Assessment of health-related quality of life after radiofrequency ablation or laparoscopic surgery for small renal cell carcinoma: a prospective study with medical outcomes Study 36-Item Health Survey (SF-36)

OBJECTIVE: The purpose of this study was to assess the changes in health-related quality of life (HRQoL) during follow-up period in patients treated with percutaneous radiofrequency ablation (RFA) or laparoscopic surgery for small renal cell carcinoma. METHODS: From December 2004 through September 2006, for 37 consecutive patients, who were diagnosed with renal cell carcinoma and underwent percutaneous RFA (n = 20) or laparoscopic radical nephrectomy (n = 17) at our institution. HRQoL was evaluated prospectively using SF-36 Health survey pre- and post-operatively (1, 4, 12 and 24 weeks after surgery). RESULTS: Four of the eight scale scores of SF-36 were significantly lower pre-operatively in the RFA group than in the laparoscopic surgery group. The QoL scores in physical functioning, role-physical functioning and role-emotional functioning were significantly reduced one week after laparoscopic surgery. However, there was no reduction of the SF-36 QoL scores one week after operation in the RFA group. Furthermore, HRQoL scores in the RFA group showed a tendency to improve during follow-up periods. CONCLUSIONS: This is the first study to evaluate HRQoL changes (up to 24 weeks) in patients who have undergone RFA or laparoscopic radical nephrectomy for small renal cell carcinoma. No reduction, but rather an improvement, in HRQoL was seen in the RFA group during follow-up periods. From the point of view of QoL, RFA could be a viable alternative treatment for selected patients with small renal cell carcinoma. RFA could be a viable alternative treatment for the selected patients with small renal cell carcinoma.     

Percutaneous radiofrequency ablation: minimally invasive therapy for renal tumors

Currently, up to 60% of renal tumors are detected incidentally by abdominal imaging. Most of these tumors are small and localized to the kidney. Owing to the shift to lower stage at diagnosis, radical nephrectomy has fallen out of favor and has been replaced by nephron-sparing surgery. Currently, partial nephrectomy is the treatment of choice for patients with small renal tumors. As the trend towards less invasive therapy continues, laparoscopic and percutaneous ablation techniques have gained popularity for the treatment of renal tumors in patients who are high-risk surgical candidates, or have a solitary kidney, limited renal function or multifocal disease. Percutaneous radiofrequency ablation is a safe, minimally invasive treatment option for those patients.     

Radiofrequency ablation of small renal tumors

Technological improvements have led to increased diagnosis of small renal tumors and to the development of minimally invasive treatments for these tumors. As a minimally invasive ablative treatment, radiofrequency ablation shows promise as a therapeutic option for selected patients. By creating heat using radiofrequency waves, radiofrequency ablation leads to controlled thermal ablation within the target tissue. Experimental studies have shown radiofrequency ablation to be safe and reproducible. Clinical studies are ongoing but early evidence suggests that radiofrequency ablation is safe and oncologic results are encouraging. With further development of monitoring techniques and additional maturation of oncologic data, radiofrequency ablation may become a standard treatment option for patients with small renal tumors.     

Percutaneous microwave ablation of renal cell carcinoma using a high power microwave system: focus upon safety and efficacy

Objectives: Percutaneous ablation is an expanding, minimally invasive approach for small- to medium-sized renal masses. The purpose of this study is to review safety, and mid-term efficacy of percutaneous microwave ablation (MWA) for Renal Cell Carcinoma (RCC) treatment using a high power microwave system.

Methods and materials: Institutional database research identified 50 consecutive patients with a single lesion resembling renal cell carcinoma in CT and MRI who underwent percutaneous microwave ablation using a high power microwave system. All patients underwent biopsy on the same session with ablation using an 18G semi-automatic soft tissue biopsy needle. Contrast-enhanced computed tomography or magnetic resonance imaging was used for post-ablation follow-up. Patient and tumour characteristics, microwave technique, complications and pattern of recurrence were evaluated.

Results: Mean patient age was 74 years (male–female: 31–19). Average lesion size was 3.1?cm (range 2.0–4.3?cm). Biopsy results report RCC (n?=?48), inflammatory myofibroblastic tumour (n?=?1), and non-diagnostic sample (n?=?1). The 3-year overall survival was 95.8% (46/48). Two patients died during the 3-year follow-up period due to causes unrelated to the MW ablation and to the RCC. Minor complications including haematomas requiring nothing but observation occurred at 4% (2/50) of the cases. Local recurrence of 6.25% (3/48) was observed with 2/3 cases being re-treated achieving a total clinical success of 97.9% (47/48 lesions).

