Intravesical radiofrequency-induced hyperthermia combined with chemotherapy for non-muscle-invasive bladder cancer

Mild hyperthermia with magnetic resonance- guided high intensity focused ultrasound combined with salvage chemoradiation for recurrent rectal cancer

INTRODUCTION

Pelvic recurrences from rectal cancer present a challenging clinical scenario. Hyperthermia represents an innovative treatment option in combination with concurrent chemoradiation to enhance therapeutic effect. We provide the initial results of a prospective single center feasibility study (NCT02528175) for patients undergoing rectal cancer retreatment using concurrent chemoradiation and mild hyperthermia with MR-guided high intensity focused ultrasound (MR-HIFU).

METHODS

All patients were deemed ineligible for salvage surgery and were evaluated in a multidisciplinary fashion with a surgical oncologist, radiation oncologist and medical oncologist. Radiation was delivered to a dose of 30.6 Gy in 1.8 Gy per fraction with concurrent capecitabine. MR-HIFU was delivered on days 1, 8 and 15 of concurrent chemoradiation. Our primary objective was feasibility and toxicity.

RESULTS

Six patients (total 11 screened) were treated with concurrent chemoradiation and mild hyperthermia with MR-HIFU. Tumor size varied between 3.1-16.6 cm. Patients spent an average of 228 min in the MRI suite and sonication with the external transducer lasted an average of 35 min. There were no complications on the day of the MR-HIFU procedure and all acute toxicities (no grade >/=3 toxicities) resolved after completion of treatment. There were no late grade >/=3 toxicities.

CONCLUSION

Mild hyperthermia with MR-HIFU, in combination with concurrent chemoradiation for appropriately selected patients, is safe for localized pelvic recurrences from rectal cancer. The potential for MR-HIFU to be applied in the recurrent setting in rectal cancer treatment requires further technical development and prospective evaluation.

Enhancing the therapeutic impact of sublethal radiofrequency hyperthermia in malignant solid tumor treatment

Radiofrequency ablation (RFA) is an effective alternative to surgery for managing some malignant solid tumors. However, for medium-to-large tumors (>3 cm), tumors adjacent to large blood vessels, and certain irregular tumors, sublethal radiofrequency hyperthermia (RFH) often produces a margin of ablated tumor owing to the "heat-sink" effect. This effect typically leaves behind viable residual tumors at the margin. Several studies have reported that a sublethal RFH can significantly enhance the efficacy of chemotherapy, radiotherapy, immunotherapy, and gene therapy for malignant solid tumors. The possible mechanisms by which RFH enhances these therapies include heat-induced tissue fracturing, increased permeability of the cytoplasmic membrane, exaggerated cellular metabolism, blockade of the repair pathways of radiation-damaged tumor cells, and activation of the heat shock protein pathways. Therefore, RFA in combination with chemotherapy, radiotherapy, immunotherapy, or gene therapy may help reduce the rates of residual and recurrent tumors after RFA of malignant solid tumors.

Magnetic Particle Imaging-Guided Hyperthermia for Precise Treatment of Cancer: Review, Challenges, and Prospects

Magnetic particle imaging (MPI) is a novel quantitative imaging technique using the nonlinear magnetization behavior of magnetic nanoparticles (MNPs) to determine their local concentration. Magnetic fluid hyperthermia (MFH) is a promising non-invasive therapy using the heating effects of MNPs. MPI-MFH is expected to enable real-time MPI guidance, localized MFH, and non-invasive temperature monitoring, which shows great potential for precise treatment of cancer. In this review, we introduce the fundamentals of MPI and MFH and their applications in the treatment of cancer. Also, we discuss the challenges and prospects of MPI-MFH.

Evaluation of thermal dose effect in radiofrequency-induced hyperthermia with intravesical chemotherapy for nonmuscle invasive bladder cancer

PURPOSE

In nonmuscle invasive bladder cancer (NMIBC) patients who fail standard intravesical treatment and are unfit or unwilling to undergo a radical cystectomy, radiofrequency (RF)-induced hyperthermia combined with intravesical chemotherapy (RF-CHT) has shown promising results. We studied whether higher thermal dose improves clinical NMIBC outcome.

