Radiofrequency ablation of subcapsular hepatocellular carcinoma: Single center experience

Imaging Classification of Exophytic HCC and Our Experience with Microwave Ablation of Type 2 Lesions

Purpose  The purpose of this article is to classify hepatocellular carcinoma (HCC) based on imaging and to evaluate the role of ultrasound-guided microwave ablation (MWA) in the management of type 2 exophytic HCC. Materials and Methods  A retrospective study was performed at our institution after approval by the Institutional Review Board. The study was undertaken from January 2017 to May 2022. Based on the location, HCC was classified and categorized on cross-sectional imaging into four types. All MWA procedures were performed using ultrasound guidance. Patients were followed up every 3 months with cross-sectional imaging. Results  During the study period, 225 lesions were reviewed. MWA was performed in 13 type 2 exophytic HCC patients. Segment 3 (38%) was the most common site when categorized as per Couinaud classification and segment 6 was the next common site. Technical success of complete ablation, evaluated by postprocedure contrast-enhanced computed tomography scan, was 100%. The median follow-up period was 24 months (range: 9-24 months). One patient presented with a residual lesion on the first follow-up at 30 days. Two other patients followed up to 9 months were free of HCC. Ten patients followed up at 1 year showed no recurrence, while 7 of them were followed up for 24 months, and 1 of whom showed multicentric recurrence which was treated by selective intra-arterial radiation therapy. Conclusion  A classification system for exophytic lesions can allow for better patient selection, planning, and reporting of ablative outcomes. MWA has performed well when ablating these technically challenging lesions with a certain degree of planning.

Risk of intra-abdominal seeding after laparoscopic-assisted thermal ablation of exophytic hepatocellular carcinoma tumors

BACKGROUND

Laparoscopic-assisted thermal ablation has been used successfully to treat early hepatocellular carcinoma (HCC) tumors, defined as < 3 cm in diameter. This approach allows for ablation of tumors located in areas of the liver that are otherwise inaccessible for a percutaneous approach. Thermal ablation of exophytic tumors remains controversial due to a reported increased risk of tumor seeding of the abdominal cavity and incomplete ablation.

METHODS

This cohort study consisted of 663 HCC tumors treated with thermal ablation at a single, quaternary academic medical center between 2/2001 and 1/2021. Post treatment, patients were followed at a defined interval schedule beginning at one month post treatment, then every 3 months for 2 years, every 6 months in year 3, followed by yearly studies. Patients' medical records were reviewed for three years post ablation for evidence of complete ablation and intra-abdominal dissemination of disease.

RESULTS

326 patient records met the inclusion criteria. Comparing the exophytic and non-exophytic groups, there were statistically significant differences in etiology of liver disease (p = 0.048) and TNM stage (p = 0.03), as well as a higher rate of incomplete ablation in the non-exophytic group (10.2% vs 3.3%; p = 0.045). Otherwise, there were no statistically significant differences in baseline characteristics, tumor characteristics, or use of thermal ablation technology. Rates of intra-abdominal dissemination of HCC were low in both groups: 1.1% (n = 1) in the exophytic group and 1.7% (n = 4) in the non-exophytic group. There was no significant difference in intra-abdominal dissemination of HCC between the groups (p > 0.99, RR = 0.66; 95% CI 0.07-5.79). Additionally, no differences were seen in dissemination between microwave ablation and radiofrequency ablation (p > 0.99).

CONCLUSION

This study demonstrates that laparoscopic-assisted thermal ablation of small, exophytic tumors is safe and does not increase the risk for disseminated intra-abdominal HCC disease.

Laparoscopic radiofrequency ablation versus percutaneous radiofrequency ablation for subphrenic hepatocellular carcinoma

PURPOSE

Radiofrequency ablation is a curative treatment option for very early-stage or earlystage hepatocellular carcinoma (HCC). However, percutaneous radiofrequency ablation (PRFA) for subphrenic tumors is technically challenging. Laparoscopic radiofrequency ablation (LRFA) has been used to overcome this disadvantage. This study compared the treatment outcomes between LRFA and PRFA for subphrenic HCC.

