Microwave Ablation as Bridging Therapy for Patients with Hepatocellular Carcinoma Awaiting Liver Transplant: A Single Center Experience

Imaging-based prediction of hepatocellular carcinoma recurrence after microwave ablation as bridge therapy: A glimpse into the future

Liver transplantation (LT) remains the treatment of choice for early-stage hepatocellular carcinoma (HCC) and offers the best long-term oncological outcomes. However, the increasing waiting list for LT has led to a significant dropout rate as patients experience tumor progression beyond the Milan criteria. Currently, locoregional therapies, such as microwave ablation (MWA), have emerged as promising bridge treatments for patients awaiting LT. These therapies have shown promising results in preventing tumor progression, thus reducing the dropout rate of LT candidates. Despite the efficacy of MWA in treating HCC, tumoral recurrence after ablation remains a major challenge and significantly impacts the prognosis of HCC patients. Therefore, accurately diagnosing tumoral recurrence post-ablation is crucial. Recent studies have developed novel imaging features based on magnetic resonance imaging of HCC, which could provide essential information for predicting early tumoral recurrence after MWA. These advancements could address this unresolved challenge, improving the clinical outcomes of patients on the LT waiting list. This article explored the current landscape of MWA as a bridge therapy for HCC within the Milan criteria, highlighting the emerging role of novel imaging-based features aimed at improving the prediction of tumor recurrence after MWA.

Transient, Image-Guided Gel-Dissection for Percutaneous Thermal Ablation

Image-guided tumor ablative therapies are mainstay cancer treatment options but often require intra-procedural protective tissue displacement to reduce the risk of collateral damage to neighboring organs. Standard of care strategies, such as hydrodissection (fluidic injection), are limited by rapid diffusion of fluid and poor retention time, risking injury to adjacent organs, increasing cancer recurrence rates from incomplete tumor ablations, and limiting patient qualification. Herein, a "gel-dissection" technique is developed, leveraging injectable hydrogels for longer-lasting, shapeable, and transient tissue separation to empower clinicans with improved ablation operation windows and greater control. A rheological model is designed to understand and tune gel-dissection parameters. In swine models, gel-dissection achieves 24 times longer-lasting tissue separation dynamics compared to saline, with 40% less injected volume. Gel-dissection achieves anti-dependent dissection between free-floating organs in the peritoneal cavity and clinically significant thermal protection, with the potential to expand minimally invasive therapeutic techniques, especially across locoregional therapies including radiation, cryoablation, endoscopy, and surgery.

Microwave ablation versus radiofrequency ablation as bridge therapy in potentially transplantable patients with single HCC ≤ 3 cm: A propensity score-matched study

OBJECTIVES

The efficacy of microwave ablation (MWA) for hepatocellular carcinoma (HCC) as bridge therapy has been gradually confirmed. We aimed to compare the recurrence beyond the Milan criteria (RBM) rates in potentially transplantable patients with HCC receiving MWA or radiofrequency ablation (RFA) as bridge therapy.

METHODS

In total, 307 potentially transplantable patients with single HCC ≤ 3 cm who initially received MWA (n = 82) or RFA (n = 225) were included. RBM, recurrence-free survival (RFS), and overall survival (OS) were compared between MWA and RFA groups by using propensity score matching (PSM). Competing risks Cox regression was used to identify predictors of RBM.

RESULTS

After PSM, the 1-, 3-, and 5-year cumulative RBM rates were 6.8%, 18.3%, and 39.3% in the MWA group (n = 75), and 7.4%,18.5%, and 27.7% in the RFA group (n = 137), respectively, with no significant difference (p = 0.386). MWA and RFA were not the independent risk factors of RBM, and patients with higher alpha-fetoprotein, non-antiviral treatment, and higher MELD score were at greater risk of RBM. Neither corresponding RFS rates (66.7%, 39.2% and 21.4% vs. 70.8%, 47% and 34.7%, p = 0.310) nor OS rates (97.3%, 88.0%, and 75.4% vs. 97.8%, 85.1%, and 70.7%, p = 0.384) for 1-, 3- and 5-years were significantly different between the MWA and RFA groups. The MWA group showed more frequent major complications (21.4% vs. 7.1%, p = 0.004) and longer hospital stays (4 days vs. 2 days, p < 0.001) compared with the RFA group.

CONCLUSION

MWA showed comparable RBM, RFS, and OS rates to RFA in potentially transplantable patients with single HCC ≤ 3 cm. Compared to RFA, MWA might provide the same effect as bridge therapy.

Microwave ablation as bridging to liver transplant for patients with hepatocellular carcinoma: a single-center retrospective analysis

PURPOSE

To evaluate the efficacy and safety of microwave (MW) ablation as first-line locoregional therapy (LRT) for bridging patients with hepatocellular carcinoma (HCC) to liver transplant.

MATERIALS AND METHODS

This retrospective study evaluated 88 patients who received percutaneous MW ablation for 141 tumors as first-line LRT for HCC and listed for liver transplantation at a single medical center between 2011 and 2019. Overall survival rate status-post liver transplant, waitlist retention and disease progression were evaluated using Kaplan-Meier techniques.

RESULTS

Of 88 patients (72M, 16F, mean age 60 years, MELD=11.2) listed for transplant, median waitlist time was 9.4 months (IQR: 5.5 - 18.9). Seventy-one patients (80.7%) received transplant after median wait time of 8.5 months. Seventeen patients (19.3%) were removed from the waitlist, four (4.5%) due to tumors outside of the Milan criteria (HCC-specific dropout). No difference in tumor size or AFP was seen in transplanted vs. non-transplanted patients at time of ablation (2.1 vs. 2.1 cm and 34.4 vs. 34.7 ng/mL for transplanted vs. non-transplanted, respectively, p>0.05). Five of 88 patients (5.1%) experienced adverse events after ablation; however, all recovered. There were no cases of tract seeding. The local tumor progression (LTP) rate was 7.2%. The overall survival status-post liver transplant at 5-years was 76.7% and the disease-specific survival after LT was 89.6% with a median follow-up of 61 months for all patients.

CONCLUSION

MW ablation appears to be safe and effective for bridging patients with HCC to liver transplant without waitlist removal from seeding, adverse events, or local tumor progression.

Locoregional Treatments for Bridging and Downstaging HCC to Liver Transplantation

Liver transplantation (LT) is the first-line treatment for patients diagnosed with unresectable early-stage hepatocellular carcinoma (HCC) in the setting of cirrhosis. It is well known that HCC patients within the Milan criteria (solitary tumour ≤ 5 cm or ≤3 tumours, each <3 cm) could undergo LT with excellent results. However, there is a growing tendency to enlarge inclusion criteria since the Milan criteria are nowadays considered too restrictive and may exclude patients who would benefit from LT. On the other hand, there is a persistent shortage of donor organs. In this scenario, there is consensus about the role of loco-regional therapy (LRT) during the waiting list to select patients who would benefit more from LT, reducing the risk of drop off from the waiting list as well as decreasing tumour dimension to meet acceptable criteria for LT. In this review, current evidence on the safety, efficacy and utility of LRTs as neoadjuvant therapies before LT are summarized.