METHODS AND MATERIALS

The cohort comprised 108 patients who started with RF-CHT between November 2013 and December 2019. Patients received intravesical mitomycin-C or epirubicin. Bladder hyperthermia was accomplished with an intravesical 915 MHz RF device guided by intravesical thermometry. We assessed the association between thermal dose parameters (including median temperature and Cumulative Equivalent Minutes of T50 at 43 °C [CEM43T50]) and complete response (CR) at six months for patients with (concomitant) carcinoma in situ (CIS), and recurrence-free survival (RFS) for patients with papillary disease.

RESULTS

Median temperature and CEM43T50 per treatment were 40.9 (IQR 40.8-41.1) °C and 3.1 (IQR 0.9-2.4) minutes, respectively. Analyses showed no association between any thermal dose parameter and CR or RFS (p > 0.05). Less bladder spasms during treatment sessions was associated with increased median temperature and CEM43T50 (adjusted OR 0.01 and 0.34, both p < 0.001).

CONCLUSIONS

No significant association between thermal dose and NMIBC outcome was found. Possibly thermal dose effect in patients of the current cohort exceeds a certain threshold value. On the other hand, occurrence of bladder spasms had a thermal dose limiting effect. We advise to treat patients with temperatures >40.5 °C for at least 45 min while respecting individual tolerability, including occurrence of bladder spasms.

Systematic review about complementary medical hyperthermia in oncology

Hyperthermia is a generic term for different techniques using heat in cancer therapies. Temperatures of about 42° Celsius in combination with chemo- or radiotherapy may improve the effectiveness of those treatments. Clinical benefit is shown in “standard hyperthermia” with tumour temperatures assessed during treatment. This systematic review thoroughly assesses the state of evidence concerning the benefits and side effects of electro hyperthermia or whole-body hyperthermia (“alternative hyperthermia”) in oncology. From 26 April 2021 to 09 May 2021, a systematic search was conducted searching five electronic databases (Embase, Cochrane, PsycINFO, CINAHL and Medline) to find studies concerning the use, effectiveness and potential harm of alternative medical hyperthermia therapy on cancer patients. From all 47,388 search results, 53 publications concerning 53 studies with 2006 patients were included in this systematic review. The patients were diagnosed with different types of cancer. The hyperthermic methods included whole-body hyperthermia (WBH) with different methods and electro hyperthermia (EH). The majority of the included studies were single-arm studies, counting in total 32 studies. Six studies were randomized controlled trials (RCT). In addition, one systematic review (SR) was found. The most critical endpoints were tumour response, survival data, pain relief, myelosuppression and toxicities. Outcome was heterogeneous, and considering the methodological limitations, clinical evidence for the benefit of alternative hyperthermia in cancer patients is lacking. Neither for whole-body hyperthermia nor for electro hyperthermia there is any evidence with respect to improvement of survival or quality of life in cancer patients.

The impact of different adjuvant intravesical therapy methods on tumor biology in patients with high-risk non-muscle-invasive bladder cancer

Introduction

Expression level of the cell proliferation marker Ki-67 correlates with the degree of differentiation of tumor cells and stage in primary patients with non-muscle-invasive bladder cancer (NMIBC), but the marker is currently not used in assessing the efficacy of adjuvant intravesical therapy and risk stratification in patients with recurrent bladder tumors.

Material and methods

A retroprospective study included 107 patients with high-risk NMIBC; the patients were divided into 2 groups. The first group included patients who received adjuvant therapy after transurethral resection of the bladder using the Bacillus Calmette-Guérin (BCG) vaccine (BCG therapy group; n = 54), the second group consisted of patients who received hyperthermic intravesical chemotherapy (HIVEC^® therapy group; n = 53) using the device for local hyperthermia Combat BRS HIVEC^®.

