Long-term improvement in treatment outcome after radiotherapy and hyperthermia in locoregionally advanced cervix cancer: an update of the Dutch Deep Hyperthermia Trial

Advances in magnetic induction hyperthermia

Magnetic induction hyperthermia (MIH), is a technique that has developed rapidly in recent years in the field of tumor thermotherapy. It implants a magnetic heating medium (millimeter-sized heat seeds, micron-sized magnetic particles and nanometer-sized magnetic fluids, etc.) inside the tumor. The material heats up under the induction of an external alternating magnetic field (100-500 kHz), which causes a high temperature zone to rapidly form in the local biological tissues and induces apoptosis in tumor cells. Magnetic induction hyperthermia has the advantages of high safety, strong targeting, repeatable treatment, and the size of the incision during treatment is negligible compared to surgical resection, and is currently used in clinical treatment. However, the millimeter-scale heat seed heating that is typically used in treatments can result in uneven temperatures within the tissue. Common MIH heating devices are bulky and complex in design, and are not easy for medical staff to get their hands on, which are issues that limit the diffusion of MIH. In this view, this paper will discuss the basic theoretical research on MIH and the progress of MIH-related technologies, with a focus on the latest research and development results and research hotspots of nanoscale ferromagnetic media and magnetic heat therapy devices, as well as the validation results and therapeutic efficacy of the new MIH technology on animal experiments and clinical trials. In this paper, it is found that induction heating using magnetic nanoparticles improves the uniformity of the temperature field, and the magneto-thermal properties of nanoscale ferromagnetic materials are significantly improved. The heating device was miniaturized to simplify the operation steps, while the focusing of the magnetic field was locally enhanced. However, there are fewer studies on the biotoxicity aspects of nanomedicines, and the localized alternating magnetic field uniformity used for heating and the safety of the alternating magnetic field after irradiation of the human body have not been sufficiently discussed. Ultimately, the purpose of this paper is to advance research related to magnetic induction thermotherapy that can be applied in clinical treatment.

Thermoradiotherapy Optimization Strategies Accounting for Hyperthermia Delivery Uncertainties

PURPOSE

The combined effect of hyperthermia and radiation therapy can be quantified by an enhanced equivalent radiation dose (EQDRT). Uncertainties in hyperthermia treatment planning and adjustments during treatment can impact achieved EQDRT. We developed and compared strategies for EQDRT optimization of radiation therapy plans, focusing on robustness against common adjustments.

METHODS AND MATERIALS

Using Plan2Heat, we computed preplanning hyperthermia plans and treatment adjustment scenarios for 3 cervical cancer patients. We imported these scenarios into RayStation 12A for optimization with 4 different strategies: (1) conventional radiation therapy optimization prescribing 46 Gy to the planning target volume (PTV), (2) nominal EQDRT optimization using the preplanning scenario, targeting uniform 58 Gy in the gross tumor volume (GTV), keeping organs at risk doses as in plan 1, (3) robust EQDRT optimization, as plan 2 but adding adjusted scenarios for optimization, and (4) library of plans (4 plans) with strategy 2 criteria but optimizing on 1 adjusted scenario per plan. We calculated for each radiation therapy plan EQDRT distributions for preplanning and adjusted scenarios, evaluating each combination of GTV coverage and homogeneity objectives.

RESULTS

EQDRT95% increased from 49.9 to 50.9 Gy in strategy 1 to 56.1 to 57.4 Gy in strategy 2 with the preplanning scenario, improving homogeneity by ∼10%. Strategy 2 demonstrated the best overall robustness, with 62% of all GTV objectives within tolerance. Strategy 3 had a higher percentage of coverage objectives within tolerance than strategy 2 (68% vs 54%) but a lower percentage for uniformity (44% vs 71%). Strategy 4 showed a similar EQDRT95% and homogeneity for adjusted scenarios than strategy 2 for a preplanning scenario. D0.1% (radiation dose received by the 0.1% most irradiated volume) for organs at risk was increased by strategies 2 to 4 by up to ∼6 Gy.

CONCLUSIONS

EQDRT optimization enhances EQDRT levels and uniformity compared with conventional optimization. Better overall robustness is achieved by optimizing the preplanning hyperthermia plan. Robust optimization improves coverage but reduces homogeneity. A library of plans ensures coverage and uniformity when dealing with adjusted hyperthermia scenarios.

Biological treatment evaluation in thermoradiotherapy: application in cervical cancer patients

BACKGROUND

Hyperthermia treatment quality is usually evaluated by thermal (dose) parameters, though hyperthermic radiosensitization effects are also influenced by the time interval between the two modalities. This work applies biological modelling for clinical treatment evaluation of cervical cancer patients treated with radiotherapy plus hyperthermia by calculating the equivalent radiation dose (EQDRT, i.e., the dose needed for the same effect with radiation alone). Subsequent analyses evaluate the impact of logistics.

METHODS

Biological treatment evaluation was performed for 58 patients treated with 23-28 fractions of 1.8-2 Gy plus 4-5 weekly hyperthermia sessions. Measured temperatures (T50) and recorded time intervals between the radiotherapy and hyperthermia sessions were used to calculate the EQDRT using an extended linear quadratic (LQ) model with hyperthermic LQ parameters based on extensive experimental data. Next, the impact of a 30-min time interval (optimized logistics) as well as a 4‑h time interval (suboptimal logistics) was evaluated.

RESULTS

Median average measured T50 and recorded time intervals were 41.2 °C (range 39.7-42.5 °C) and 79 min (range 34-125 min), respectively, resulting in a median total dose enhancement (D50) of 5.5 Gy (interquartile range [IQR] 4.0-6.6 Gy). For 30-min time intervals, the enhancement would increase by ~30% to 7.1 Gy (IQR 5.5-8.1 Gy; p < 0.001). In case of 4‑h time intervals, an ~ 40% decrease in dose enhancement could be expected: 3.2 Gy (IQR 2.3-3.8 Gy; p < 0.001). Normal tissue enhancement was negligible (< 0.3 Gy), even for short time intervals.

CONCLUSION

Biological treatment evaluation is a useful addition to standard thermal (dose) evaluation of hyperthermia treatments. Optimizing logistics to shorten time intervals seems worthwhile to improve treatment efficacy.

Theoretical evaluation of the impact of diverse treatment conditions by calculation of the tumor control probability (TCP) of simulated cervical cancer Hyperthermia-Radiotherapy (HT-RT) treatments in-silico

INTRODUCTION

Hyperthermia (HT) induces various cellular biological processes, such as repair impairment and direct HT cell killing. In this context, in-silico biophysical models that translate deviations in the treatment conditions into clinical outcome variations may be used to study the extent of such processes and their influence on combined hyperthermia plus radiotherapy (HT + RT) treatments under varying conditions.

METHODS

An extended linear-quadratic model calibrated for SiHa and HeLa cell lines (cervical cancer) was used to theoretically study the impact of varying HT treatment conditions on radiosensitization and direct HT cell killing effect. Simulated patients were generated to compute the Tumor Control Probability (TCP) under different HT conditions (number of HT sessions, temperature and time interval), which were randomly selected within margins based on reported patient data.

RESULTS

Under the studied conditions, model-based simulations suggested a treatment improvement with a total CEM43 thermal dose of approximately 10 min. Additionally, for a given thermal dose, TCP increased with the number of HT sessions. Furthermore, in the simulations, we showed that the TCP dependence on the temperature/time interval is more correlated with the mean value than with the minimum/maximum value and that comparing the treatment outcome with the mean temperature can be an excellent strategy for studying the time interval effect.

CONCLUSION

The use of thermoradiobiological models allows us to theoretically study the impact of varying thermal conditions on HT + RT treatment outcomes. This approach can be used to optimize HT treatments, design clinical trials, and interpret patient data.

