Reirradiation combined with hyperthermia in breast cancer recurrences: Overview of experience in Erasmus MC

Application of the ESHO-QA guidelines for determining the performance of the LCA superficial hyperthermia heating system

PURPOSE

This study aimed to assess the quality of the lucite cone applicator (LCA), the standard applicator for superficial hyperthermia at the Erasmus MC Cancer Institute, using the most recent quality assurance guidelines, thus verifying their feasibility.

MATERIALS AND METHODS

The assessment was conducted on each of the six LCAs available for clinical treatments. The temperature distribution was evaluated using an infrared camera across different layers of a fat-muscle mimicking phantom. The maximum temperature increase, thermal effective penetration depth (TEPD), and thermal effective field size (TEFS) were used as quality metrics. The experimental results were validated through comparison with simulated results, using a canonical phantom model and a realistic phantom model segmented from CT imaging.

RESULTS

A maximum temperature increase above 6 °C at 2 cm depth in the fat-muscle phantom for all the experiments was found. A mean negative difference between simulated and experimental data was of 1.3 °C when using the canonical phantom model. This value decreased to a mean negative difference of 0.4 °C when using the realistic model. Simulated and measured TEPD showed good agreement for both in silico scenarios, while discrepancies were present for TEFS.

CONCLUSIONS

The LCAs passed all QA guidelines requirements for superficial hyperthermia delivery when used singularly or in an array configuration. A further characterization of parameters such as antenna efficiency and heat transfer coefficients would be beneficial for translating experimental results to simulated values. Implementing the QA guidelines was time-consuming and demanding, requiring careful preparation and correct setup of antenna elements.

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.

Radiotherapy and hyperthermia for breast cancer patients at high risk of recurrence

PURPOSE

To evaluate the long-term efficacy of combined radiotherapy (RT) and hyperthermia (HT) in a large mono-institutional cohort of breast cancer (BC) patients affected by recurrent, newly diagnosed non-resectable or high risk resected tumor.

MATERIALS AND METHODS

Records of BC patients treated with RT + HT between 1995 and 2018 were retrospectively analyzed. RT doses of 50-70 Gy concurrent to a twice per week superficial HT were applied. For HT, a temperature between 41 and 42 °C was applied for approximately 1 h. Primary endpoint was local control (LC), secondary endpoints comprised toxicity, overall survival (OS), and progression-free survival (PFS).

RESULTS

A total of 191 patients and 196 RT + HT treatments were analyzed. In 154 cases (78.6%) RT + HT was performed for patients with recurrent BC. Among these, 93 (47.4% of the entire cohort) had received RT prior to RT + HT. Median follow up was 12.7 years. LC at 2, 5, and 10 years was 76.4, 72.8, and 69.5%, respectively. OS at 2, 5, and 10 years was 73.5, 52.3, and 35.5%, respectively. PFS at 2, 5, and 10 years was 55.6, 41, and 33.6%, respectively. Predictive factors for LC were tumor stage, distant metastases, estrogen/progesterone receptor expression, resection status and number of HT fractions. At multivariate analysis tumor stage and receptor expression were significant. No acute or late toxicities higher than grade 3 were observed.

CONCLUSION

Combined RT + HT offers long-term high LC rates with acceptable toxicity for patients with recurrent, newly diagnosed non-resectable or resected BC at high risk of relapse.

Magnetic nanoparticles and clusters for magnetic hyperthermia: optimizing their heat performance and developing combinatorial therapies to tackle cancer

Magnetic hyperthermia (MHT) is a therapeutic modality for the treatment of solid tumors that has now accumulated more than 30 years of experience. In the ongoing MHT clinical trials for the treatment of brain and prostate tumors, iron oxide nanoparticles are employed as intra-tumoral MHT agents under a patient-safe 100 kHz alternating magnetic field (AMF) applicator. Although iron oxide nanoparticles are currently approved by FDA for imaging purposes and for the treatment of anemia, magnetic nanoparticles (MNPs) designed for the efficient treatment of MHT must respond to specific physical-chemical properties in terms of magneto-energy conversion, heat dose production, surface chemistry and aggregation state. Accordingly, in the past few decades, these requirements have boosted the development of a new generation of MNPs specifically aimed for MHT. In this review, we present an overview on MNPs and their assemblies produced via different synthetic routes, focusing on which MNP features have allowed unprecedented heating efficiency levels to be achieved in MHT and highlighting nanoplatforms that prevent magnetic heat loss in the intracellular environment. Moreover, we review the advances on MNP-based nanoplatforms that embrace the concept of multimodal therapy, which aims to combine MHT with chemotherapy, radiotherapy, immunotherapy, photodynamic or phototherapy. Next, for a better control of the therapeutic temperature at the tumor, we focus on the studies that have optimized MNPs to maintain gold-standard MHT performance and are also tackling MNP imaging with the aim to quantitatively assess the amount of nanoparticles accumulated at the tumor site and regulate the MHT field conditions. To conclude, future perspectives with guidance on how to advance MHT therapy will be provided.