Results

Tumor recurrences were recorded in 21 (39%) patients receiving intravesical BCG therapy and in 9 (17%) patients after intravesical hyperthermic chemotherapy (p = 0.012). The expression level of Ki-67 in primary tumors did not differ; in recurrent tumors it was significantly different in both groups (32.05 ±13.80 vs 11.00 ± 6.86). The frequency of recurrence-free survival (RFS) in patients receiving chemohyperthermia was significantly higher than in patients after the BCG therapy (log-rank test result: p = 0.048).

Conclusions

Assessment of Ki-67 expression in recurrent tumors can be a criterion for the effectiveness of intravesical bladder-preserving treatment. The use of hyperthermic chemotherapy can reduce the number of radical cystectomies in a separate group of patients with NMIBC.

Loco-regional deep hyperthermia combined with intravesical Mitomycin instillation reduces the recurrence of non-muscle invasive papillary bladder cancer

OBJECTIVES

To compare the therapeutic effects of locoregional deep hyperthermia combined with intravesical chemotherapy with those of intravesical chemotherapy alone in patients with intermediate-/high-risk non-muscle invasive bladder cancer (NMIBC). To evaluate the impact of thermal dose in hyperthermia treatment.

METHODS

We analyzed data retrieved from the medical records of patients with intermediate-/high-risk NMIBC treated with intravesical mitomycin (IM group) or locoregional deep hyperthermia combined with intravesical mitomycin (CHT group) at a single tertiary care hospital between May 2016 and June 2019. The primary and secondary endpoints were the recurrence-free survival rate and progression-free survival rate, respectively. Thermal dose was evaluated and adverse events were also recorded.

RESULTS

In total, 43 patients (CHT: 18 patients, IM: 25 patients) were enrolled. The median follow-up durations were 14 and 23 months, respectively. The recurrence rate at 12 months was significantly lower in the CHT group than in the IM group (11.1% vs. 44%, p = .048); this trend persisted at 24 months (CHT: 11.1%, IM: 48%; p = .027). The recurrence-free survival was also significantly higher in the CHT group than in the IM group (p = .028). No tumor recurrence was noted in patients who received a thermal dose of ≥4 CEM43. All adverse events were well tolerated, and there was no treatment-related mortality.

CONCLUSIONS

Intravesical chemotherapy combined with locoregional deep hyperthermia for intermediate-/high-risk papillary NMIBC can significantly decrease the recurrence rate relative to that observed after intravesical chemotherapy alone.

Long-Term Experience with Radiofrequency-Induced Hyperthermia Combined with Intravesical Chemotherapy for Non-Muscle Invasive Bladder Cancer

BACKGROUND

The recurrence rate of non-muscle invasive bladder cancer (NMIBC) is high, despite intravesical treatments. Importantly, patients are frequently unfit or unwilling to undergo a recommended radical cystectomy when standard intravesical treatments fail, due to the substantial risk of morbidity and mortality. For these patients, radiofrequency-induced hyperthermia combined with intravesical chemotherapy (RF-CHT) has shown promising results. We aim to determine treatment outcomes and assess the effect of (ablative) dose.

METHODS

299 intensively pretreated patients treated with RF-CHT were included in safety analysis. Of these, 274 patients who fulfilled induction treatments were included in efficacy analysis. Six-month complete response (CR) and durable response were reported for (concomitant) carcinoma in situ (CIS) patients and recurrence-free survival (RFS) for papillary patients.

RESULTS

For CIS, six-month CR-rate was 56.0%; and durable response rates were 79.7%, 66.5%, and 40.3% at one-, two- and five-year, respectively. RFS rates for papillary patients were 77.9%, 57.5%, and 37.2%, respectively. Patients treated with ablative dose are less likely to develop recurrence (adjusted Hazard Ratio 0.54, p = 0.01), compared to adjuvant dose.