Radiosensitization by Hyperthermia Critically Depends on the Time Interval

PURPOSE

Hyperthermia is a potent sensitizer of radiation therapy that improves both tumor control and survival in women with locally advanced cervical cancer (LACC). The optimal sequence and interval between hyperthermia and radiation therapy are still under debate.

METHODS AND MATERIALS

We investigated the interval and sequence in vitro in cervical cancer cell lines, patient-derived organoids, and SiHa cervical cancer hind leg xenografts in athymic nude mice and compared the results with retrospective results from 58 women with LACC treated with thermoradiotherapy.

RESULTS

All 3 approaches confirmed that shortening the interval between hyperthermia and radiation therapy enhanced hyperthermic radiosensitization by 2 to 8 times more DNA double-strand breaks and apoptosis and 10 to 100 times lower cell survival, delayed tumor growth in mice, and increased the 5-year survival rate of women with LACC from 22% (interval ≥80 minutes) to 54% (interval <80 minutes). In vitro and in vivo results showed that the sequence of hyperthermia and radiation therapy did not affect the outcome.

CONCLUSIONS

Shortening the interval between hyperthermia and radiation therapy significantly improves treatment outcomes. The sequence of hyperthermia and radiation therapy (before or after) does not seem to matter.

Efficacy of mFOLFOX6 plus bevacizumab regimen in advanced colorectal cancer after deep hyperthermia: a single-center retrospective study

Background

This study aimed to explore the clinical efficacy and safety of a modified FOLFOX6 (oxaliplatin + leucovorin + 5-fluorouracil) plus bevacizumab regimen after deep hyperthermia in advanced colorectal cancer.

Methods

A total of 80 colorectal cancer patients treated at our hospital were selected as research subjects. According to the random number table method, patients were divided into a control group (mFOLFOX6 plus bevacizumab) and a combination group (mFOLFOX6 plus bevacizumab after deep hyperthermia treatment), with 40 patients in each group. After six cycles of treatment, the objective response rate (ORR), disease control rate (DCR), levels of serum tumor markers carcinoembryonic antigen (CEA), vascular epidermal growth factor (VEGF), Karnofsky performance status (KPS) scores, and the occurrence of adverse events were compared between the two groups.

Results

After six cycles of treatment, the ORR in the combination group was higher than that in the control group, but the difference was not statistically significant (P>0.05). The DCR in the combination group was significantly higher than that in the control group (P<0.05). The serum CEA levels in the control and combination groups after treatment were significantly lower than those before treatment, and the serum CEA and VEGF levels in the combination group were significantly lower than those in the control group (all P<0.001). The KPS scores in both groups after treatment were higher than those before treatment, and the KPS scores in the combination group after treatment were significantly higher than those in the control group (all P<0.001). The incidence of fatigue and pain in the combination group was significantly lower than that in the control group (P<0.05).

Conclusion

mFOLFOX6 plus bevacizumab after deep hyperthermia is effective in advanced colorectal cancer patients, which can effectively improve their quality of life, and the adverse events are controllable and tolerable. A randomized or prospective trial will be required to further prove these data and explore its potentiality, especially if compared to conventional treatment.

Intracavitary Applicator for Sequential Delivery of Localized Hyperthermia Through Non-Metallic Uterine Tandem

In this article, we report the design and demonstration of a flexible coaxial wire antenna with a low profile flexible choke for delivering localized hyperthermia (HT) treatment to the cervix through a custom designed uterine tandem applicator. Resistive and magnetic materials were investigated for determining the flexible choke design suited for intracavitary HT treatment at 915 MHz. Measurements of the intracavitary antenna with the flexible choke in tissue mimicking phantom and ex-vivo bovine muscle through the non-metallic uterine tandem prototype confirm the ability to deliver localized HT to the cervix at 915 MHz and 50 mm insertion depth.

Assessment of the thermal tissue models for the head and neck hyperthermia treatment planning

PURPOSE

To compare different thermal tissue models for head and neck hyperthermia treatment planning, and to assess the results using predicted and measured applied power data from clinical treatments.

METHODS

Three commonly used temperature models from literature were analysed: "constant baseline", "constant thermal stress" and "temperature dependent". Power and phase data of 93 treatments of 20 head and neck patients treated with the HYPERcollar3D applicator were used. The impact on predicted median temperature T50 inside the target region was analysed with maximum allowed temperature of 44 °C in healthy tissue. The robustness of predicted T50 for the three models against the influence of blood perfusion, thermal conductivity and the assumed hotspot temperature level was analysed.

RESULTS

We found an average predicted T50 of 41.0 ± 1.3 °C (constant baseline model), 39.9 ± 1.1 °C (constant thermal stress model) and 41.7 ± 1.1 °C (temperature dependent model). The constant thermal stress model resulted in the best agreement between the predicted power (P = 132.7 ± 45.9 W) and the average power measured during the hyperthermia treatments (P = 129.1 ± 83.0 W).

CONCLUSION

The temperature dependent model predicts an unrealistically high T50. The power values for the constant thermal stress model, after scaling simulated maximum temperatures to 44 °C, matched best to the average measured powers. We consider this model to be the most appropriate for temperature predictions using the HYPERcollar3D applicator, however further studies are necessary for developing of robust temperature model for tissues during heat stress.

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.

Field and Temperature Shaping for Microwave Hyperthermia: Recent Treatment Planning Tools to Enhance SAR-Based Procedures

The aim of the article is to provide a summary of the work carried out in the framework of a research project funded by the Italian Ministry of Research. The main goal of the activity was to introduce multiple tools for reliable, affordable, and high-performance microwave hyperthermia for cancer therapy. The proposed methodologies and approaches target microwave diagnostics, accurate in vivo electromagnetic parameters estimation, and improvement in treatment planning using a single device. This article provides an overview of the proposed and tested techniques and shows their complementarity and interconnection. To highlight the approach, we also present a novel combination of specific absorption rate optimization via convex programming with a temperature-based refinement method implemented to mitigate the effect of thermal boundary conditions on the final temperature map. To this purpose, numerical tests were carried out for both simple and anatomically detailed 3D scenarios for the head and neck region. These preliminary results show the potential of the combined technique and improvements in the temperature coverage of the tumor target with respect to the case wherein no refinement is adopted.

A Review of the Current Clinical Evidence for Loco-Regional Moderate Hyperthermia in the Adjunct Management of Cancers

Regional hyperthermia therapy (RHT) is a treatment that applies moderate heat to tumours in an attempt to potentiate the effects of oncological treatments and improve responses. Although it has been used for many years, the mechanisms of action are not fully understood. Heterogenous practices, poor quality assurance, conflicting clinical evidence and lack of familiarity have hindered its use. Despite this, several centres recognise its potential and have adopted it in their standard treatment protocols. In recent times, significant technical improvements have been made and there is an increasing pool of evidence that could revolutionise its use. Our narrative review aims to summarise the recently published prospective trial evidence and present the clinical effects of RHT when added to standard cancer treatments. In total, 31 studies with higher-quality evidence across various subsites are discussed herein. Although not all of these studies are level 1 evidence, benefits of moderate RHT in improving local tumour control, survival outcomes and quality of life scores were observed across the different cancer subsites with minimal increase in toxicities. This paper may serve as a reference when considering this technique for specific indications.

The Emerging Evidence Supporting Integration of Deep Regional Hyperthermia With Chemoradiation in Bladder Cancer

For decades, the antineoplastic potential of hyperthermia alone or in combination with radiotherapy and/or chemotherapy has been subject of intensive preclinical and clinical research in various tumor entities. The clinical evidence on the beneficial effects of additional hyperthermia in combination with intravesical Mitomycin C for superficial non-muscle-invasive bladder cancer as well as for deep regional microwave hyperthermia techniques applied during an external beam radiotherapy or chemoradiation treatment for more advanced tumors are summarized. In some series, deep regional hyperthermia in combination with an initial transurethral resection and Cisplatin-based chemoradiation increased the 5-year overall survival rates up to 20%. The presented data justifies a fresh irrespective chance for mild regional hyperthermia in the context of new progressive prospective trials on multimodality treatment for bladder preservation.

