Survival analysis following microwave ablation or surgical resection in patients with hepatocellular carcinoma conforming to the Milan criteria

Microwave ablation vs. liver resection for patients with hepatocellular carcinomas

BACKGROUNDS/AIMS

Microwave ablation (MWA) is an emerging ablative therapy that surpasses previous methods by achieving higher temperatures and creating larger ablation zones within shorter periods. This study compared the therapeutic outcomes of MWA with those of liver resection in real-world clinical practice.

METHODS

A total of 178 patients with 259 nodules who underwent MWA or liver resection between January 2015 and July 2023 were enrolled. Local tumor progression (LTP)-free survival, overall progression (OP)-free survival, and overall survival (OS) were assessed based on the treatment modality for the index nodule.

RESULTS

Of the 178 patients, 134 with 214 nodules underwent MWA, and 44 with 45 nodules underwent liver resection. The median follow-up period was 2.0±1.5 years. The annual incidence of LTP was 3.7% for MWA and 1.4% for liver resection. Treatment modality did not significantly affect LTP-free survival (hazard ratio, 0.61; 95% confidence interval, 0.14-2.69; P=0.511). For nodules larger than 3 cm, LTP-free survival was not affected by the treatment modality. Similarly, OP-free survival and OS were not influenced by treatment modality.

CONCLUSIONS

MWA and liver resection demonstrated comparable treatment outcomes in terms of local tumor control, overall recurrence, and survival. MWA may be an alternative treatment option for select patients; however, further studies are necessary to generalize these findings.

Primary treatments for solitary hepatocellular carcinoma ≤ 3 cm: A systematic review and network meta-analysis

Various treatment modalities are available for small solitary hepatocellular carcinoma (HCC), yet the optimal primary treatment strategy for tumors ≤ 3 cm remains unclear. This network meta-analysis investigates the comparative efficacy of various interventions on the long-term outcomes of patients with solitary HCC ≤ 3 cm. A systematic search of electronic databases from January 2000 to December 2023 was conducted to identify studies that compared at least two of the following treatments: surgical resection (SR), radiofrequency ablation (RFA), microwave ablation (MWA), and transarterial chemoembolization (TACE). Survival data were extracted, and pooled hazard ratios with 95% confidence intervals were calculated using a frequentist network meta-analysis. A total of 30 studies, comprising 2 randomized controlled trials and 28 retrospective studies, involving 8,053 patients were analyzed. Surgical resection showed the highest overall survival benefit with a p-score of 0.95, followed by RFA at 0.59, MWA at 0.23, and TACE, also at 0.23. Moreover, SR provided the most significant recurrence-free survival advantage, with a p-score of 0.95, followed by RFA at 0.31 and MWA at 0.19. Sensitivity analyses, excluding low-quality or retrospective non-matched studies, corroborated these findings. This network meta-analysis demonstrates that SR is the most effective first-line curative treatment for single HCC ≤ 3 cm, followed by RFA in patients with preserved liver function. The limited data on MWA and TACE underscore the need for further studies.

The tumor burden score may be a discriminator in microwave ablation versus liver resection for hepatocellular carcinoma within the Milan criteria: a propensity score matching and inverse probability of treatment weighting study

PURPOSE

This study aims to compare the prognostic outcome of resection (RES) and microwave ablation (MWA) in different tumor burden score (TBS) cohorts.

PATIENTS AND METHODS

We retrospectively analyzed 479 patients with primary hepatocellular carcinoma (HCC) who underwent RES (n = 329) or MWA (n = 150) with curative intent at our institution. We assessed their overall survival (OS) and progression-free survival (PFS) using the Kaplan-Meier curve. Propensity score matching (PSM) and inverse probability of treatment weighting (IPTW) were performed to minimize selection and confounding biases. Multivariate Cox regression was used to define the association between surgical modalities and outcomes.

RESULTS

Following PSM, in the TBS ≤3 cohort, the cumulative 1-, 3-, 5- year OS in the RES and MWA groups were 92.5% vs. 98.8%, 82.7% vs. 90.0%, and 82.7% vs. 83.2% (P = 0.366), respectively. The corresponding PFS rates in the RES and MWA groups were 82.7% vs. 88.0%, 63.6% vs. 68.3% and 55.2% vs. 56.3, respectively (P = 0.218). In the TBS >3 cohort, the cumulative 1-, 3-, 5- year OS between the RES and MWA groups were 92.5% vs. 95.0%, 82.8% vs. 73.2% and 76.3% vs. 55.1%, (P = 0.034), respectively. The corresponding PFS rates in the RES and MWA groups were 78.0% vs. 67.5%, 63.6% vs. 37.5% and 55.2% vs. 37.1%, respectively (P = 0.044). The IPTW analysis showed similar results as shown in PSM analysis. The multivariate Cox regression indicated that the type of surgical modality was not associated with a poorer prognostic outcome in the TBS ≤3 cohort, unlike in the TBS >3 cohort.

