Radiofrequency thermal ablation of renal tumors

Local ablation of pancreatic tumors: State of the art and future perspectives

BACKGROUND

Currently, the technologies most commonly used to treat locally advanced pancreatic cancer are radiofrequency ablation (RFA), microwave ablation, and irreversible (IRE) or reversible electroporation combined with low doses of chemotherapeutic drugs.

AIM

To report an overview and updates on ablative techniques in pancreatic cancer.

METHODS

Several electronic databases were searched. The search covered the years from January 2000 to January 2021. Moreover, the reference lists of the found papers were analysed for papers not indexed in the electronic databases. All titles and abstracts were analysed.

RESULTS

We found 30 studies (14 studies for RFA, 3 for microwave therapy, 10 for IRE, and 3 for electrochemotherapy), comprising 1047 patients, which were analysed further. Two randomized trials were found for IRE. Percutaneous and laparotomy approaches were performed. In the assessed patients, the median maximal diameter of the lesions was in the range of 2.8 to 4.5 cm. All series included patients unfit for surgical treatment, but Martin et al assessed a subgroup of patients with borderline resectable tumours who underwent resection with margin attenuation with IRE. Most studies administered chemotherapy prior to ablative therapies. However, several studies suggest that the key determinant of improved survival is attributable to ablative treatment alone. Nevertheless, the authors suggested chemotherapy before local therapies for several reasons. This strategy may not only downstage a subgroup of patients to curative-intent surgery but also support to recognize patients with biologically unfavourable tumours who would likely not benefit from ablation treatments. Ablation therapies seem safe based on the 1047 patients assessed in this review. The mortality rate ranged from 1.8% to 2%. However, despite the low mortality, the reported rates of severe post procedural complications ranged from 0%-42%. Most reported complications have been self-limiting and manageable. Median overall survival varied between 6.0 and 33 mo. Regarding the technical success rate, assessed papers reported an estimated rate in the range of 85% to 100%. However, the authors reported early recurrence after treatment. A distinct consideration should be made on whether local treatments induce an immune response in the ablated area. Preclinical and clinical studies have shown that RFA is a promising mechanism for inducing antigen-presenting cell infiltration and enhancing the systemic antitumour T-cell immune response and tumour regression.

CONCLUSION

In the management of patients with pancreatic cancer, the possibility of a multimodal approach should be considered, and conceptually, the combination of RFA with immunotherapy represents a novel angle of attack against this tumour.

Percutaneous radiofrequency for the treatment of small renal masses: Analysis of outcomes and complications after 10 years of experience

INTRODUCTION AND OBJECTIVE

The management of renal tumors ≤ 4 cm in elderly population or patients with comorbidities is a challenge, for which ablative therapies are an interesting alternative. The objective is to evaluate in our center the role of percutaneous radiofrequency in the treatment of small renal masses, the associated complications and the results obtained.

MATERIAL AND METHODS

Retrospective evaluation of the radiofrequency treatments carried out between April 2010 and April 2020 in our center. Demographic data, associated comorbidities, tumor characteristics, complications and oncological and functional outcomes were reviewed.

RESULTS

Fifty-seven tumors were treated in 53 patients. Mean follow-up of 48.2 months. The percentage of complete ablations obtained was of 89.5%. There were 19.3% of complications. According to Clavien-Dindo and SIR classification systems, 3.5% and 5.3% were major complications. A statistically significant association was found between the initial result of ablation and age (p = 0.047), RENAL-m (p = 0.044), the presence of cystic component (p = 0.049) and tumor size (p = 0.01). The cut-off point for size was established at 25 mm (p = 0.012). In multivariate analysis, only size remained as a predictor of initial ablation result (p = 0.01; OR 1.183; CI 95% 1.041-1.345). Cancer-specific survival and 5-year recurrence-free survival were 98.1% and 89.5%, respectively. A mean decrease of MDRD-4 of 6.59 mL/min (p = 0.005) was observed in the first six months after RFA.

CONCLUSIONS

Given the excellent oncological and functional results demonstrated, ultrasound-guided percutaneous radiofrequency ablation is an effective and safe treatment for small renal masses in selected patients.