Using MRI to measure position and anatomy changes and assess their impact on the accuracy of hyperthermia treatment planning for cervical cancer

PURPOSE

We studied the differences between planning and treatment position, their impact on the accuracy of hyperthermia treatment planning (HTP) predictions, and the relevance of including true treatment anatomy and position in HTP based on magnetic resonance (MR) images.

MATERIALS AND METHODS

All volunteers were scanned with an MR-compatible hyperthermia device, including a filled waterbolus, to replicate the treatment setup. In the planning setup, the volunteers were scanned without the device to reproduce the imaging in the current HTP. First, we used rigid registration to investigate the patient position displacements between the planning and treatment setup. Second, we performed HTP for the planning anatomy at both positions and the treatment mimicking anatomy to study the effects of positioning and anatomy on the quality of the simulated hyperthermia treatment. Treatment quality was evaluated using SAR-based parameters.

RESULTS

We found an average displacement of 2 cm between planning and treatment positions. These displacements caused average absolute differences of ∼12% for TC25 and 10.4%-15.9% in THQ. Furthermore, we found that including the accurate treatment position and anatomy in treatment planning led to an improvement of 2% in TC25 and 4.6%-10.6% in THQ.

CONCLUSIONS

This study showed that precise patient position and anatomy are relevant since these affect the accuracy of HTP predictions. The major part of improved accuracy is related to implementing the correct position of the patient in the applicator. Hence, our study shows a clear incentive to accurately match the patient position in HTP with the actual treatment.

Application of photogrammetry reconstruction for hyperthermia quality control measurements

PURPOSE

Hyperthermia is a cancer treatment in which the target region is heated to temperatures of 40-44 °C usually applying external electromagnetic field sources. The behavior of the hyperthermia applicators (antennas) in clinical practice should be periodically checked with phantom experiments to verify the applicator's performance over time. The purpose of this study was to investigate the application of photogrammetry reconstructions of 3D applicator position in these quality control procedure measurements.

METHODS

Photogrammetry reconstruction was applied at superficial hyperthermia scenario using the Lucite cone applicator (LCA) and phased-array heating in the head and neck region using the HYPERcollar3D. Wire-frame models of the entire measurement setups were created from multiple-view images and used for recreation of the setup inside 3D electromagnetic field simulation software. We evaluated applicator relation (R_a) between measured and simulated absolute specific absorption rate (SAR) for manually created and photogrammetry reconstructed simulation setups.

RESULTS

We found a displacement of 7.9 mm for the LCA and 8.2 mm for the HYPERcollar3D setups when comparing manually created and photogrammetry reconstructed applicator models placements. R_a improved from 1.24 to 1.18 for the LCA and from 1.17 to 1.07 for the HYPERcollar3D when using photogrammetry reconstructed simulation setups.

CONCLUSION

Photogrammetry reconstruction technique holds promise to improve measurement setup reconstruction and agreement between measured and simulated absolute SAR.

Detailed in vitro analyses of the impact of multimodal cancer therapy with hyperthermia and radiotherapy on the immune phenotype of human glioblastoma cells

PURPOSE

Improvements of heat-delivery systems have led to hyperthermia (HT) being increasingly recognized as an adjunct treatment modality also for brain tumors. But how HT affects the immune phenotype of glioblastoma cells is only scarcely known.

MATERIALS AND METHODS

We therefore investigated the effect of in vitro HT, radiotherapy (RT), and the combination of both (RHT) on cell death modalities, immune checkpoint molecule (ICM) expression and release of the danger signal HSP70 of two human glioblastoma cell lines (U87 and U251) by using multicolor flow cytometry and ELISA. Hyperthermia was performed once or twice for 60-minute sessions reaching temperatures of 39 °C, 41 °C, and 44 °C, respectively. RT was administered with 5 x 2 Gy.

RESULTS

A hyperthermia chamber for cell culture t-flasks regulating the temperature via a contact sensor was developed. While the glioblastoma cells were rather radioresistant, particularly in U251 cells, the combination of RT with HT significantly increased the percentage of apoptotic and necrotic cells for all temperatures examined and for both, single and double HT application. In line with that, an increased release of HSP 70 was seen only in U251 cells, mainly following treatment with HT at temperatures of 44 °C alone or in combination with RT. In contrast, immune suppressive (PD-L1, PD-L2, HVEM) and immune stimulatory (ICOS-L, CD137-L and Ox40-L) ICMs were significantly increased mostly on U87 cells, and particularly after RHT with 41 °C.

CONCLUSIONS

Individual assessment of the glioblastoma immune cell phenotype with regard to the planned treatment is mandatory to optimize multimodal radio-immunotherapy protocols including HT.

Design and Characterization of an RF Applicator for In Vitro Tests of Electromagnetic Hyperthermia

The evaluation of the biological effects of therapeutic hyperthermia in oncology and the precise quantification of thermal dose, when heating is coupled with radiotherapy or chemotherapy, are active fields of research. The reliable measurement of hyperthermia effects on cells and tissues requires a strong control of the delivered power and of the induced temperature rise. To this aim, we have developed a radiofrequency (RF) electromagnetic applicator operating at 434 MHz, specifically engineered for in vitro tests on 3D cell cultures. The applicator has been designed with the aid of an extensive modelling analysis, which combines electromagnetic and thermal simulations. The heating performance of the built prototype has been validated by means of temperature measurements carried out on tissue-mimicking phantoms and aimed at monitoring both spatial and temporal temperature variations. The experimental results demonstrate the capability of the RF applicator to produce a well-focused heating, with the possibility of modulating the duration of the heating transient and controlling the temperature rise in a specific target region, by simply tuning the effectively supplied power.

Prognostic impact of waiting time between diagnosis and treatment in patients with cervical cancer: A nationwide population-based study

OBJECTIVE

Prior research underlined the importance of timely oncological care as longer waiting times from diagnosis to treatment may result in poorer survival outcomes. The aim of this study was to determine the impact of waiting time from diagnosis to treatment on overall survival (OS) in patients with cervical cancer treated with curative intent.

METHODS

Patients from a nationwide population-based cohort with newly diagnosed cervical cancer between 2010 and 2019 were studied. Patients who underwent surgery or (chemo)radiotherapy with curative intent were selected. Waiting time (i.e. interval between first pathologic confirmation and treatment) was modelled as continuous (i.e. linear per week), dichotomized (i.e. ≤8 versus >8 weeks), and polynomial (i.e. restricted cubic splines). The association with OS was examined using Cox regression analyses.

RESULTS

Among 6895 patients with cervical cancer, 2755 treated with primary surgery and 1898 who received primary (chemo)radiotherapy were included. Mean waiting time was 8.5 (±4.2) weeks to surgery and 7.7 (±2.9) weeks to (chemo)radiotherapy. Adjusted for confounders, waiting time to surgery was not significantly associated with OS (continuous HR 0.97 [95%CI: 0.93-1.01], dichotomized HR 0.93 [95%CI: 0.68-1.27], polynomial HR not significant). Similarly, a longer waiting time to (chemo)radiotherapy was not significantly associated with poorer OS (continuous HR 0.97 [95%CI: 0.93-1.00], dichotomized HR 0.91 [95%CI: 0.75-1.09], polynomial HR not significant).

CONCLUSIONS

This large population-based study demonstrates that a longer waiting time (of up to 12 weeks) from diagnosis to treatment in patients with cervical cancer treated with curatively intended surgery or (chemo)radiotherapy does not negatively impact survival.

