10-year single-center experience of combined intravesical chemohyperthermia for nonmuscle invasive bladder cancer

Non-muscle-invasive bladder cancer: An overview of potential new treatment options

AIM

This review article summarizes the current clinical practice guidelines around disease definitions and risk stratifications, and the treatment of non-muscle-invasive bladder cancer (NMIBC). Recently completed and ongoing clinical trials of novel and investigational therapies in Bacillus Calmette-Guérin (BCG)-naïve, BCG-recurrent, and BCG-unresponsive patient populations are also described, e.g., those involving immune checkpoint inhibitors, targeted therapies, other chemotherapy regimens, vaccines, and viral- or bacterial-based treatments. Finally, a brief overview of enhanced cystoscopy and drug delivery systems for the diagnosis and treatment of NMIBC is provided.

BACKGROUND

A global shortage of access to BCG is affecting the management of BCG-naïve and BCG-recurrent/unresponsive NMIBC; hence, there is an urgent need to assist patients and urologists to enhance the treatment of this disease.

METHODS

Searches of ClinicalTrials.gov, PubMed, and Google Scholar were conducted. Published guidance and conference proceedings from major congresses were reviewed.

CONCLUSION

Treatment strategies for NMIBC are generally consistent across guidelines. Several novel therapies have demonstrated promising antitumor activity in clinical trials, including in high-risk or BCG-unresponsive disease. The detection, diagnosis, surveillance, and treatment of NMIBC have also been improved through enhanced disease detection.

A multi-institutional retrospective study of hyperthermic plus intravesical chemotherapy versus intravesical chemotherapy treatment alone in intermediate and high risk nonmuscle-invasive bladder cancer

Objective:

To compare the efficacy and safety of hyperthermic intravesical chemotherapy (HIVEC) and intravesical chemotherapy (IVEC) in patients with intermediate and high risk nonmuscle-invasive bladder cancer (NMIBC) after transurethral resection.

Methods:

We included 560 patients diagnosed with primary or recurrent NMIBC between April 2009 and December 2015 at 1 of 6 tertiary centers. We matched 364 intermediate or high risk cases and divided them into 2 groups: the HIVEC+IVEC group [chemohyperthermia (CHT) composed of 3 consecutive sessions followed by intravesical instillation without hyperthermia] and the IVEC group (intravesical instillation without hyperthermia). The data were recorded in the database. The primary endpoint was 2-year recurrence-free survival (RFS) in all NMIBC patients (n = 364), whereas the secondary endpoints were the assessment of radical cystectomy (RC) and 5-year overall survival (OS).

Results:

There was a significant difference in the 2-year RFS between the two groups in all patients (n = 364; HIVEC+IVEC: 82.42% vs. IVEC: 74.18%, P = 0.038). Compared with the IVEC group, the HIVEC+IVEC group had a lower incidence of RC (P = 0.0274). However, the 5-year OS was the same between the 2 groups (P = 0.1434). Adverse events (AEs) occurred in 32.7% of all patients, but none of the events was serious (grades 3–4). No difference in the incidence or severity of AEs between each treatment modality was observed.

Conclusions:

This retrospective study showed that HIVEC+IVEC had a higher 2-year RFS and a lower incidence of RC than IVEC therapy in intermediate and high risk NMIBC patients. Both treatments were well-tolerated in a similar manner.

The role of device-assisted therapies in the management of non-muscle invasive bladder cancer: A systematic review

OBJECTIVE

Despite optimal treatment, patients affected by non-muscle invasive bladder cancer (NMIBC) suffer from high risk of recurrence and progression. Intravescical device assisted therapies such as radiofrequency induced thermochemotherapeutic effect (RITE) and electromotive drug administration (EMDA) have shown promising effect in enhancing the effect of intravescical chemotherapies. The aim of the study was to assess clinical outcomes of these two devices in non-muscle invasive bladder cancer.

METHODS

A systematic literature review was performed in December 2019 using the Medline, Embase, and Web of Science databases. Only articles published in the last 10 years were considered (2009-2019). The articles were selected using the following keywords association: "bladder cancer" AND "EMDA' AND "synergo" AND "hyperchemotherapy" AND "electromotive drug administration", AND "radiofrequency induced thermochemotherapeutic" AND "RITE".

