Immunomodulatory effects of radiofrequency ablation in a breast cancer model

Radiofrequency ablation combined with immunotherapy to treat hepatocellular carcinoma: a comprehensive review

BACKGROUND AND AIM

Hepatocellular carcinoma (HCC) is a highly immunogenic tumor and the third leading cause of cancer-related deaths worldwide with an increasing incidence. Therefore, the combination of immunotherapy with other approaches, such as anti-angiogenic agents and local area therapy, has become a new strategy for HCC treatment.

METHODS

We searched PubMed and Web of Science and extracted publications relating to the radiofrequency ablation (RFA) and immunotherapy. The search terms were: "radiofrequency ablation", "immunotherapy" and "hepatocellular carcinoma", and manual searches of eligible articles from literature reference lists were performed. We then thoroughly reviewed the literature on ablation combined with immunotherapy for HCC, analyzed the relevant mechanism, and explored the safety and effectiveness of this form of combination therapy.

RESULTS

RFA combined with immunotherapy in HCC is reported to have good efficacy and controllable safety. On the one hand, RFA can induce the immunogenic substances including Ficolin-3, IL-1 and heat shock protein and regulate the immune cells by mediating the Th1/Th2 ratio, increasing Th17 cells, etc. On the other hand, RFA treatment can lead to tumor immune microenvironment reconstruction, increasing the proportion of functional T cells and upregulate PD-1 in T cells in distant tumors without RFA. This combined strategy has the ability to enhance the anti-tumor immune response through synergies, significantly reduce the risk of recurrence and improve survival.

CONCLUSIONS

RFA combined with immunotherapy yields a good synergistic effect: it can further strengthen anti-tumor response, delay distant tumor growth, reduce tumor recurrence and metastasis, providing new options for HCC systemic treatment.

Potential of Thermal Ablation Combined with Immunotherapy in Peripheral Lung Tumors: A Review and Prospect

BACKGROUND

Lung tumors are prevalent malignancies associated with a high mortality rate, imposing significant medical and societal burdens. Although immunotherapy shows promise in improving survival, response rates are relatively modest. Thermal ablation can not only eliminate tumor cells directly but also enhance antitumor immunity response, thus manifesting a remarkable propensity to synergize with immunotherapy.

SUMMARY

In this review, we provided a brief overview of the application of thermal ablation in peripheral lung tumors. We summarized the patient selection of thermal ablation. We highlighted the potential of thermal ablation to augment the antitumor immune response, offering a promising avenue for combined therapies. We summarized studies assessing the synergistic effects of thermal ablation and immunotherapy in preclinical and clinical settings. Lastly, we underscored the urgent issues that warrant in-depth exploration when applying thermal ablation and immunotherapy to lung tumor patients.

KEY MESSAGES

This review emphasized the prospects of using thermal ablation combined with immunotherapy in patients with peripheral lung tumors. However, further research is needed to enhance and optimize this treatment strategy.

Contribution of immune cells in synergistic anti-tumor effect of ablation and immunotherapy

Thermal ablation results in the damage of tumor tissue, which leads to localized necrosis and incites a significant inflammatory response, accompanied by the infiltration of numerous immune cells. Nevertheless, depending solely on the singular approach of thermal ablation frequently is difficult in eliciting a robust anti-tumor response. Research suggests that integrating immune modulators into conventional ablation techniques has the potential to enhance the elicited immune response, finally initiating synergistic effect without significantly elevated risk profiles. This article comprehensively analyses the immunological effects resulting from post-ablation alone and its synergy with immunotherapies, and accentuates the heterogeneous alterations noted in immune cells across distinct malignancies. Collectively, the article delves into the theoretical framework and advancements in clinical trials concerning the combined thermal ablation and immunotherapy for treating malignant tumors.