Combined modality including novel sensitizers in gynecological cancers

Standard treatment of locally advanced gynecological cancers relies mainly on platinum-based concurrent chemoradiotherapy followed by brachytherapy. Current chemotherapeutic drugs are only transiently effective and patients with advanced disease often develop resistance and subsequently, distant metastases despite significant initial responses of the primary tumor. In addition, some patients still develop local failure or progression, suggesting that there is still a place for increasing the anti-tumor radiation effect. Several strategies are being developed to increase the probability of curing patients. Vaginal cancer and vulva cancer are rare diseases, which resemble cervical cancer in their histology and pathogenesis. These gynecological cancers are predominantly associated with human papilloma virus infection. Treatment strategies in other unresectable gynecologic cancers are usually derived from evidence in locally advanced cervical cancers. In this review, we discuss mechanisms by which novel therapies could work synergistically with conventional chemoradiotherapy, from pre-clinical and ongoing clinical data. Trimodal, even quadrimodal treatment are currently being tested in clinical trials. Novel combinations derived from a metastatic setting, and being tested in locally advanced tumors, include anti-angiogenic agents, immunotherapy, tumor-infiltrating lymphocytes therapy, adoptive T-cell therapy and apoptosis inducers to enhance chemoradiotherapy efficacy through complementary molecular pathways. In parallel, radiosensitizers, such as nanoparticles and radiosensitizers of hypoxia aim to maximize the effect of radiotherapy locally.

Present Practice of Radiative Deep Hyperthermia in Combination with Radiotherapy in Switzerland

BACKGROUND

Moderate hyperthermia is a potent and evidence-based radiosensitizer. Several indications are reimbursed for the combination of deep hyperthermia with radiotherapy (dHT+RT). We evaluated the current practice of dHT+RT in Switzerland.

METHODS

All indications presented to the national hyperthermia tumor board for dHT between January 2017 and June 2021 were evaluated and treatment schedules were analyzed using descriptive statistics.

RESULTS

Of 183 patients presented at the hyperthermia tumor board, 71.6% were accepted and 54.1% (99/183) finally received dHT. The most commonly reimbursed dHT indications were "local recurrence and compression" (20%), rectal (14.7%) and bladder (13.7%) cancer, respectively. For 25.3% of patients, an individual request for insurance cover was necessary. 47.4% of patients were treated with curative intent; 36.8% were in-house patients and 63.2% were referred from other hospitals.

CONCLUSIONS

Approximately two thirds of patients were referred for dHT+RT from external hospitals, indicating a general demand for dHT in Switzerland. The patterns of care were diverse with respect to treatment indication. To the best of our knowledge, this study shows for the first time the pattern of care in a national cohort treated with dHT+RT. This insight will serve as the basis for a national strategy to evaluate and expand the evidence for dHT.

Effects of Modulated Electro-Hyperthermia (mEHT) on Two and Three Year Survival of Locally Advanced Cervical Cancer Patients

(1) Background: Modulated electro-hyperthermia (mEHT) is a mild to moderate, capacitive-coupled heating technology that uses amplitude modulation to enhance the cell-killing effects of the treatment. We present three year survival results and a cost effectiveness analysis from an ongoing randomised controlled Phase III trial involving 210 participants evaluating chemoradiotherapy (CRT) with/without mEHT, for the management of locally advanced cervical cancer (LACC) in a resource constrained setting (Ethics Approval: M120477/M704133; ClinicalTrials.gov ID: NCT033320690). (2) Methods: We report hazard ratios (HR); odds ratio (OR), and 95% confidence intervals (CI) for overall survival and disease free survival (DFS) at two and three years in the ongoing study. Late toxicity, quality of life (QoL), and a cost effectiveness analysis (CEA) using a Markov model are also reported. (3) Results: Disease recurrence at two and three years was significantly reduced by mEHT (HR: 0.67, 95%CI: 0.48-0.93, p = 0.017; and HR: 0.70, 95%CI: 0.51-0.98, p = 0.035; respectively). There were no significant differences in late toxicity between the groups, and QoL was significantly improved in the mEHT group. In the CEA, mEHT + CRT dominated the model over CRT alone. (4) Conclusions: CRT combined with mEHT improves QoL and DFS rates, and lowers treatment costs, without increasing toxicity in LACC patients, even in resource-constrained settings.

The role of hyperthermia in the treatment of locally advanced cervical cancer: a comprehensive review

Radiotherapy with cisplatin (chemoradiation) is the standard treatment for women with locally advanced cervical cancer. Radiotherapy with deep hyperthermia (thermoradiation) is a well established alternative, but is rarely offered as an alternative to chemoradiation, particularly for patients in whom cisplatin is contraindicated. The scope of this review is to provide an overview of the biological rationale of hyperthermia treatment delivery, including patient workflow, and the clinical effectiveness of hyperthermia as a radiosensitizer in the treatment of cervical cancer. Hyperthermia is especially effective in hypoxic and nutrient deprived areas of the tumor where radiotherapy is less effective. Its radiosensitizing effectiveness depends on the temperature level, duration of treatment, and the time interval between radiotherapy and hyperthermia. High quality hyperthermia treatment requires an experienced team, adequate online adaptive treatment planning, and is preferably performed using a phased array radiative locoregional hyperthermia device to achieve the optimal thermal dose effect. Hyperthermia is well tolerated and generally leads to only mild toxicity, such as patient discomfort. Patients in whom cisplatin is contraindicated should therefore be referred to a hyperthermia center for thermoradiation.

Targeting Hypoxia: Revival of Old Remedies

Tumour hypoxia is significantly correlated with patient survival and treatment outcomes. At the molecular level, hypoxia is a major driving factor for tumour progression and aggressiveness. Despite the accumulative scientific and clinical efforts to target hypoxia, there is still a need to find specific treatments for tumour hypoxia. In this review, we discuss a variety of approaches to alter the low oxygen tumour microenvironment or hypoxia pathways including carbogen breathing, hyperthermia, hypoxia-activated prodrugs, tumour metabolism and hypoxia-inducible factor (HIF) inhibitors. The recent advances in technology and biological understanding reveal the importance of revisiting old therapeutic regimens and repurposing their uses clinically.

Chemoradiotherapy with hyperthermia versus chemoradiotherapy alone in locally advanced cervical cancer: a systematic review and meta-analysis

PURPOSE

Concurrent chemoradiotherapy (CCRT) is recommended as the standard treatment for locally advanced cervical cancer (LACC). However, the synergistic effect of hyperthermia (HT) with CCRT remains unclear. Therefore, we performed a meta-analysis to evaluate the effect of HT with CCRT on LACC patients.

METHODS AND MATERIALS

A systematic literature search was conducted on the MEDLINE, PubMed, Embase, Cochrane library and SCOPUS databases for articles that compared CCRT with HT and CCRT alone as treatments for LACC. Hazard ratios (HRs) and risk ratios (RRs) were used to compare five-year overall survival (OS), local relapse-free survival (LRFS) and incidence of acute and chronic toxicity between the two treatments.

RESULTS

Two articles out of 2860 were finally selected for analysis. A total of 536 patients were evaluated (CCRT with HT group: 268, CCRT group: 268). FIGO stages I-II and III-IV were found in 295 (55.0%) and 241 patients (45.0%), respectively. The CCRT with HT group had significantly better five-year OS than the CCRT group (HR 0.67, 95% confidence interval [CI] 0.47-0.96, p = 0.03). LRFS of patients was superior in the CCRT with HT group than in the CCRT group, but without significance (HR 0.74, 95% CI 0.49-1.12; p = 0.16). Moreover, there was no difference between the two groups regarding acute and chronic toxicity.

CONCLUSION

This systematic review and meta-analysis showed that CCRT with HT significantly improved OS in LACC patients without increasing acute and chronic toxicity. Therefore, tri-modality treatment could be a feasible approach for patients with LACC.

Visualization of thermal washout due to spatiotemporally heterogenous perfusion in the application of a model-based control algorithm for MR-HIFU mediated hyperthermia

PURPOSE

This article will report results from the in-vivo application of a previously published model-predictive control algorithm for MR-HIFU hyperthermia. The purpose of the investigation was to test the controller's in-vivo performance and behavior in the presence of heterogeneous perfusion.