RESULTS

We found 16 studies published in the last ten years regarding the efficacy of RITE (12 studies) and EMDA (4 studies) in the treatment of NMIBC. Both RITE and EMDA showed promising results in the treatment of intermediate and high risk NMIBC as well as in patients affected by recurrent BCa after BCG failure. In high-risk BCG naïve NMIBC patients treated with EMDA recurrence and progression rates were 68% and 95%, respectively. Considering RITE, recurrence and progression range rates were 43%-88% and 62%-97%, respectively. Discordance results were reported regarding its effect on patients with carcinoma in situ. However, only few studies could be compared since differences exist regarding inclusion criteria with high patients' heterogeneity. Considering recurrence after BCG, recurrence and progression range rates were 29%-29.2% and 62%-83% for RITE and 25% and 75% for EMDA, respectively.

CONCLUSION

Delivery of intravescical hyperthermia seems to enhance the normal effect of intravescical chemotherapy instillation. Although prospective trials supported its effect on both BCG naïve and BCG failure patients, data are urgently required to validate these findings and to understand its effect on patients with carcinoma in situ.

LEVEL OF PROOF

3.

Heated Intravesical Chemotherapy: Biology and Clinical Utility

Non-muscle-invasive bladder cancer can be a challenging disease to manage. In recent years, hyperthermia therapy in conjunction with intravesical therapy has been gaining traction as a treatment option for bladder cancer, especially if Bacillus Calmette-Guerin might not be available. Trials of intravesical chemotherapy with heat are few and there has been considerable heterogeneity between studies. However, multiple new trials have accrued and high-quality data are forthcoming. In this review, we discuss the role of combined intravesical hyperthermia and chemotherapy as a novel approach for the treatment of bladder cancer.

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.

Intravesical device-assisted therapies for non-muscle-invasive bladder cancer

Non-muscle-invasive bladder cancer (NMIBC), the most prevalent type of bladder cancer, accounts for ~75% of bladder cancer diagnoses. This disease has a 50% risk of recurrence and 20% risk of progression within 5 years, despite the use of intravesical adjuvant treatments (such as BCG or mitomycin C) that are recommended by clinical guidelines. Intravesical device-assisted therapies, such as radiofrequency-induced thermochemotherapeutic effect (RITE), conductive hyperthermic chemotherapy, and electromotive drug administration (EMDA), have shown promising efficacy. These device-assisted treatments are an attractive alternative to BCG, as issues with supply have been a problem in some countries. RITE might be an effective treatment option for some patients who have experienced BCG failure and are not candidates for radical cystectomy. Data from trials using EMDA suggest that it is effective in high-risk disease but requires further validation, and results of randomized trials are eagerly awaited for conductive hyperthermic chemotherapy. Considerable heterogeneity in patient cohorts, treatment sessions, use of maintenance regimens, and single-arm study design makes it difficult to draw solid conclusions, although randomized controlled trials have been reported for RITE and EMDA.

Hyperthermic Intravesical Chemotherapy for BCG Unresponsive Non-Muscle Invasive Bladder Cancer Patients

Background:

Adjuvant intravesical instillations with bacillus Calmette-Guérin (BCG) is the recommended treatment option for patients with intermediate-and high-risk non-muscle invasive bladder cancer (NMIBC). Despite adequate BCG treatment, a large proportion of patients experience a recurrence. Although radical cystectomy is the gold standard for BCG unresponsive NMIBC, some patients are unfit or unwilling to consider this option.

Objective:

To assess the effectiveness of Hyperthermic IntraVEsical Chemotherapy (HIVEC^®) in BCG unresponsive NMIBC patients.

Methods:

A post-hoc analysis was conducted of prospectively included intermediate-and high-risk NMIBC patients who were planned to receive HIVEC^® treatment between October 2014 and November 2017. For the present analysis, only patients who met the BCG unresponsive definition were included. Patients were followed by cystoscopy and cytology every 3 months and a CT-urography scan yearly. The primary outcome was the disease-free survival (DFS). The Common Terminology Criteria for Adverse Events (CTCAE) was used to assess side-effects.

Results:

The study population consisted of 55 BCG unresponsive NMIBC patients of whom 52 underwent≥5 HIVEC^® treatments. The median age and follow-up were 73 years and 14.0 months (IQR 7.6 – 24.6). The median DFS was 17.7 months (SE 6.72) and progression occurred in four patients. The 1-year cumulative incidence rate of disease recurrence/progression was 53%. Two patients experienced severe side-effects (CTCAE≥3).