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

Image-guided tumor ablation eliminates tumor cells by physical or chemical stimulation, which shows less invasive and more precise in local tumor treatment. Tumor ablation provides a treatment option for medically inoperable patients. Currently, clinical ablation techniques are widely used in clinical practice, including cryoablation, radiofrequency ablation (RFA), and microwave ablation (MWA). Previous clinical studies indicated that ablation treatment activated immune responses besides killing tumor cells directly, such as short-term anti-tumor response, immunosuppression reduction, specific and non-specific immune enhancement, and the reduction or disappearance of distant tumor foci. However, tumor ablation transiently induced immune response. The combination of ablation and immunotherapy is expected to achieve better therapeutic results in clinical application. In this paper, we provided a summary of the principle, clinical application status, and immune effects of tumor ablation technologies for tumor treatment. Moreover, we discussed the clinical application of different combination of ablation techniques with immunotherapy and proposed possible solutions for the challenges encountered by combined therapy. It is hoped to provide a new idea and reference for the clinical application of combinate treatment of tumor ablation and immunotherapy.

Feasibility and efficacy of microwave ablation for treating breast fibroadenoma

BACKGROUND

To investigate the safety, efficacy, and follow-up outcomes of microwave ablation (MWA) in patients with breast fibroadenoma.

METHODS

An institutional review board-approved this study of patients treated with MWA for breast fibroadenoma from October 2017 to March 2019. Clinical features of patients and breast fibroadenoma were analyzed. At follow-up all patients received physical examination and ultrasound imaging.

RESULTS

In total, 171 patients with 271 lesions were enrolled. The mean lesion diameter was 1.35 ± 0.47 cm. The results revealed differential lesion states, including stability, enlargement, reduction, and complete regression, at 1-6, 6-12, and >12 months of follow-up. The size was reduced in 22.14% (31/140), 26.36% (29/110), and 36.36% (16/44) of the lesions at 1-6, 6-12, and >12 months of follow-up, respectively. The proportion of lesions with complete regression was 24.29% (34/140) at 1-6 months, 45.45% (50/110) at 6-12 months, and 40.91% (18/44) at >12 months of follow up. There was no significant relationship between the curative effect and age, lesion location, and blood flow in patients with breast fibroadenoma after MWA (p > .05), but there was statistically significant relationship with lesion diameter (categorized as <1.5 cm and ≥1.5 cm) (p < .05).

CONCLUSIONS

The current evidence indicates that MWA is a safe and effective method for treating breast fibroadenoma. Nevertheless, further large-scale prospective trials and well-designed future studies are warranted to validate our findings.

Natural Killer Cells and Anti-Cancer Therapies: Reciprocal Effects on Immune Function and Therapeutic Response

Simple Summary

Natural Killer (NK) cells are innate lymphocytes that play an important role in the immune response against cancer. Their activity is controlled by a balance of inhibitory and activating receptors, which in cancer can be skewed to favor their suppression in support of immune escape. It is therefore imperative to find ways to optimize their antitumor functionality. In this review, we explore and discuss how their activity influences, or even mediates, the efficacy of various anti-cancer therapies and, vice versa, how their activity can be affected by these therapies. Knowledge of the mechanisms underlying these observations could provide rationales for combining anti-cancer treatments with strategies enhancing NK cell function in order to improve their therapeutic efficacy.

Abstract

Natural Killer (NK) cells are innate immune cells with the unique ability to recognize and kill virus-infected and cancer cells without prior immune sensitization. Due to their expression of the Fc receptor CD16, effector NK cells can kill tumor cells through antibody-dependent cytotoxicity, making them relevant players in antibody-based cancer therapies. The role of NK cells in other approved and experimental anti-cancer therapies is more elusive. Here, we review the possible role of NK cells in the efficacy of various anti-tumor therapies, including radiotherapy, chemotherapy, and immunotherapy, as well as the impact of these therapies on NK cell function.

Microwave ablation of primary breast cancer inhibits metastatic progression in model mice via activation of natural killer cells

Surgery is essential for controlling the symptoms and complications of stage IV breast cancer. However, locoregional treatment of primary tumors often results in distant progression, including lung metastasis, the most common type of visceral metastasis. As a minimally invasive thermal therapy, microwave ablation (MWA) has been attempted in the treatment of breast cancer, but the innate immune response after MWA has not yet been reported. Using two murine models of stage IV breast cancer, we found that MWA of primary breast cancer inhibited the progression of lung metastasis and improved survival. NK cells were activated after MWA of the primary tumor and exhibited enhanced cytotoxic functions, and the cytotoxic pathways of NK cells were activated. Depletion experiments showed that NK cells but not CD4+ or CD8+ T cells played a pivotal role in prolonging survival. Then, we found that compared with surgery or control treatment, MWA of the primary tumor induced completely different NK-cell-related cytokine profiles. Macrophages were activated after MWA of the primary tumor and produced IL-15 that activated NK cells to inhibit the progression of metastasis. In addition, MWA of human breast cancer stimulated an autologous NK-cell response. These results demonstrate that MWA of the primary tumor in metastatic breast cancer inhibits metastatic progression via the macrophage/IL-15/NK-cell axis. MWA of the primary tumor may be a promising treatment strategy for de novo stage IV breast cancer, although further substantiation is essential for clinical testing.