Non-thermal membrane effects of electromagnetic fields and therapeutic applications in oncology

The temperature-independent effects of electromagnetic fields (EMF) have been controversial for decades. Here, we critically analyze the available literature on non-thermal effects of radiofrequency (RF) and microwave EMF. We present a literature review of preclinical and clinical data on non-thermal antiproliferative effects of various EMF applications, including conventional RF hyperthermia (HT, cRF-HT). Further, we suggest and evaluate plausible biophysical and electrophysiological models to decipher non-thermal antiproliferative membrane effects. Available preclinical and clinical data provide sufficient evidence for the existence of non-thermal antiproliferative effects of exposure to cRF-HT, and in particular, amplitude modulated (AM)-RF-HT. In our model, transmembrane ion channels function like RF rectifiers and low-pass filters. cRF-HT induces ion fluxes and AM-RF-HT additionally promotes membrane vibrations at specific resonance frequencies, which explains the non-thermal antiproliferative membrane effects via ion disequilibrium (especially of Ca²⁺) and/or resonances causing membrane depolarization, the opening of certain (especially Ca²⁺) channels, or even hole formation. AM-RF-HT may be tumor-specific owing to cancer-specific ion channels and because, with increasing malignancy, membrane elasticity parameters may differ from that in normal tissues. Published literature suggests that non-thermal antiproliferative effects of cRF-HT are likely to exist and could present a high potential to improve future treatments in oncology.

Surgery for orbital metastasis from breast carcinoma initially presenting with progressive proptosis

We present a 45-year-old woman with metastatic breast disease who initially presented with progressive proptosis of her right eye causing limited motility, diplopia and eye pain. MRI done showed an avidly enhancing right sphenoorbital mass causing displacement in the lateral and superior recti muscles with lysis and infiltration of the greater sphenoid wing and lateral orbital wall. The patient underwent surgery resulting in immediate relief of proptosis and resolution of symptoms. Although surgery is not recommended for orbital metastasis as it is not curative, it should be considered as a treatment option as it can provide relief to patients and improve their quality of life.

Hyperthermic chest wall re-irradiation in recurrent breast cancer: a prospective observational study

PURPOSE

To prospectively investigate the role of re-irradiation (re-RT) combined with hyperthermia (HT) in a contemporary cohort of patients affected by recurrent breast cancer (RBC).

METHODS

Within the prospective registry HT03, patients with resected RBC and previous irradiation were included. Re-RT was applied to the recurrence region with doses of 50-50.4 Gy, with a boost up to 60-60.4 Gy to the microscopically or macroscopically positive resection margins (R1/R2) region. Concurrent HT was performed at 40-42 ℃. Primary endpoint was LC. Acute and late toxicity, overall survival, cancer-specific survival (CSS), and progression-free survival (PFS) were also evaluated.

RESULTS

20 patients and 21 RBC were analyzed. Median re-RT dose was 50.4 Gy and a median of 11 HT fractions were applied. Re-RT+HT was well tolerated, with three patients who experienced a grade (G) 3 acute skin toxicity and no cases of ≥G3 late toxicity. With a median follow up of 24.7 months, two local relapses occurred. Ten patients experienced regional and/or distant disease progression. Five patients died, four of them from breast cancer. PFS was favorable in patients treated with re-RT+HT for the first recurrence with doses of 60 Gy. A trend towards better CSS was found in patients with negative or close margins and after doses of 60 Gy.

CONCLUSION

Full-dose re-RT+HT for RBC is well tolerated, provides good LC, and seems to be more effective when applied at the time of the first relapse and after doses of 60 Gy. The registry will be continued for validation in a larger cohort and with longer follow-up.

Suppression of SESN1 reduces cisplatin and hyperthermia resistance through increasing reactive oxygen species (ROS) in human maxillary cancer cells

INTRODUCTION

Cisplatin is used as a standard chemotherapeutic agent for head and neck cancer treatment. However, some head and neck cancers have cisplatin resistance, leading to difficulty in treatment and poor prognosis. Overcoming cisplatin resistance remains an important strategy to improve prognoses for head and neck cancer patients.

OBJECTIVE

Elucidation of the mechanisms underlying cisplatin resistance can suggest novel targets to enhance the anticancer effects of cisplatin for treating head and neck cancers.

MATERIAL AND METHODS

We used a cisplatin-resistant human maxillary cancer cell line, IMC-3CR to analyse the cisplatin resistance mechanisms. Cisplatin-induced genes were analysed in IMC-3CR cells using PCR array. Among the genes with expression increased by cisplatin, we specifically examined SESN1. SESN family reportedly regenerates peroxiredoxin and suppresses oxidative DNA injury by reactive oxygen species (ROS), which can be induced by chemotherapeutic agents such as cisplatin, radiation, and hyperthermia. The function of SESN1 in cisplatin resistance and ROS generation were analysed using specific RNAi.

RESULTS

Results show that SESN1 was induced by cisplatin treatment in IMC-3CR cells. Suppression of SESN1 by RNAi induced apoptosis and reduced cell viability through enhancement of ROS after cisplatin treatment. Moreover, suppression of SESN1 enhanced the cell-killing effects of hyperthermia with increased ROS, but did not affect the cell-killing effects of radiation.

CONCLUSIONS

This study demonstrated the participation of SESN1 in cisplatin and hyperthermia resistance of human head and neck cancers. SESN1 is a novel molecular target to overcome cisplatin resistance and hyperthermia resistance and improve head and neck cancer treatment.

Magnetic Hyperthermia and Radiation Therapy: Radiobiological Principles and Current Practice †

Hyperthermia, though by itself generally non-curative for cancer, can significantly increase the efficacy of radiation therapy, as demonstrated by in vitro, in vivo, and clinical results. Its limited use in the clinic is mainly due to various practical implementation difficulties, the most important being how to adequately heat the tumor, especially deep-seated ones. In this work, we first review the effects of hyperthermia on tissue, the limitations of radiation therapy and the radiobiological rationale for combining the two treatment modalities. Subsequently, we review the theory and evidence for magnetic hyperthermia that is based on magnetic nanoparticles, its advantages compared with other methods of hyperthermia, and how it can be used to overcome the problems associated with traditional techniques of hyperthermia.