Conclusions:

HIVEC^® seems a valid treatment option for BCG unresponsive NMIBC patients. We report a median DFS of 17.7 months (SE 6.72), potentially avoiding or postponing the need for radical surgery in a proportion of these patients.

A model of thermotherapy treatment for bladder cancer

In this work, we investigate chemo- thermotherapy, a recently clinically-approved post-surgery treatment of non muscle invasive urothelial bladder carcinoma. We developed a mathematical model and numerically simulated the physical processes related to this treatment. The model is based on the conductive Maxwell's equations used to simulate the therapy administration and Convection-Diffusion equation for incompressible fluid to study heat propagation through the bladder tissue. The model parameters correspond to the data provided by the thermotherapy device manufacturer. We base our computational domain on a CT image of a human bladder. Our numerical simulations can be applied to further research on the effects of chemo- thermotherapy on bladder and surrounding tissues and for treatment personalization in order to maximize the effect of the therapy while avoiding burning of the bladder.

Chemohyperthermia in non-muscle-invasive bladder cancer: An overview of the literature and recommendations

Non-muscle-invasive bladder cancer (NMIBC) is characterised by a high risk of recurrence for the present standard treatment of transurethral resection of the bladder (TURB) followed by intravesical instillation of Mitomycin-C (MMC) or bacillus Calmette-Guérin (BCG). To decrease this high recurrence rate, alternative treatments are studied. Intravesical MMC combined with hyperthermia could be an interesting alternative active treatment for intermediate- and high-risk NMIBC, and has been investigated in the past years. Hyperthermia, raising tumour temperatures to 40-44 °C, can be achieved with several hyperthermia systems, based on three different techniques: 1) intravesical microwave induced heating, 2) conductive heating, and 3) loco-regional, using external radiofrequency antennas. In this review an overview is given of the available hyperthermia systems and the reported outcomes. Future directions are discussed. Optimal implementation of a combined regimen of MMC and hyperthermia requires further clinical trials to identify patients who will benefit most from this treatment, to optimise treatment schedules and to compare the efficacy of different hyperthermia devices.

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

Although many treatment modalities and schedules for non-muscle-invasive bladder cancer (NMIBC) exist, all yet prove to have limitations. Therefore the search for new forms of therapy continues. One of these forms consists of combining intravesical chemotherapy, typically mitomycin C (MMC), with hyperthermia achieved by a microwave-applicator. We aimed to review the current status of intravesical radiofrequency (RF) induced chemohyperthermia (CHT) for NMIBC with regard to efficacy, adverse-events (AEs) and its future perspective. A search for RF-induced CHT in MEDLINE, Embase, Cochrane and ClinicalTrials.gov databases was performed. Relevant conference abstracts were searched for manually. If applicable, experts on the area were consulted. Papers were selected based on abstract and title. A table of newly published clinical trials since 2011 was constructed. No meta-analysis could be performed based on these new papers. Efficacy proved to be better for RF-induced CHT compared to both MMC alone and bacillus Calmette-Guérin (BCG) instillations, with the latter being based on just one abstract of a randomised controlled trial. The AE rate in CHT is higher compared to MMC instillation, but is similar compared to BCG, albeit different in the type of AE. In almost all studies no severe AEs are reported. Although heterogeneity in methodology exists, RF-induced CHT seems promising. However, alternative methods of applying hyperthermia are starting to present their first results, imposing as effective options too. Intravesical RF-induced CHT may become an alternative for BCG instillation, and possibly for cystectomy, although further level 1 evidence is required for both reliable and reproducible data on efficacy and adverse events.

Results of Intravesical Chemo-Hyperthermia in High-risk Non-muscle Invasive Bladder Cancer

PURPOSE

To examine the effectiveness of mitomycin-C and chemo-hyperthermia in combination for patients with high-risk non-muscle-invasive bladder cancer.

MATERIALS AND METHODS

Between November 2011-September 2013, 43 patients with high-risk non-muscle-invasive bladder cancer undergoing adjuvant chemo-hyperthermia in two centers were evaluated retrospectively. Treatment consisted of 6 weekly sessions, followed by 6 sessions. Recurrence and progression rate, recurrence-free interval and side effects were examined. Analyzed factors included age, gender, smoking status, AB0 blood group, body mass index, T stage and grade, concominant CIS assets. The associations between predictors and recurrence were assessed using multivariate Cox proportional hazard analyses.

