rare and include significant hemorrhage and thermal injury to the ureter. Reports of infectious complications after ablation are uncommon, but increased risks in patients with ileal conduits have been reported. The present report describes two patients with ileal conduits who underwent percutaneous renal RF ablation and developed infectious complications (a renal abscess and a calyceal-cutaneous fistula) despite prophylactic antibiotic treatment.     

Minimizing diaphragmatic injury during radiofrequency ablation: efficacy of intraabdominal carbon dioxide insufflation

OBJECTIVE: The purpose of our study was to determine whether intraperitoneal insufflation of carbon dioxide (CO(2)) reduces adjacent diaphragmatic injury. MATERIALS AND METHODS: In seven pigs under anesthesia, a 17-gauge percutaneous insufflation needle was inserted in the infraumbilical midline using a standard insufflator. Three to six liters of CO(2) was infused into the peritoneal space to achieve at least a 1-cm separation between the liver and the diaphragm and maintained by a pressure of 8-10 mm Hg. Seven control lesions in six historical controls were used. In addition, five lesions were created in one animal from this cohort who served as a control. Superficial areas of liver separated from diaphragm were fluoroscopically targeted for radiofrequency ablation, and several 2-cm-diameter radiofrequency lesions were generated. The pigs were sacrificed at 48 hr, and at laparotomy, the liver surface was inspected and sectioned to select lesions with centers within 1 cm of the surface. The thermal injury to the corresponding adjacent diaphragm was examined to determine the depth of injury. Diaphragmatic injury was graded on a scale from 0 to III (0, no injury; I, mild injury to one-third thickness; II, moderate injury to two-thirds thickness; III, severe injury to full thickness.) RESULTS: Of 72 total lesions created, 60 had centers less than 1 cm from the liver surface (i.e., superficial) at laparotomy. Of these 60 lesions, 55 caused no significant diaphragmatic injury, two caused grade I injury and three caused grade III injury. In comparison, seven of seven historic superficial control lesions and five of five superficial radiofrequency control lesions from the current cohort caused grade III injury. Superficial radiofrequency lesions created after intraperitoneal CO(2) insufflation caused significantly less (p < 0.01) diaphragmatic injury. CONCLUSION: We have shown that in pigs, intraperitoneal CO(2) insufflation helped significantly reduce severe diaphragmatic injury when superficial hepatic radiofrequency ablation was performed.     

Intrahepatic tumor recurrence after partial hepatectomy: value of percutaneous radiofrequency ablation

PURPOSE: To determine the risks and benefits of percutaneous radiofrequency (RF) ablation of recurrent hepatic tumors in patients who have undergone hepatic resection. MATERIALS AND METHODS: Retrospective review of the institutional RF ablation database yielded 35 patients with recurrent hepatic tumor after hepatectomy. Sixty-one recurrent hepatic tumors (mean diameter +/- SD, 1.7 +/- 1.1 cm; range, 0.5-5.3 cm) were ablated percutaneously under sonographic guidance or combined guidance with sonographic and fluoroscopic computed tomography (CT). Follow-up CT, magnetic resonance imaging, or both were used for assessment of the primary and secondary therapeutic effectiveness rate and failure of RF ablation. Patients' survival status was determined by contacting the primary care physician or searching the Social Security Death Index. RESULTS: Complete ablation was accomplished in 54 of 61 hepatic tumors (primary therapeutic effectiveness rate, 88.5%). During a mean follow-up time of 18 months (range, 1-65 months), 14.8% of the tumors (n = 9) were incompletely ablated. Three of the nine incompletely ablated tumors were treated with a second RF ablation, all three of which failed (secondary therapeutic effectiveness rate, 0%). Distant intrahepatic tumor progression appeared in 23 of 35 patients (65.7%). One major complication (2.1%, one of 48 sessions) and eight minor complications (16.7%, eight of 48 sessions) were reported. The major complication was hepatic abscess formation. The overall survival rates for all patients at 1, 2, and 3 years were 76%, 68%, and 45%, respectively. For patients with metastases from colorectal cancer (n = 14), the overall survival rates were 72%, 60%, and 60% at 1, 2, and 3 years, respectively; and for patients with hepatocellular carcinoma (n = 8), the overall survival rates were 72%, 58%, and 44% at 1, 2, and 3 years, respectively. CONCLUSION: Percutaneous RF ablation offers a safe and effective treatment option for recurrent hepatic tumors after previous partial hepatectomy.     

Percutaneous radiofrequency ablation of liver tumors with the LeVeen probe: is roll-off predictive of response?

