Effects of hyperthermia in neutralising mechanisms of drug resistance in non-muscle-invasive bladder cancer

Magnetic field-induced synergistic therapy of cancer using magnetoplasmonic nanoplatform

Combining photothermal and chemotherapy using single nanoplatform is an emerging direction in cancer nanomedicine. Herein, a magnetic field (MF) induced combination of chemo/photothermal therapy is demonstrated using Fe3O4@mSiO2@Au core@shell@satellites nanoparticles (NPs) loaded with chemotherapeutic drug doxorubicin (DOX), both in vitro and in vivo. An application of an external MF to the NPs dispersion causes magnetophoretic movement and aggregation of the NPs. While the synthesized NPs only slightly absorb light at ∼800 nm, their aggregation results in a significant near infrared (NIR) absorption associated with plasmon resonance coupling between the Au satellites in the NPs aggregates. As a result, the aggregates revealed an enhanced photothermal conversion efficiency (∼67 % versus ∼19 % for NPs in absence of MF) and an enhanced NIR photothermal effect was observed under 808 nm laser irradiation. A combination of the MF induced NIR photothermal therapy (PTT) with DOX chemotherapeutic action resulted in an efficient killing of NPs treated cancer cells in vitro and tumor growth restriction in 4T1-tumor-bearing mice in vivo. Histological studies showed striking differences in development and malignancy between tumors treated with the combination of NPs, MF and an 808 nm laser, and the control treatments, revealing a synergy of the MF-induced NIR PTT and chemotherapy and suggesting a promising strategy for cancer therapy.

Intravesical thermochemotherapy in the treatment of high-risk and very high-risk non-muscle-invasive urothelial bladder cancer: a single-arm study

AIM

Intravesical thermochemotherapy, also known as HIVEC (Hyperthermic Intra-VEsical Chemotherapy), represents an alternative adjuvant topical treatment for non-muscle-invasive urothelial bladder cancer (NMIBC). High-risk (HR) and very HR tumors carry a substantial risk of recurrence and progression. In this study, we present our own results using HIVEC as an alternative to unavailable Bacillus Calmette-Guérin (BCG) vaccine in the treatment of such groups of patients.

METHODS

During the period of November 2014-June 2022, a total of 47 patients with HR and very HR NMIBC underwent treatment with HIVEC after transurethral resection. They were given an induction of 6 instillations with/without a maintenance. The aim was to evaluate the time to recurrence, event-free survival (recurrence or progression), as measured by Kaplan-Meier analysis, the effect of maintenance treatment and other factors on survival (log-rank test and multivariable Cox regression analysis), and complications.

RESULTS

The median follow-up for patients who did not experience an event was 32 months. The median time to HR (high grade and/or T1 tumor) recurrence in those who recurred was 15 months. The survival rate without HR recurrence at 12, 24, and 48 months was 84, 70, and 59%, respectively. Progression was detected in 10.6% of patients, which translated to 89% of patients living without progression after 24 months. Maintenance treatment (defined as more than six instillations) and presence of CIS significantly correlated with risk of HR recurrence (Hazard ratio 0.34 and 3.12, respectively). One female patient underwent salvage cystectomy due to contractory bladder, and 19.1% of patients experienced transient lower urinary tract symptoms.

CONCLUSION

Based on our experience, HIVEC represents an adequate and safe alternative treatment for HR and very HR NMIBC in situations where BCG is not available or radical cystectomy is not an option for the patient. However, high-quality data from prospective randomized studies are still lacking, and thus, thermochemotherapy should still be regarded as an experimental treatment modality.

Photodynamic and Photothermal Therapies: Synergy Opportunities for Nanomedicine

Tumoricidal photodynamic (PDT) and photothermal (PTT) therapies harness light to eliminate cancer cells with spatiotemporal precision by either generating reactive oxygen species or increasing temperature. Great strides have been made in understanding biological effects of PDT and PTT at the cellular, vascular and tumor microenvironmental levels, as well as translating both modalities in the clinic. Emerging evidence suggests that PDT and PTT may synergize due to their different mechanisms of action, and their nonoverlapping toxicity profiles make such combination potentially efficacious. Moreover, PDT/PTT combinations have gained momentum in recent years due to the development of multimodal nanoplatforms that simultaneously incorporate photodynamically- and photothermally active agents. In this review, we discuss how combining PDT and PTT can address the limitations of each modality alone and enhance treatment safety and efficacy. We provide an overview of recent literature featuring dual PDT/PTT nanoparticles and analyze the strengths and limitations of various nanoparticle design strategies. We also detail how treatment sequence and dose may affect cellular states, tumor pathophysiology and drug delivery, ultimately shaping the treatment response. Lastly, we analyze common experimental design pitfalls that complicate preclinical assessment of PDT/PTT combinations and propose rational guidelines to elucidate the mechanisms underlying PDT/PTT interactions.