RESULTS

A total of 40 patients completed induction therapy. Thirteen (32.5%) were diagnosed with tumor recurrence. Median follow-up was 30 months (range 9-39). Median recurrence-free survival was 23 months (range 6-36). The Kaplan-Meier-estimated recurrence-free rates for the entire group at 12 and 24 months were 82% and 61%. There was no statistically significant difference between patient subgroups. Cox hazard analyses showed that an A blood type (OR=6.23, p=0.031) was an independent predictor of recurrence- free. Adverse effects were seen in 53% of patients and these were frequently grades 1 and 2.

CONCLUSIONS

Intravesical therapy with combination of mitomycin-C and chemohyperthermia seems to be appropriate in high-risk patients with non-muscle-invasive bladder cancer who cannot tolerate or have contraindications for standard BCG therapy.

Radiofrequency-Induced Thermo-Chemotherapy Effect (Rite) for Non Muscle Invasive Bladder Cancer Treatment: Current Role and Perspectives

Although many treatment modalities and schedules for nonmuscle invasive bladder cancer (NMIBC) exist, all yet prove to have limitations and the search for new therapeutic strategies continues. Among these, the combination of intravesical chemotherapy and microwave-induced local hyperthermia has been investigated and clinically tested during more than 15 years.

Objective

An updated review of intravesical radiofrequency (RF)-induced thermo-chemotherapy effect (RITE) for NMIBC with regard to efficacy, adverse events (AEs) and perspectives.

Evidence Acquisition

An extensive and sensitive search for RF-induced chemo-hyperthermia in Medline, Embase, Cochrane and ClinicalTrials.gov databases was performed. A table of published clinical trials up to 2016 was constructed. No meta-analysis could be performed on the basis of new papers.

Evidence Synthesis

Recurrence was seen 59% less after RITE than after mitomycin C (MMC) alone in adjuvant clinical setting with an overall bladder preservation rate after RITE of 85%. The efficacy was proved to be comparable to that of Bacillus Calmette-Guèrin (BCG), based on a single comparative multicentric study. Due to short follow-up, no conclusions can be drawn about time to recurrence and progression. The AE rate in RITE was higher, although not statistically significant, than MMC alone and similar to that of BCG, albeit different in the type of AE. In almost all studies, no severe AEs are reported.

Conclusions

RITE appears as a promising treatment option for NMIBC, particularly for high-risk patients with recurrent tumors, for those unsuitable for radical cystectomy and when Bacillus Calmette-Guèrin treatment is contraindicated. Further high-level evidence is needed for both reliable and reproducible data on efficacy and adverse events.

Intravesical bacillus Calmette-Guérin versus chemohyperthermia for high-risk non-muscle-invasive bladder cancer

INTRODUCTION

Patients with high-risk non-muscle invasive bladder cancer (NMIBC) need adjuvant intravesical treatment after surgery. Although bacillus Calmette-Guérin (BCG) is highly effective, new adjuvant treatments to decrease recurrences and toxicity have been studies. We performed a retrospective propensity score-matched study to compare the efficacy of BCG and chemohyperthermia (C-HT).

METHODS

We included 1937 patients diagnosed with bladder cancer between January 2004 and January 2014. The primary efficacy endpoint was recurrence-free interval. Patients treated with C-HT were matched with patients treated with BCG using propensity score-matched analysis. Cox-regression models were used to estimate the association between intravesical treatments and the presence of recurrence and progression.

RESULTS

Of the 710 patients treated with intravesical treatments, 40 and 142 were eligible for inclusion in C-HT and BCG groups, respectively. Following case matching, there were no differences in patient or tumour characteristics between treatment groups. The 2-year recurrence-free interval in C-HT and BCG groups were 76.2% and 93.9%, respectively (p = 0.020). C-HT treatment (hazard ratio [HR] 5.42; 95% confidence interval [CI] 1.11-26.43; p = 0.036) and high-grade tumour (HR 4.60; 95% CI 1.01-20.88; p = 0.048) are associated with an elevated odds of tumour recurrence. In multivariate Cox-regression analysis, there was no significant difference between C-HT and BCG in the odds of recurrence (p = 0.054). There were no differences in progression between C-HT and BCG.