CONCLUSIONS

RF-CHT is effective in NMIBC patients in whom standard intravesical treatments have failed and should be considered in patients who are unwilling or unfit to undergo radical cystectomy. Patients with CIS or residual papillary tumor at baseline benefit from ablative dose.

DPPG2-Based Thermosensitive Liposomes with Encapsulated Doxorubicin Combined with Hyperthermia Lead to Higher Doxorubicin Concentrations in the Bladder Compared to Conventional Application in Pigs: A Rationale for the Treatment of Muscle-Invasive Bladder Cancer

Purpose

Current treatment options for muscle-invasive bladder cancer (MIBC) are associated with substantial morbidity. Local release of doxorubicin (DOX) from phosphatidyldiglycerol-based thermosensitive liposomes (DPPG₂-TSL-DOX) potentiated by hyperthermia (HT) in the bladder wall may result in bladder sparing without toxicity of systemic chemotherapy. We investigated whether this approach, compared to conventional DOX application, increases DOX concentrations in the bladder wall while limiting DOX in essential organs.

Materials and Methods

Twenty-one pigs were anaesthetized, and a urinary catheter equipped with a radiofrequency-emitting antenna for HT (60 minutes) was placed. Experimental groups consisted of iv low or full dose (20 or 60 mg/m²) DPPG₂-TSL-DOX with/without HT, iv low dose (20 mg/m²) free DOX with HT, and full dose (50 mg/50 mL) intravesical DOX with/without HT. After the procedure, animals were immediately sacrificed. HPLC was used to measure DOX levels in the bladder, essential organs and serum, and fluorescence microscopy to evaluate DOX distribution in the bladder wall.

Results

Iv DPPG₂-TSL-DOX with HT resulted in a significantly higher bladder wall DOX concentration which was more homogeneous distributed, than iv and intravesical free DOX administration with HT. Specifically in the detrusor, DPPG₂-TSL-DOX with HT led to a >7- and 44-fold higher DOX concentration, compared to iv free DOX with HT and intravesical DOX, respectively. Organ DOX concentrations were significantly lower in heart and kidneys, and similar in liver, spleen and lungs, following iv DPPG₂-TSL-DOX with HT, compared to iv free DOX. Intravesical DOX led to the lowest organ DOX concentrations.

Conclusion

Iv DPPG₂-TSL-DOX combined with HT achieved higher DOX concentrations in the bladder wall including the detrusor, compared to conventional iv and intravesical DOX application. In combination with lower DOX accumulation in heart and kidneys, compared to iv free chemotherapy, DPPG₂-TSL-DOX with HT has great potential to attain a role as a bladder-sparing treatment for MIBC.

The effect of ibrutinib on radiosensitivity in pancreatic cancer cells by targeting EGFR/AKT/mTOR signaling pathway

Radiotherapy is an effective treatment for pancreatic cancer. However, radio-resistance often resulted in poor prognostic. Ibrutinib is an orally small molecule drug in B cell malignancies. Here, we investigated for the first time the effect of ibrutinib on radio-sensitivity of human pancreatic cancer cells in vitro and the potential mechanism involved in it. Human BXPC3 and Capan2 cell lines were treated with ibrutinib, and cell viability was conducted with CCK-8 assay. Cell clone formation was observed after treated with ibrutinib and (or) radiation by clone formation assay. The cell cycle and cell apoptosis were measured by flow cytometry. Protein levels was analyzed by western blot. The results revealed that ibrutinib inhibited the proliferation of pancreatic cancer cells. Ibrutinib enhanced the effect of radiation with a sensitization enhancement ratio (SER) of 1.34, 1.68 in BXPC3 and Capan2 cells respectively. Ibrutinib combined with radiation induced G2/M arrest and cell apoptosis. Further investigations revealed that ibrutinib decreased the phosphorylation of EGFR, then reversed the upregulation of p-AKT and downstream genes by radiation. In conclusion, these results suggested that ibrutinib might be an excellent radiosensitizer in pancreatic cancer.