MATERIALS AND METHODS

Hyperthermia at 42°C was induced and maintained for up to 30 min in a circular section of a thermometry slice in the biceps femoris of German landrace pigs (n=5) using a commercial MR-HIFU system and a recently developed MPC algorithm. The heating power allocation was correlated with heat sink maps and contrast-enhanced MRI images. The temporal change in perfusion was estimated based on the power required to maintain hyperthermia.

RESULTS

The controller performed well throughout the treatments with an absolute average tracking error of 0.27 ± 0.15 °C and an average difference of 1.25 ± 0.22 °C between T10 and T90. The MPC algorithm allocates additional heating power to sub-volumes with elevated heat sink effects, which are colocalized with blood vessels visible on contrast-enhanced MRI. The perfusion appeared to have increased by at least a factor of ∼1.86 on average.

CONCLUSIONS

The MPC controller generates temperature distributions with a narrow spectrum of voxel temperatures inside the target ROI despite the presence of spatiotemporally heterogeneous perfusion due to the rapid thermometry feedback available with MR-HIFU and the flexible allocation of heating power. The visualization of spatiotemporally heterogeneous perfusion presents new research opportunities for the investigation of stimulated perfusion in hypoxic tumor regions.

Advances in management of locally advanced cervical cancer

Globally, cervical cancer has the fourth highest cancer incidence and mortality in women. Cervical cancer is unique because it has effective prevention, screening, and treatment options. This review discusses the current cervical cancer advances with a focus on locally advanced cervical cancer. Topics discussed include diagnostic imaging principles, surgical management with adjuvant therapy and definitive concurrent chemoradiotherapy. Emphasis is given on current advances and future research directions in radiation therapy (RT) with an emphasis on three-dimensional brachytherapy, intensity-modulated RT, image-guided RT, proton RT and hyperthermia.

Advanced patient-specific hyperthermia treatment planning

Hyperthermia treatment planning (HTP) is valuable to optimize tumor heating during thermal therapy delivery. Yet, clinical hyperthermia treatment plans lack quantitative accuracy due to uncertainties in tissue properties and modeling, and report tumor absorbed power and temperature distributions which cannot be linked directly to treatment outcome. Over the last decade, considerable progress has been made to address these inaccuracies and therefore improve the reliability of hyperthermia treatment planning. Patient-specific electrical tissue conductivity derived from MR measurements has been introduced to accurately model the power deposition in the patient. Thermodynamic fluid modeling has been developed to account for the convective heat transport in fluids such as urine in the bladder. Moreover, discrete vasculature trees have been included in thermal models to account for the impact of thermally significant large blood vessels. Computationally efficient optimization strategies based on SAR and temperature distributions have been established to calculate the phase-amplitude settings that provide the best tumor thermal dose while avoiding hot spots in normal tissue. Finally, biological modeling has been developed to quantify the hyperthermic radiosensitization effect in terms of equivalent radiation dose of the combined radiotherapy and hyperthermia treatment. In this paper, we review the present status of these developments and illustrate the most relevant advanced elements within a single treatment planning example of a cervical cancer patient. The resulting advanced HTP workflow paves the way for a clinically feasible and more reliable patient-specific hyperthermia treatment planning.

Heating technology for malignant tumors: a review

The therapeutic application of heat is very effective in cancer treatment. Both hyperthermia, i.e., heating to 39-45 °C to induce sensitization to radiotherapy and chemotherapy, and thermal ablation, where temperatures beyond 50 °C destroy tumor cells directly are frequently applied in the clinic. Achievement of an effective treatment requires high quality heating equipment, precise thermal dosimetry, and adequate quality assurance. Several types of devices, antennas and heating or power delivery systems have been proposed and developed in recent decades. These vary considerably in technique, heating depth, ability to focus, and in the size of the heating focus. Clinically used heating techniques involve electromagnetic and ultrasonic heating, hyperthermic perfusion and conductive heating. Depending on clinical objectives and available technology, thermal therapies can be subdivided into three broad categories: local, locoregional, or whole body heating. Clinically used local heating techniques include interstitial hyperthermia and ablation, high intensity focused ultrasound (HIFU), scanned focused ultrasound (SFUS), electroporation, nanoparticle heating, intraluminal heating and superficial heating. Locoregional heating techniques include phased array systems, capacitive systems and isolated perfusion. Whole body techniques focus on prevention of heat loss supplemented with energy deposition in the body, e.g., by infrared radiation. This review presents an overview of clinical hyperthermia and ablation devices used for local, locoregional, and whole body therapy. Proven and experimental clinical applications of thermal ablation and hyperthermia are listed. Methods for temperature measurement and the role of treatment planning to control treatments are discussed briefly, as well as future perspectives for heating technology for the treatment of tumors.

Hyperthermia by near infrared radiation induced immune cells activation and infiltration in breast tumor

Breast cancer is the most common cancer that causes death in women. Conventional therapies, including surgery and chemotherapy, have different therapeutic effects and are commonly associated with risks and side effects. Near infrared radiation is a technique with few side effects that is used for local hyperthermia, typically as an adjuvant to other cancer therapies. The understanding of the use of near NIR as a monotherapy, and its effects on the immune cells activation and infiltration, are limited. In this study, we investigate the effects of HT treatment using NIR on tumor regression and on the immune cells and molecules in breast tumors. Results from this study demonstrated that local HT by NIR at 43 °C reduced tumor progression and significantly increased the median survival of tumor-bearing mice. Immunohistochemical analysis revealed a significant reduction in cells proliferation in treated tumor, which was accompanied by an abundance of heat shock protein 70 (Hsp70). Increased numbers of activated dendritic cells were observed in the draining lymph nodes of the mice, along with infiltration of T cells, NK cells and B cells into the tumor. In contrast, tumor-infiltrated regulatory T cells were largely diminished from the tumor. In addition, higher IFN-γ and IL-2 secretion was observed in tumor of treated mice. Overall, results from this present study extends the understanding of using local HT by NIR to stimulate a favourable immune response against breast cancer.

Simulation guided design of the MRcollar: a MR compatible applicator for deep heating in the head and neck region

PURPOSE

To develop a head and neck hyperthermia phased array system compatible with a 1.5 T magnetic resonance (MR) scanner for noninvasive thermometry.

METHODS

We designed a dielectric-parabolic-reflector antenna (DiPRA) based on a printed reflector backed dipole antenna and studied its predicted and measured performance in a flat configuration (30 mm thick water bolus and muscle equivalent layer). Thereafter, we designed a phased array applicator model ('MRcollar') consisting of 12 DiPRA modules placed on a radius of 180 mm. Theoretical heating performance of the MRcollar model was benchmarked against the current clinical applicator (HYPERcollar3D) using specific (3D) head and neck models of 28 treated patients. Lastly, we assessed the influence of the DiPRA modules on MR scanning quality.

RESULTS

The predicted and measured reflection coefficients (S₁₁) of the DiPRA module are below -20 dB. The maximum specific absorption rate (SAR) in the area under the antenna was 47% higher than for the antenna without encasing. Compared to the HYPERcollar3D, the MRcollar design incorporates 31% less demineralized water (-2.5 L), improves the predicted TC25 (target volume enclosed by 25% iso-SAR contour) by 4.1% and TC50 by 8.5%, while the target-to-hotspot quotient (THQ) is minimally affected (-1.6%). MR experiments showed that the DiPRA modules do not affect MR transmit/receive performance.

CONCLUSION

Our results suggest that head and neck hyperthermia delivery quality with the MRcollar can be maintained, while facilitating simultaneous noninvasive MR thermometry for treatment monitoring and control.