CONCLUSION

C-HT is not as effective treatment as BCG in high-risk NMIBC patients who are BCG-naive. Although, there were no significant difference in the odds of recurrence, recurrence-free interval is significantly improved by the administration of BCG.

The effects and effectiveness of electromotive drug administration and chemohyperthermia for treating non-muscle invasive bladder cancer

INTRODUCTION

Preliminary studies show that device assisted intravesical therapies appear more effective than passive diffusion intravesical therapy for the treatment of non-muscle invasive bladder cancer (NMIBC) in specific settings, and phase III studies are now being conducted. Consequently, we have undertaken a non-systematic review with the objective of describing the scientific basis and mechanisms of action of electromotive drug administration (EMDA) and chemohyperthermia (CHT).

METHODS

PubMed, ClinicalTrials.gov and the Cochrane Library were searched to source evidence for this non-systematic review. Randomised controlled trials, systematic reviews and meta-analyses were evaluated. Publications regarding the scientific basis and mechanisms of action of EMDA and CHT were identified, as well as clinical studies to date.

RESULTS

EMDA takes advantage of three phenomena: iontophoresis, electro-osmosis and electroporation. It has been found to reduce recurrence rates in NMIBC patients and has been proposed as an addition or alternative to bacillus Calmette-Guérin (BCG) therapy in the treatment of high risk NMIBC. CHT improves the efficacy of mitomycin C by three mechanisms: tumour cell cytotoxicity, altered tumour blood flow and localised immune responses. Fewer studies have been conducted with CHT than with EMDA but they have demonstrated utility for increasing disease-free survival, especially in patients who have previously failed BCG therapy.

CONCLUSIONS

It is anticipated that EMDA and CHT will play important roles in the management of NMIBC in the future. Techniques of delivery should be standardised, and there is a need for more randomised controlled trials to evaluate the benefits of the treatments alongside quality of life and cost-effectiveness.

Magnetic fluid hyperthermia for bladder cancer: a preclinical dosimetry study

PURPOSE

This paper describes a preclinical investigation of the feasibility of thermotherapy treatment of bladder cancer with magnetic fluid hyperthermia (MFH), performed by analysing the thermal dosimetry of nanoparticle heating in a rat bladder model.

MATERIALS AND METHODS

The bladders of 25 female rats were instilled with magnetite-based nanoparticles, and hyperthermia was induced using a novel small animal magnetic field applicator (Actium Biosystems, Boulder, CO). We aimed to increase the bladder lumen temperature to 42 °C in <10 min and maintain that temperature for 60 min. Temperatures were measured within the bladder lumen and throughout the rat with seven fibre-optic probes (OpSens Technologies, Quebec, Canada). An MRI analysis was used to confirm the effectiveness of the catheterisation method to deliver and maintain various nanoparticle volumes within the bladder. Thermal dosimetry measurements recorded the temperature rise of rat tissues for a variety of nanoparticle exposure conditions.

RESULTS

Thermal dosimetry data demonstrated our ability to raise and control the temperature of rat bladder lumen ≥1 °C/min to a steady state of 42 °C with minimal heating of surrounding normal tissues. MRI scans confirmed the homogenous nanoparticle distribution throughout the bladder.

CONCLUSION

These data demonstrate that our MFH system with magnetite-based nanoparticles provides well-localised heating of rat bladder lumen with effective control of temperature in the bladder and minimal heating of surrounding tissues.

The anti-hepatoma effect of nanosized Mn-Zn ferrite magnetic fluid hyperthermia associated with radiation in vitro and in vivo

Joint therapy is a promising area of study in cancer treatment. In this paper, we prepared Mn-Zn ferrite (Mn0.5Zn0.5Fe2O4) magnetofluid using PEI as a surfactant, and investigated the anticancer effect of Mn0.5Zn0.5Fe2O4 magnetic fluid hyperthermia (MFH) combined with radiotherapy on hepatocellular carcinoma. Both in vitro and in vivo results suggest that this combined treatment with MFH and radiation has a better therapeutic effect than either of them alone. The apoptotic rate and necrotic rate of the combined treatment group was 38.80 and 25.20%, respectively. In contrast, it was only 7.49 and 3.62% in the radiation-alone group, 15.23 and 7.90% in the MFH-alone group, only 3.52 and 2.16% in the blank control group, and 23.56 and 27.56% in the adriamycin group. The cell proliferation inhibition rate of the combined treatment group (88.5%) was significantly higher than that of the radiation-alone group (37.5%), MFH-alone group (60.6%) and adriamycin group (70.6%). The tumor volume inhibition and mass inhibition rate of the combined treatment group was 87.62 and 88.62%, respectively, obviously higher than the 41.04 and 34.20% of the radiation-alone group, 79.87 and 77.92% of the MFH-alone group and 71.76 and 66.87% of the adriamycin group. It is therefore concluded that this combined application of MFH and radiation can give good synergistic and complementary effects, which offers a viable approach for treatment of cancer.