Development of a high-precision bladder hyperthermic intracavitary chemotherapy device for bladder cancer and pharmacokinetic study

BACKGROUND

Bladder hyperthermic intracavitary chemotherapy (HIVEC) has good effectiveness for bladder cancer, but conventional HIVEC systems lack precision and convenient application. To test the safety of a new HIVEC device (BR-TRG-II-type) in pigs and to perform a preliminary clinical trial in patients with bladder cancer.

METHODS

This device was tested on six pigs to optimize the temperature and time parameters. Then, 165 patients (HIVEC after transurethral resection (TUR), n = 128; or HIVEC, n = 37) treated between December 2006 and December 2016 were recruited. Mitomycin C (MMC) was the chemotherapeutic agent. A serum pharmacokinetic study was performed. The primary endpoints were tumor recurrence, disease-free survival (DFS), and cumulative incidence rate (CIR) during follow-up. The adverse effects were graded.

RESULTS

The animal experiment showed that 45 °C for 1 h was optimal. HIVEC was successful, with the infusion tube temperature stably controlled at about 45 °C, and outlet tube temperature of about 43 °C in all patients, for three sessions. Serum MMC levels gradually increased during HIVEC and decreased thereafter. The mean DFS was 39 ± 3.21 months (ranging from 8 to 78 months), and the DFS rate was 89.1% during follow-up. No adverse events occurred.

CONCLUSION

The use of the BR-TRG-II-type HIVEC device is feasible for the treatment of bladder cancer. Future clinical trials in patients with different stages of bladder cancer will further confirm the clinical usefulness of this device.

TRIAL REGISTRATION

chictr.org.cn: ChiCTR1900022099 (registered on Mar. 252,019). Retrospectively registered.

Intravesical BCG: where do we stand? Past, present and future

High and intermediate risk non-muscle invasive bladder cancer poses a real challenge for treatment. Approximately 70% of bladder cancer presents as non-muscle invasive and 20–25% will progress to muscle invasive disease. Recurrences occur in up to 70% but treatment options are limited. Intravesical bacillus Calmette–Guérin is still considered the bladder sparing treatment of choice despite its well documented pitfalls. This review considers how bacillus Calmette–Guérin has become the recommended treatment, its benefits and risks and the alternative options for treatment.

Level of evidence: Not applicable for this multicentre audit.

Device-assisted intravesical therapy for non-muscle invasive bladder cancer

Non-muscle invasive bladder cancer (NMIBC) is a challenging disease, with a high risk of recurrence and even progression to muscle invasive disease. The present standard treatment is suboptimal, and consists of a complete transurethral resection of the visible bladder tumour(s), followed by prophylactic intravesical instillations mitomycin-C (MMC) or bacillus Calmette-Guérin (BCG). In search for higher efficacy, several adjuvant device-assisted intravesical therapies are developed. Chemohyperthermia may be based on microwave-/radiofrequency-induced (RF) hyperthermia systems, for which most evidence exists, or on hyperthermic intravesical chemotherapy, which is applied by conductive or loco-regional heating systems. RF-induced CHT has shown superiority over MMC alone, and in one prospective study superiority over BCG in per-protocol analysis, which has led to the ‘weak’ recommendation in the EAU guidelines to consider RF-based CHT as a bladder preservation strategy in patients with BCG-refractory tumours, who are not candidates for radical cystectomy due to comorbidities. Prospective studies on hyperthermic intravesical chemotherapy for patients with intermediate-risk NMIBC are awaited next year. The combination of electromotive drug administration (EMDA) with MMC has shown superiority over MMC as well, and seems promising when combined with BCG in sequential treatment. Photodynamic therapy should still be considered experimental, in which a study with the intravenous photosensitizer Radachlorin^® has shown promising results.

