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

Deep learning-based automatic pipeline for 3D needle localization on intra-procedural 3D MRI

PURPOSE

Accurate and rapid needle localization on 3D magnetic resonance imaging (MRI) is critical for MRI-guided percutaneous interventions. The current workflow requires manual needle localization on 3D MRI, which is time-consuming and cumbersome. Automatic methods using 2D deep learning networks for needle segmentation require manual image plane localization, while 3D networks are challenged by the need for sufficient training datasets. This work aimed to develop an automatic deep learning-based pipeline for accurate and rapid 3D needle localization on in vivo intra-procedural 3D MRI using a limited training dataset.

METHODS

The proposed automatic pipeline adopted Shifted Window (Swin) Transformers and employed a coarse-to-fine segmentation strategy: (1) initial 3D needle feature segmentation with 3D Swin UNEt TRansfomer (UNETR); (2) generation of a 2D reformatted image containing the needle feature; (3) fine 2D needle feature segmentation with 2D Swin Transformer and calculation of 3D needle tip position and axis orientation. Pre-training and data augmentation were performed to improve network training. The pipeline was evaluated via cross-validation with 49 in vivo intra-procedural 3D MR images from preclinical pig experiments. The needle tip and axis localization errors were compared with human intra-reader variation using the Wilcoxon signed rank test, with p < 0.05 considered significant.

RESULTS

The average end-to-end computational time for the pipeline was 6 s per 3D volume. The median Dice scores of the 3D Swin UNETR and 2D Swin Transformer in the pipeline were 0.80 and 0.93, respectively. The median 3D needle tip and axis localization errors were 1.48 mm (1.09 pixels) and 0.98°, respectively. Needle tip localization errors were significantly smaller than human intra-reader variation (median 1.70 mm; p < 0.01).

CONCLUSION

The proposed automatic pipeline achieved rapid pixel-level 3D needle localization on intra-procedural 3D MRI without requiring a large 3D training dataset and has the potential to assist MRI-guided percutaneous interventions.

Thermal ablation for hepatic tumors in high-risk locations

Thermal ablative techniques such as radiofrequency and microwave ablation are minimally invasive and cost-effective approaches that are currently being adopted as alternatives to surgical resection for primary and metastatic liver malignancies. However, they are considered to be relatively contraindicated for tumors in high-risk locations due to technical difficulties and a perceived increased risk of perioperative complications. Several techniques, including artificial ascites, non-touch multibipolar ablation, and laparoscopically assisted ablation, can be used to improve the outcomes of ablation for high-risk tumors. This review aims to provide a comprehensive summary of the techniques currently used to improve thermal ablation outcomes for high-risk liver tumors.

Efficacy and safety of laparoscopic liver resection versus radiofrequency ablation in patients with early and small hepatocellular carcinoma: an updated meta-analysis and meta-regression of observational studies

BACKGROUND

Hepatocellular carcinoma (HCC) is the most common type of liver cancer, accounting for 90% of cases worldwide and a significant contributor to cancer-related deaths. This study comprehensively compares the safety and efficacy of laparoscopic liver resection (LLR) versus laparoscopic or percutaneous radiofrequency ablation (LRFA or PRFA) in patients with early and small HCC.

METHODS

We systematically searched Cochrane Library, PubMed, Scopus, and Web of Science databases to include studies comparing LLR versus LRFA or PRFA in patients with early HCC meets the Milan criteria (defined as solitary nodule < 5 cm or three nodules ≤ 3 cm with no extrahepatic spread or vascular invasion). Pooled results were examined for overall survival, disease-free survival, recurrence-free survival, local, intrahepatic and extrahepatic recurrence rates, and complications. We conducted subgroup analyses based on the type of RFA. Meta-regression analyzed the association between overall survival, local recurrence, and various factors. The quality of the included studies was assessed using the Newcastle-Ottawa Scale. We analyzed the data using the R (v.4.3.0) programming language and the "meta" package of RStudio software.