METHODS

This retrospective study screened patients who underwent PRFA or LRFA for subphrenic HCC between 2013 and 2018. Therapeutic outcomes, including local tumor progression (LTP), intrahepatic distant recurrence (IDR), extrahepatic metastasis (EM), disease-free survival (DFS), and overall survival (OS), were compared between the two groups.

RESULTS

Thirty patients in the PRFA group and 23 patients in the LRFA group were included. LTP was observed in six patients in the PRFA group (20%), but in no patients in the LRFA group. The cumulative LTP rates at 1, 3, and 5 years were 3.7%, 23.4%, and 23.4%, respectively, in the PRFA group and 0.0% in the LRFA group (P=0.015). The IDR, EM, and DFS rates were not significantly different between the two groups (P=0.304, P=0.175, and P=0.075, respectively). The OS rates at 1, 3, and 5 years were 96.6%, 85.7%, and 71.6%, respectively, in the PRFA group and 100%, 95.7%, and 95.7%, respectively, in the LRFA group (P=0.049).

CONCLUSION

LRFA demonstrated better therapeutic outcomes than did PRFA for subphrenic tumors in terms of LTP and OS. Therefore, LRFA can be considered as the first-line treatment option for subphrenic HCC.

Guidewire-catheter induced hydrodissection to assist radiofrequency ablation for subcapsular hepatocellular carcinoma with iodized oil retention in patients with failed artificial ascites due to perihepatic adhesion

PURPOSE

We aimed to evaluate the usefulness of guidewire-catheter induced hydrodissection (GIH) to assist radiofrequency ablation (RFA) for subcapsular hepatocellular carcinoma (HCC) with iodized oil retention in patients with failed artificial ascites due to perihepatic adhesion.

METHODS

This retrospective study included 17 patients with small subcapsular HCC ineligible for ultrasonography-guided RFA who received RFA under guidance of fluoroscopy and cone-beam computed tomography immediately after iodized oil transarterial chemoembolization (TACE) between April 2011 and January 2016. In the study patients, creation of artificial ascites to protect the perihepatic structures failed due to perihepatic adhesion and GIH was attempted to separate the perihepatic structures from the ablation zone. The technical success rate of GIH, technique efficacy of RFA with GIH, local tumor progression (LTP), peritoneal seeding, and complications were evaluated.

RESULTS

The technical success rate of GIH was 88.24% (15 of 17 patients). Technique efficacy was achieved in all 15 patients receiving RFA with GIH. During an average follow-up period of 48.1 months, LTP developed in three patients. Cumulative LTP rates at 1, 2, 3, and 5 years were 13.3%, 20.6%, 20.6%, and 20.6%, respectively. No patient had peritoneal seeding. Two of the 15 patients receiving RFA with GIH had a CIRSE grade 3 liver abscess, but none had complications associated with thermal injury to the diaphragm or abdominal wall near the ablation zone.

CONCLUSION

GIH can be a useful method to assist RFA for subcapsular HCC with iodized oil retention in patients with failed artificial ascites due to perihepatic adhesion.

The Incidence of Bacteremia and Risk Factors of Post-Radiofrequency Ablation Fever for Patients with Hepato-Cellular Carcinoma

Post-radiofrequency ablation (RFA) fever is a self-limited complication of RFA. The correlation between post-RFA fever and bacteremia and the risk factors associated with post-RFA fever have not been evaluated. Patients with newly diagnosed or recurrent hepatocellular carcinoma who underwent ultrasonography-guided RFA between April 2014 and February 2019 were retrospectively enrolled. Post-RFA fever was defined as any episode of body temperature >38.0 °C after RFA during hospitalization. A total of 272 patients were enrolled, and there were 452 applications of RFA. The frequency of post-RFA fever was 18.4% (83/452), and 65.1% (54/83) of post-RFA fevers occurred on the first day after ablation. Patients with post-RFA fever had a longer hospital stay than those without (9.06 days vs. 5.50 days, p < 0.001). Only four (4.8%) patients with post-RFA fever had bacteremia. The independent factors associated with post-RFA fever were younger age (adjusted odds ratio (OR) = 0.96, 95% CI, 0.94-0.99, p = 0.019), low serum albumin level (adjusted OR = 0.49, 95% CI, 0.25-0.95, p = 0.036), general anesthesia (adjusted OR = 2.06, 95% CI, 1.15-3.69, p = 0.015), tumor size (adjusted OR = 1.52, 95% CI, 1.04-2.02, p = 0.032), and tumor number (adjusted OR = 1.71, 95% CI, 1.20-2.45, p = 0.003).