CONCLUSION

TBS, as a discriminator, might help guide treatment decision-making for HCC within the Milan criteria.

Emerging curative-intent minimally-invasive therapies for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the most common cause of liver malignancy and the fourth leading cause of cancer deaths universally. Cure can be achieved for early stage HCC, which is defined as 3 or fewer lesions less than or equal to 3 cm in the setting of Child-Pugh A or B and an ECOG of 0. Patients outside of these criteria who can be down-staged with loco-regional therapies to resection or liver transplantation (LT) also achieve curative outcomes. Traditionally, surgical resection, LT, and ablation are considered curative therapies for early HCC. However, results from recently conducted LEGACY study and DOSISPHERE trial demonstrate that transarterial radio-embolization has curative outcomes for early HCC, leading to its recent incorporation into the Barcelona clinic liver criteria guidelines for early HCC. This review is based on current evidence for curative-intent loco-regional therapies including radioembolization for early-stage HCC.

Percutaneous Thermal Ablation Therapy of Hepatocellular Carcinoma (HCC): Microwave Ablation (MWA) versus Laser-Induced Thermotherapy (LITT)

The purpose of this study is to compare the efficacy and safety of microwave ablation (MWA) versus laser-induced thermotherapy (LITT) as a local treatment for hepatocellular carcinoma (HCC,) with regard to therapy response, survival rates, and complication rates as measurable outcomes. This retrospective study included 250 patients (52 females and 198 males; mean age: 66 ± 10 years) with 435 tumors that were treated by MWA and 53 patients (12 females and 41 males; mean age: 67.5 ± 8 years) with 75 tumors that were treated by LITT. Tumor response was evaluated using CEMRI (contrast-enhanced magnetic resonance imaging). Overall, 445 MWA sessions and 76 LITT sessions were performed. The rate of local tumor progression (LTP) and the rate of intrahepatic distant recurrence (IDR) were 6% (15/250) and 46% (115/250) in the MWA-group and 3.8% (2/53) and 64.2% (34/53) in the LITT-group, respectively. The 1-, 3-, and 5-year overall survival (OS) rates calculated from the date of diagnosis were 94.3%, 65.4%, and 49.1% in the MWA-group and 96.2%, 54.7%, and 30.2% in the LITT-group, respectively (p-value: 0.002). The 1-, 2-, and 3-year disease-free survival (DFS) rates were 45.9%, 30.6%, and 24.8% in the MWA-group and 54.7%, 30.2%, and 17% in the LITT-group, respectively (p-value: 0.719). Initial complete ablation rate was 97.7% (425/435) in the MWA-group and 98.7% (74/75) in the LITT-group (p-value > 0.99). The overall complication rate was 2.9% (13/445) in the MWA-group and 7.9% (6/76) in the LITT-group (p-value: 0.045). Based on the results, MWA and LITT thermal ablation techniques are well-tolerated, effective, and safe for the local treatment of HCC. However, MWA is recommended over LITT for the treatment of HCC, since the patients in the MWA-group had higher survival rates.

New era of electrochemotherapy in treatment of liver tumors in conjunction with immunotherapies

Electrochemotherapy is a local ablative therapy that increases the cytotoxicity of either bleomycin or cisplatin by applying electric pulses (electroporation) to tumors. It has already been widely used throughout Europe for the treatment of various types of human and veterinary cutaneous tumors, with an objective response rate ranging from 70%-90%, depending on the tumor histotype. Recently, electrochemotherapy was introduced for the treatment of primary liver tumors, such as hepatocellular carcinoma (HCC). The complete response rate was 85% per treated lesion, with a durable response. Therefore, electrochemotherapy could become a treatment of choice for HCC, especially after achieving a transition from an open surgery approach to a percutaneous approach that uses dedicated electrodes. Electrochemotherapy elicits a local immune response and can be considered an in situ vaccination. HCC, among others, is a potentially immunogenic tumor; thus, electrochemotherapy could boost adjuvant immunotherapy to achieve a better and longer-lasting antitumor response. Therefore, therapeutic strategies that combine electrochemotherapy with immune checkpoint inhibitors or adjuvant treatment with cytokines are indicated for HCC. Immunogene therapy using electroporation as a delivery system for plasmid DNA coding for interleukin-12 is a highly promising approach. This electroporation approach has shown efficacy in preclinical settings and veterinary oncology and is awaiting translation for the treatment of liver tumors, i.e., HCC.