Conclusions: Percutaneous microwave ablation of RCC using a high power microwave system is a safe and efficacious technique for the treatment of small- to medium-sized renal masses.     

Electrical-thermal performance of a cooled RF applicator for hepatic ablation with additional distant infusion of hypertonic saline: In vivo study and preliminary computer modeling

Purpose: The Cool-tip electrode is one of the most widely employed applicators in radiofrequency (RF) hepatic ablation. Previous research demonstrated that it is possible to enlarge coagulation volume when the single cooled electrode is associated with distant infusion of saline (hybrid applicator). The aim of this study was to compare the electrical-thermal behaviour of the Cool-tip electrode with that of the hybrid applicator.

Materials and methods: Forty-two RF ablations were performed on a total of 10 pigs: 22 with the Cool-tip electrode and 20 with the hybrid applicator (low infused saline volumetric flow rate of 6?mL/h at 2?mm distance). We compared both electrical performance (delivered power and number of roll-offs, i.e. sudden rises in impedance that interrupt the power delivery) and coagulation zone characteristics. In addition, we built a one-dimensional model to provide a basic physical explanation of the difference in performance between the different applicators.

Results: The experimental results showed that the number of roll-offs with the Cool-tip electrode was higher (24.3?±?3.1 versus 6.7?±?7.0). The hybrid applicator created larger coagulation volumes (19.7?±?9.5 cm³ versus 9.5?±?5.8 cm³) with larger transverse diameters (2.5?±?0.6 versus 1.9?±?0.5?cm). The one-dimensional model confirmed the delay in the incidence of the first roll-off, but not the heterogeneity of the hybrid applicator's electrical performance in the experiments.

Conclusions: The hybrid applicator produces fewer roll-off episodes than the Cool-tip electrode and creates larger coagulation volumes with larger transverse diameters.     

RF-energised intracoronary guidewire to enhance bipolar ablation of the interventricular septum: in-silico feasibility study

Purpose: Although bipolar radiofrequency (RF) ablation (RFA) is broadly used to eliminate ventricular tachycardias in the interventricular septum wall, it can fail to create transmural lesions in thick ventricular walls. To solve this problem, we explored whether an RF-energised guidewire inserted into the ventricular wall would enhance bipolar RFA in the creation of transmural lesions through the ventricular wall.

Methods: We built three-dimensional computational models including two irrigated electrodes placed on opposing sides of the interventricular septum and a metal guidewire inserted into the septum. Computer simulations were conducted to compare the temperature distributions obtained with two ablation modes: bipolar mode (RF power delivered between both irrigated electrode) and time-division multiplexing (TDM) technique, which consists of activating the bipolar mode for 90% of the time and applying RF power between the guidewire and both irrigated electrodes during the remaining time.

Results: The TDM technique was the most suitable in terms of creating wider lesions through the entire ventricular wall, avoiding the hour-glass shape of thermal lesions associated with the bipolar mode. This was especially apparent in the case of thick walls (15?mm). Furthermore, the TDM technique was able to create transmural lesions even when the guidewire was displaced from the midplane of the wall.

Conclusions: An RF-energised guidewire could enhance bipolar RFA by allowing transmural lesions to be made through thick ventricular walls. However, the safety of this new approach must be assessed in future pre-clinical studies, especially in terms of the risk of stenosis and its clinical impact.     

Percutaneous radiofrequency ablation of renal tumours: Case series of 11 tumours and review of published work

Detection of renal cell carcinoma (RCC) is increasing with the greater use of cross‐sectional imaging and up to two‐thirds of RCCs are discovered incidentally in asymptomatic patients. The traditional option of nephrectomy or partial nephrectomy may not always be appropriate. A minimally invasive treatment alternative is radiofrequency ablation (RFA). We retrospectively reviewed the RFA cases for renal tumours at our institution between January 2004 and June 2006. Thirteen RFA treatment sessions were conducted for 11 neoplasms in 11 patients. Mean patient age was 74.4 years (61–88 years). Imaging was carried out after ablation with a mean follow up of 8.0 months (2–26 months). No residual tumour was observed after the first RFA treatment in 82% of patients (nine of 11). Two patients required a second RFA treatment for residual (one) or recurrent tumour (one). RFA is emerging as a useful technique for treatment of small renal tumour. A number of short‐term studies reflect this, however, long‐term findings are still lacking.     