Preclinical Dosimetry of Magnetic Fluid Hyperthermia for Bladder Cancer

BACKGROUND

Despite positive efficacy, thermotherapy is not widely used in clinical oncology. Difficulties associated with field penetration and controlling power deposition patterns in heterogeneous tissue have limited its use for heating deep in the body. Heat generation using iron-oxide super-paramagnetic nanoparticles excited with magnetic fields has been demonstrated to overcome some of these limitations. The objective of this preclinical study is to investigate the feasibility of treating bladder cancer with magnetic fluid hyperthermia (MFH) by analyzing the thermal dosimetry of nanoparticle heating in a rat bladder model.

METHODS

The bladders of 25 female rats were injected with 0.4 ml of Actium Biosystems magnetite-based nanoparticles (Actium Biosystems, Boulder CO) via catheters inserted in the urethra. To assess the distribution of nanoparticles in the rat after injection we used the 7 T small animal MRI system (Bruker ClinScan, Bruker BioSpin MRI GmbH, Ettlingen, Germany). Heat treatments were performed with a small animal magnetic field applicator (Actium Biosystems, Boulder CO) with a goal of raising bladder temperature to 42°C in <10min and maintaining for 60min. Temperatures were measured throughout the rat with seven fiberoptic temperature probes (OpSens Technologies, Quebec Canada) to characterize our ability to localize heat within the bladder target.

RESULTS

The MRI study confirms the effectiveness of the catheterization procedure to homogenously distribute nanoparticles throughout the bladder. Thermal dosimetry data demonstrate our ability to controllably raise temperature of rat bladder ≥1°C/min to a steady-state of 42°C.

CONCLUSION

Our data demonstrate that a MFH system provides well-localized heating of rat bladder with effective control of temperature in the bladder and minimal heating of surrounding tissues.

Role of the Combined Regimen with Local Chemotherapy and Mw-Induced Hyperthermia for Non-Muscle Invasive Bladder Cancer Management. A Systematic Review

Objectives

To give an updated review concerning the role of combined regimen (CT) based on microwave-induced hyperthermia (MwHT, CT-MwHT) with intravesical chemotherapy (ICT) as a treatment for non-muscle invasive bladder cancer (NMIBC).

Evidence Acquisition

The review process followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. An electronic search of the Medline, Embase, Cochrane Library, CancerLit, and ClinicalTrials.gov databases was undertaken. Relevant conference abstracts and urology journals were also included. The primary end-point was the time to recurrence. Secondary end-points included time to progression, bladder preservation rate, and adverse event (AE) rate.

Evidence Synthesis

A total of 24 studies met inclusion criteria and underwent data extraction. When feasible, data were combined using random-effects meta-analytic techniques. Recurrence was seen 59% less after CT-MwHT than after MMC alone, however, due to the short follow-up, no definitive conclusions can be drawn about the impact on the time to recurrence and progression. The overall bladder preservation rate after CT-MwHT was 87.6%. This rate appeared higher than after MMC alone, but valid comparison studies could not be drawn due to the absence of randomized trials in neo-adjuvant settings. AEs were higher with CT-MwHT than with MMC alone, but this difference was not statistically significant.

Conclusions

Published data suggest that recurrence rates for chemo-hyperthermia are substantially reduced compared with chemotherapy alone in adjuvant settings. Patients with refractory disease fare worse than those being treated with chemo-hyperthermia for their first tumor. Progression rates to muscle-invasive disease are markedly lower after combination treatment than after chemotherapy alone, with very high rates of bladder preservation. Tolerability is good, with few dropouts in the clinical trials. The results support CT-MwHT in the future as a standard procedure for high-risk recurrent patients, for subjects in whom the treatment with Bacillus Calmette-Guérin is contraindicated, and those unsuitable for radical cystectomy.