Multi-Channel RF Supervision Module for Thermal Magnetic Resonance Based Cancer Therapy

Glioblastoma multiforme (GBM) is the most lethal and common brain tumor. Combining hyperthermia with chemotherapy and/or radiotherapy improves the survival of GBM patients. Thermal magnetic resonance (ThermalMR) is a hyperthermia variant that exploits radio frequency (RF)-induced heating to examine the role of temperature in biological systems and disease. The RF signals' power and phase need to be supervised to manage the formation of the energy focal point, accurate thermal dose control, and safety. Patient position during treatment also needs to be monitored to ensure the efficacy of the treatment and avoid damages to healthy tissue. This work reports on a multi-channel RF signal supervision module that is capable of monitoring and regulating RF signals and detecting patient motion. System characterization was performed for a broad range of frequencies. Monte-Carlo simulations were performed to examine the impact of power and phase errors on hyperthermia performance. The supervision module's utility was demonstrated in characterizing RF power amplifiers and being a key part of a feedback control loop regulating RF signals in heating experiments. Electromagnetic field simulations were conducted to calculate the impact of patient displacement during treatment. The supervision module was experimentally tested for detecting patient motion to a submillimeter level. To conclude, this work presents a cost-effective RF supervision module that is a key component for a hyperthermia hardware system and forms a technological basis for future ThermalMR applications.

Bevacizumab Plus FOLFOX-4 Combined With Deep Electro-Hyperthermia as First-line Therapy in Metastatic Colon Cancer: A Pilot Study

Bevacizumab plus FOLFOX-4 regimen represents the first-line therapy in patients affected by metastatic colorectal cancer (mCRC). Hyperthermia has been considered an effective ancillary treatment for cancer therapy through several anti-tumor mechanisms, sharing with Bevacizumab the inhibition of angiogenesis. Up to now, scientific literature offers very few clinical data on the combination of bevacizumab plus oxaliplatin-based chemotherapy with deep electro-hyperthermia (DEHY) for metastatic colon cancer (mCC) patients. Therefore, we aimed at evaluating the efficacy of this combination based on the possible interaction between the DEHY and bevacizumab anti-tumor mechanisms. We conducted a retrospective analysis on 40 patients affected by mCC treated with the combination of bevacizumab plus FOLFOX-4 (fluorouracil/folinic acid plus oxaliplatin) and DEHY (EHY2000), between January 2017 and May 2020. DEHY treatment was performed weekly, with capacitive electrodes at 80-110 W for 50 min, during and between subsequent bevacizumab administrations, on abdomen for liver or abdominal lymph nodes metastases and thorax for lung metastases. Treatment response assessment was performed according to the Response Evaluation Criteria for Solid Tumors (RECIST). The primary endpoints were disease control rate (DCR) and progression-free survival (PFS). The secondary endpoint was overall survival (OS). DCR, counted as the percentage of patients who had the best response rating [complete response (CR), partial response (PR), or stable disease (SD)], was assessed at 90 days (timepoint-1) and at 180 days (timepoint-2). DCR was 95% and 89.5% at timepoint-1 and timepoint-2, respectively. The median PFS was 12.1 months, whereas the median OS was 21.4 months. No major toxicity related to DEHY was registered; overall, this combination regimen was safe. Our results suggest that the combined treatment of DEHY with bevacizumab plus FOLFOX-4 as first-line therapy in mCC is feasible and effective with a favorable disease control, prolonging PFS of 2.7 months with respect to standard treatment without DEHY for mCC patients. Further studies will be required to prove its merit and explore its potentiality, especially if compared to conventional treatment.

Analysis of the effects of mEHT on the treatment-related toxicity and quality of life of HIV-positive cervical cancer patients

Introduction: HIV infection is associated with increased treatment-related toxicity and worse outcomes in locally advanced cervical cancer patients (LACC), especially in resource-constrained settings. Local control (LC) in a phase III randomized, controlled trial investigating modulated electro-hyperthermia (mEHT) on LACC patients in South Africa (ethics registration: M120477/M190295), was significantly higher in participants randomized to receive chemoradiotherapy (CRT) with mEHT compared to CRT alone (stratum: HIV status, accounting for age and stage). This analysis investigates whether mEHT adds to the toxicity profile of CRT in HIV-positive LACC participants.Methods: Inclusion criteria: signed informed consent; International Federation of Gynecology and Obstetrics stages IIB to IIIB squamous cell carcinoma of the cervix; HIV-positive patients: CD4 count >200 cell/µL/on antiretroviral treatment for >6 months; eligible for CRT with radical intent. Recruitment: January 2014 to November 2017 (ClinicalTrials.gov: NCT03332069). Acute toxicity (evaluated using CTCAE v4 criteria) and quality of life (according to EORTC forms) in 206 participants randomized for treatment were evaluated alongside the LC results to determine safety and efficacy in HIV-positive participants.Results: Compliance to mEHT treatment was high (97% completed ≥8 treatments) with no significant differences in CRT-related toxicity between treatment groups or between HIV-positive and -negative participants. Adverse events attributed to mEHT were minor, even in obese patients, and did not affect CRT compliance. Participants treated with mEHT reported improved fatigue, pain, emotional and cognitive functioning.Conclusion: mEHT did not cause unexpected CRT-related toxicities and is a safe treatment modality for HIV-positive patients, with minor limitations regarding body weight, even in a low-resource setting.

Quo Vadis Oncological Hyperthermia (2020)?

Heating as a medical intervention in cancer treatment is an ancient approach, but effective deep heating techniques are lacking in modern practice. The use of electromagnetic interactions has enabled the development of more reliable local-regional hyperthermia (LRHT) techniques whole-body hyperthermia (WBH) techniques. Contrary to the relatively simple physical-physiological concepts behind hyperthermia, its development was not steady, and it has gone through periods of failures and renewals with mixed views on the benefits of heating seen in the medical community over the decades. In this review we study in detail the various techniques currently available and describe challenges and trends of oncological hyperthermia from a new perspective. Our aim is to describe what we believe to be a new and effective approach to oncologic hyperthermia, and a change in the paradigm of dosing. Physiological limits restrict the application of WBH which has moved toward the mild temperature range, targeting immune support. LRHT does not have a temperature limit in the tumor (which can be burned out in extreme conditions) but a trend has started toward milder temperatures with immune-oriented goals, developing toward immune modulation, and especially toward tumor-specific immune reactions by which LRHT seeks to target the malignancy systemically. The emerging research of bystander and abscopal effects, in both laboratory investigations and clinical applications, has been intensified. Our present review summarizes the methods and results, and discusses the trends of hyperthermia in oncology.

Integrating Loco-Regional Hyperthermia Into the Current Oncology Practice: SWOT and TOWS Analyses

Moderate hyperthermia at temperatures between 40 and 44°C is a multifaceted therapeutic modality. It is a potent radiosensitizer, interacts favorably with a host of chemotherapeutic agents, and, in combination with radiotherapy, enforces immunomodulation akin to “in situ tumor vaccination.” By sensitizing hypoxic tumor cells and inhibiting repair of radiotherapy-induced DNA damage, the properties of hyperthermia delivered together with photons might provide a tumor-selective therapeutic advantage analogous to high linear energy transfer (LET) neutrons, but with less normal tissue toxicity. Furthermore, the high LET attributes of hyperthermia thermoradiobiologically are likely to enhance low LET protons; thus, proton thermoradiotherapy would mimic ¹²C ion therapy. Hyperthermia with radiotherapy and/or chemotherapy substantially improves therapeutic outcomes without enhancing normal tissue morbidities, yielding level I evidence reported in several randomized clinical trials, systematic reviews, and meta-analyses for various tumor sites. Technological advancements in hyperthermia delivery, advancements in hyperthermia treatment planning, online invasive and non-invasive MR-guided thermometry, and adherence to quality assurance guidelines have ensured safe and effective delivery of hyperthermia to the target region. Novel biological modeling permits integration of hyperthermia and radiotherapy treatment plans. Further, hyperthermia along with immune checkpoint inhibitors and DNA damage repair inhibitors could further augment the therapeutic efficacy resulting in synthetic lethality. Additionally, hyperthermia induced by magnetic nanoparticles coupled to selective payloads, namely, tumor-specific radiotheranostics (for both tumor imaging and radionuclide therapy), chemotherapeutic drugs, immunotherapeutic agents, and gene silencing, could provide a comprehensive tumor-specific theranostic modality akin to “magic (nano)bullets.” To get a realistic overview of the strength (S), weakness (W), opportunities (O), and threats (T) of hyperthermia, a SWOT analysis has been undertaken. Additionally, a TOWS analysis categorizes future strategies to facilitate further integration of hyperthermia with the current treatment modalities. These could gainfully accomplish a safe, versatile, and cost-effective enhancement of the existing therapeutic armamentarium to improve outcomes in clinical oncology.