Development and investigation of a novel device with gemcitabine for hyperthermic intravesical chemotherapy

PURPOSE

To evaluate the safety and efficacy of a novel hyperthermic intravesical chemotherapy (HIVEC) device in combination with gemcitabine.

MATERIALS AND METHODS

A pilot clinical trial was performed on patients with high-risk non-muscle invasive bladder cancer (NMIBC), who received HIVEC via the novel device (BR-PRG). Treatment regimen included eight weekly instillations of intravesical GEM (3 g in 150 mL normal saline [NS]) at a temperature of 45 °C for 60 min. Assessment of adverse events (AEs) was the primary objective of the trial. Disease recurrence and the thermal stability of GEM were also analyzed.

RESULTS

A total of 116 HIVEC treatments were delivered. Fifteen and eighteen patients were included in the effectiveness and safety analysis, respectively. Median follow-up was 12 months; five patients experienced a disease recurrence. One-year cumulative incidence of recurrence was 23.8% in EORTC intermediate risk group and 37.5% in high-risk group. Ten patients experienced at least one AE, with the most common being acute urinary tract infection, followed by urinary tract pain, and hematuria. Two patients experienced acute cystitis (grade 3 AE) and instillations were postponed until full recovery. Other AEs were minor, and no systemic toxicity was observed. The contents of GEM in solution of 0.9% NS or NS mixed with artificial urine were stable at 25 °C, 37 °C, 43 °C, 45 °C, 47 °C and 50 °C for 2 h.

CONCLUSION

GEM can be an ideal drug for use in HIVEC due to its good thermal stability. BR-PRG, combined with GEM was safe and effective in administering HIVEC.

Advances in nanobiotechnology-propelled multidrug resistance circumvention of cancer

Multidrug resistance (MDR) is one of the main reasons for the failure of tumor chemotherapy and has a negative influence on the therapeutic effect. MDR is primarily attributable to two mechanisms: the activation of efflux pumps for drugs, which can transport intracellular drug molecules from cells, and other mechanisms not related to efflux pumps, e.g., apoptosis prevention, strengthened DNA repair, and strong oxidation resistance. Nanodrug-delivery systems have recently attracted much attention, showing some unparalleled advantages such as drug targeting and reduced drug efflux, drug toxicity and side effects in reversing MDR. Notably, in drug-delivery platforms based on nanotechnology, multiple therapeutic strategies are integrated into one system, which can compensate for the limitations of individual strategies. In this review, the mechanisms of tumor MDR as well as common vectors and nanocarrier-combined therapy strategies to reverse MDR were summarized to promote the understanding of the latest progress in improving the efficiency of chemotherapy and synergistic strategies. In particular, the adoption of nanotechnology has been highlighted and the principles underlying this phenomenon have been elucidated, which may provide guidance for the development of more effective anticancer strategies.

Impact of Effective Intravesical Therapies on Quality of Life in Patients with Non-Muscle Invasive Bladder Cancer: A Systematic Review

BACKGROUND

Conventional and newly emerged intravesical modalities have demonstrated prophylactic effectiveness that may improve quality of life (QoL) in non-muscle invasive bladder cancer. The purpose of this study is to analyze existing QoL evidence in patients receiving any form of intravesical therapy.

METHODS

A PubMed search without time restriction was conducted to identify all relevant studies in accordance with the PICOT question. Additionally, a search was also performed in the Cochrane library database, Internet, and citation. The CONSORT 2010 checklist and STROBE statement checklist were used to evaluate the risk of bias of the included studies.

RESULTS

A total of 24 eligible articles were included, which consisted of 11 interventional and 13 observational studies. Intravesical therapy with Bacillus Calmette-Guérin (BCG) or certain chemotherapeutic agents worsens symptom burdens and functional performance during the initial induction phase while continuous improved is observed throughout the maintenance treatment and beyond. Hyperthermia has shown a positive trend in enhancing QoL of patients receiving intravesical chemotherapy, which requires more investigations. However, QoL data were unavailable for other forms of immunotherapy, immune checkpoint inhibitors, electromotive drug administration, and photodynamic therapy.