Quality assurance guidelines for interstitial hyperthermia

Quality assurance (QA) guidelines are essential to provide uniform execution of clinical hyperthermia treatments and trials. This document outlines the clinical and technical consequences of the specific properties of interstitial heat delivery and specifies recommendations for hyperthermia administration with interstitial techniques. Interstitial hyperthermia aims at tumor temperatures in the 40-44 °C range as an adjunct to radiation or chemotherapy. The clinical part of this document imparts specific clinical experience of interstitial heat delivery to various tumor sites as well as recommended interstitial hyperthermia workflow and procedures. The second part describes technical requirements for quality assurance of current interstitial heating equipment including electromagnetic (radiative and capacitive) and ultrasound heating techniques. Detailed instructions are provided on characterization and documentation of the performance of interstitial hyperthermia applicators to achieve reproducible hyperthermia treatments of uniform high quality. Output power and consequent temperature rise are the key parameters for characterization of applicator performance in these QA guidelines. These characteristics determine the specific maximum tumor size and depth that can be heated adequately. The guidelines were developed by the ESHO Technical Committee with participation of senior STM members and members of the Atzelsberg Circle.

Ex vivo assays to predict enhanced chemosensitization by hyperthermia in urothelial cancer of the bladder

INTRODUCTION

Bladder cancer (urothelial carcinoma) is a common malignancy characterized by high recurrence rates and intense clinical follow-up, indicating the necessity for more effective therapies. Current treatment regimens include intra-vesical administration of mitomycin C (MMC) for non-muscle invasive disease and systemic cisplatin for muscle-invasive or metastatic disease. Hyperthermia, heating a tumor to 40-44°C, enhances the efficacy of these chemotherapeutics by various modes of action, one of which is inhibition of DNA repair via homologous recombination. Here, we explore whether ex vivo assays on freshly obtained bladder tumors can be applied to predict the response towards hyperthermia.

MATERIAL AND METHODS

The cytochrome C release assay (apoptosis) and the RAD51 focus formation assay (DNA repair) were first established in the bladder cancer cell lines RT112 and T24 as measurements for hyperthermia efficiency, and subsequently tested in freshly obtained bladder tumors (n = 59).

RESULTS

Hyperthermia significantly increased the fraction of apoptotic cells after cisplatin or MMC treatment in both RT112 and T24 cells and in most of the bladder tumors (8/10). The RAD51 focus formation assay detected both morphological and numerical changes of RAD51 foci upon hyperthermia in the RT112 and T24 cell lines. In 64% of 37 analyzed primary bladder tumor samples, hyperthermia induced similar morphological changes in RAD51 foci.

CONCLUSION

The cytochrome C assay and the RAD51 focus formation assay are both feasible on freshly obtained bladder tumors, and could serve to predict the efficacy of hyperthermia together with cytotoxic agents, such as MMC or cisplatin.

Clinical validation of a novel thermophysical bladder model designed to improve the accuracy of hyperthermia treatment planning in the pelvic region

PURPOSE

Hyperthermia treatment planning for deep locoregional hyperthermia treatment may assist in phase and amplitude steering to optimize the temperature distribution. This study aims to incorporate a physically correct description of bladder properties in treatment planning, notably the presence of convection and absence of perfusion within the bladder lumen, and to assess accuracy and clinical implications for non muscle invasive bladder cancer patients treated with locoregional hyperthermia.

METHODS

We implemented a convective thermophysical fluid model based on the Boussinesq approximation to the Navier-Stokes equations using the (finite element) OpenFOAM toolkit. A clinician delineated the bladder on CT scans obtained from 14 bladder cancer patients. We performed (1) conventional treatment planning with a perfused muscle-like solid bladder, (2) with bladder content properties without and (3) with flow dynamics. Finally, we compared temperature distributions predicted by the three models with temperature measurements obtained during treatment.

RESULTS

Much higher and more uniform bladder temperatures are predicted with physically accurate fluid modeling compared to previously employed muscle-like models. The differences reflect the homogenizing effect of convection, and the absence of perfusion. Median steady state temperatures simulated with the novel convective model (3) deviated on average -0.6 °C (-12%) from values measured during treatment, compared to -3.7 °C (-71%) and +1.5 °C (+29%) deviation for the muscle-like (1) and static (2) models, respectively. The Grashof number was 3.2 ± 1.5 × 10⁵ (mean ± SD).