Imaging guided percutaneous renal biopsy: do it or not?

Since its first reported application, renal biopsy became an important part of the diagnostic algorithm, considered advantages and risks, to better manage therapeutic options. The biopsy can be performed with different techniques (open, laparoscopic, transjugular, transurethral and percutaneous). Currently, the percutaneous approach is the modality of choice. Percutaneous biopsy can be performed under CT or US guidance, but critical benefits and disadvantages have to be considered. Core needle biopsy is usually preferred to fine-needle aspiration because of the sample quality, usually obtaining multiple cores, especially in heterogeneous tumors. Principal complications are hematuria (1-10%), perinephric hematoma (10-90%), pneumothorax (0,6%), clinically significant pain (1,2%).

An Exploratory Study of Dose Escalation vs Standard Focal High-Intensity Focused Ultrasound for Treating Nonmetastatic Prostate Cancer

Objective: Analysis of treatment success regarding oncological recurrence rate between standard and dose escalation focal high-intensity focused ultrasound (HIFU) of prostate cancer. Materials and Methods: In this analysis of our prospectively maintained HIFU (Sonablate^® 500) database, 598 patients were identified who underwent a focal HIFU (Sonablate 500) between March 2007 and November 2016. Follow-up occurred with 3-monthly clinic visits and prostate specific antigen (PSA) testing in the first year. Thereafter, PSA was measured 6-monthly or annually at least. Routine and for-cause multiparametric MRI (mpMRI) was conducted with biopsy for MRI suspicion of recurrence. Treatments were delivered in a quadrant or hemiablation fashion depending on the gland volume as well as tumor volume and location. Before mid-2015, standard focal HIFU was used (two HIFU blocks); after this date, some urologists conducted dose escalation focal HIFU (three overlapping HIFU blocks). Propensity matching was used to ensure two matched groups, leading to 162 cases for this analysis. Treatment failure was defined by any secondary treatment (systemic therapy, cryotherapy, radiotherapy, prostatectomy, or further HIFU), metastasis from prostate cancer without further treatment, tumor recurrence with Gleason score ≥7 (≥3 + 4) on prostate biopsy without further treatment, or prostate cancer-related mortality. Complications and side-effects were also compared. Results: Median age was 64.5 years (interquartile range [IQR] 60-73.5) in the standard focal-HIFU group and 64.5 years (IQR 60-69) in the dose-escalation group. Median prostate volume was 37 mL (IQR 17-103) in the standard group and 47.5 mL (IQR 19-121) in the dose-escalation group. As tumor volume on mpMRI and Gleason score were major matching criteria, these were identical with 0.43 mL (IQR 0.05-2.5) and Gleason 3 + 3 = 6 in 1 out of 32 (3%), 3 + 4 = 7 in 27 out of 32 (84%), and 4 + 3 = 7 in 4 out of 32 (13%). Recurrence in treated areas was found in 10 out of 32 (31%) when standard treatment zones were applied, and in 6 out of 32 (19%) of dose-escalation focal HIFU (p = 0.007). Conclusion: This exploratory study shows that dose escalation focal HIFU may achieve higher rates of disease control compared with standard focal HIFU. Further prospective comparative studies are needed.

Radiofrequency ablation (RFA) of T1a renal cancer with externally cooled multitined expandable electrodes

INTRODUCTION

To retrospectively evaluate the mid-term outcomes of percutaneous radiofrequency ablation (RFA) with multitined expandable electrodes externally cooled with saline solution in patients with T1a renal cell carcinoma (RCC).

MATERIALS AND METHODS

In this retrospective study, we evaluated 39 RCC in 35 patients treated with CT-guided RFA in 41 procedures (2011-2017). All patients were staged T1a, N0, M0 prior to RFA. Mean tumor size was 24.48 mm. A 4-tined expandable RFA electrode cooled with pump-circulating saline was used. Efficacy was evaluated verifying complete tumor necrosis (no contrast enhancement on imaging) at the end of the procedure and on subsequent controls. Follow-up observation period was 5 years. Minor/major complications, hospitalization days, serum creatinine and GFR pre- and post-RFA (compared using paired t test) and post-operative pain (evaluated with NRS after treatment) were considered as safety indicators. Overall survival was also calculated (Kaplan-Meier method).