Cryoablation or radiofrequency ablation of the small renal mass : a meta-analysis

BACKGROUND.

The incidence of renal cell carcinoma is rising because of incidental detection of small renal masses (SRMs). Although surgical resection remains the standard of care, cryoablation and radiofrequency ablation (RFA) have emerged as minimally invasive treatment alternatives. The authors of this report performed a comparative meta‐analysis evaluating cryoablation and RFA as primary treatment for SRMs.

METHODS.

A search of the MEDLINE database was performed reviewing the world literature for clinically localized renal masses treated by cryoablation or RFA.

RESULTS.

Forty‐seven studies representing 1375 kidney lesions treated by cryoablation or RFA were analyzed. No differences were detected between ablation modalities with regard to mean patient age (P = .17), tumor size (P = .12), or duration of follow‐up (P = .53). Pretreatment biopsy was performed more often for cryoablated lesions (82.3%) than for RFA (62.2%; P < .0001). Unknown pathology occurred at a significantly higher rate for SRMs that underwent RFA (40.4%) versus cryoablation (24.5%; P < .0001). Repeat ablation was performed more often after RFA (8.5% vs 1.3%; P < .0001), and the rates of local tumor progression were significantly higher for RFA (12.9% vs 5.2%; P < .0001) compared with cryoablation. The higher incidence of local tumor progression was found to be correlated significantly with treatment by RFA on univariate analysis (P = .001) and on multivariate regression analysis (P = .003). Metastasis was reported less frequently for cryoablation (1.0%) versus RFA (2.5%; P = .06). Cryoablation usually was performed laparoscopically (65%), whereas 94% of lesions that were treated with RFA were approached percutaneously.

CONCLUSIONS.

Ablation of SRMs is a viable strategy based on short‐term oncologic outcomes. Although extended oncologic efficacy remains to be established for ablation modalities, the current data suggest that cryoablation results in fewer retreatments and improved local tumor control, and it may be associated with a lower risk of metastatic progression compared with RFA. Cancer 2008. © 2008 American Cancer Society.     

Radiofrequency ablation lesion detection using MR-based electrical conductivity imaging: A feasibility study of ex vivo liver experiments

Abstract

Purpose: The aim of this study was to show the potential of magnetic resonance electrical impedance tomography (MREIT) conductivity imaging in terms of its capability to detect ablated lesions and differentiate tissue conditions in liver radiofrequency (RF) ablation. Materials and methods: RF ablation procedures were performed in bovine livers using a LeVeen RF needle electrode. Ablation lesions were created using a power-controlled mode at 30, 50, and 70?W for 1, 3, and 5?min of exposure time, respectively. After the ablation, the liver was cut into several blocks including the ablated lesion, and positioned inside a phantom filled with agarose gel. Electrodes were attached on the side of the phantom and it was placed inside the MRI bore. For MREIT imaging, multi-spin-echo pulse sequence was used to obtain the magnetic flux density data according to the injection currents. Results: The conductivity of ablation lesions was significantly changed with the increase of exposure time (pKW?<?0.01, Kruskal-Wallis test). With RF powers of 30 and 50?W, significant differences between the coagulation necrosis and hyperaemic rim were observed for more than 5?min and 3?min, respectively (pMW?<?0.01, Mann-Whitney test). At 70?W, all cases showed significant differences except 3?min (pMW?<?0.01). The positive correlation between the exposure time and tissue conductivity was observed in both two ablation areas (pSC?<?0.01, Spearman correlation). Conclusions: This ex vivo feasibility study demonstrates that current MREIT conductivity imaging can detect liver RF ablation lesions without using any contrast media or additional MR scan.     

