Clinical application status and prospect of the combined anti-tumor strategy of ablation and immunotherapy

High-intensity focused ultrasound ablation combined with immunotherapy for treating liver metastases: A prospective non-randomized trial

PURPOSE

Given the unique features of the liver, it is necessary to combine immunotherapy with other therapies to improve its efficacy in patients of advanced cancer with liver metastases (LM). High-intensity focused ultrasound (HIFU) ablation is now widely used in clinical practice and can enhanced immune benefits. The study is intended to prospectively evaluate the safety and clinical feasibility of HIFU ablation in combination with systemic immunotherapy for patients with liver metastases.

METHODS

The study enrolled 14 patients with LM who received ultrasound-guided HIFU ablation combined with immune checkpoint inhibitors (ICIs) such as anti-programmed cell death protein 1 (anti-PD-1 agents manufactured in China) at Mianyang Central Hospital. Patients were followed up for adverse events (AEs) during the trial, using the CommonTerminology Criteria for Adverse Events v5.0(CTCAE v5.0) as the standard. Tumour response after treatment was assessed using computerized tomography.

RESULTS

The 14 patients (age range, 35-84 years) underwent HIFU ablation at 19 metastatic sites and systemic immunotherapy. The mean lesion volume was 179.9 cm3 (maximum: 733.1 cm3). Median follow-up for this trial was 9 months (range: 3-21) months. The study is clinically feasible and acceptable to patients.

CONCLUSION

This prospective study confirmed that HIFU combined with immunotherapy is clinically feasible and safe for treating liver metastases.

Immunostimulatory effects of thermal ablation: Challenges and future prospects

ABSTRACT

This literature explores the immunostimulatory effects of thermal ablation in the tumor microenvironment, elucidating the mechanisms such as immunogenic cell death, tumor-specific antigens, and damage-associated molecular patterns. Furthermore, it outlines critical issues associated with thermal ablation-induced immunostimulatory challenges and offers insights into future research avenues and potential therapeutic strategies.

Electrochemotherapy combined with immunotherapy - a promising potential in the treatment of cancer

Electrochemotherapy is a novel, locoregional therapy that is used to treat cutaneous and deep-seated tumors. The electric pulses used in electrochemotherapy increase the permeability of the cell membranes of the target lesion and thus enhance the delivery of low-permeant cytotoxic drugs to the cells, leading to their death. It has also been postulated that electrochemotherapy acts as an in situ vaccination by inducing immunogenic cell death. This in turn leads to an enhanced systemic antitumor response, which could be further exploited by immunotherapy. However, only a few clinical studies have investigated the role of combined treatment in patients with melanoma, breast cancer, hepatocellular carcinoma, and cutaneous squamous cell carcinoma. In this review, we therefore aim to review the published preclinical evidence on combined treatment and to review clinical studies that have investigated the combined role of electrochemotherapy and immunotherapy.

Radiofrequency ablation for stage <IIB non-small cell lung cancer: Opportunities, challenges, and the road ahead

Pulmonary carcinoma represents the second common cancer for human race while its mortality rate ranked the first all over the world. Surgery remains the primary option for early-stage non-small cell lung cancer (NSCLC) in some surgical traditions. Nevertheless, only less than half of patients are operable subjected to the limited lung function and multiple primary/metastatic lesions. Recent improvements in minimally invasive surgical techniques have made the procedure accessible to more patients, but this percentage still does not exceed half. In recent years, radiofrequency ablation (RFA), one of the thermal ablation procedures, has gradually advanced in the treatment of lung cancer in addition to being utilized to treat breast and liver cancer. Several guidelines, including the American College of Chest Physicians (ACCP), include RFA as an option for some patients with NSCLC although the level of evidence is mostly limited to retrospective studies. In this review, we emphasize the use of the RFA technique in patients with early-stage NSCLC and provide an overview of the RFA indication population, prognosis status, and complications. Meanwhile, the advantages and disadvantages of RFA proposed in existing studies are compared with surgical treatment and radiotherapy. Due to the high rate of gene mutation and immunocompetence in NSCLC, there are considerable challenges to clinical translation of combining targeted drugs or immunotherapy with RFA that the field has only recently begun to fully appreciate.

Autophagy-amplifying nanoparticles evoke immunogenic cell death combined with anti-PD-1/PD-L1 for residual tumors immunotherapy after RFA

Incomplete radiofrequency ablation (IRFA) triggers mild protective autophagy in residual tumor cells and results in an immunosuppressive microenvironment. This accelerates the recurrence of residual tumors and causes resistance to anti-PD-1/PDL1 therapy, which bringing a great clinical challenge in residual tumors immunotherapy. Mild autophagy activation can promote cancer cell survival while further amplification of autophagy contributes to immunogenic cell death (ICD). To this regard, we constructed active targeting zeolitic imidazolate framework-8 (ZIF-8) nanoparticles (NPs) loaded with STF62247 or both STF62247 and BMS202, namely STF62247@ZIF-8/PEG-FA (SZP) or STF62247-BMS202@ZIF-8/PEG-FA (SBZP) NPs. We found that SZP NPs inhibited proliferation and stimulated apoptosis of residual tumor cells exposed to sublethal heat stress in an autophagy-dependent manner. Further results discovered that SZP NPs could amplify autophagy in residual tumor cells and evoke their ICD, which dramatically boosted the maturation of dendritic cells (DCs). Through vaccination experiments, we found for the first time that vaccination with heat + SZP treatment could efficiently suppress the growth of new tumors and establish long-term immunological memory. Furthermore, SBZP NPs could remarkably promote the ICD of residual tumor cells, obviously activate the anti-tumor immune microenvironment, and significantly inhibit the growth of residual tumors. Thus, amplified autophagy coupled with anti-PD-1/PDL1 therapy is potentially a novel strategy for treating residual tumors after IRFA.