RESULTS

Of 35 patients, 30/35 had 1 treatment (primary effectiveness rate 86%), 4/35 had 2 treatments and 1/35 had 3 treatments for residual disease. There were no relapses and no mid-long-term complications; 3 minor (8%) and 1 major (2.7%) complications during perioperative period were reported. Mean before and after RFA serum creatinine rates were, respectively, 1.08 mg/dl and 1.11 mg/dl (p value: 0.4117). NRS median value is 0.8. Hospitalization days median value is [2.8 ± 1.9] days. 91.4% of all patients survived, with a median overall survival time of 65 months.

CONCLUSIONS

Mid-term results show that CT-guided RFA with multitined expandable electrodes externally cooled with saline solution is an effective and safe treatment in patients with RCC-staged T1aN0M0. Data reported in our study are in line with data reported in the literature from patients treated with other devices.

Imaging after radiofrequency ablation of renal tumors

The number of percutaneous radiofrequency ablation procedures performed for renal tumors is progressively increasing worldwide. Periodic imaging follow-up has the double role to guarantee the treatment efficacy over time and to early detect any possible complication. Tumor size reductions, as well as the appearance of the characteristic ‘halo sign’, are normal findings that represent good ablative outcomes. However the most reliable factor of ablation efficacy remains the total absence of contrast enhancing zones within the ablated area. The aim of this article is to illustrate the typical aspect of an effective radiofrequency ablation treatment, which are the imaging findings that may suggest the presence of residual tumoral tissue and which are the main early and late procedural complications.

Ultrasound-guided hydrodissection for assisting percutaneous microwave ablation of renal cell carcinomas adjacent to intestinal tracts: a preliminary clinical study

PURPOSE

To evaluate the safety and efficacy of the clinical application of hydrodissection under ultrasound (US) guidance for assisting percutaneous microwave ablation (MWA) for the treatment of renal cell carcinomas (RCCs) adjacent to the intestinal tract.

MATERIALS AND METHODS

From April 2014 to December 2016, clinical data from 24 patients with 25 RCCs were retrospectively analysed. Percutaneous MWA under the assistance of US-guided hydrodissection were performed to treat RCCs with a mean maximal diameter of 3.80 ± 1.60 cm because the distance between the index tumour and the adjacent intestinal tracts were less than 0.5 cm on imaging. The separation success rate of the hydrodissection, technique efficacy rate of the MWA, local tumour progression (LTP), complications, and renal function including serum creatinine (Cr) and blood urea nitrogen (BUN) were assessed.

RESULTS

In total, 28 sessions of hydrodissection and MWA procedures were performed (one procedure in 22 patients and two procedures in 3 patients), and the separation success rate was 100% (28/28). The technique efficacy rate was 100% (25/25), and no LTP occurred. One patient exhibited a major complication (4.2%). Minor complications in 5 patients (20.8%) and side effects in 12 patients (50.0%) occurred. Compared with the pre-MWA levels, there were no significant differences in serum Cr and BUN 1-day post-MWA and at the last follow-up.

CONCLUSIONS

US-guided hydrodissection assistance for percutaneous MWA could be a safe and effective alternative for selected patients with RCCs adjacent to the intestinal tracts and can achieve good local tumour control and renal function preservation.

Effect of thermal dose on heat shock protein expression after radio-frequency ablation with and without adjuvant nanoparticle chemotherapies

PURPOSE

The aim of this study was to evaluate the effect of different radio-frequency ablation (RFA) thermal doses on coagulation and heat shock protein (HSP) response with and without adjuvant nanotherapies.