CONCLUSIONS

Limited studies suggested the long-term positive impact of intravesical BCG immunotherapy and chemotherapy. However, existing evidence was lacking to clarify the impact of many emerging intravesical therapies that have suggested to be effective and safe, which demands treatment-specific QoL studies.

Solid Magnetoliposomes as Multi-Stimuli-Responsive Systems for Controlled Release of Doxorubicin: Assessment of Lipid Formulations

Stimuli-responsive liposomes are a class of nanocarriers whose drug release occurs, preferentially, when exposed to a specific biological environment, to an external stimulus, or both. This work is focused on the design of solid magnetoliposomes (SMLs) as lipid-based nanosystems aiming to obtain multi-stimuli-responsive vesicles for doxorubicin (DOX) controlled release in pathological areas under the action of thermal, magnetic, and pH stimuli. The effect of lipid combinations on structural, colloidal stability, and thermodynamic parameters were evaluated. The results confirmed the reproducibility for SMLs synthesis based on nine lipid formulations (combining DPPC, DSPC, CHEMS, DOPE and/or DSPE-PEG), with structural and colloidal properties suitable for biological applications. A loss of stability and thermosensitivity was observed for formulations containing dioleoylphosphatidylethanolamine (DOPE) lipid. SMLs PEGylation is an essential step to enhance both their long-term storage stability and stealth properties. DOX encapsulation (encapsulation efficiency ranging between 87% and 96%) in the bilayers lowered its pK_a, which favors the displacement of DOX from the acyl chains to the surface when changing from alkaline to acidic pH. The release profiles demonstrated a preferential release at acidic pH, more pronounced under mimetic mild-hyperthermia conditions (42 °C). Release kinetics varied with the lipid formulation, generally demonstrating hyperthermia temperatures and acidic pH as determining factors in DOX release; PEGylation was shown to act as a diffusion barrier on the SMLs surface. The integrated assessment and characterization of SMLs allows tuning lipid formulations that best respond to the needs for specific controlled release profiles of stimuli-responsive nanosystems as a multi-functional approach to cancer targeting and therapy.

A scalable hyperthermic intravesical chemotherapy (HIVEC) setup for rat models of bladder cancer

Hyperthermic intravesical chemotherapy (HIVEC)—whereby the bladder is heated to ± 43 °C during a chemotherapy instillation—can improve outcomes of non-muscle invasive bladder cancer (NMIBC) treatments. Experiments in animal models are required to explore new hyperthermia based treatments. Existing HIVEC devices are not suitable for rodents or large-scale animal trials. We present a HIVEC setup compatible with orthotopic rat models. An externally heated chemotherapeutic solution is circulated in the bladder through a double-lumen catheter with flow rates controlled using a peristaltic pump. Temperature sensors in the inflow channel, bladder and outflow channel allow temperature monitoring and adjustments in real-time. At a constant flow rate of 2.5 mL/min the system rapidly reaches the desired bladder temperature of 42–43 °C with minimal variability throughout a one-hour treatment in a rat bladder phantom, as well as in euthanised and live rats. Mean intraluminal bladder temperatures were 42.92 °C (SD = 0.15 °C), 42.45 °C (SD = 0.37 °C) and 42.52 °C (SD = 0.09 °C) in the bladder phantom, euthanised, and live rats respectively. Thermal camera measurements showed homogenous heat distributions over the bladder wall. The setup provides well-controlled thermal dose and the upscaling needed for performing large scale HIVEC experiments in rats.

Encapsulation of doxorubicin prodrug in heat-triggered liposomes overcomes off-target activation for advanced prostate cancer therapy