RESULTS

We included 19 observational studies, compromising 3756 patients. LLR showed higher 5-year overall survival compared to RFA (RR = 1.17, 95% CI [1.06, 1.3], P > 0.01). Our subgroup analysis showed that LLR had higher 5-year survival than PRFA (RR = 1.15, 95% CI [1.02, 1.31], P = 0.03); however, there was no significant difference between LLR and LRFA (RR = 1.26, 95% CI [0.98, 1.63], P = 0.07). LLR was associated with higher disease-free survival) RR = 1.19, 95% CI [1.05, 1.35], P < 0.01; RR = 1.61, 95% CI [1.31, 1.98], P < 0.01(and recurrence-free survival) RR = 1.21, 95% CI [1.09, 1.35], P < 0.01; RR = 1.45, 95% CI [1.15, 1.84], P < 0.01(at 1 and 3 years. LLR was associated with lower local (RR = 0.28, 95% CI [0.16, 0.47], P < 0.01) and intrahepatic recurrence (RR = 0.7, 95% CI [0.5, 0.97], P = 0.03) than RFA. However, complications were significantly higher with LLR (RR = 2.01, 95% CI [1.51, 2.68], P < 0.01). Our meta-regression analysis showed that younger patients had higher risk for local recurrence (P = 0.008), while age wasn't significantly linked to overall survival (P = 0.25). Other covariates like total bilirubin, alpha-fetoprotein levels, and tumor size also showed no significant associations with either overall survival or local recurrence.

CONCLUSION

LLR offers improved long-term outcomes and lower recurrence rates than PRFA. However, no significant distinctions were observed between LRFA and LLR in overall survival, recurrence-free survival, and local recurrence. More robust well-designed RCTs are essential to validate our findings.

Predictive Factors of Treatment Outcomes After Percutaneous Radiofrequency Ablation of Hepatocellular Carcinoma in the Hepatocaval Confluence: A Propensity Score Matching Analysis

RATIONALE AND OBJECTIVES

To compare the efficacy and complications of ultrasound-guided percutaneous radiofrequency ablation of hepatocellular carcinoma (HCC) in the hepatocaval confluence with those of HCC in the non-hepatocaval confluence and to explore the risk factors that lead to radiofrequency ablation failure and patient local tumor progression (LTP).

MATERIALS AND METHODS

From January 2017 to January 2022, 86 patients with HCC in the hepatocaval confluence who had radiofrequency ablation were included. A 1:1 propensity-matched group of patients with HCC in the non-hepatocaval confluence with comparable clinical baseline traits, such as tumor diameter and tumor number, served as the control group. The two groups' complications, primary efficacy rate (PER), technical success rate (TSR), and prognosis were estimated.

RESULTS

After PSM, no significant difference of TSR (91.7% vs 95.8%, p = 0.491) and PER (95.8% vs 97.2%, p = 1.000) and 1-, 3-, and 5-year LTP rate (12.5% vs 9.9%, 28.2% vs 27.7%, 40.8% vs 43.8%, p = 0.959) and 1-, 3-, and 5-year DFS rate (87.5% vs 87.5%, 62.3% vs 54.2%, 18.1% vs 22.6%, p = 0.437) and 1-, 3-, and 5-year OS rate (94.3% vs 95.7%, 72.7% vs 69.6%, 20.9% vs 33.6%, p = 0.904) was detected between the two groups. The tumor-to-IVC distance was an independent risk factor for radiofrequency ablation failure in HCC patients in the hepatocaval confluence (OR = 0.611, p = 0.022). Besides, tumor diameter was an independent risk factor for predicting LTP in patients with HCC in the hepatocaval confluence (HR = 2.209, p = 0.046).

CONCLUSION

HCC in the hepatocaval confluence can be effectively treated with radiofrequency ablation. To maximize treatment efficacy, the tumor-to-IVC distance and tumor diameter should be assessed before the operation begins.