MATERIALS AND METHODS

First, Fischer rats were assigned to nine different thermal doses of hepatic RFA (50-90 °C, 2-20 min, three per group) or no treatment (n = 3). Next, five of these RF thermal doses were combined with liposomal-doxorubicin (Lipo-Dox, 1 mg intravenously) in R3230 breast tumours, or no tumour treatment (five per group). Finally, RFA/Lipo-Dox was given without and with an Hsp70 inhibitor, micellar quercetin (Mic-Qu, 0.3 mg intravenously) for two different RFA doses with similar coagulation but differing peri-ablational Hsp70 (RFA/Lipo-Dox at 70 °C × 5 min and 90 °C × 2 min, single tumours, five per group). All animals were sacrificed 24 h post-RFA and gross tissue coagulation and Hsp70 (maximum rim thickness and % cell positivity) were correlated to thermal dose including cumulative equivalent minutes at 43 °C (CEM₄₃).

RESULTS

Incremental increases in thermal dose (CEM₄₃) correlated to increasing liver tissue coagulation (R² = 0.7), but not with peri-ablational Hsp70 expression (R² = 0.14). Similarly, increasing thermal dose correlated to increasing R3230 tumour coagulation for RF alone and RFA/Lipo-Dox (R² = 0.7 for both). The addition of Lipo-Dox better correlated to increasing Hsp70 expression compared to RFA alone (RFA: R² = 0.4, RFA/Lipo-Dox: R² = 0.7). Finally, addition of Mic-Qu to two thermal doses combined with Lipo-Dox resulted in greater tumour coagulation (p < 0.0003) for RFA at 90 °C × 2 min (i.e. greater baseline Hsp70 expression) than an RFA dose that produced similar coagulation but less HSP expression (p < 0.0004).

CONCLUSION

Adjuvant intravenous Lipo-Dox increases peri-ablational Hsp70 expression in a thermally dependent manner. Such expression can be exploited to produce greater tumour destruction when adding a second adjuvant nanodrug (Mic-Qu) to suppress peri-ablational HSP expression.

Exploiting natural anti-tumor immunity for metastatic renal cell carcinoma

Clinical observations of spontaneous disease regression in some renal cell carcinoma (RCC) patients implicate a role for tumor immunity in controlling this disease. Puzzling, however, are findings that high levels of tumor infiltrating lymphocytes (TIL) are common to RCC. Despite expression of activation markers by TILs, functional impairment of innate and adaptive immune cells has been consistently demonstrated contributing to the failure of the immune system to control RCC. Immunotherapy can overcome the immunosuppressive effects of the tumor and provide an opportunity for long-term disease free survival. Unfortunately, complete response rates remain sub-optimal indicating the effectiveness of immunotherapy remains limited by tumor-specific factors and/or cell types that inhibit antitumor immune responses. Here we discuss immunotherapies and the function of multiple immune system components to achieve an effective response. Understanding these complex interactions is essential to rationally develop novel therapies capable of renewing the immune system's ability to respond to these tumors.

Radiofrequency ablation versus magnetic resonance guided focused ultrasound surgery for minimally invasive treatment of osteoid osteoma: a propensity score matching study

OBJECTIVES

To compare outcomes in pain relief and motor functional recovery in patients with an osteoid osteoma treated by magnetic resonance guided focused ultrasound surgery (MRgFUS) or radiofrequency ablation (RFA) using a propensity score matching study design.

METHODS

Thirty patients with osteoid osteomas were included in this institutional review board (IRB)-approved study. MRgFUS was performed in 15 subjects. These subjects were matched by propensity analysis with a group of 15 subjects treated by RFA. Pain relief in terms of complete response (CR) and motor functional recovery were measured.

RESULTS

A similar proportion of subjects treated by MRgFUS (94 %) or RFA (100 %) experienced CR 12 weeks after treatment, with no significant difference. The improvement in pain control following MRgFUS or RFA paralleled with improved motor functional recovery. The treatment failure rate was 6.6 % in the MRgFUS group and 0 % in the RFA group. No major complications were observed following either ablative treatment.

CONCLUSIONS

Although this study involved a limited number of patients, MRgFUS favourably improves perceived pain and motor functional recovery, with no major complications. No difference was found in the achievement of primary and secondary outcome measures with respect to RFA.

KEY POINTS

• To demonstrate the effectiveness of a recent technique for treating osteoid osteoma • MRgFUS results compared with results of the gold standard treatment (RFA) • MRgFUS is effective both from a clinical and functional point of view • No significant side effects compared with RFA.