Radiofrequency ablation versus repeat hepatectomy in the treatment of recurrent hepatocellular carcinoma in subcapsular location: a retrospective cohort study

Background

Repeat hepatectomy and radiofrequency ablation (RFA) are widely used to treat early recurrent hepatocellular carcinoma (RHCC) located in the subcapsular region, but the optimal treatment strategy remains to be controversial.

Methods

A total of 126 RHCC patients in the subcapsular location after initial radical hepatectomy were included in this study between Dec 2014 and Jan 2018. These patients were divided into the RFA group (46 cases) and the repeat hepatectomy group (80 cases). The primary endpoints include repeat recurrence-free survival (rRFS) and overall survival (OS), and the secondary endpoint was complications. The propensity-score matching (PSM) was conducted to minimize the bias. Complications were evaluated using the Clavien-Dindo classification, and severe complications were defined as classification of complications of ≥grade 3.

Results

There were no significant differences in the incidence of severe complications were observed between RFA group and repeat hepatectomy group in rRFS and OS both before (1-, 2-, and 3-year rRFS rates were 65.2%, 47.5%, and 33.3% vs 72.5%, 51.2%, and 39.2%, respectively, P = 0.48; 1-, 2-, and 3-year OS rates were 93.5%, 80.2%, and 67.9% vs 93.7%, 75.8%, and 64.2%, respectively, P = 0.92) and after PSM (1-, 2-, and 3-year rRFS rates were 68.6%, 51.0%, and 34.0% vs 71.4%, 42.9%, and 32.3%, respectively, P = 0.78; 1-, 2-, and 3-year OS rates were 94.3%, 82.9%, and 71.4% vs 88.6%, 73.8%, and 59.0%, respectively, P = 0.36). Moreover, no significant differences in the incidence of severe complications were observed between the RFA group and repeat hepatectomy group.

Conclusion

Both repeat hepatectomy and RFA are shown to be effective and safe for the treatment of RHCC located in the subcapsular region.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12957-021-02277-4.

Comparison of Percutaneous Radiofrequency Ablation for Subcapsular and Non-Subcapsular Colorectal Cancer Liver Metastases

Purpose

To evaluate the efficacy and safety of percutaneous radiofrequency ablation (RFA) for subcapsular colorectal cancer liver metastases (CLMs).

Materials and Methods

With the approval of the Institutional Review Board, the clinical data of CLM patients who underwent percutaneous RFA for the first time from August 2010 to August 2020 were continuously collected. All CLMs were divided into subcapsular and non-capsular groups. Baseline characteristic data, technical effectiveness, minimal ablative margin, complications, local tumor progression (LTP), and overall survival (OS) between the two groups were analyzed using the t-test or chi-square test. A Cox regression model was used to evaluate the prognostic factors of LTP.

Results

One hundred and ninety-nine patients (124 males; mean age, 60.2 years) with 402 CLMs (221 subcapsular; mean size, 16.0 mm) were enrolled in the study. Technical effectiveness was achieved in 93.5% (376/402) of CLMs, with a major complication rate of 5.5%. Compared with non-subcapsular tumors, the minimal ablative margin achieved in subcapsular CLM was smaller (χ² = -8.047, P < 0.001). With a median follow-up time of 23 months (range, 3−96 months), 37.1% of the tumors had LTP. The estimated cumulative OS at 1, 3, and 5 years was 96.1%, 66.0%, and 44.2%, respectively. There were no statistically significant differences between the two groups in terms of technical effectiveness (χ² = 0.484, P = 0.487), major complications (χ² = 0.082, P = 0.775), local tumor progression-free survival (LTPFS) (χ² = 0.881, P = 0.348), and OS (χ² = 2.874, P = 0.090). Minimal ablative margin, tumor size (≥20 mm), and technical effectiveness were predictors of LTP (all P < 0.05).

Conclusion

RFA is a safe and effective technique for local tumor control of subcapsular CLMs.