Salvage of local recurrence after primary thermal ablation for small renal masses

The management of renal tumors has evolved rapidly over the last two decades, with the ascendance of nephron-sparing surgery (NSS), largely spurred by the increased incidental detection of small renal masses (SRMs) and evidence that preservation of renal parenchyma reduces the risk of chronic kidney disease. The field of NSS itself has advanced beyond the standard of open partial nephrectomy, with the application of minimally invasive techniques, such as laparoscopy and thermal ablation. Energy-based ablative therapies, which include cryoablation and radiofrequency ablation, are associated with reduced morbidity and represent a nascent but promising alternative to surgical extirpation in the treatment of SRMs. However, thermal ablation is associated with a higher rate of local tumor recurrence when compared with surgical excision, indicating that salvage therapy will be a necessity for some patients. With recent studies indicating that surgical excision of previously ablated kidneys can be complicated by significant fibrosis, clinicians who advocate thermal ablation must be cognizant of the sequelae of this treatment modality and versed on the potential difficulties associated with salvage surgery. We provide, herein, an assessment of the efficacy and limitations of primary thermal ablation and strategies for salvage treatment of local recurrence in this growing patient population.     

State-of-the-art surgical management of renal cell carcinoma

There is a recognizable increase in the incidence of renal cell carcinoma and a parallel rise in the surgical management of renal cell carcinoma has occurred. However, recent literature shows that not all small, suspected renal cell carcinoma needs to be treated surgically, especially in elderly patients or those with multiple medical comorbidities. The surgical options for renal cell carcinoma have expanded from traditional open nephrectomy to partial nephrectomy and, at present, more recent outcomes data are available for the laparoscopic versions of these surgeries. Short-term results of thermal ablative technology (radiofrequency and cryoablation) show real promise as minimally invasive therapies. This review examines the most up-to-date outcomes and future directions of the surgical management of renal cell carcinoma.     

US-guided microwave ablation for secondary hyperparathyroidism in patients after renal transplantation: a pilot study

Objective: To assess the safety and efficacy of ultrasound-guided microwave ablation (MWA) in the treatment of patients who develop secondary hyperparathyroidism (SHPT) after renal transplantation (RT).

Methods: In total, nine patients, each with symptomatic SHPT caused by RT and at least one enlarged parathyroid gland, underwent MWA via hydrodissection. Intact parathyroid hormone (i-PTH), serum calcium, serum phosphorus, creatinine and blood urea nitrogen concentrations, before and after MWA, were assessed and compared.

Results: Complete ablation was achieved in all patients for a total of 14 ablated parathyroid glands. The mean follow-up time was 17.2?±?1.7?months post-operation. The mean maximum diameter of the parathyroid glands was 1.3?±?0.4?cm (range: 0.4–2.0?cm). The ablation power implemented was 30?W and the mean time for each parathyroid gland to achieve complete ablation was 287.5?±?83.4?s. The mean i-PTH, serum calcium and phosphorus concentrations at one day post-MWA (69.6?pg/mL, 2.23?±?0.29?mmol/L, 1.2 2?±?0.48?mmol/L, respectively) were significantly lower than those before MWA (780.0?pg/mL, 2.62?±?0.32?mmol/L, 1.39?±?0.61?mmol/L, respectively; p?<?.01), whereas the creatinine and blood urea nitrogen concentrations before and after MWA did not differ significantly from each other (p?>?.05). No significant differences were found between the biomarker concentrations observed at one day post-MWA and at the follow-ups (p?>?.05). No major operation-related complications occurred.

Conclusion: Ultrasound-guided MWA is a safe and effective technique for destroying parathyroid gland tissue in patients who develop SHPT after RT and its clinical effects are long-lasting.     

Lipid peroxidation: a novel and unifying concept of the etiology of renal cell carcinoma (United States)

Multiple studies have noted that obese individuals are at a high risk of renal cell cancer. Similarly, numerous case–control and cohort studies have consistently reported that individuals with a history of hypertension experience an increased risk of renal cancer. In spite of this compelling body of epidemiologic data, no credible hypothesis has been advanced to explain this dual etiologic association. In this communication we propose that lipid peroxidation, which is increased in obese and hypertensive subjects, is the mechanism responsible, at least in part, for their increased risk of renal cell carcinoma. In experimental animals lipid peroxidation of the proximal renal tubules is a necessary mechanistic pathway in renal carcinogenesis induced by several different chemicals. Our hypothesis may also explain the roles of other risk (oophorectomy/hysterectomy, parity, smoking, diabetes) and protective factors (dietary antioxidants) for renal cell cancer.     