Dantrolene Attenuates Cardiotoxicity of Doxorubicin Without Reducing its Antitumor Efficacy in a Breast Cancer Model

Dysregulation of calcium homeostasis is a major mechanism of doxorubicin (DOX)-induced cardiotoxicity. Treatment with DOX causes activation of sarcoplasmic reticulum (SR) ryanodine receptor (RYR) and rapid release of Ca²⁺ in the cytoplasm resulting in depression of myocardial function. The aim of this study was to examine the effect of dantrolene (DNT) a RYR blocker on both the cardiotoxicity and antitumor activity of DOX in a rat model of breast cancer. Female F344 rats with implanted MAT B III breast cancer cells were randomized to receive intraperitoneal DOX twice per week (12 mg/kg total dose), 5 mg/kg/day oral DNT or a combination of DOX + DNT for 3 weeks. Echocardiography and blood troponin I levels were used to measure myocardial injury. Hearts and tumors were evaluated for histopathological alterations. Blood glutathione was assessed as a measure of oxidative stress. The results showed that DNT improved DOX-induced alterations in the echocardiographic parameters by 50%. Histopathologic analysis of hearts showed reduced DOX induced cardiotoxicity in the group treated with DOX + DNT as shown by reduced interstitial edema, cytoplasmic vacuolization, and myofibrillar disruption, compared with DOX-only–treated hearts. Rats treated with DNT lost less body weight, had higher blood GSH levels and lower troponin I levels than DOX-treated rats. These data indicate that DNT is able to provide protection against DOX cardiotoxicity without reducing its antitumor activity. Further studies are needed to determine the optimal dosing of DNT and DOX in a tumor-bearing host.

Clinical application of ultrasound-guided percutaneous microwave ablation for benign breast lesions: a prospective study

BACKGROUND

Background: Benign breast lesions are the most common diseases in adult women, which have been treated with minimally invasive therapies in recent years. Little is known about the feasibility of Microwave ablation (MWA) for benign breast lesion treatment. The primary aim of this prospective study was to evaluate the safety and efficiency of MWA as a potential therapeutic option for benign breast lesions in a single-center cohort study.

METHODS

Women with possibly benign breast lesions based on an ultrasound (US) assessment who were scheduled to undergo MWA between November 2014 to July 2018 were included in the study. The patients underwent conventional US to measure the size of the lesion, Doppler US to assess the vascularity of the lesion, elastography to evaluate the stiffness of the mass, core needle biopsy of suspicious lesions, contrast-enhanced US to help determine the treatment plan and eventually MWA of the lesion. Lesions were followed at one, three, six, twelve and eighteen months after treatment to with the same imaging modalities.

RESULTS

A total of 314 women aged 17 to 69 years old (mean = 36.9 ± 9.9 years) with 725 benign breast lesions (mean of maximum diameter = 10.86 ± 5.40 mm) were included. The frequency of palpable mass, pain and nipple discharge significantly decreased after treatment. Complete ablation rate was 97.8%, immediately after ablation, which increased to 100% after supplementary ablation of the 15 cases with incomplete ablation. Blood flow classification and lesion's volume also showed a significant decrease, while both volume reduction ratio and disappearance rate significantly increased following treatment. The elasticity score of the lesions showed fluctuations across different follow-up intervals. None of the patients experienced major complications and the 1% who had mild symptoms were successfully treated.

CONCLUSION

MWA treatment is shown to be safe and efficient and has the potential to be considered as an alternative first line treatment for benign breast lesions.