Evaluation of the efficacy and postoperative outcomes of hydrodissection-assisted microwave ablation for subcapsular hepatocellular carcinoma and colorectal liver metastases

PURPOSE

To explore the effect of hydrodissection assisted percutaneous microwave ablation (MWA) on the primary technique efficacy (PTE) and local tumor progression (LTP) of subcapsular hepatocellular carcinoma (HCC) and colorectal liver metastases (CRLM).

METHODS

A retrospective review of 135 patients with 181 hepatic subcapsular HCC and CRLM that underwent MWA with (hydrodissection group) and without the use of hydrodissection (control group). The PTE, cumulative LTP rate, and postoperative complications were compared between the two groups.

RESULTS

Amongst the 135 patients with 181 tumors, 60 patients with 72 tumors were in the hydrodissection group and 75 patients with 109 tumors were in the control group. The PTEs were 97.2% and 85.3% in hydrodissection and control groups, respectively (P = 0.019). Multivariate analysis showed that hydrodissection significantly improved the PTE of MWA [odds ratio (OR) 0.147; 95% confidence interval (CI) 0.031-0.703; P = 0.016). Among the tumors which achieved complete response at the first (1 month) follow-up, the overall LTP rates were 8.6% (6/70) and 11.8% (11/93) in the hydrodissection and control groups, respectively. The 1- and 2-year cumulative LTP rates were 3.0% and 5.0% for the hydrodissection group and 6.8% and 13.5% in the control group, respectively (P = 0.391). No significant differences were observed in major postoperative complications between the two groups.

CONCLUSION

Hydrodissection-assisted MWA had a significantly higher PTE than MWA alone in hepatic subcapsular HCC and CRLM. Hydrodissection did not significantly impact the cumulative LTP rate or the incidence of postoperative complications.

Percutaneous cryoablation of subcapsular hepatocellular carcinoma: a retrospective study of 57 cases

PURPOSE This study aims to evaluate the safety and effectiveness of the percutaneous cryoablation for subcapsular hepatocellular carcinoma (HCC). METHODS A total of 57 patients with subcapsular (<1 cm form the liver edge) HCCs (68 lesions), who were treated with CT-guided percutaneous cryoablation in the Department of Interventional Radiology of our hospital between July 1, 2016 and September 1, 2018, were retrospectively included. Complete ablation rate, local tumor progression (LTP) and treatment-related complications were evaluated. Furthermore, the degree of intraoperative and postoperative pain was measured with the visual analog scale (VAS), and laboratory findings were compared before and after the procedure. RESULTS All patients successfully completed the treatment. The mean follow-up period was 12.8 months (range, 3-27 months), and the complete ablation rate was 97% (66/68). Local tumor progression occurred in 11 lesions (16.2%), and the 6-, 12- and 18-month cumulative LTP rates were 4.0%, 8.2% and 20.5%, respectively. Two patients (3.5%, 2/57) developed major complications, and 12 patients had minor complications (22.8%, 12/57). The mean VAS score during the operation was 1.65 points (range, 1-3 points). Postoperative pain worsened in 3 patients, and the VAS scores reached 4-5. Transient changes in biochemical and hematologic markers were observed. CONCLUSION Percutaneous cryoablation for subcapsular HCC is safe and effective, the procedure is simple and the patients suffer less pain.

Minimally invasive surgery versus radiofrequency ablation for single subcapsular hepatocellular carcinoma ≤ 2 cm with compensated liver cirrhosis

BACKGROUND

There is currently no consensus regarding the relative applicability of minimally invasive treatment, including radiofrequency ablation (RFA) and minimally invasive surgery (MIS) in patients with a single small peripheral hepatocellular carcinoma (HCC) and compensated cirrhosis. This study investigated the clinical outcomes of MIS and RFA for single subcapsular HCC ≤ 2 cm in patients with compensated cirrhosis.

METHODS

In this retrospective study, we enrolled 75 patients who had a single subcapsular HCC ≤ 2 cm along with Child-Pugh class A cirrhosis and a preoperative platelet count ≥ 100 k/μl. These patients underwent RFA (n = 39) or MIS (n = 36) between 2010 and 2016. Clinical outcomes including disease-free survival (DFS), survival without recurrence beyond the Milan criteria (RBM), and overall survival (OS) were compared.