Enhancing the abscopal effect of radiation and immune checkpoint inhibitor therapies with magnetic nanoparticle hyperthermia in a model of metastatic breast cancer

Purpose: Enhancing immune responses in triple negative breast cancers (TNBCs) remains a challenge. Our study aimed to determine whether magnetic iron oxide nanoparticle (MION) hyperthermia (HT) can enhance abscopal effects with radiotherapy (RT) and immune checkpoint inhibitors (IT) in a metastatic TNBC model.Methods: One week after implanting 4T1-luc cells into the mammary glands of BALB/c mice, tumors were treated with RT (3 × 8 Gy)±local HT, mild (HT_M, 43 °C/20 min) or partially ablative (HT_Abl, 45 °C/5 min plus 43 °C/15 min),±IT with anti-PD-1 and anti-CTLA-4 antibodies (both 4 × 10 mg/kg, i.p.). Tumor growth was measured daily. Two weeks after treatment, lungs and livers were harvested for histopathology evaluation of metastases.Results: Compared to untreated controls, all treatment groups demonstrated a decreased tumor volume; however, when compared against surgical resection, only RT + HT_M+IT, RT + HT_Abl+IT and RT + HT_Abl had similar or smaller tumors. These cohorts showed more infiltration of CD3⁺ T-lymphocytes into the primary tumor. Tumor growth effects were partially reversed with T-cell depletion. Combinations that proved most effective for primary tumors generated modest reductions in numbers of lung metastases. Conversely, numbers of lung metastases showed potential to increase following HT + IT treatment, particularly when compared to RT. Compared to untreated controls, there was no improvement in survival with any treatment.Conclusions: Single-fraction MION HT added to RT + IT improved local tumor control and recruitment of CD3⁺ T-lymphocytes, with only a modest effect to reduce lung metastases and no improvement in overall survival. HT + IT showed potential to increase metastatic dissemination to lungs.

A moderate thermal dose is sufficient for effective free and TSL based thermochemotherapy

Hyperthermia, i.e. heating the tumor to a temperature of 40-43 °C is considered by many a valuable treatment to sensitize tumor cells to radiotherapy and chemotherapy. In recent randomized trials the great potential of adding hyperthermia to chemotherapy was demonstrated for treatment of high risk soft tissue sarcoma: +11.4% 5 yrs. overall survival (OS) and for ovarian cancer with peritoneal involvement nearly +12 months OS gain. As a result interest in combining chemotherapy with hyperthermia, i.e. thermochemotherapy, is growing. Extensive biological research has revealed that hyperthermia causes multiple effects, from direct cell kill to improved oxygenation, whereby each effect has a specific temperature range. Thermal sensitization of the tumor cell for chemotherapy occurs for many drugs at temperatures ranging from 40 to 42 °C with little additional increase of sensitization at higher temperatures. Increasing perfusion/oxygenation and increased extravasation are two other important hyperthermia induced mechanisms. The combination of free drug and hyperthermia has not been found to increase tumor drug concentration. Hence, enhanced effectiveness of free drug will depend on the thermal sensitization of the tumor cells for the applied drug. In contrast to free drugs, experimental animal studies combining hyperthermia and thermo-sensitive liposomal (TSL) drugs delivery have demonstrated to result in a substantial increase of the drug concentration in the tumor. For TSL based chemotherapy, hyperthermia is critical to both increase perfusion and extravasation as well as to trigger TSL drug release, whereby the temperature controlled induction of a local high drug concentration in a highly permeable vessel is driving the enhanced drug uptake in the tumor. Increased drug concentrations up to 26 times have been reported in rodents. Good control of the tissue temperature is required to keep temperatures below 43 °C to prevent vascular stasis. Further, careful timing of the drug application relative to the start of heating is required to benefit optimal from the combined treatment. From the available experimental data it follows that irrespective whether chemotherapy is applied as free drug or using a thermal sensitive liposomal carrier, the optimal thermal dose for thermochemotherapy should be 40-42 °C for 30-60 min, i.e. equivalent to a CEM43 of 1-15 min. Timing is critical: most free drug should be applied simultaneous with heating, whereas TSL drugs should be applied 20-30 min after the start of hyperthermia.

Outcomes for Hyperthermia Combined with Concurrent Radiochemotherapy for Patients with Cervical Cancer

PURPOSE

To evaluate the effect of hyperthermia combined with concurrent radiochemotherapy (RCT) and treatment-related toxicity in patients with cervical cancer (CC) stage IB-IV.

METHODS AND MATERIALS

This study was conducted between 2009 and 2013 in patients with International Federation of Gynecology and Obstetrics (FIGO) stage IB-IV CC. The patients were randomly assigned into 2 treatment groups: RCT and RCT plus hyperthermia (RCHT). Five-year survival, treatment-related toxicity, and other prognostic factors were evaluated.

RESULTS

Three hundred seventy-three patients completed treatment and were analyzed by per-protocol (PP) analysis. The 5-year overall survival (OS) in the RCHT group (81.9%) was better than that in RCT group (72.3%), and the log-rank test showed a statistically significant difference between the 2 groups (P = .040). Univariate and multivariate Cox regression analysis for 5-year OS showed a statistically significant difference (P = .043, P = .045, respectively). The 5-year local relapse-free survival in RCHT (86.8%) was also better than that in RCT (82.7%), but the difference was not significant. Acute or late toxicity was not significantly different between the 2 groups. Advanced clinical stage (FIGO) and larger tumor size showed higher risk of death and a relatively poor prognosis in univariate and multivariate analysis.

CONCLUSIONS

The study confirmed that hyperthermia combined with RCT yielded a better 5-year OS in CC. Acute and late toxicity was similar between the RCT and RCHT groups. Clinical stage (FIGO) and tumor size were independent prognostic factors in CC.

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.

Thermosensitive Nanosystems Associated with Hyperthermia for Cancer Treatment

Conventional chemotherapy regimens have limitations due to serious adverse effects. Targeted drug delivery systems to reduce systemic toxicity are a powerful drug development platform. Encapsulation of antitumor drug(s) in thermosensitive nanocarriers is an emerging approach with a promise to improve uptake and increase therapeutic efficacy, as they can be activated by hyperthermia selectively at the tumor site. In this review, we focus on thermosensitive nanosystems associated with hyperthermia for the treatment of cancer, in preclinical and clinical use.

Review of the Clinical Evidences of Modulated Electro-Hyperthermia (mEHT) Method: An Update for the Practicing Oncologist

Background: Modulated electro-hyperthermia (mEHT) is a variation of the conventional hyperthermia which selectively targets the malignant cell membranes in order to heat the malignant tissue and sensitize the tissue to oncology treatments. Although widely applied, the formulation of guidelines for the use thereof is still in progress for many tumors. Aim: In this paper we review the literature on the effects of mEHT in cancer patients on local disease control and survival. Methodology: Our review on data presents the collected experience with capacitive hyperthermia treatments with the EHY-2000+ device (OncoTherm Ltd., Germany). A literature search was conducted in Pubmed and articles were grouped and discussed according to: trial type, animal studies, in vitro studies, and reviews. Search results from Conference Abstracts; Trial Registries; Thesis and Dissertations and the Oncothermia Journal were included in the discussions. Results: Modulated electro-hyperthermia is a safe form of hyperthermia which has shown to effectively sensitizes deep tumors, regardless of the thickness of the adipose layers. The technology has demonstrated equal benefits compared to other forms of hyperthermia for a variety of tumors. Given the effective heating ability to moderate temperatures, the improved tumor perfusion, and ability to increase drug absorption, mEHT is a safe and effective heating technology which can be easily applied to sensitize tumors which have demonstrated benefits with the addition of hyperthermia. Modulated electro-hyperthermia also appears to improve local control and survival rates and appears to induce an abscopal (systemic) response to ionizing radiation. Conclusion: Based on clinical studies, the method mEHT is a feasible hyperthermia technology for oncological applications. Concomitant utilization of mEHT is supported by the preclinical and clinical data.