Simulating radiofrequency ablation of hepatocellular carcinomas proximal to bare area of liver

PURPOSE

To numerically assess the significance of dextrose 5% in water (D5W) thermo-protection during radiofrequency ablation (RFA) of hepatocellular carcinomas (HCCs) located near the 'bare area of liver'.

MATERIAL AND METHODS

This study utilises quasi-anatomical structures extracted from CT images. A multi-tine electrode, deployed inside the extracted organs and operated under temperature-controlled mode was used as the source of ablation. Geometrically, D5W was modelled around the 'bare area' and sandwiched between the liver and diaphragm. RFA at different sites relative to the 'bare area' was simulated to answer when to consider modelling D5W.

RESULTS

For targets near the edge of 'bare area' and at 0.5 mm gap (between the electrode and the 'bare area'), ignoring D5W and using ground conditions could result in underestimation of ablation volume by almost 25%. The importance of D5W becomes negligible for ablations near the centre of the 'bare area'.

CONCLUSIONS

Consideration of D5W during RFA of HCCs proximal to the 'bare area' can significantly influence the ablation outcome, especially when ablation is performed near the edge of the 'bare area'.

I-125 seeds brachytherapy with transcatheter arterial chemoembolization for subcapsular hepatocellular carcinoma

Background

I-125 seeds brachytherapy (ISB) has been used to improve the clinical effectiveness of transarterial chemoembolization (TACE) for hepatocellular carcinoma (HCC). We aim to appraise the safety and clinical efficacy of combined ISB and TACE for the treatment of subcapsular HCC.

Materials and methods

A retrospective investigative study extending from January 2017 to December 2020, involved individuals suffering from subcapsular HCC, who were subjected to TACE treatment with or without ISB in our center. The clinical effectiveness was compared between 2 groups.

Results

Sixty-four patients, in total, with subcapsular HCC had to undergo TACE with (n = 32) or without (n = 32) ISB in our center. After CT-guided ISB, only 2 (6.3%) patients experienced a self-limited pneumothorax. Combined treatment resulted in a significantly higher complete response (56.3% vs. 18.8%, P = 0.002) and total response (90.7% vs. 59.4%, P = 0.004) rates than that of TACE alone. In comparison to the TACE alone group, the median progression-free survival was substantially longer in the combined treatment group (11 months vs. 5 months, P = 0.016). Further, 15 and 28 patients in combined and TACE alone groups respectively died within the follow-up. The median OS was comparable between combined and TACE alone groups (22 months vs. 18 months, P = 0.529).

Conclusions

Combined TACE and ISB therapy is a safe treatment method for individuals suffering from subcapsular HCC. When compared, combined treatment had significantly enhanced clinical efficacy as a subcapsular HCC therapy, in comparison to TACE alone.

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 Hepatic Resection Versus Laparoscopic Radiofrequency Ablation for Subcapsular Hepatocellular Carcinomas Smaller Than 3 cm: Analysis of Treatment Outcomes Using Propensity Score Matching

Objective

To compare the therapeutic outcomes of laparoscopic hepatic resection (LHR) and laparoscopic radiofrequency ablation (LRFA) for single subcapsular hepatocellular carcinoma (HCC).

Materials and Methods

We screened 244 consecutive patients who had received either LHR or LRFA between January 2014 and December 2016. The feasibility of LRFA in patients who underwent LHR was retrospectively assessed by two interventional radiologists. Finally, 60 LRFA-feasible patients who had received LHR and 29 patients who had received LRFA as the first treatment for a solitary subcapsular HCC between 1 cm and 3 cm were finally included. We compared the therapeutic outcomes, including local tumor progression (LTP), recurrence-free survival (RFS), and overall survival (OS) between the two groups before and after propensity score (PS) matching. Multivariable Cox proportional hazard regression was also used to evaluate the difference in OS and RFS between the two groups for all 89 patients.