Development and evaluation of an isolated limb infusion model for investigation of drug delivery kinetics to solid tumors by thermosensitive liposomes and hyperthermia

The combined administration of thermosensitive liposomes (TSLs) and hyperthermia (HT) has been increasingly shown to be a powerful tool for the treatment of solid tumors. At present, it is hypothesized that the circulation of TSLs through the vasculature of a heated tumor results in the rapid release of the entrapped drug, followed by its uptake and distribution within the tumor microenvironment. However, simple questions on the transport kinetics of TSLs through the heated tumor and how much drug is retained upon passage of TSLs through the tumor microcirculation have not been investigated in an experimental setting to-date. The present work describes a novel methodology for investigating these parameters by isolated limb infusion (ILI), developed in a rat model of sarcoma. This approach was used to assess the efficacy of Doxorubicin (Dox) delivery by TSL in a heated (42°C) tumor following a single passage of TSL through the tumor vasculature. Analysis of the effluent post-ILI, whole-tumor histological sections, and tissue homogenates revealed that upon a single passage, Dox delivery by TSL at 42°C did not exceed delivery under conventional (i.e. free Dox) or physiological (i.e. TSL at 37°C, or normothermia; NT) conditions. In fact, mathematical modeling demonstrated that at least thirteen passages are required to obtain the intratumoral Dox levels typically achieved using TSL (i.e. ~5%ID/g). Overall, this work investigates TSL-based determinants for achieving efficacious drug delivery using a model of ILI in tumor-bearing rats and the results bear important implications for TSL disposition in vivo.

Heat-induced BRCA2 degradation in human tumours provides rationale for hyperthermia-PARP-inhibitor combination therapies

PURPOSE

Hyperthermia (40-44 °C) effectively sensitises tumours to radiotherapy by locally altering tumour biology. One of the effects of heat at the cellular level is inhibition of DNA repair by homologous recombination via degradation of the BRCA2-protein. This suggests that hyperthermia can expand the group of patients that benefit from PARP-inhibitors, a drug exploiting homologous recombination deficiency. Here, we explore whether the molecular mechanisms that cause heat-mediated degradation of BRCA2 are conserved in cell lines from various origins and, most importantly, whether, BRCA2 protein levels can be attenuated by heat in freshly biopted human tumours.

EXPERIMENTAL DESIGN

Cells from four established cell lines and from freshly biopsied material of cervical (15), head- and neck (9) or bladder tumours (27) were heated to 42 °C for 60 min ex vivo. In vivo hyperthermia was studied by taking two biopsies of the same breast or cervical tumour: one before and one after treatment. BRCA2 protein levels were measured by immunoblotting.

RESULTS

We found decreased BRCA2-levels after hyperthermia in all established cell lines and in 91% of all tumours treated ex vivo. For tumours treated with hyperthermia in vivo, technical issues and intra-tumour heterogeneity prevented obtaining interpretable results.

CONCLUSIONS

This study demonstrates that heat-mediated degradation of BRCA2 occurs in tumour material directly derived from patients. Although BRCA2-degradation may not be a practical biomarker for heat deposition in situ, it does suggest that application of hyperthermia could be an effective method to expand the patient group that could benefit from PARP-inhibitors.

Design and characterisation of a phased antenna array for intact breast hyperthermia

PURPOSE

Currently available hyperthermia technology is not well suited to treating cancer malignancies in the intact breast. This study investigates a microwave applicator incorporating multiple patch antennas, with the goal of facilitating controllable power deposition profiles for treating lesions at diverse locations within the intact breast.

MATERIALS AND METHODS

A 3D-computational model was implemented to assess power deposition profiles with 915 MHz applicators incorporating a hemispheric groundplane and configurations of 2, 4, 8, 12, 16 and 20 antennas. Hemispheric breast models of 90 mm and 150 mm diameter were considered, where cuboid target volumes of 10 mm edge length (1 cm³) and 30 mm edge length (27 cm³) were positioned at the centre of the breast, and also located 15 mm from the chest wall. The average power absorption (αPA) ratio expressed as the ratio of the PA in the target volume and in the full breast was evaluated. A 4-antenna proof-of-concept array was fabricated and experimentally evaluated.

RESULTS

Computational models identified an optimal inter-antenna spacing of 22.5° along the applicator circumference. Applicators with 8 and 12 antennas excited with constant phase presented the highest αPA at centrally located and deep-seated targets, respectively. Experimental measurements with a 4-antenna proof-of-concept array illustrated the potential for electrically steering power deposition profiles by adjusting the relative phase of the signal at antenna inputs.

CONCLUSIONS

Computational models and experimental results suggest that the proposed applicator may have potential for delivering conformal thermal therapy in the intact breast.

Temperature induces significant changes in both glycolytic reserve and mitochondrial spare respiratory capacity in colorectal cancer cell lines

Thermotherapy, as a method of treating cancer, has recently attracted considerable attention from basic and clinical investigators. A number of studies and clinical trials have shown that thermotherapy can be successfully used as a therapeutic approach for various cancers. However, the effects of temperature on cancer bioenergetics have not been studied in detail with a real time, microplate based, label-free detection approach. This study investigates how changes in temperature affect the bioenergetics characteristics (mitochondrial function and glycolysis) of three colorectal cancer (CRC) cell lines utilizing the Seahorse XF96 technology. Experiments were performed at 32°C, 37°C and 42°C using assay medium conditions and equipment settings adjusted to produce equal oxygen and pH levels ubiquitously at the beginning of all experiments. The results suggest that temperature significantly changes multiple components of glycolytic and mitochondrial function of all cell lines tested. Under hypothermia conditions (32°C), the extracellular acidification rates (ECAR) of CRC cells were significantly lower compared to the same basal ECAR levels measured at 37°C. Mitochondrial stress test for SW480 cells at 37°C vs 42°C demonstrated increased proton leak while all other OCR components remained unchanged (similar results were detected also for the patient-derived xenograft cells Pt.93). Interestingly, the FCCP dose response at 37°C vs 42°C show significant shifts in profiles, suggesting that single dose FCCP experiments might not be sufficient to characterize the mitochondrial metabolic potential when comparing groups, conditions or treatments. These findings provide valuable insights for the metabolic and bioenergetic changes of CRC cells under hypo- and hyperthermia conditions that could potentially lead to development of better targeted and personalized strategies for patients undergoing combined thermotherapy with chemotherapy.