Initial ablation ratio predicts the recurrence of low-risk papillary thyroid microcarcinomas treated with microwave ablation: a 5-year, single-institution cohort study

Objective

To assess the long-term efficacy and safety of microwave ablation (MWA) in treating low-risk papillary thyroid microcarcinomas (PTMC) and to identify predictive factors for the postoperative local tumor progression of PTMC.

Methods

A total of 154 low-risk PTMC patients treated with MWA who were followed up for at least 3 months were retrospectively recruited. Ultrasonography was performed after MWA to assess the local tumor progression. Adverse events associated with MWA were recorded. The ablated volume (Va) and initial ablation ratio (IAR) were measured to assess their influences on the recurrence risk of PTMC.

Results

The mean tumor volume of PTMC before MWA was 0.071 (0.039, 0.121) cm3, with a maximum diameter of 0.60 ± 0.18 cm. All PTMC patients were followed up for 6 (3, 18) months. Va increased immediately after MWA, then gradually decreased over time, till significantly smaller at 12 months than that before MWA (P < 0.05). The median volume reduction ratio at 24 months reached 100%, which was maintained during a 60-month follow-up. A total of 7 (4.55%) cases of local tumor progression were recorded during the follow-up. Kaplan-Meier survival analysis revealed that the rate of local tumor progression was significantly lower in PTMC patients with a maximum tumor diameter < 0.70 cm than in those with ≥0.70 cm (P = 0.031). A significant better prognosis was achieved in PTMC patients with IAR ≥ 15 than in those with IAR < 15 (P = 0.015). Sex, age (<55 years) and preoperative thyroid-stimulating hormone (>2.0 mU/L) of PTMC patients were not correlated with local tumor progression.

Conclusion

MWA is an effective therapeutic strategy for low-risk PTMC with high safety. The maximum tumor diameter and IAR are predictive factors for the local tumor progression of PTMC after MWA.

Radiofrequency ablation for the management of pancreatic mass lesions

PURPOSE OF REVIEW

Patients with pancreatic tumors may have limited treatment options. Pancreatic tumor ablation is a novel and emerging treatment modality which can now be performed using endoscopic ultrasound (EUS) guidance. This modality is well suited to guide energy delivery for radiofrequency ablation (RFA) and microwave ablation. These approaches provide minimally invasive, nonsurgical methods for delivering energy to ablate pancreatic tumors in situ. This review summarizes the current data and safety profile for ablation in managing pancreatic cancer and pancreatic neuroendocrine tumors.

RECENT FINDINGS

RFA uses thermal energy to induce cell death by coagulative necrosis and protein denaturation. Studies have reported increased overall survival in patients with pancreatic tumors treated with EUS-guided RFA in a multimodality systemic approach and when used in palliative surgeries. Radiofrequency ablation may have corollary benefits in inducing an immune-modulatory effect. Tumor marker carbohydrate antigen 19-9 has been reported to decrease in response to RFA. Microwave ablation is an emerging modality.

SUMMARY

RFA utilizes focal thermal energy to induce cell death. RFA has been applied through open, laparoscopic, and radiographic modalities. EUS-guided approaches are now allowing RFA and microwave ablation to be performed for pancreatic tumors in situ.

Spatiotemporal local and abscopal cell death and immune responses to histotripsy focused ultrasound tumor ablation

Introduction

Histotripsy is a novel focused ultrasound tumor ablation modality with potent immunostimulatory effects.

Methods

To measure the spatiotemporal kinetics of local andabscopal responses to histotripsy, C57BL/6 mice bearing bilateral flank B16 melanoma or Hepa1-6 hepatocellular carcinoma tumors were treated with unilateral sham or partial histotripsy. Treated and contralateral untreated (abscopal) tumors were analyzed using multicolor immunofluorescence, digital spatial profiling, RNA sequencing (RNASeq), and flow cytometry.

Results

Unilateral histotripsy triggered abscopal tumor growth inhibition. Within the ablation zone, early high mobility group box protein 1 (HMGB1) release and necroptosis were accompanied by immunogenic cell death transcriptional responses in tumor cells and innate immune activation transcriptional responses in infiltrating myeloid and natural killer (NK) cells. Delayed CD8+ T cell intratumoral infiltration was spatiotemporally aligned with cancer cell features of ferroptosis; this effect was enhanced by CTLA-4 blockade and recapitulated in vitro when tumor-draining lymph node CD8+ T cells were co-cultured with tumor cells. Inoculation with cell-free tumor fractions generated by histotripsy but not radiation or freeze/thaw conferred partial protection from tumor challenge.

Discussion

We propose that histotripsy may evoke local necroptotic immunogenic cell death, priming systemic adaptive immune responses and abscopal ferroptotic cancer cell death.