RESULTS

The 7-year DFS rates in the MIS and RFA groups were 86.1% and 35.9% (p < 0.001), respectively, the 7-year RBM rates were 88.9% and 66.7% (p = 0.014), respectively, and the 7-year OS rates were 97.2% and 82.1% (p = 0.008), respectively. RFA was associated with more ipsilateral lobe recurrence (20% vs. 83.4%, p = 0.004), and 40% were in direct contact with the ablation penumbra. A Cox proportional hazard analysis identified RFA as an independent predictor of mortality (adjusted hazard ratio, 9.625, p = 0.038). No major complications occurred in either group. RFA patients had a shorter hospital stay (median of 2 vs. 6 days, p < 0.001) and operation time (median of 23.5 vs. 216 min, p = 0.001).

CONCLUSIONS

MIS was associated with a better 7-year OS, RBM, and DFS among patients with single subcapsular HCC ≤ 2 cm, Child-Pugh A liver function, and no clinically significant portal hypertension when compared to those who underwent percutaneous RFA.

Percutaneous thermal ablation of subcapsular hepatocellular carcinomas: influence of tumor-surface contact and protrusion on therapeutic efficacy and safety

PURPOSE

To evaluate therapeutic efficacy and complication of percutaneous thermal ablation of subcapsular hepatocellular carcinomas (HCCs), and how these may be influenced by the degree of tumor to liver surface contact and tumor protrusion from liver surface.

MATERIALS AND METHODS

Our retrospective study was approved by the Institutional Review Board. Between January 2006 and December 2013, 290 patients (82 women, 208 men; mean age, 64.5 years; range, 33-89 years) with 474 subcapsular (within 1 cm to the liver surface) HCCs (mean size, 23.7 mm; range, 6-71 mm) underwent percutaneous thermal ablation. The HCCs were divided into surface contact group (n = 243) and non-surface contact group (n = 231). The former was further subdivided into exophytic and non-exophytic HCCs. Technical success, primary technique efficacy, local tumor progression (LTP), and secondary technique efficacy rates were analyzed and compared by the chi-square test or Fisher exact test. Prognostic factors for LTP and secondary technique efficacy were assessed using the Cox regression model. Major complications were also assessed.

RESULTS

With median follow-up of 15 months (range, 1-87 months), technical success and primary technique efficacy were 98.7% and 95.7% % in the non-surface contact group; 96.4% and 94.0% in the non-exophytic group; and 100% and 94.7% in the exophytic group (p > 0.05). Tumor size > 3 cm was a significant predictor for LTP, but not for secondary efficacy. Overall major complication rate was 3.8% (24/624) and was not different among the three groups.

CONCLUSION

Subcapsular HCCs can be effectively treated with thermal ablation techniques. Degree of tumor-surface contact including moderate protrusion does not appear to limit feasibility or procedure effectiveness.

KEY POINTS

• Subcapsular HCCs can be effectively treated with thermal therapy when proper image-guided technique and assistive techniques are applied. • Degree of tumor surface contact including moderate protrusion does not appear to limit feasibility or procedure effectiveness. • Major complications after percutaneous thermal ablation of subcapsular HCCs such as tumor seeding can be minimized by avoiding breach of the tumor capsule exposed to the peritoneal surface and use of tract ablation.

Efficacy and Safety of Microwave Ablation (MWA) for Hepatocellular Carcinoma (HCC) in Difficult Anatomical Sites in Egyptian Patients with Liver Cirrhosis

Background and aim: Imaging guided microwave ablation (MWA) for hepatocellular carcinoma (HCC) has become a widely used method over recent years. Tumors close to the diaphragm, gastrointestinal tract, gallbladder, pancreas, hepatic hilum and major bile duct or vessels are generally considered relative contraindications for microwave ablation. This study was conducted to assess the effectiveness and safety of ultrasonography-guided MWA in treating patients with HCC in difficult anatomical sites in comparison to those in conventional sites. Patients and methods: Eighty-eight patients were included and divided into two groups: the study group of 44 with 46 lesions lying <5mm from the diaphragm, hepatic capsule, gall bladder (GB) or large vessel; and the control group of 44 patients with 50 lesions in non-risky sites. Each lesion was ablated using an ultrasound guided microwave probe using a detailed protocol. Results: Most of the patients were males, with a mean age of 57.8 years. In the study group, two patients had lesions adjacent to the GB, twelve were perivascular and 32 were subcapsular. The overall successful ablation rates were 84.8% and 92% in the study and control groups, respectively. Within the study group, ablation rates were 100%, 75% and 87.5% for lesions close to the GB, perivascular lesions and subcapsular lesions, respectively. One patient developed a subcutaneous abscess, with good outcome after proper treatment. Fever, pain and asymptomatic pleural effusion were reported after ablation without statistically significant difference between the groups or among subgroups. In conclusion: MWA for HCC in difficult anatomical sites is as effective and safe as for ordinary sites.