Hypofractionated re-irradiation of large-sized recurrent breast cancer with thermography-controlled, contact-free water-filtered infra-red-A hyperthermia: a retrospective study of 73 patients

PURPOSE

Evaluation of the efficacy and toxicity of a new setup of thermographically controlled water-filtered infra-red-A (wIRA) superficial hyperthermia (HT) combined with hypofractionated re-irradiation (re-RT) to treat large-sized breast cancer recurrences.

METHODS

Records of 73 heavily pre-irradiated patients with 103 treatment regions, treated from September 2009 to July 2015 were retrospectively analysed. Sixty-four patients with macroscopic disease were treated with 94 regions including 46 patients with lymphangiosis carcinomatosa. Hypofractionated RT consisted of 4 Gy once per week up to a total dose of 20 Gy delivered within 1-4 min after wIRA-HT. Heating of tumour nodules and diffusely spreading cancer lesions was performed under real-time thermographic temperature monitoring, maintaining the maximum skin temperature in the ROI between 42 °C and 43 °C, achieving intratumoural temperatures up to a depth of 2 cm between 39.5 °C and 42 °C. Seventeen patients received re-re-irradiation (re-re-RT) using the same HT/RT-treatment schedule.

RESULTS

Response rates in patients with macroscopic disease: 61% CR, 33% PR, 5% NC and 1% PD. Local control throughout life time after CR of macroscopic disease: 59%. All nine patients with microscopic disease had CR and local control throughout lifetime. Only grade 1 toxicities were observed.

CONCLUSIONS

Application of thermographically controlled wIRA-HT combined with extremely low-dose re-irradiation provides good local control throughout lifetime of heavily pre-treated breast cancer recurrences. The twin wIRA radiator provides a sufficiently homogeneous heat deposition for the treatment of larger areas. The time lag between HT and re-RT is substantially reduced. The possibility of re-re-RT opens new therapeutic options for the future.

Hyperthermia-driven aberrations of secreted microRNAs in breast cancer in vitro

PURPOSE

Expression profile alterations of nine breast cancer (BC)-associated secreted microRNAs (miRs) were determined under microenvironmental alterations occurring in tumour progression, metastasis or specific oncological treatment modalities. Thereto, the potential influence of the exogenic stimuli hypoxia, acidosis and hyperthermia was investigated in vitro.

MATERIAL AND METHODS

Four established BC cell lines were applied as in vitro BC model systems. Quantitative analyses of secreted microRNA specimens were performed by RNA isolation from cell culture supernatant and subsequent real-time PCR in cells under physiological versus hypoxic, acidic or hyperthermia conditions.

RESULTS

The in vitro application of exogenic stimuli hypoxia, extracellular acidosis and hyperthermia caused heterogeneous expression alterations for the investigated secreted miRNA phenotypes. The majority of relevant exogenic stimuli-dependent microRNA expression alterations were restricted to single events displaying distinct cell type and stimulus dependent correlations only. Most remarkably, hyperthermia triggered a uniform significant down-regulatory effect on the expression levels of the three secreted microRNAs miR-10b, miR-15b and miR-139, respectively. The marked decrease in miR-10b and miR-15b levels was detectable in all four, while miR-139 was found significantly reduced in three out of four BC cell lines.

CONCLUSION

Hyperthermia-dependent down-regulatory influence on three distinct BC-related microRNAs in vitro generates translational aspects for clinical BC treatment, since the identified microRNAs miR-10b, miR-15b and miR-139 are known to have oncogenic as well as tumour suppressor functions in BC. However, an evaluation regarding the potential impact of microRNA-related hyperthermia-dependent alterations for innovative BC treatment approaches demands further analysis including in vivo data.

Nrf2 silencing to inhibit proteolytic defense induced by hyperthermia in HT22 cells

Nrf2 pathway has been known to be protective against cancer progression however recent studies have revealed that the antioxidant activity of Nrf2 contributes to chemotherapy resistance. For many years, hyperthermia has been used as an additional therapy to increase the efficiency of chemotherapy and radiotherapy. Besides the positive effects of hyperthermia during treatment procedure, thermotolerance has been found to develop against heat treatment. Although the involved molecular mechanisms have not been fully clarified, heat shock proteins (HSP) and proteasome activity are known to be involved in the acquisition of thermotolerance. The aim of this study was to investigate the potential beneficial effects of combining hyperthermia with Nrf2 silencing to inhibit molecular mechanisms leading to induction of defense mechanisms in transcription level. Following heat treatment of HT22 cells, HSP70 and the proteasome levels and as well as proteasome activity were found to be elevated in the nucleus. Our results demonstrated that Nrf2 silencing reduced defense mechanisms against heat treatment both in antioxidant and proteolytic manner and Nrf2 may be a potential target for therapeutic approach in order to improve the beneficial effects of hyperthermia in cancer therapy.

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Hyperthermia increases HSP70, β5 levels and Proteasome activity in the nucleus.

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Nrf2 pathway contributes to thermotolerance by HO-1 and GSTα.

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Nrf2 contributes to thermotolerance via proteasome and HSP related degradation.