CONCLUSIONS

Incorporating fluid modeling in hyperthermia treatment planning yields significantly improved predictions of the temperature distribution in the bladder lumen during hyperthermia treatment.

Intravesical Radiofrequency-Induced Chemohyperthermia for Carcinoma in Situ of the Urinary Bladder: A Retrospective Multicentre Study

Objective:

To examine the effect of intravesical radiofrequency-induced chemohyperthermia (RF-CHT) in carcinoma in-situ (CIS) patients overall and split according to previously received therapy.

Methods:

CIS patients that underwent an induction and maintenance phase of≥6 RF-CHT instillations, and had either pathology or cystoscopy plus cytology available at 6 months of follow-up were retrospectively included. Complete response (CR), recurrences, cystectomy-free rate, overall survival (OS), and adverse events were evaluated. Analysis was performed for overall, bacillus Calmette-Guérin (BCG)-unresponsive, other BCG-treated, and treatment naïve patients.

Results:

Patients (n = 150) had a mean of 17.5, 9.2, or 0 previous BCG instillations in the BCG-unresponsive (n = 50), other BCG-treated (n = 46, missing n = 4), and treatment naïve groups (n = 47, missing n = 3), respectively. After 6 months, a CR of 46.0%, 71.7%, and 83.0% was found (p < 0.001). Subsequent 2-year recurrence rates were 17.4%, 27.3%, and 12.8%, respectively. The overall cystectomy-free rate and OS at mean follow-up (35.8 months) were 78.5% and 78.0%, respectively. These were 71.4% vs. 84.1% vs. 86.7% (cystectomy-free rate, p = 0.006) and 76.0% vs. 69.6% vs. 87.2% (OS, p = 0.06) for BCG-unresponsive vs. other BCG-treated vs. treatment naïve patients. Progression to muscle-invasive disease was seen in 13.3% of patients. Patients stopped induction or maintenance RF-CHT instillations due to adverse events in respectively 13.4% and 17.8%.

Conclusions:

Intravesical RF-CHT showed good results in both treatment naïve and BCG-treated CIS patients, avoiding the need for cystectomy in 78.5% of cases for at least 3 years with a modest risk of progression. Thus, RF-CHT proves an alternative to cystectomy in selected high-risk patients.

Current Clinical Trials in Non-muscle Invasive Bladder Cancer

PURPOSE OF REVIEW

As our molecular understanding of bladder cancer continues to advance, more and more novel agents are entering clinical trials across the spectrum of bladder cancer stages. The clinical trial activity for non-muscle invasive bladder cancer (NMIBC) has been boosted further by the evolution of specific disease states that set more uniform inclusion criteria for clinical trial design. Here, we aimed to review the current clinical trials landscape in non-muscle invasive bladder cancer with respect to these disease states.

RECENT FINDINGS

Most active clinical trials focus on high-risk NMIBC in either the BCG-naïve or BCG-unresponsive setting. Strict criteria to define the disease state and a clear pathway to drug registration have encouraged trials for patients with BCG-unresponsive NMIBC. The most promising potential breakthroughs for BCG-naïve patients include alternative BCG strains, immune-priming with intradermal BCG vaccination, and systemic immune checkpoint blockade. The latter therapy is also being actively investigated in multiple trials in BCG-unresponsive NMIBC, along with novel viral agents such as INSTILADRIN (nadofaragene firadenovec) and targeted agents such as oportuzumab monatox. After many years of relative stagnation, multiple new therapies currently under investigation in well-designed clinical trials appear poised for routine clinical implementation in the near future. These therapies should dramatically improve the outcome of patients with NMIBC. We can look forward to the challenges of biomarker-driven drug selection, optimal drug sequencing, and rational combination therapies.