Transarterial chemoembolization plus multi-imaging-guided radiofrequency ablation for elimination of hepatocellular carcinoma nodules measuring 3.1 to 5.0 cm: a single-center study

Objective This study was performed to determine whether transarterial chemoembolization (TACE) plus multi-imaging-guided radiofrequency ablation (MIG-RFA) can completely eliminate 3.1- to 5.0-cm hepatocellular carcinoma (HCC) nodules and identify factors that may influence the complete elimination rate (CER) of this therapy. Methods Patients who underwent TACE+MIG-RFA for initial treatment of HCC from January 2008 to January 2016 were retrospectively reviewed. In total, 162 patients with 216 HCC nodules (3.1-5.0 cm) were enrolled. TACE was performed first; MIG-RFA was performed 2 to 4 weeks later. Contrast-enhanced computed tomography was performed 1, 3, 6, and 12 months after TACE+MIG-RFA. If tumor enhancement was not detected by the end of the 12-month follow-up, the lesion was considered completely eliminated. Additional TACE+MIG-RFA was performed for residual lesions. The CER was calculated 12 months after the last therapy. Factors that may influence the CER were analyzed. Results In total, 207 (95.8%) nodules showed no residual lesions and were completely eliminated after one or more TACE+MIG-RFA sessions. Nine (4.2%) nodules were incompletely eliminated even with repeated TACE+MIG-RFA. Tumor location was the only significant prognostic factor influencing the CER. Conclusions TACE+MIG-RFA can eliminate 3.1- to 5.0-cm HCC nodules; the tumor location may affect the treatment outcome.

Predictive Value of Procalcitonin for Bacterial Infection after Transarterial Chemoembolization or Radiofrequency Ablation for Hepatocellular Carcinoma

This prospective observational study aimed at investigating the role of procalcitonin (PCT) in diagnosing bacterial infection and guiding antibiotic therapy for hepatocellular carcinoma (HCC) patients with fever after transarterial chemoembolization (TACE) and/or radiofrequency ablation (RFA). Ninety-seven cases (84 patients) were enrolled. Serum PCT, C-reactive protein (CRP), and white blood cell (WBC) counts were measured on the day of fever onset (day 0) and days 1, 3, 5, and 7 of fever. Empirical antibiotics were initiated only if PCT was ≥0.5 ng/mL or specific infection foci were suspected. An infectious cause was found in nine cases. PCT on day 0 of fever was significantly higher in patients with bacterial infection than in those without infection (P = 0.035). The area under the receiver operating characteristic curve for PCT was 0.715 (95% confidence interval, 0.538–0.892) and was higher than that for CRP (0.598 (0.368–0.828)) or WBC counts (0.502 (0.307–0.697)). In patients undergoing TACE and/or RFA, a significantly lower number of antibiotics were prescribed during the study period than during the prestudy period (P < 0.001). In conclusion, PCT might be a biomarker for diagnosing infection and guiding antibiotic treatment to reduce unnecessary antibiotic use in patients with fever after TACE and/or RFA.

Percutaneous microwave ablation of exophytic tumours in hepatocellular carcinoma patients: Safe or not?

BACKGROUND & AIMS

To explore the long-term outcomes and safety of ultrasound-guided percutaneous microwave ablation (MWA) of exophytic tumours in hepatocellular carcinoma (HCC) patients.