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Nrf2 Inhibition may be a useful approach to overcome the thermotolerance.

Rib fractures after reirradiation plus hyperthermia for recurrent breast cancer: Predictive factors

Background

Combining reirradiation (reRT) and hyperthermia (HT) has shown high therapeutic value for patients with locoregional recurrent breast cancer (LR). However, additional toxicity of reirradiation (e.g., rib fractures) may occur. The aim of this study is to determine the impact of potential risk factors on the occurrence of rib fractures.

Patients and methods

From 1982–2005, 234 patients were treated with adjuvant reRT + HT after surgery for LR. ReRT consisted typically of 8 fractions of  4 Gy twice a week, or 12 fractions of  3 Gy four times a week. A total of 118 patients were irradiated with abutted photon and electron fields. In all, 60 patients were irradiated using either one or alternating combinations of abutted AP electron fields. Hyperthermia was given once or twice a week.

Results

The 5-year infield local control (LC) rate was 70 %. Rib fractures were detected in 16 of 234 patients (actuarial risk: 7 % at 5 years). All rib fractures occurred in patients treated with a combination of photon and abutted electron fields (p = 0.000); in 15 of 16 patients fractures were located in the abutment regions. The other significant predictive factors for rib fractures were a higher fraction dose (p = 0.040), large RT fields, and treatment before the year 2000.

Discussion and conclusion

ReRT + HT results in long-term LC. The majority of rib fractures were located in the photon/electron abutment area, emphasizing the disadvantage of field overlap. Large abutted photon/electron fields combined with 4 Gy fractions increase the number of rib fractures in this study group. However, as these factors were highly correlated no relative importance of the individual factors could be estimated. Increasing the number of HT sessions a week does not increase the risk of rib fractures.

Is hyperthermia combined with radiotherapy adequate in elderly patients with muscle-invasive bladder cancers? Thermo-radiobiological implications from an audit of initial results

PURPOSE

The aim of this study was to evaluate the outcomes of loco-regional hyperthermia (HT) with radiotherapy (RT) and/or chemotherapy (CT) in elderly patients with muscle-invasive bladder cancers (MIBC).

MATERIAL AND METHODS

Twenty consecutive MIBC patients were treated with HTRT (n = 8) or HTCTRT (n = 12) following transurethral resection of their bladder tumours. Weekly HT was administered prior to RT to a mean temperature of 40.6-42.7 °C for 60 min. A mean RT dose of 54.6 Gy (SD ± 4.2) was delivered. Single-agent cisplatin (n = 2) or carboplatin (n = 10) was used in HTCTRT patients.

RESULTS

The median age was 81 years. HTRT patients received a mean RT dose of 51.0 Gy compared to 57.1 Gy with HTCTRT (p < 0.001) in a shorter overall treatment time (OTT) (30.8 ± 6.9 versus 43.9 ± 4.0 days, p < 0.001). All HTRT patients had long-term local disease control, while 41.6% of HTCTRT recurred during follow-up. None of the HTRT patients experienced grade III/IV acute and late toxicities, while these were evident in two and one HTCTRT patients respectively. Taken together, the 3-year bladder preservation, local disease-free survival, cause-specific survival and overall survival were 86.6%, 60.7%, 55% and 39.5% respectively. Even though the mean biological effective dose (BED) for both groups was similar (57.8 Gy15), the thermo-radiobiological BED estimated from HT-induced reduction of α/β was significantly higher for HTRT patients (91 ± 4.4 versus 85.8 ± 4.3 Gy3, p = 0.018).

CONCLUSIONS

Thermal radiosensitisation with consequent reduction in α/β results in a higher thermo-radiobiological BED with a relatively higher RT dose/fraction and shorter OTT. This translates into a favourable outcome in elderly MIBC patients. Any benefit of CT in these patients needs further investigation.

Absence of acute ocular damage in humans after prolonged exposure to intense RF EMF

The eye is considered to be a critical organ when determining safety standards for radio frequency (RF) radiation. Experimental data obtained using animals showed that RF heating of the eye, particularly over a specific threshold, can induce cataracts. During the treatment of cancer in the head and neck by hyperthermia, the eyes receive a considerable dose of RF radiation due to stray radiation from the prolonged (60 min) and intense exposure at 434 MHz of this region. In the current study, we verified the exposure guidelines for humans by determining the association between the electromagnetic and thermal dose in the eyes with the reported ocular effects. We performed a simulation study to retrospectively assess the specific absorption rate (SAR) and temperature increase in the eyes of 16 selected patients (encompassing a total of 74 treatment sessions) whose treatment involved high power delivery as well as a minimal distance between the tumor site and the eye. Our results show that the basic restrictions on the peak 10 g spatial-averaged SAR (10 W kg(-1)) and peak tissue temperature increase (1 °C) are exceeded by up to 10.4 and 4.6 times, on average, and by at least 6.2 and 1.8 times when considering the lower limit of the 95% confidence interval. Evaluation of the acute effects according to patients' feedback (all patients), the common toxicity criteria scores (all patients) and an ophthalmology investigation (one patient with the highest exposure) revealed no indication of any serious acute ocular effect, even though the eyes were exposed to high electromagnetic fields, leading to a high thermal dose. We also found that, although there is a strong correlation (R (2) =  0.88) between the predicted induced SAR and temperature in the eye, there are large uncertainties regarding the temperature-SAR relationship. Given this large uncertainty (129%) compared with the uncertainty of 3D temperature simulations (61%), we recommend using temperature simulations as a dosimetric measure in electromagnetic exposure risk assessments.