L-377,202 prodrug consists of doxorubicin (Dox) conjugated to a prostate-specific antigen (PSA) peptide substrate that can be cleaved by enzymatically active PSA at the tumor site. Despite the initial promise in phase I trial, further testing of L-377,202 (herein called Dox-PSA) was ceased due to some degree of non-specific activation and toxicity concerns. To improve safety of Dox-PSA, we encapsulated it into low temperature-sensitive liposomes (LTSL) to bypass systemic activation, while maintaining its biological activity upon controlled release in response to mild hyperthermia (HT). A time-dependent accumulation of activated prodrug in the nuclei of PSA-expressing cells exposed to mild HT was observed, showing that Dox-PSA was efficiently released from the LTSL, cleaved by PSA and entering the cell nucleus as free Dox. Furthermore, we have shown that Dox-PSA loading in LTSL can block its biological activity at 37°C, while the combination with mild HT resulted in augmented cytotoxicity in both 2D and 3D PC models compared to the free Dox-PSA. More importantly, Dox-PSA encapsulation in LTSL prolonged its blood circulation and reduced Dox accumulation in the heart of C4-2B tumor-bearing mice over the free Dox-PSA, thus significantly improving Dox-PSA therapeutic window. Finally, Dox-PSA-loaded LTSL combined with HT significantly delayed tumor growth at a similar rate as mice treated with free Dox-PSA in both solid and metastatic PC tumor models. This indicates this strategy could block the systemic cleavage of Dox-PSA without reducing its efficacy in vivo, which could represent a safer option to treat patients with locally advanced PC. STATEMENT OF SIGNIFICANCE: This study investigates a new tactic to tackle non-specific cleavage of doxorubicin PSA-activatable prodrug (L-377,202) to treat advanced prostate cancer. In the present study, we report a nanoparticle-based approach to overcome the non-specific activation of L-377,202 in the systemic circulation. This includes encapsulating Dox-PSA in low temperature-sensitive liposomes to prevent its premature hydrolysis and non-specific cleavage. This class of liposomes offers payload protection against degradation in plasma, improved pharmacokinetics and tumor targeting, and an efficient and controlled drug release triggered by mild hyperthermia (HT) (∼42°C). We believe that this strategy holds great promise in bypassing any systemic toxicity concerns that could arise from the premature activation of the prodrug whilst simultaneously being able to control the spatiotemporal context of Dox-PSA cleavage and metabolism.

A computational study of combination HIFU-chemotherapy as a potential means of overcoming cancer drug resistance

The application of local hyperthermia, particularly in conjunction with other treatment strategies (like chemotherapy and radiotherapy) has been known to be a useful means of enhancing tumor treatment outcomes. However, to our knowledge, there has been no mathematical model designed to capture the impact of the combination of hyperthermia and chemotherapies on tumor growth and control. In this study, we propose a nonlinear Partial Differential Equation (PDE) model which describes the tumor response to chemotherapy, and use the model to study the effects of hyperthermia on the response of prototypical tumor to the generic chemotherapeutic agent. Ultrasound energy is delivered to the tumor through High Intensity Focused Ultrasound (HIFU), as a noninvasive technique to elevate the tumor temperature in a controlled manner. The proposed tumor growth model is coupled with the nonlinear density dependent Westervelt and Penne's bio-heat equations, used to calculate the net delivered energy and temperature of the tumor and its surrounding normal tissue. The tumor is assumed to be composed of two species: drug-sensitive and drug-resistant. The central assumption underlying our model is that the drug-resistant species is converted to a drug-sensitive type when the tumor temperature is elevated above a certain threshold temperature. The "in silico" results obtained, confirm that hyperthermia can result in less aggressive tumor development and emphasize the importance of designing an optimized thermal dose strategy. Furthermore, our results suggest that increasing the length of the on/off cycle of the transducer is an efficient approach to treatment scheduling in the sense of optimizing tumor eradication.

Safety and efficacy of intravesical chemotherapy and hyperthermia in the bladder: results of a porcine study

BACKGROUND

Hyperthermia (heating to 43 °C) activates the innate immune system and improves bladder cancer chemosensitivity.

OBJECTIVE

To evaluate the tissue penetration and safety of convective hyperthermia combined with intravesical mitomycin C (MMC) pharmacokinetics in live porcine bladder models using the Combat bladder recirculation system (BRS).

METHODS

Forty 60 kg-female swine were anesthetized and catheterized with a 3-way, 16 F catheter. The Combat device was used to heat the bladders to a target temperature of 43 °C with recirculating intravesical MMC at doses of 40, 80, and 120 mg. Dwell-heat time varied from 30-180 min. Rapid necropsy with immediate flash freezing of tissues, blood and urine occurred. MMC concentrations were measured by liquid chromatography tandem-mass spectrometry.

RESULTS

The Combat BRS system was able to achieve target range temperature (42-44 °C) in 12 mins, and this temperature was maintained as long as the device was running. Two factors increased tissue penetration of MMC in the bladder: drug concentration, and the presence of heat. In the hyperthermia arm, MMC penetration saturated at 80 mg, suggesting that with heating, drug absorption may saturate and not require higher doses to achieve the maximal biological effect. Convective hyperthermia did not increase the MMC concentration in the liver, heart, kidney, spleen, lung, and lymph node tissue even at the 120 mg dose.