Hyperthermia Treatment Planning Including Convective Flow in Cerebrospinal Fluid for Brain Tumour Hyperthermia Treatment Using a Novel Dedicated Paediatric Brain Applicator

Hyperthermia therapy (40-44 °C) is a promising option to increase efficacy of radiotherapy/chemotherapy for brain tumours, in particular paediatric brain tumours. The Chalmers Hyperthermia Helmet is developed for this purpose. Hyperthermia treatment planning is required for treatment optimisation, but current planning systems do not involve a physically correct model of cerebrospinal fluid (CSF). This study investigates the necessity of fluid modelling for treatment planning. We made treatments plans using the Helmet for both pre-operative and post-operative cases, comparing temperature distributions predicted with three CSF models: a convective "fluid" model, a non-convective "solid" CSF model, and CSF models with increased effective thermal conductivity ("high-k"). Treatment plans were evaluated by T90, T50 and T10 target temperatures and treatment-limiting hot spots. Adequate heating is possible with the helmet. In the pre-operative case, treatment plan quality was comparable for all three models. In the post-operative case, the high-k models were more accurate than the solid model. Predictions to within ±1 °C were obtained by a 10-20-fold increased effective thermal conductivity. Accurate modelling of the temperature in CSF requires fluid dynamics, but modelling CSF as a solid with enhanced effective thermal conductivity might be a practical alternative for a convective fluid model for many applications.

Confirmation of thermal dose as a predictor of local control in cervical carcinoma patients treated with state-of-the-art radiation therapy and hyperthermia

BACKGROUND

Addition of deep hyperthermia results in improved local control (LC) and overall survival (OS) compared to radiotherapy alone in patients with cervical carcinoma. Previously, we showed that the thermal dose of hyperthermia significantly correlates with LC and disease specific survival (DSS). Over the last decade, new radiation techniques were introduced resulting in improved LC.

AIM

To validate the effect of thermal dose in a more recent cohort of patients treated with modern radiotherapy techniques, including image guided brachytherapy (IGBT).

METHODS

We analyzed primary cervical carcinoma patients treated with a combination of radiotherapy and deep hyperthermia between 2005 and 2016 at our institute. Data on patient, tumor and treatment were collected including the thermal dose parameters TRISE and CEM43T90. Follow-up data on LC, disease free survival, DSS, OS as well as late toxicity data were collected. Data were analyzed using the Cox proportional hazard and Kaplan-Meier analyses.

RESULTS

227 patients were included. In multivariate analysis, histology, FIGO stage, lymphadenopathy, TRISE, CEM43T90 and IGBT had a significant effect on LC. In the patients treated with IGBT, the thermal dose parameter TRISE remained to have a significant effect on LC in univariate analysis.

CONCLUSIONS

The positive association between thermal dose and clinical outcome is replicated in an independent, recent cohort of cervical carcinoma patients. Importantly, in patients receiving IGBT, the effect of thermal dose on clinical outcome is still observed.

The effect of modulated electro-hyperthermia on local disease control in HIV-positive and -negative cervical cancer women in South Africa: Early results from a phase III randomised controlled trial

BACKGROUND

The global burden of cervical cancer remains high with the highest morbidity and mortality rates reported in developing countries. Hyperthermia as a chemo- and radiosensitiser has shown to improve treatment outcomes. This is an analysis of the local control results at six months post-treatment of patients enrolled in an ongoing study investigating the effects of the addition of modulated electro-hyperthermia (mEHT) to chemoradiotherapy for the treatment of HIV-positive and -negative cervical cancer patients in a low-resource setting.

METHODS

This ongoing Phase III randomised controlled trial, conducted at a state hospital in Johannesburg, South Africa, was registered with the appropriate ethics committee. After signing an informed consent, participants with FIGO stages IIB to IIIB squamous cell carcinoma of the cervix were randomised to receive chemoradiotherapy with/without mEHT using a secure online random-sampling tool (stratum: HIV status) accounting for age and stage. Reporting physicians were blind to treatment allocation. HIV-positive participants on antiretroviral treatment, or with a CD4 count >200cell/μL were included. mEHT was administered 2/weekly immediately before external beam radiation. The primary end point is local disease control (LDC) and secondary endpoints are toxicity; quality of life analysis; and two year survival. We report on six month LDC, including nodes visualised in the radiation field on 18F-FDG PET/CT (censored for six month survival), and six month local disease free survival (LDFS) (based on intention to treat). Trial status: Recruitment closed (ClinicalTrials.gov: NCT03332069).

RESULTS

271 participants were recruited between January 2014 and November 2017, of which 210 were randomised for trial and 202 were available for analysis at six months post-treatment (mEHT: n = 101; Control: n = 101). Six month LDFS was higher in the mEHT Group (n = 39[38.6%]), than in the Control Group (n = 20[19.8%]); p = 0.003). LDC was also higher in the mEHT Group (n = 40[45.5%]) than the Control Group (n = 20[24.1%]); (p = 0.003).

CONCLUSION

Our results show that mEHT is effective as a chemo-radiosensitiser for cervical cancer, even in high risk a patients and resource-constrained settings.

Hyperthermia with radiotherapy reduces tumour alpha/beta: Insights from trials of thermoradiotherapy vs radiotherapy alone

PURPOSE

Hyperthermia inhibits the repair of irradiation-induced DNA damage and thereby could alter the α/β values of tumours. This study estimates the clinical α/β_HTRT values from clinical trials of thermoradiotherapy (HTRT) vs radiotherapy (RT) in recurrent breast (RcBC), head and neck (III/IV) (LAHNC) and cervix cancers (IIB-IVA) (LACC).

METHODS

Three recently published meta-analyses for HTRT vs RT in RcBC, LAHNC and LACC were evaluated for complete response (CR). Studies with specified RT dose (D), dose/fraction (d) and corresponding CRs were selected. Tumour biological effective dose (BED) for each study with RT (BED_RT) was computed assuming an α/β_RT of 10 Gy. As outcomes were favourable with HTRT, thermoradiobiological BED (BED_HTRT) was calculated as a product of BED_RT and %CR_HTRT/%CR_RT. The α/β_HTRT was estimated as Dd/(BED_HTRT - D).

RESULTS

12 trials with 864 patients were shortlisted - RcBC (3 studies, n = 259), LAHNC (5 studies, n = 338) and LACC (4 studies, n = 267). Overall risk difference of 0.28 favoured HTRT (p < 0.001). Mean BED_RT and BED_HTRT were 64.7 Gy (SD: ±15.5) and 109.5 Gy (SD: ±32.1) respectively and global α/β_HTRT was 2.25 Gy (SD: ±0.79). Mean α/β_HTRT for RcBC, LAHNC and LACC were 2.05 Gy, 1.74 Gy and 3.03 Gy respectively. On meta-regression, α/β_HTRT was the sole predictor for the corresponding risk differences of the studies (coefficient = -0.096; p = 0.03).

CONCLUSION

Thermoradiobiological effects on the repair of RT induced DNA damage results in reduction in α/β values of tumours. This should be considered to effectively optimize HTRT dose-fractionation schedules in the clinic.