Ultrasound-guided hydrodissection for assisting percutaneous microwave ablation of renal cell carcinomas adjacent to intestinal tracts: a preliminary clinical study

Purpose: To evaluate the safety and efficacy of the clinical application of hydrodissection under ultrasound (US) guidance for assisting percutaneous microwave ablation (MWA) for the treatment of renal cell carcinomas (RCCs) adjacent to the intestinal tract.

Materials and methods: From April 2014 to December 2016, clinical data from 24 patients with 25 RCCs were retrospectively analysed. Percutaneous MWA under the assistance of US-guided hydrodissection were performed to treat RCCs with a mean maximal diameter of 3.80?±?1.60?cm because the distance between the index tumour and the adjacent intestinal tracts were less than 0.5?cm on imaging. The separation success rate of the hydrodissection, technique efficacy rate of the MWA, local tumour progression (LTP), complications, and renal function including serum creatinine (Cr) and blood urea nitrogen (BUN) were assessed.

Results: In total, 28 sessions of hydrodissection and MWA procedures were performed (one procedure in 22 patients and two procedures in 3 patients), and the separation success rate was 100% (28/28). The technique efficacy rate was 100% (25/25), and no LTP occurred. One patient exhibited a major complication (4.2%). Minor complications in 5 patients (20.8%) and side effects in 12 patients (50.0%) occurred. Compared with the pre-MWA levels, there were no significant differences in serum Cr and BUN 1-day post-MWA and at the last follow-up.

Conclusions: US-guided hydrodissection assistance for percutaneous MWA could be a safe and effective alternative for selected patients with RCCs adjacent to the intestinal tracts and can achieve good local tumour control and renal function preservation.     

新型胆道射频消融导管在离体猪肝应用的实验研究

目的 观察新型胆道双极射频消融导管HabibTM EndoHPB设置不同功率及持续时间的消融效果。方法 在恒温下（37.0℃）使用新型胆道射频消融导管对新鲜离体猪肝进行实验,分别设置功率5、10和15W,时间60、90、120和150s。观察在不同功率／时间参数时,消融区域的温度、宏观（短轴／长轴）及微观的变化。结果 设置功率5W、时间60～150s,消融区域的最高温度为42.0～54.0℃;10W、60～150s,最高温度为52.0～70.0℃;15W、60～120s,最高温度为62.0～77.0℃。10W和60、90、120及150s时,短轴长度（mm）分别为8.5±0.8、9.0±0.8、9.5±0.8及10.0±0.8;长轴长度（mm）分别为21.0±1.0、23.5±1.0、25.5±1.0及30.0±1.0。5、10、15W时,短轴和长轴长度均有小幅增大,其中功率为10W及15W时,两组差异无统计学意义（P＞0.05）。镜下消融区域均出现肝组织解离、细胞间距变大、细胞广泛变性,程度随着功率和时间增加而加重,且在10W、150s及15W、120s时,出现片状液化性坏死。结论 HabibTM EndoHPB导管设置功率10W、时间90至120s进行消融比较合适,在临床实际操作中可参考本实验结果进行适当的调整。     

Parametric study of irreversible electroporation with different needle electrodes: Electrical and thermal analysis

Purpose: Irreversible electroporation (IRE) is a new tumour ablation method used in cancer treatment procedures. In a successful IRE treatment it is crucial to impose minimum thermal damage to the tumour and its surrounding healthy tissue, while subjecting the entire tumour to a strong electric field. Method: Here we present a 3D model of a subcutaneous tumour in a four-layer skin using a geometry-based finite element approach. Four common needle electrode configurations were studied in this paper. The study evaluated six essential factors which are important in the electrical and thermal distributions in tumour and normal tissue. Results: The results revealed that a hexagonal 3?×?3 geometry provides the maximum electrical coverage of the tumour, compared to other electrode configurations. However, in some cases the hexagonal 2?×?2 geometry can ablate the entire tumour with less damage to normal tissue. We found that the deeper insertion of 2- and 4-electrode geometries can lead to more damage to healthy tissue. The results also indicate that the insertion of the electrodes into tumour tissue can increase thermal damage dramatically due to existing large electrical conductivity. Conclusion: These findings suggest that needle electrodes should not be placed within the tumour tissue if the goal is to prevent thermal damage. This method can be used as a trade-off between electric field coverage in tumour tissue and thermal damage to both tumour and normal tissue.     