Inducing intravesical hyperthermia of the ex-vivo porcine bladder wall: radiofrequency-induction versus recirculation using a custom-made device

INTRODUCTION

Several techniques can be used to treat intravesical chemohyperthermia (ChHT). We compared radiofrequency-induced hyperthermia (RF-HT) with conductive hyperthermia (C-HT) for their ability to induce bladder wall temperatures of >40.5 °C, the target temperature for ChHT.

MATERIALS AND METHODS

Fresh porcine bladders (n = 12) were placed in a temperature-controlled saline bath to simulate body temperature and circulation. HT was induced with RF-HT (43 °C) or C-HT (inflow temperature 44 and 46 °C) using a custom-made device. In two additional bladders, we varied intravesical solution and volume. Temperatures were recorded with a three-way catheter containing three mucosal and two urethral thermocouples (TCs) and a 915 MHz RF antenna, and with external TCs in the bladder wall at three different levels and three different locations.

RESULTS

Target temperature (40.5 °C) was reached in the submucosa at all locations by both techniques. In the detrusor, target temperature was reached by RF-HT at the bladder neck and side wall. C-HT₄₆ reached significantly higher submucosal temperatures at the side wall. The bladder dome seemed best heated by C-HT, although a high inflow temperature (46 vs. 44 °C) was required (ns). Intravesical saline resulted in higher temperatures than sterile water for RF-HT. A volume of 100 mL resulted in higher bladder dome temperatures for RF-HT, and higher bladder neck with lower dome temperatures for C-HT.

CONCLUSION

Our results indicate a slightly superior heating capacity for RF-HT compared to C-HT, whereas for the bladder dome, the reverse seems true. Comparative studies are warranted to evaluate whether HT efficacy differs between both techniques, with emphasis on tumor location.

Intravesical radiofrequency induced hyperthermia enhances mitomycin C accumulation in tumour tissue

INTRODUCTION

Non-muscle invasive bladder cancer (NMIBC) is a highly recurrent disease with potential progression to muscle invasive disease despite the standard bladder instillations with mitomycin C (MMC) or Bacille Calmette-Guérin immunotherapy. Therefore, alternatives such as radiofrequency-induced chemohyperthermia (RF-CHT) with MMC are being investigated. The mechanism explaining the efficacy of RF-CHT is only partly understood. We examined whether RF-CHT results in higher MMC tissue concentrations as compared to cold MMC instillation.

PATIENTS AND METHODS

Prior to a planned transurethral resection of bladder tumour (TURBT), patients with stage Ta NMIBC were allocated to either (1) cold MMC instillation or (2) RF-CHT. After MMC instillation, three biopsies were taken of both normal and tumour tissue. Biopsies were snap-frozen and MMC tissue concentrations were analysed using ultra-performance liquid chromatography.

RESULTS

Eleven patients were included of which six received RF-CHT. Ten patients had TaG2-LG/HG papillary tumours at pathology. One patient in the RF-CHT group appeared to be free of malignancy and was excluded from the analysis as no tumour biopsies were available. The median MMC concentration in tumour tissue was higher in the RF-CHT group (median 665.00 ng/g vs. 63.75 ng/g, U = 51.0, p = 0.018). Moreover, in both techniques the MMC concentration was lower in normal tissue compared to tumour tissue. Tissue MMC concentration measurements varied substantially within, and between, different patients from the same group.

CONCLUSION

Intravesical RF-CHT results in higher tumour MMC concentrations vs. cold MMC instillation which contributes to its superior efficacy.

It's Getting Hot in Here: Targeting Cancer Stem-like Cells with Hyperthermia

Cancer stem-like cells (CSCs) are a subset of cancer cells that are resistant to conventional radiotherapy and chemotherapy. As such, CSCs have been recognized as playing a large role in tumor initiation and recurrence. Although hyperthermia is broadly used in cancer treatment either alone or in combination with radio- or chemo-therapy, its potential to target CSCs is not well understood. In this review, we discuss different types of hyperthermia and potential mechanisms of action in cancer treatment, particularly in regards to killing CSCs.