METHODS

One hundred and thirty-two patients with subcapsular HCC were enrolled in this retrospective study. These patients were divided into the exophytic group (n=71) and non-exophytic group (n=61) according to the location of the tumour(s). A special technology of puncture and ablation was performed to treat the exophytic tumours. The local tumour progression (LTP), progression free survival (PFS) and overall survival (OS) were analysed using Kaplan-Meier and Log-rank tests.

RESULTS

Sixty-nine of 71 exophytic tumours and 60 of 61 subcapsular tumours were completely ablated. The complete ablation rates were 97.2% and 98.4% respectively. The follow-up periods ranged from 6 to 62 months with a median of 31 months in the exophytic group, and ranged from 5 to 61 months, with a median of 27 months in the non-exophytic group. The 1-, 3- and 5-year cumulative LTP rates were 2.4%, 12.3%, 18.4% and 5.1%, 12.0%, 17.8% in the exophytic and non-exophytic groups respectively (P=.733). The 1-, 3- and 5-year OS rates were 100%, 75.7%, 52.9% and 95.0%, 73.8%, 61.5% in the exophytic group and non-exophytic group respectively (P=.980). There was no procedure-related mortality or major complication.

CONCLUSION

Ultrasound-guided percutaneous MWA is safe and effective for exophytic tumours in HCC patients. Treated by MWA, the HCC patients with exophytic tumours can get the similar local response and long-term outcome to those with non-exophytic subcapsular tumours.

Early complications after percutaneous radiofrequency ablation for hepatocellular carcinoma: an analysis of 1,843 ablations in 1,211 patients in a single centre: experience over 10 years

AIM

To evaluate the incidence of adverse events and associated factors after radiofrequency ablation (RFA) in patients with hepatocellular carcinoma within 30 days.

MATERIALS AND METHODS

The early complications that occurred within 30 days after RFA at a single institution from January 2000 to July 2010 were reviewed in order to evaluate the morbidity, mortality, and risk factors associated with the complications. In total, 1,211 patients (845 men, 70.5%) with a mean age of 68 years (range, 27-88 years) underwent 1,843 RFA procedures.

RESULTS

The overall incidence rate of complications was 6.8% (125 cases). Major complications (n=36, 2%) included liver abscess (n=15, 0.8%), intraperitoneal bleeding (n=8, 0.4%), liver failure (n=5, 0.3%), variceal bleeding (n=3, 0.2%), haemothorax (n=2, 0.1%), cholecystitis (n=2, 0.1%), and bowel perforation (n=1, 0.1%). Among the minor complications (n=89, 4.8%), the most common was the post RFA syndrome accompanied by pain and fever (n=75, 4.1%). Other minor complications included significant pleural effusion (n=7, 0.4%), skin wound infection (n=4, 0.2%), and thermal injuries to the skin (n=3, 0.2%). Procedural infections significantly increased with tumour size (OR=1.379; 95% confidence interval [CI], 1.191-1.579; p<0.001), and multiple overlapping ablations (OR=1.118; 95% CI, 1.019-1.227, p=0.018). Thrombocytopenia (<50,000/μl), prothrombin time, and serum albumin level were significantly associated with post-RFA bleeding episodes (p=0.041, p=0.021, and p=0.003, respectively). The overall mortality rate was 0.3% (three cases of hepatic failure, two case of sepsis, and one case of renal failure).

CONCLUSIONS

RFA is a safe and effective local treatment for hepatocellular carcinoma. Careful selection of patients and appropriate RFA planning could decrease procedural mortality and morbidity.

Cryoablation of Hepatocellular Carcinoma with High-Risk for Percutaneous Ablation: Safety and Efficacy

PURPOSE

The aim of this study was to evaluate the safety and effectiveness of cryoablation in the treatment of subcapsular hepatocellular carcinoma (HCC) adjacent to various organs.

MATERIALS AND METHODS

Twenty-eight patients with subcapsular HCC were treated with cryoablation in our institution. The degree of peri-procedural pain was measured using the visual analog scale (VAS). Technical success, local tumor progression, and overall disease progression rates were calculated. Procedure-related complications were identified by reviewing electronic medical records. Biochemical data, including serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), and total bilirubin levels before and after the procedure were collected.

