Characterization of Ferromagnetic Composite Implants for Tumor Bed Hyperthermia
TL;DR: In this article, a composite ferromagnetic surgical implant was inserted in a tumor bed for the delivery of local hyperthermia therapy (HT) by inductively coupling energy from an external magnetic field of sub-megahertz frequency.
Abstract: Hyperthermia therapy (HT) is becoming a well-recognized method for the treatment of cancer when combined with radiation or chemotherapy. There are many ways to heat a tumor and the optimum approach depends on the treatment site. This study investigates a composite ferromagnetic surgical implant inserted in a tumor bed for the delivery of local HT. Heating of the implant is achieved by inductively coupling energy from an external magnetic field of sub-megahertz frequency. Implants are formed by mechanically filling a resected tumor bed with self-polymerizing plastic mass mixed with small ferromagnetic thermoseeds. Model implants were manufactured and then heated in a 35 cm-diameter induction coil of our own design. Experimental results showed that implants were easily heated to temperatures that allow either traditional HT (39 °C–45 °C) or thermal ablation therapy (>50 °C) in an external magnetic field with a frequency of 90 kHz and amplitude not exceeding 4 kA/m. These results agreed well with a numerical solution of combined electromagnetic and heat transfer equations solved using the finite-element method.
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TL;DR: The mechanisms of tumour cell death that are induced by the most common thermoablative techniques are examined and the rapidly developing areas of research in the field are discussed, including combinatorial ablation and immunotherapy, synergy with conventional chemotherapy and radiation, and the development of a new ablation modality in irreversible electroporation.
Abstract: Minimally invasive thermal ablation of tumours has become common since the advent of modern imaging. From the ablation of small, unresectable tumours to experimental therapies, percutaneous radiofrequency ablation, microwave ablation, cryoablation and irreversible electroporation have an increasing role in the treatment of solid neoplasms. This Opinion article examines the mechanisms of tumour cell death that are induced by the most common thermoablative techniques and discusses the rapidly developing areas of research in the field, including combinatorial ablation and immunotherapy, synergy with conventional chemotherapy and radiation, and the development of a new ablation modality in irreversible electroporation.
1,354 citations
TL;DR: The clinical results achieved to date have confirmed the expectations raised by results from experimental studies and justify using hyperthermia as part of standard treatment in tumour sites for which its efficacy has been proven and, furthermore, to initiate new studies with other tumours.
1,016 citations
TL;DR: The purpose of this article is to provide an overview on the current clinical application of hyperthermia combined with conventional treatment modalities (e.g. ionizing radiation, chemotherapy) in the treatment of malignant disease.
Abstract: The purpose of this article is to provide an overview on the current clinical application of hyperthermia combined with conventional treatment modalities (e.g. ionizing radiation, chemotherapy) in the treatment of malignant disease. The clinical application of hyperthermia with increase of tissue temperatures (range 40-44 degrees C) has been integrated in multimodal anti-cancer strategies. This review describes selected phase I or II (n = 17) and phase III trials (n = 16) investigating the effect of hyperthermia combined with radiotherapy (n = 10 trials), chemotherapy (n = 15 trials), or both (n = 8 trials) in a total of more than 2200 patients. The trials were performed in a variety of solid tumours (e.g. melanoma, head and neck cancer, breast cancer, cancer of the gastrointestinal or urogenital tract, glioblastoma, sarcoma) in paediatric or adult patients. Profound research has produced a scientific basis for the simultaneous application of hyperthermia in combination with ionizing radiation and/or systemic chemotherapy. Hyperthermia is becoming more accepted clinically, due to the substantial technical improvements made in achieving selected increase of temperatures in superficial and deep-seated tumours. At present, the combination of hyperthermia and chemotherapy or radiochemotherapy is further tested within clinical protocols (phase II/III) in order to improve local tumour control and relapse-free survival in patients with high-risk or advanced tumours of different entities.
562 citations
TL;DR: The review summarizes the outcomes from various clinical studies where hyperthermia is used as a thermal sensitizer of radiotherapy and-/or chemotherapy in various solid tumors and presents an overview of the progresses in loco-regionalhyperthermia.
407 citations
TL;DR: Practical aspects, limitations, and the state of the art for the application of magnetic heating in magnetic particle hyperthermia as thermal treatment of small tumours are illuminated.
Abstract: In this review article we present basic principles of magnetically induced heat generation of magnetic nanoparticles for application in magnetic particle hyperthermia. After explanation of heating mechanisms, the role of particle-particle as well as particle-tissue interactions is discussed with respect to achievable heating power of the particles inside the tumour. On the basis of heat transfer theory at the micro-scale, the balance between generated and dissipated heat inside the tumour and the resulting damaging effects for biological tissue is examined. The heating behaviour as a function of tumour size is examined in combination with feasible field strength and frequency. Numerical calculations and experimental investigations are used to show the lower tumour size limit for tumour heating to therapeutically suitable temperatures. In summary, this article illuminates practical aspects, limitations, and the state of the art for the application of magnetic heating in magnetic particle hyperthermia as thermal treatment of small tumours.
388 citations