Transcatheter arterial embolization combined with radiofrequency ablation activates CD8(+) T-cell infiltration surrounding residual tumors in the rabbit VX2 liver tumors

Purpose

To evaluate the effect of transcatheter arterial embolization (TAE) combined with radiofrequency ablation (RFA) treatment (TAE + RFA) on the expression of heat shock protein 70 (HSP70) in residual tumors and explore the relationship between the HSP70 and CD8⁺ T-cell infiltrate surrounding residual tumors in the rabbit VX2 liver tumor model.

Materials and methods

Animals with VX2 liver tumors were randomized into four groups (control, TAE, RFA, and TAE + RFA) with 15 rabbits in each group. Five rabbits in each group were sacrificed on days 1, 3, and 7 after treatment. HSP70 expression and infiltration of CD8⁺ T-cells in the liver and residual tumors surrounding the necrosis zone were detected by immunohistochemistry staining. The maximal diameters of tumor necrosis, numbers of metastases, and tumor growth rate were compared on day 7 after treatment.

Results

TAE + RFA achieved larger maximal diameter of tumor necrosis, lower tumor growth rate, and fewer metastatic lesions, compared with other treatments on day 7. The number of CD8⁺ T-cells in the TAE + RFA group was significantly higher than in other groups on days 1, 3, and 7. There was a positive correlation between HSP70 expression level and infiltration of CD8⁺ T-cells surrounding the residual tumor on day 1 (r=0.9782, P=0.012), day 3 (r=0.93, P=0.021), and day 7 (r=0.8934, P=0.034).

Conclusion

In the rabbit VX2 liver tumor model, TAE + RFA activated the highest number of CD8⁺ T-cells surrounding residual tumors. TAE + RFA appears to be a beneficial therapeutic modality for tumor control and antitumor immune response in this model.

Changes of CD4+CD25+FOXP3+ and CD8+CD28- regulatory T cells in non-small cell lung cancer patients undergoing surgery

Little is known about the regulatory T cells (Tregs) in the peripheral blood after surgery of non-small cell lung cancer (NSCLC) patients. In this study, we investigated whether CD4+CD25+FOXP3+ and CD8+CD28- regulatory T cells are decreased in the peripheral blood of NSCLC patients undergoing surgery. The study group (n = 49) comprised NSCLC, and the control group (n = 24) consisted of age- and sex-matched nonmalignant diseases. The prevalence of CD4+CD25+FOXP3+ and CD8+CD28- Tregs was analyzed using flow cytometry. The study group showed significantly higher percentage of CD4+CD25+FOXP3+ and CD8+CD28- Tregs than control. The percentage of CD4+CD25+FOXP3+ and CD8+CD28- Tregs increased with tumor stage. One way ANOVA test shows the significant differences between all subgroups. LSD test shows that there was a statistical significance between each of the two subgroups except stage II in CD4+CD25+FOXP3+ Tregs and control vs. each stage, stage I vs. stage III, and stage IV in CD8+CD28- Tregs. There is no significant difference among stages II, III, and IV in CD8+CD28- Tregs. No differences were found between squamous carcinoma and adenocarcinoma. These levels were dropped significantly after operation. Furthermore postoperative Treg percentage in the early stages (stage I and stage II) was not statistically different from that of controls. Postoperative Treg percentage in advanced stage (III+IV) remained above the values shown by controls. Our findings indicate that the percentage of CD4+CD25+FOXP3+ and CD8+CD28- Tregs correlated with the pathological stage in NSCLC and tumor burden.

More than just tumor destruction: immunomodulation by thermal ablation of cancer

Over the past decades, thermoablative techniques for the therapy of localized tumors have gained importance in the treatment of patients not eligible for surgical resection. Anecdotal reports have described spontaneous distant tumor regression after thermal ablation, indicating a possible involvement of the immune system, hence an induction of antitumor immunity after thermoinduced therapy. In recent years, a growing body of evidence for modulation of both adaptive and innate immunity, as well as for the induction of danger signals through thermoablation, has emerged. Induced immune responses, however, are mostly weak and not sufficient for the complete eradication of established tumors or durable prevention of disease progression, and combination therapies with immunomodulating drugs are being evaluated with promising results. This article aims to summarize published findings on immune modulation through radiofrequency ablation, cryoablation, microwave ablation therapy, high-intensity focused ultrasound, and laser-induced thermotherapy.