PURPOSE: The LeVeen radiofrequency (RF) probe uses roll-off of electrical impedance as the endpoint for RF cautery of hepatic tumors. The purpose of this study is to determine the relation of roll-off to local control of hepatic tumors. MATERIALS AND METHODS: Twenty hepatic tumors, including 10 hepatomas and 10 metastases, were treated. Lesions ranged from 1.4 cm to 6.0 cm in diameter; 13 (57%) were smaller than 3.0 cm. Each lesion was ablated with use of the LeVeen 15-gauge RF needle according to the manufacturer's protocol. Five patients underwent chemoembolization the day before. Patients were followed up with contrast-enhanced computed tomography or magnetic resonance imaging at 1 month and every 3 months thereafter. RESULTS: Among the 20 lesions, roll-off was achieved at all burn locations in 11 (55%), no burn locations in eight (40%), and two of three burn locations in one (5%). Roll-off was observed in all patients who had undergone chemoembolization the day before. Six local recurrences occurred, five after RF ablation without roll-off and one after RF ablation with roll-off. According to life-table analysis, the local recurrence rate at 6 months without roll-off was 43% and with roll-off was 15% (P =.024; OR = 8.3; 95% CI = 0.93-66). CONCLUSION: Roll-off is a significant predictor of local control after RF ablation. Strategies to enhance roll-off, such as concurrent embolization, may be important to optimize the therapeutic effect of this device.     

Therapeutic efficacy and safety of percutaneous radiofrequency ablation of hepatocellular carcinoma abutting the gastrointestinal tract

OBJECTIVE: The purpose of this study was to evaluate the therapeutic efficacy and safety of percutaneous radiofrequency ablation in the treatment of hepatocellular carcinomas abutting the gastrointestinal tract. MATERIALS AND METHODS: Forty-one patients with hepatocellular carcinomas abutting the gastrointestinal tract underwent sonographically guided percutaneous radiofrequency ablation. Forty-one tumors (1.2-4.3 cm in maximum diameter) had parts 5 mm or greater (or at least one quarter of their circumferences) abutting the stomach in 23 patients and the colon in 18 patients. Thirty tumors were ablated with internally cooled electrodes and 11 with multitined expandable electrodes. All patients were followed up for at least 1 year after ablation. Therapeutic efficacy and safety were evaluated with follow-up sonography and multiphase helical CT. RESULTS: At 1-month follow-up CT, three (7%) of the 41 tumors showed residual unablated tumor in the ablation zone. Of the remaining 38 hepatocellular carcinomas (93%) with no evidence of residual unablated tumor, four (11%) showed local tumor progression in the ablation zones on subsequent follow-up CT. We observed one major complication-a small perihepatic abscess-that needed specific treatment. CONCLUSION: Percutaneous radiofrequency ablation is an effective and safe technique for treating hepatocellular carcinomas abutting the gastrointestinal tract.     

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

PURPOSE: Radiofrequency (RF) ablation is an increasingly accepted treatment for nonsurgical candidates with a limited number of colorectal hepatic metastases. RF ablation is most effective in tumors smaller than 4.0 cm. This report describes 5-year survival in patients with single tumors with a maximum diameter of 4 cm. MATERIALS AND METHODS: Forty of 291 patients (14%; 24 men, 16 women; mean age, 67 years; age range, 34-86 y) with no or treated extrahepatic disease were identified who were not candidates for resection and who had a minimum follow-up of 6 months. Sixteen had undergone hepatic resection and two had undergone lung resection and lung ablation. Thirty-two (80%) received chemotherapy. Thirty-five were treated under general anesthesia and five under conscious sedation. Our standard ablation protocol used internally water-cooled electrodes introduced percutaneously with ultrasonography and computed tomography guidance and monitoring. Follow-up data were obtained from primary care physicians or oncologists. RESULTS: Mean tumor diameter was 2.3 cm (range, 0.8-4.0 cm). There were two successfully treated systemic complications: a chest infection and an exacerbation of asthma. There were no local complications. Mean follow-up was 38 months (range, 6-132 months). The median survival duration and 1-, 3-, and 5-year survival rates were 59 months and 97%, 84%, 40%, respectively, after ablation; and 63 months, 100%, 88%, and 54%, respectively, from the diagnosis of liver metastases. History of liver resection did not impact survival. CONCLUSIONS: RF ablation of solitary liver metastases 4 cm or smaller can be performed with minimal morbidity and results in excellent long-term survival, approaching that of surgical resection, even in patients who are not surgical candidates.