CONCLUSIONS

Convective bladder hyperthermia using the Combat BRS device is safe and the temperature can be maintained at 43 °C. Hyperthermia therapy may increase MMC penetration into the bladder wall but does not result in an increase of MMC levels in other organs.

Overcoming multidrug resistance in cancer: Recent progress in nanotechnology and new horizons

Multidrug resistance (MDR), defined as the ability of cancer cells to gain resistance to both conventional and novel chemotherapy agents, is an important barrier in treating malignancies. Initially, it was discovered that cellular pumps dependent on ATP were the cause of resistance to chemotherapy, and further studies have found that other mechanisms such as increased metabolism of drugs, decreased drug entry, and defective apoptotic pathways are involved in this process. MDR has been the focus of numerous initiatives and countless studies have been undertaken to better understand MDR and formulate strategies to overcome its effects. The current review highlights various nano-drug delivery systems including polymeric/solid lipid/mesoporous silica/metal nanoparticles, dendrimers, liposomes, micelles, and nanostructured lipid carriers to overcome the mechanism of MDR. Nanoparticles are novel gateways to enhance the therapeutic efficacy of anticancer agents at the target site of action due to their tumor-targeting abilities, which can limit the unwanted systemic effects of chemotherapy agents and also reduce drug resistance. Additionally, other innovative strategies including RNA interference as a biological process used to inhibit or silence specific gene expression, natural products as MDR modulators with little systemic toxic effects, which interfere with the functions of proteins involved in drug efflux, and physical approaches such as combination of conventional drug administration with thermal/ultrasound/photodynamic strategies are also highlighted.

Molecular and biological rationale of hyperthermia as radio- and chemosensitizer

Mild hyperthermia, local heating of the tumour up to temperatures <43 °C, has been clinically applied for almost four decades and has been proven to substantially enhance the effectiveness of both radiotherapy and chemotherapy in treatment of primary and recurrent tumours. Clinical results and mechanisms of action are discussed in this review, including the molecular and biological rationale of hyperthermia as radio- and chemosensitizer as established in in vitro and in vivo experiments. Proven mechanisms include inhibition of different DNA repair processes, (in)direct reduction of the hypoxic tumour cell fraction, enhanced drug uptake, increased perfusion and oxygen levels. All mechanisms show different dose effect relationships and different optimal scheduling with radiotherapy and chemotherapy. Therefore, obtaining the ideal multi-modality treatment still requires elucidation of more detailed data on dose, sequence, duration, and possible synergisms between modalities. A multidisciplinary approach with different modalities including hyperthermia might further increase anti-tumour effects and diminish normal tissue damage.

Ultrasound Hyperthermia Technology for Radiosensitization

Hyperthermia therapy (HT) raises tissue temperature to 40-45°C for up to 60 min. Hyperthermia is one of the most potent sensitizers of radiation therapy (RT). Ultrasound-mediated HT for radiosensitization has been used clinically since the 1960s. Recently, magnetic resonance-guided high-intensity focused ultrasound (MRgHIFU), which has been approved by the United States Food and Drug Administration for thermal ablation therapy, has been adapted for HT. With emerging clinical trials using MRgHIFU HT for radiosensitization, there is a pressing need to review the ultrasound HT technology. The objective of this review is to overview existing HT technology, summarize available ultrasound HT devices, evaluate clinical studies combining ultrasound HT with RT and discuss challenges and future directions.

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.

The effect of air pockets in the urinary bladder on the temperature distribution during loco-regional hyperthermia treatment of bladder cancer patients

PURPOSE

Loco-regional hyperthermia combined with mitomycin C is used for treatment of nonmuscle invasive bladder cancer (NMIBC). Air pockets may be present in the bladder during treatment. The aim of this study is to quantify the effect of air pockets on the thermal dose of the bladder.

METHODS

We analysed 16 patients treated for NMIBC. Loco-regional hyperthermia was performed with the in-house developed 70 MHz AMC-4 hyperthermia device. We simulated treatments with the clinically applied device settings using Plan2Heat (developed in-house) including the air pockets delineated on CT scans made following treatment, and with the same volume filled with urine. Temperature distributions simulated with and without air pockets were compared.