Reirradiation and hyperthermia for irresectable locoregional recurrent breast cancer in previously irradiated area: Size matters

BACKGROUND/PURPOSE

Treatment options for irresectable locoregional recurrent breast cancer in previously irradiated area are limited. Hyperthermia, elevating tumor temperature to 40-45°C, sensitizes radio-and-chemotherapy. Four hundred and fourteen patients treated with reirradiation+hyperthermia (reRT+HT) in the AMC(n=301) and the BVI(n=113), from 1982 to 2005 were retrospectively analyzed for treatment response, locoregional control (LC) and prognostic factors for LC and toxicity.

PATIENTS/METHODS

All patients received previous irradiation (median 50 Gy). reRT consisted of 8 × 4 Gy-2/week (AMC) or 12 × 3 Gy-4/week (BVI). Hyperthermia was added once (AMC)/twice (BVI) a week.

RESULTS

Overall clinical response rate was 86%. The 3-year LC rate was 25%. The number of recurrence episodes, distant metastases (DM), tumor site, tumor size, time to recurrence and treatment year were significant for LC. Acute ⩾ grade 3 toxicity occurred in 24% of patients. Actuarial late ⩾ grade 3 toxicity was 23% at 3-years. In multivariable analysis reRT fraction dose was significantly related to late ⩾ grade 3 toxicity.

CONCLUSION

reRT+HT is an effective curative and palliative treatment option for patients with irresectable locoregional recurrent breast cancer in previously irradiated area. Early referral, treatment of chest wall recurrences ⩽ 5 cm in the absence of distant metastases, provided the highest local control rates. The cumulative effects of past and present treatments should be accounted for by adjusting treatment protocol to minimize toxicity.

Design and characterisation of miniaturised cavity-backed patch antenna for microwave hyperthermia

PURPOSE

The aim of this study was to describe the design and characterisation of a miniaturised 434 MHz patch antenna enclosed in a metal cavity for microwave hyperthermia treatment of cancer.

MATERIALS AND METHODS

Electromagnetic (EM) field distribution in the near field of a microstrip patch irradiating body tissue was studied using finite element method (FEM) simulations. Antenna miniaturisation was achieved through dielectric loading with very high permittivity, metal enclosure, patch folding and shorting post. Frequency dependent electrical properties of materials were incorporated wherever appropriate using dispersion model and measurements. Antenna return loss and specific absorption rate (SAR) at 434 MHz were measured on muscle phantoms for characterisation.

RESULTS

The design was progressively optimised to yield a compact 434 MHz patch (22 mm × 8.8 mm × 10 mm) inside a metal cavity (40 mm × 12 mm) with integrated coupling water bolus (35 mm). The fabricated antenna with integrated water bolus was self resonant at 434 MHz without load, and has better than -10 dB return loss (S11) with 13-20 MHz bandwidth on two different phantoms. SAR at 434 MHz measured using an infrared (IR) thermal camera on split phantoms indicated penetration depth for -3 dB SAR as 8.25 mm compared to 8.87 mm for simulation. The simulated and measured SAR coverage along phantom depth was 3.09 cm(2) and 3.21 cm(2) respectively at -3 dB, and 6.42 cm(2) and 9.07 cm(2) respectively at -6 dB. SAR full width at half maximum (FWHM) at 5 mm and 20 mm depths were 54.68 mm and 51.18 mm respectively in simulation, and 49.47 mm and 43.75 mm respectively in experiments. Performance comparison of the cavity-backed patch indicates more than 89% co-polarisation and higher directivity which resulted in deeper penetration compared to the patch applicators of similar or larger size proposed for hyperthermia treatment of cancer.

CONCLUSION

The fabricated cavity-backed applicator is self-resonant at 434 MHz with a negligible shift in resonance when coupled to different phantoms, Δf/f0 less than 1.16%. IR thermography-based SAR measurements indicated that the -3 dB SAR of the cavity-backed aperture antenna covered the radiating aperture surface at 5 mm and 20 mm depths. It can be concluded that the compact cavity-backed patch antenna has stable resonance, higher directivity and low cross polarisation, and is suitable for design of microwave hyperthermia array applicators with adjustable heating pattern for superficial and/or deep tissue heating.

Local control rate after the combination of re-irradiation and hyperthermia for irresectable recurrent breast cancer: Results in 248 patients

BACKGROUND AND PURPOSE

Randomized studies have shown that adding hyperthermia (HT) to re-irradiation (re-RT) improves treatment outcome for patients with breast cancer recurrences. We evaluated the efficacy and side effects in patients treated with re-RT and HT for irresectable locoregional breast cancer recurrences.

MATERIAL AND METHODS

From September 1996 to December 2011, 248 patients with a macroscopic breast cancer recurrence were treated with re-RT and HT. Radiotherapy (RT) was applied to a dose of 32 Gy in 4 Gy fractions, twice weekly. HT was prescribed once weekly after RT. Primary endpoints for this analysis were complete response (CR) and local control (LC). Secondary endpoints were overall survival (OS), and toxicity. Patient-, tumor-, and treatment-related characteristics predictive for the endpoints were identified in univariate and multivariate analyses.

RESULTS

The median follow-up period was 32 months. The CR rate was 70%. At 1, 3, and 5 years LC was 53%, 40% and 39%, and OS was 66%, 32%, and 18%, respectively. OS after 10 years was 10%. Thermal burns developed in 23% patients, healing with conservative measures. The incidence of 5 years late grade 3 toxicity was 1%. A few patients survived more than 10 years without evidence of disease.

CONCLUSIONS

The combination of re-RT and HT results in a high rate of long-term LC with acceptable late toxicity, and many patients remained locally controlled for the rest of their survival period.