RESULTS

Subcapsular HCC tumors were located near the gallbladder, colon, stomach, kidney, diaphragm, or abdominal wall. The technical success rate of cryoablation was 96.4 % (27/28). Local recurrence- and progression-free survival rates were 96 and 84 % at 6 months, and 82 and 43 % at 1 year, respectively. All patients survived during the follow-up period. The VAS pain score ranged from 0 to 3 (mean, 1.57). A major complication occurred in one patient (3.6 %) and minor complications occurred at a rate of 17.9 %. Transient elevations of serum AST, ALT, and bilirubin levels were observed.

CONCLUSION

Cryoablation is a safe and an effective procedure for the treatment of subcapsular HCC adjacent to various major organs.

Long-term Therapeutic Outcomes of Radiofrequency Ablation for Subcapsular versus Nonsubcapsular Hepatocellular Carcinoma: A Propensity Score Matched Study

Purpose To compare the long-term therapeutic outcomes of radiofrequency (RF) ablation for hepatocellular carcinoma (HCC) in subcapsular versus nonsubcapsular locations by using propensity score matching. Materials and Methods RF ablation for subcapsular HCC is controversial because of a high risk of incomplete ablation or major complications. This retrospective study was approved by the institutional review board, and the requirement for informed consent was waived. Between April 2006 and December 2011, 508 consecutive patients (396 men, 112 women; age range, 30-80 years) with a single HCC (Barcelona Clinic Liver Cancer stage 0 or A) underwent ultrasonography-guided percutaneous RF ablation as a first-line treatment. The patients were divided into two groups according to tumor location: subcapsular (n = 227) and nonsubcapsular (n = 281). Subcapsular HCC was defined as an index tumor located within 0.1 cm of the liver capsule. The association of subcapsular location and therapeutic outcomes of RF ablation was evaluated, including (a) local tumor progression (LTP) by using a competing risk regression model and (b) overall survival (OS) by using a Cox proportional hazards model according to propensity score matched data. The major complication rates from both overall data and matched data were assessed. Results Matching yielded 163 matched pairs of patients. In the two matched groups, cumulative LTP rates were 18.8% and 20.9% at 3 and 5 years, respectively, in the subcapsular group and 13.2% and 16.0% in the nonsubcapsular group. Corresponding OS rates were 90.7% for 3 years and 83.2% for 5 years in the subcapsular group and 91.4% and 79.1%, respectively, in the nonsubcapsular group. Hazard ratios (HRs) for LTP (HR = 1.37, P = .244) and OS (HR = 0.86, P = .604) were not significantly different between the two matched groups. Additionally, differences in major complication rates were not significant between groups for the two sets of data (P > .05). Conclusion The differences in LTP, OS, and major complication rates of RF ablation for HCC were not significant between subcapsular and nonsubcapsular groups. (©) RSNA, 2016.

Flat-panel cone-beam CT-guided radiofrequency ablation of very small (≤ 1.5 cm) liver tumors: technical note on a preliminary experience

PURPOSE

The aim of the present study was to investigate the technical feasibility of flat-panel cone-beam CT (CBCT)-guided radiofrequency ablation (RFA) of very small (<1.5 cm) liver tumors.

MATERIALS AND METHODS

Patients included were candidates for hepatic percutaneous RFA as they had single biopsy-proven hepatic tumors sized ≤ 1.5 cm and poorly defined on ultrasonography. Following apnea induction, unenhanced CBCT scans were acquired and used to deploy the RF electrode with the aid of a virtual navigation system. If the tumor was not clearly identified on the unenhanced CBCT scan, a right retrograde arterial femoral access was established to carry out hepatic angiography and localize the tumor. Patients' lesions and procedural variables were recorded and analyzed.

RESULTS

Three patients (2 male and 1 female), aged 68, 76, and 87 years were included; 3 lesions (2 hepato-cellular carcinoma and 1 metastasis from colorectal cancer) were treated. One patient required hepatic angiography. Cycles of apnea used to acquire CBCT images and to deploy the electrode lasted <120 s. Mean fluoroscopic time needed to deploy the electrode was 36.6 ± 5.7 min. Mean overall procedural time was 66.0 ± 22.9 min. No peri- or post-procedural complications were noted. No cases of incomplete ablation were noted at 1-month follow-up.

CONCLUSION

Percutaneous CBCT-guided liver RFA with or without arterial hepatic angiography is technically feasible.