Results

PS matching yielded 23 patients in each group. The cumulative LTP and OS rates were not significantly different between the LHR and LRFA groups after PS matching (p = 0.900 and 0.003, respectively). The 5-year LTP rates were 4.6% and 4.4%, respectively, and OS rates were 100% and 90.7%, respectively. The RFS rate was higher in LHR group without statistical significance (p = 0.070), with 5-year rates of 78.3% and 45.3%, respectively. OS was not significantly different between the LHR (reference) and LRFA groups in multivariable analyses, with a hazard ratio (HR) of 1.33 (95% confidence interval, 0.12–1.54) (p = 0.818). RFS was higher in LHR (reference) than in LRFA without statistical significance in multivariable analysis, with an HR of 2.01 (0.87–4.66) (p = 0.102).

Conclusion

There was no significant difference in therapeutic outcomes between LHR and LRFA for single subcapsular HCCs measuring 1–3 cm. The difference in RFS should be further evaluated in a larger study.

Periprocedural risk factors for incomplete radiofrequency ablation of liver metastases from colorectal cancer: a single-center retrospective analysis

OBJECTIVE

To explore independent risk factors for incomplete radiofrequency ablation (iRFA) of colorectal cancer liver metastases (CRLM) and evaluate adverse outcomes following iRFA.

MATERIALS AND METHODS

Magnetic resonance imaging data of CRLM patients who received percutaneous RFA were randomized into training (70%) and validation set 1 (30%) data sets. An independent validation set 2 was derived from computed tomography scans. Uni- and multivariate analyses identified independent risk factors for iRFA. Area under the curve (AUC) values were used to evaluate the predictive model performance. Risk points were assigned to independent predictors, and iRFA was predicted according to the total risk score. Kaplan-Meier curves were used to assess new intrahepatic metastases (NIHM), unablated tumor progression, and overall survival (OS).

RESULTS

Multivariate regression determined as independent iRFA risk factors perivascular tumor location, subcapsular tumor location, tumor size ≥20 mm, and minimal ablative margin ≤5 mm. The AUC values of the model in the training set, validation set 1, and validation set 2 were 0.867, 0.772, and 0.820, respectively. The respective AUC values of the total risk score were 0.864, 0.768, and 0.817. During the 6-year follow-up, the cumulative OS was significantly shorter in the iRFA than in the complete RFA group, and NIHM (hazard ratio [HR] = 2.79; 95% confidence interval [CI]: 1.725, 4.513) and unablated tumor progression (HR = 3.473; 95% CI: 1.506, 8.007) were more severe.

CONCLUSIONS

Perivascular tumor location, subcapsular tumor location, tumor size ≥20 mm, and minimal ablative margin ≤5 mm were independent risk factors for iRFA. iRFA may be a potential predictor of NIHM, unablated tumor progression, and OS.

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.

Laparoscopic radiofrequency ablation of subcapsular hepatocellular carcinomas: risk factors related to a technical failure

BACKGROUND

This study aimed to evaluate the risk factors related to a technical failure after laparoscopic radiofrequency ablation (RFA) for subcapsular hepatocellular carcinomas (HCCs).

MATERIALS AND METHODS

A total of 110 patients with 114 HCCs who underwent laparoscopic RFA for HCCs (new HCC [n = 85] and local tumor progression [LTP] [n = 29]) between January 2013 and December 2018 were included. We evaluated the incidence of technical failure on immediate post-RFA CT images. Risk factors for a technical failure after laparoscopic RFA were assessed using univariable logistic regression analyses. The cumulative LTP rate was estimated using the Kaplan-Meier method.

RESULTS

Technical failure was noted in 3.5% (4/114) of the tumors. All four tumors that showed a technical failure were cases of LTP from previous treatment and were invisible on laparoscopy. On univariate analysis, LTP lesion, invisibility of the index tumor on laparoscopy, and peri-hepatic vein location of the tumor were identified as risk factors for a technical failure. The cumulative LTP rates at 1, 3, and 5 years were estimated to be 2.8%, 4.8%, and 4.8%, respectively.