Association of acute adverse effects with high local SAR induced in the brain from prolonged RF head and neck hyperthermia

To provide an adequate level of protection for humans from exposure to radio-frequency (RF) electromagnetic fields (EMF) and to assure that any adverse health effects are avoided. The basic restrictions in terms of the specific energy absorption rate (SAR) were prescribed by IEEE and ICNIRP. An example of a therapeutic application of non-ionizing EMF is hyperthermia (HT), in which intense RF energy is focused at a target region. Deep HT in the head and neck (H&N) region involves inducing energy at 434 MHz for 60 min on target. Still, stray exposure of the brain is considerable, but to date only very limited side-effects were observed. The objective of this study is to investigate the stringency of the current basic restrictions by relating the induced EM dose in the brain of patients treated with deep head and neck (H&N) HT to the scored acute health effects. We performed a simulation study to calculate the induced peak 10 g spatial-averaged SAR (psSAR₁₀g) in the brains of 16 selected H&N patients who received the highest SAR exposure in the brain, i.e. who had the minimum brain-target distance and received high forwarded power during treatment. The results show that the maximum induced SAR in the brain of the patients can exceed the current basic restrictions (IEEE and ICNIRP) on psSAR₁₀g for occupational environments by 14 times. Even considering the high local SAR in the brain, evaluation of acute effects by the common toxicity criteria (CTC) scores revealed no indication of a serious acute neurological effect. In addition, this study provides pioneering quantitative human data on the association between maximum brain SAR level and acute adverse effects when brains are exposed to prolonged RF EMF.

Bleomycin electrochemotherapy in elderly metastatic breast cancer patients: clinical outcome and management considerations

PURPOSE

To evaluate the efficacy and toxicity of electrochemotherapy (ECT) in elderly metastatic breast cancer (BC) patients.

METHODS

Retrospective analysis of 55 patients with superficial metastases who underwent ECT according to the European Standard Operative Procedures of electrochemotherapy. Treatment schedule consisted of intravenous or intratumoral bleomycin followed by locally delivered electric pulses. Statistical comparisons were performed between two groups: the patients aged <70 years (n = 27) and those ≥70 years (n = 28). Treatment outcomes were as follows: complete response (CR) rate, local progression-free survival (LPFS), new lesions-free survival (NLFS), toxicity and patient compliance.

RESULTS

Patient groups were comparable for clinical-pathological features, except for the number of comorbidities (P < .001). The median follow-up was 32 months (range 6-53). Overall, CR rate was 40 % and was significantly higher in elderly patients (57 vs. 26 %, P = .023) and in patients with better performance status (PS = 0-1, 53 vs. PS = 2, 21 %, P = .048), although local tumor control showed a trend for lower values (2-year LPFS, 67 vs. 93 % among elderly and young patients, respectively; P = .061). Older women seemed less likely to progress outside the ECT field (2-year NLFS, 39 vs. 30 %, P = .075), but discontinued treatment more frequently due to impaired performance status (P = .002). Local pain was graded ≥3, according to a 10-point visual analog scale, by 16/28 (57.1 %) and 8/28 (28.6 %) elderly patients at 4 and 8 weeks, respectively. Wound debridement was required in 5/28 (18 %) older women, due to G3 skin ulceration.

CONCLUSIONS

Elderly BC patients are highly responsive to ECT and achieve durable local tumor control. Physicians should be aware of possible debilitating side effects, such as pain and skin toxicity. Performance status and frailty screening could be a helpful addition to improve patient selection.

Targeted thermosensitive liposomes: an attractive novel approach for increased drug delivery to solid tumors

INTRODUCTION

Currently available chemotherapy is hampered by a lack in tumor specificity and resulting toxicity. Small and long-circulating liposomes can preferentially deliver chemotherapeutic drugs to tumors upon extravasation from tumor vasculature. Although clinically used liposomal formulations demonstrated significant reduction in toxicity, enhancement of therapeutic activity has not fully met expectations.

AREAS COVERED

Low drug bioavailability from liposomal formulations and limited tumor accumulation remain major challenges to further improve therapeutic activity of liposomal chemotherapy. The aim of this review is to highlight strategies addressing these challenges. A first strategy uses hyperthermia and thermosensitive liposomes to improve tumor accumulation and trigger liposomal drug bioavailability. Image-guidance can aid online monitoring of heat and drug delivery and further personalize the treatment. A second strategy involves tumor-specific targeting to enhance drug delivery specificity and drug internalization. In addition, we review the potential of combinations of the two in one targeted thermosensitive-triggered drug delivery system.

EXPERT OPINION

Heat-triggered drug delivery using thermosensitive liposomes as well as the use of tumor vasculature or tumor cell-targeted liposomes are both promising strategies to improve liposomal chemotherapy. Preclinical evidence has been encouraging and both strategies are currently undergoing clinical evaluation. A combination of both strategies rendering targeted thermosensitive liposomes (TTSL) may appear as a new and attractive approach promoting tumor drug delivery.

Enhanced drug delivery in rabbit VX2 tumours using thermosensitive liposomes and MRI-controlled focused ultrasound hyperthermia

PURPOSE

The efficacy of anticancer drugs in solid tumours is impaired by their inability to reach all cancer cells in sufficient concentration to cause cytotoxicity. Hyperthermia-triggered release of drugs from thermosensitive liposomes can increase tumour drug concentration, but tumour-specific drug delivery requires precise temperature control, and effects on microregional distribution of anticancer drugs in tumours are unknown. Here we evaluate thermally triggered release of doxorubicin in a rabbit tumour model by comparing free versus thermosensitive liposomal doxorubicin administered systemically during magnetic resonance imaging (MRI)-controlled focused ultrasound hyperthermia.