Comparison of efficacy and complications between radiofrequency ablation and repeat surgery in the treatment of locally recurrent thyroid cancers: a single-center propensity score matching study

Purpose: To compare the efficacy and complication rates of radiofrequency ablation (RFA) and repeat surgery in the treatment of locally recurrent thyroid cancers.

Materials and methods: A total of 221 patients with locally recurrent thyroid cancers who underwent either RFA (n?=?96) or repeat surgery (n?=?125) between March 2008 and March 2017 were retrospectively enrolled (range of follow-up, 1–10?years). Each cohort consisted of 70 patients after propensity score adjustment. Patients with more than three recurrent lesions were excluded. The primary and secondary end points were recurrence-free survival and complication rates, respectively. Recurrence-free survival curves were compared via the log-rank test. The complications—voice changes, hypocalcemia, and immediate procedural complications—were compared between the groups. In addition, pretreatment serum thyroglobulin (T_g) levels and those at the last follow-up were also compared between the two groups to examine therapeutic efficacy.

Results: After propensity score matching, both groups showed no significant differences in baseline characteristics. The recurrence-free survival rates were comparable between the RFA and surgery groups (p?=?.2). There were no significant differences in mean serum T_g levels and their mean decrease after treatment between the groups (p?=?.891 and p?=?.963, respectively). Immediate procedural complications and voice changes also showed no significant between-group differences (p?=?.316, p?=?.084, respectively). Hypocalcemia occurred only in the repeat surgery group (n?=?18). Overall complications were significantly more frequent in the repeat surgery group (RFA, n?=?7; surgery, n?=?27; p?<?.001).

Conclusion: RFA may be an effective and safe alternative to repeat surgery in the treatment of a small number of locally recurrent thyroid cancers.     

Post‐radiofrequency ablation syndrome after percutaneous radiofrequency of abdominal tumours: One centre experience and review of published works

The aim of this study was to evaluate prospectively post‐radiofrequency ablation (RFA) syndrome and to determine its effect on the quality of life in the 15 days after percutaneous RFA treatment. We carried out an internal review board‐approved prospective study of the delayed symptoms that occurred after 71 consecutive RFA sessions in 53 patients (12 women and 41 men; age range 45–83 years; mean age 71.6 years) with 45 primary liver tumours, 34 liver metastases, 3 renal cell carcinoma (RCC), 2 residual lesions from RCC after nephrectomy and 1 pancreatic metastases from RCC. Postablation symptoms occurred in 17 of 53 (32%) patients. Six of 17 patients developed low‐grade fever (from 37.5 to 38.5°C). Other symptoms included delayed pain (9/17), nausea (7/17), vomiting (3/17), malaise (3/17) and myalgia (1). Postablation syndrome is a common phenomenon after RFA of solid abdominal tumours. Not only in our study but also in the previous ones the occurrence is observed in approximately one‐third patients. Patients should be informed that these symptoms are self‐limiting after RFA and most patients should be able to resume near‐complete preprocedural levels of activity within 10 days after the procedure.     

Radiofrequency ablation for hepatocellular carcinoma and metastatic liver tumors: a comparative study

BACKGROUND: This study compared the effectiveness of radiofrequency ablation (RFA) for hepatocellular carcinoma (HCC) and liver metastases. METHODS: We compared the outcomes of 240 patients with HCC and 44 patients with liver metastases treated with RFA. Data were prospectively collected and retrospectively analyzed. Effects of different variables on recurrences were studied. RESULTS: A total of 406 tumor nodules were treated. The median size of the largest ablated tumor was 2.5 cm, and the median tumor number was 1. Complete tumor ablation was achieved in 91.2%. Local recurrence rate was 15.4% after a median follow-up of 24.5 months. There was no significant impact of tumor pathology on local recurrence. However, patients with liver metastasis had higher extrahepatic recurrence rate (P = 0.019) and shorter disease-free survival (P = 0.007). Patients with multiple tumors had higher local (P = 0.047) and extrahepatic (P = 0.019) recurrence rates than those with a solitary tumor. Tumor size had an impact on local recurrence rate only in patients with liver metastasis with a higher rate in those with tumor > 2.5 cm in diameter (P = 0.028). CONCLUSIONS: Tumor pathology does not appear to have a significant impact on local recurrence rates. RFA is effective in local tumor control for both HCC and liver metastasis.