CONCLUSIONS

LTP lesion, invisibility of the index tumor on laparoscopy, and peri-hepatic vein location of the tumor were identified as the risk factors for a technical failure after laparoscopic RFA.

Outcome of Laparoscopic Assisted Percutaneous Microwave Ablation for Exophytic Versus Non-exophytic Hepatocellular Carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the most common malignancies and is the third cause of cancer-related death worldwide. Surgery is the optimal treatment for early HCC; however, the majority of cases are not suitable for curative resection at the time of diagnosis. Surgical resection difficulties may be related to size, site, number of tumors, extrahepatic involvement, and patient general condition. Exophytic tumors were considered as relative contraindication for thermal ablation because of the risk of incomplete ablation or major complications as hemorrhage and seeding.

AIM OF THIS STUDY

to evaluate the safety and efficacy of microwave ablation (MWA) of exophytic HCC in comparison with non-exophytic HCC.

METHODS

Prospective comparative study carried on 30 patients having 30 exophytic (six of those patients had another non-exophytic lesion) and 32 patients having 44 non-exophytic HCC lesions (22 had single lesion, 8 patients had 2 lesions, and 2 patients had 3 lesions) within Milan criteria. All patients were child A or B, they were subjected to full clinical assessment, laboratory investigations, and radiological investigations. Laparoscopic assisted percutaneous MWA was the procedure of choice in our study for all patients either having exophytic or non-exophytic lesions using no-touch wedge technique for exophytic lesions and direct puncture for non-exophytic lesions.

RESULTS

Technical success was 100% in both groups, all lesions were completely ablated as confirmed by LIOUS. There were no major complications or perioperative mortality and low incidence of local tumor progression in both exophytic and non-exophytic groups.

CONCLUSION

Laparoscopic assisted MWA of exophytic HCC is safe and effective with comparable results to non-exophytic HCC. Exophytic HCC is not contraindication for MWA with proper technique selection.

Computed Tomography-Guided Percutaneous Cryoablation for ‎ Subcardiac Hepatocellular Carcinoma: Safety, Efficacy, Therapeutic Results and Risk Factors for Survival Outcomes

Objective

To investigate the clinical safety, efficacy, therapeutic outcomes and risk factors of computed tomography-guided percutaneous cryoablation (CT-PCRA) for subcardiac hepatocellular carcinoma (HCC).

Patients and Methods

In this study, patients with single HCC nodules located on the left lobe who subsequently underwent CT-PCRA were reviewed from July 2012 to August 2016. According to the definition of subcardiac HCC, the patients were grouped into the subcardiac HCC group (n=33) and the non-subcardiac HCC group (n=40). The technical success rates, tumour response rates, oncological outcomes including overall survival (OS) and recurrence-free survival (RFS) and complications were compared. Multivariate analysis was performed on clinicopathological variables to identify factors affecting long-term outcomes.

Results

Seventy-three patients with subcardiac HCC were included in this study. After a median follow-up time of 37.8 months, 27.4% (20/73) of the patients died. The technical success and complete response rates were not significantly different between the two groups (p = 1.000; p = 0.590). The cumulative OS and RFS of the subcardiac HCC group were comparable to those of the non-subcardiac HCC group (p =0.820, p =0.922). Two major complications, intra-abdominal bleeding and right pleural effusion, were found at 2.2 and 3.1 months in the subcardiac HCC group, which were comparable with those in the non-subcardiac HCC group (p = 0.683). The multivariate analysis results showed that older age (hazard ratio [HR]: 2.382, 95% confidence interval [CI]: 1.884–7.823; p = 0.038) and ALBI grade 2–3 (HR: 3.398, 95% CI: 1.950–6.058; p = 0.021) may be predictors of poor OS and that tumour size ≥3 cm in diameter (HR: 3.302, 95% CI: 2.232–8.293; p = 0.012) may be a predictor of poor RFS.

Conclusion

CT-PCRA for subcardiac HCC can be performed safely and efficiently and contribute to improving survival prognosis.