MATERIALS AND METHODS

Twelve rabbits with a transplanted VX2 tumour in each thigh had a 10 mm diameter region in one tumour heated to 43°C using focused ultrasound with temperature control by MRI thermometry. Delivery of doxorubicin to tumours and normal tissues was quantified by fluorescence in tissue homogenates, and by fluorescence microscopy.

RESULTS

Using thermosensitive liposomal doxorubicin (2.5 mg/kg), doxorubicin concentrations in heated tumours were 26.7 times higher than in unheated tumours (n = 7, p = 0.017, two-sided Wilcoxon signed-rank test). There was no significant enhancement with free doxorubicin in heated versus unheated tumours (n = 3, p = 0.5). With thermosensitive liposomes (8.3 mg/kg), fluorescence microscopy demonstrated increased doxorubicin fluorescence in heated versus unheated tumours, co-localised with nuclear staining throughout the tumour.

CONCLUSIONS

Localised image-guided delivery of high concentrations of doxorubicin to cancer cells was achieved non-invasively in implanted tumours with temperature-sensitive drug carriers and a preclinical MRI-controlled focused ultrasound hyperthermia system.

Effect of a combined surgery, re-irradiation and hyperthermia therapy on local control rate in radio-induced angiosarcoma of the chest wall

PURPOSE

Radiation-induced angiosarcoma (RAS) of the chest wall/breast has a poor prognosis due to the high percentage of local failures. The efficacy and side effects of re-irradiation plus hyperthermia (reRT + HT) treatment alone or in combination with surgery were assessed in RAS patients.

PATIENTS AND METHODS

RAS was diagnosed in 23 breast cancer patients and 1 patient with melanoma. These patients had previously undergone breast conserving therapy (BCT, n = 18), mastectomy with irradiation (n=5) or axillary lymph node dissection with irradiation (n = 1). Treatment consisted of surgery followed by reRT + HT (n = 8), reRT + HT followed by surgery (n = 3) or reRT + HT alone (n = 13). Patients received a mean radiation dose of 35 Gy (32-54 Gy) and 3-6 hyperthermia treatments (mean 4). Hyperthermia was given once or twice a week following radiotherapy (RT).

RESULTS

The median latency interval between previous radiation and diagnosis of RAS was 106 months (range 45-212 months). Following reRT + HT, the complete response (CR) rate was 56 %. In the subgroup of patients receiving surgery, the 3-month, 1- and 3-year actuarial local control (LC) rates were 91, 46 and 46 %, respectively. In the subgroup of patients without surgery, the rates were 54, 32 and 22 %, respectively. Late grade 4 RT toxicity was seen in 2 patients.

CONCLUSION

The present study shows that reRT + HT treatment--either alone or combined with surgery--improves LC rates in patients with RAS.

The tolerance of reirradiation and hyperthermia in breast cancer patients with reconstructions

BACKGROUND

Breast cancer recurrences in previously irradiated areas are treated with reirradiation (reRT) and hyperthermia (HT). The aim of this retrospective study is to quantify the toxicity of HT in breast cancer patients with reconstruction.

METHODS

Between 1992 and 2009, 36 patients were treated with reRT with a scheme of 8 fractions of 4.0 Gy in 4 weeks, and HT on a total of 37 tissue reconstructions. The types of reconstructions were: split-thickness skin graft (15), transverse rectus abdominis myocutaneous flap (1), latissimus dorsi flap (14), rhomboid flap (1) or a combination of grafts and flaps (6). Toxicities were graded according to the Common Terminology Criteria for Adverse Events (CTCAE), version 3.0. Patient, tumour, and treatment characteristics predictive for the endpoints were identified in univariate and multivariate analyses. The primary endpoint was HT toxicity. Secondary endpoints were acute and late radiotherapy (RT) toxicity, complete response (CR), local control (LC) and overall survival (OS).

RESULTS

The median follow-up time was 64 months. Grade 2 HT toxicity occurred in four patients and grade 3 in three. The three patients with grade 3 HT toxicity required reoperation. None of the evaluated parameters showed a significant relationship with HT toxicity. The CR rate in 15 patients with macroscopic disease was 80%. The 3 and 5 year LC rates were 74% and 69%; the median OS was 55 months.

CONCLUSIONS

Combined reRT and HT in breast cancer patients with reconstruction is safe and effective.

Procedure for creating a three-dimensional (3D) model for superficial hyperthermia treatment planning

PURPOSE

To make a patient- and treatment-specific computed tomography (CT) scan and to create a three-dimensional (3D) patient model for superficial hyperthermia treatment planning (SHTP).

PATIENTS, MATERIALS, AND METHODS

Patients with recurrent breast adenocarcinoma in previously irradiated areas referred for radiotherapy (RT) and hyperthermia (HT) treatment and giving informed consent were included. After insertion of the thermometry catheters in the treatment area, a CT scan in the treatment position was made.

RESULTS

A total of 26 patients have been, thus far, included in the study. During the study period, five types of adjustments were made to the procedure: (1) marking the RT field with radioopaque markers, (2) making the CT scan after the first HT treatment instead of before, (3) using an air- and foam-filled (dummy) water bolus, (4) a change to radiolucent catheters for which radioopaque markers were needed, and (5) marking the visible/palpable extent of the tumor with radioopaque markers, if necessary. With these adjustments, all necessary information is visible on the CT scan. Each CT slice was automatically segmented into muscle, fat, bone, and air. RT field, catheters, applicators, and tumor lesions, if indicated, were outlined manually using the segmentation program iSeg. Next the model was imported into SEMCAD X, a 3D electromagnetic field simulator.

CONCLUSION

Using the final procedure to obtain a patient- and treatment-specific CT scan, it is possible to create a 3D model for SHTP.