RESULTS

The average air and fluid volumes in the bladder were 6.0 ml (range 0.8 - 19.3 ml) and 183 ml (range 47-322 ml), respectively. The effect of these air pockets varied strongly between patients. Averaged over all patients, the median bladder wall temperature (T₅₀) remained unchanged when an air pocket was present. Temperature changes exceeded ±0.2 °C in, on average, 23% of the bladder wall volume (range 1.3-59%), in 6.0% (range 0.6-20%) changes exceeded ±0.5 °C and in 3.2% (range 0.0-7.4%) changes exceeded ±1.0 °C. There was no correlation between the differences in temperature and the air pocket or bladder volume. There was a positive correlation between air pocket surface and temperature heterogeneity.

CONCLUSION

Presence of air causes more heterogeneous bladder wall temperatures and lower T₉₀, particularly for larger air pockets. The size of air pockets must therefore be minimized during bladder hyperthermia treatments.

Hyperthermia-mediated drug delivery induces biological effects at the tumor and molecular levels that improve cisplatin efficacy in triple negative breast cancer

Triple negative breast cancer is an aggressive disease that accounts for at least 15% of breast cancer diagnoses, and a disproportionately high percentage of breast cancer related morbidity. Intensive research efforts are focused on the development of more efficacious treatments for this disease, for which therapeutic options remain limited. The high incidence of mutations in key DNA repair pathways in triple negative breast cancer results in increased sensitivity to DNA damaging agents, such as platinum-based chemotherapies. Hyperthermia has been successfully used in breast cancer treatment to sensitize tumors to radiation therapy and chemotherapy. It has also been used as a mechanism to trigger drug release from thermosensitive liposomes. In this study, mild hyperthermia is used to trigger release of cisplatin from thermosensitive liposomes in the vasculature of human triple negative breast cancer tumors implanted orthotopically in mice. This heat-triggered liposomal formulation of cisplatin resulted in significantly delayed tumor growth and improved overall survival compared to treatment with either non-thermosensitive liposomes containing cisplatin or free cisplatin, as was observed in two independent tumor models (i.e. MDA-MB-231 and MDA-MB-436). The in vitro sensitivity of the cell lines to cisplatin and hyperthermia alone and in combination was characterized extensively using enzymatic assays, clonogenic assays, and spheroid growth assays. Evaluation of correlations between the in vitro and in vivo results served to identify the in vitro approach that is most predictive of the effects of hyperthermia in vivo. Relative expression of several heat shock proteins and the DNA damage repair protein BRCA1 were assayed at baseline and in response to hyperthermia both in vitro and in vivo. Interestingly, delivery of cisplatin in thermosensitive liposomes in combination with hyperthermia resulted in the most significant tumor growth delay, relative to free cisplatin, in the less cisplatin-sensitive cell line (i.e. MDA-MB-231). This work demonstrates that thermosensitive cisplatin liposomes used in combination with hyperthermia offer a novel method for effective treatment of triple negative breast cancer.

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.

Bladder intracavitary hyperthermic perfusion chemotherapy for the prevention of recurrence of non-muscle invasive bladder cancer after transurethral resection

Preventing the recurrence of non-muscle invasive bladder cancer (NMIBC) post-transurethral resection (TUR) remains challenging. The aim of the present study was to investigate the effectiveness and safety of bladder intracavitary hyperthermic perfusion chemotherapy (BHPC) for prevention of NMIBC recurrence post-TUR. Between December 2006 and December 2014, 53 patients with NMIBC who underwent TUR were randomly assigned to receive BHPC (BHPC group, 28 patients) or intravesical chemotherapy alone (chemotherapy group, 25 patients) at the Intracelom Hyperthermic Perfusion Therapy Center of Guangzhou Medical University Cancer Hospital (Guangzhou, China). BHPC was performed by combining perfusion-based hyperthermia with chemotherapeutic agent mitomycin C (MMC) in the bladder, and the chemotherapy group of patients received bladder MMC perfusion. The concentration of MMC in the perfusion fluid and serum were assessed at different time-points. Tumor recurrence, disease-free survival (DFS), and side-effects were recorded and compared between the 2 groups. Results revealed that BHPC was performed smoothly, at ~44̊C in the bladder cavity. Patients tolerated BHPC, and no side-effects were observed. Both BHPC and intravesical chemotherapy achieved a high MMC concentration in the bladder perfusion liquid, but low MMC concentration in the serum, although serum MMC concentrations in the BHPC group were significantly higher (P<0.05). The tumor recurrence rate was significantly lower (10.7 vs. 28.0%; P=0.02) and the DFS period was significantly longer (37±1.2 vs. 19±0.9 months; P=0.001) in the BHPC group than in the chemotherapy group. Our results demonstrated that BHPC is safe and effective for preventing NMIBC recurrence post-TUR and prolongs DFS.