Termoterapia en cáncer de próstata mediante el uso de nanopartículas magnéticas

Abstract

En recientes ensayos clínicos, se ha evaluado en tumores malignos humanos, un nuevo método de dispensación de calor en pequeños espacios (intersticios) utilizando nanopartículas magnéticas y una técnica de inyección directa. En el cáncer de próstata, este procedimiento se ha investigado en dos estudios fase I separados empleando en uno solamente termoterapia de nanopartículas magnéticas y en otro en combinación con braquiterapia (implantes permanentes). En ambos estudios se demostró viabilidad y buena tolerancia, usando el primer prototipo de un aplicador de campo magnético. Como con cualquier otra técnica por calor, este nuevo procedimiento requiere herramientas específicas para su planificación, control de calidad y monitorización térmica, basado en una imagen apropiada y en técnicas de planificación. En estos primeros estudios, se evalúa un nuevo método que permite una planificación y distribución tridimensional no invasiva de la temperatura basado en la tomografía computerizada (TC). En la actualidad, los factores limitantes de este procedimiento son el malestar del paciente a altas intensidades de campos magnéticos y la distribución intratumoral subóptima de las nanopartículas. Hasta que estas limitaciones sean superadas y la termoablación pueda ser aplicada con seguridad como monoterapia, esta modalidad de tratamiento está siendo evaluada en combinación con la irradiación en pacientes con cáncer de próstata localizado.Palabras clave: Termoterapia. Cáncer de próstata. Nanopartículas magnéticas. ABSTRACT THERMAL THERAPY OF PROSTATE CANCER USING MAGNETIC NANOPARTICLESA novel method of interstitial heating using magnetic nanoparticles and a direct injection technique has been evaluated in human cancers in recent clinical trials. In prostate cancer, this approach was investigated in two separate phase-I-studies, employing magnetic nanoparticle thermotherapy alone and in combination with permanent seed brachytherapy. The feasibility and good tolerability was shown in both trials, using the first prototype of a magnetic field applicator. As with any other heating technique, this novel approach requires specific tools for planning, quality control and thermal monitoring, based on appropriate imaging and modelling techniques. In these first clinical trials, a newly developed method for planning and non-invasive calculations of the 3-dimensional temperature distribution based on computed tomography could be validated. Limiting factors of this approach at present are patient discomfort at high magnetic field strengths and suboptimal intratumoral distribution of nanoparticles. Until these limitations will be overcome and thermal ablation can safely be applied as a monotherapy, this treatment modality is being evaluated in combination with irradiation in patients with localized prostate cancer.

Improved efficiency of heat generation in nonlinear dynamics of magnetic nanoparticles

“…Knowing that in the practice [23] H 0 ≈ 18 kA/m we find that ω L is of the order of 10 9 Hz. In hyperthermia the frequency of the applied field is advised to be chosen between 10 5 and 5 × 10 5 Hz, so that ω is four orders of magnitude below ω L .…”

“…Nonlinear dynamics of the magnetization in singledomain ferromagnetic nanoparticle systems has received a considerable attention due to a wide range of their applicability such as magnetic resonance imaging, ultrahigh density magnetic data recording, spintronics, ferrofluids and in biomedical engineering, in particular, drug delivery or hyperthermia [1][2][3]. Among many forms of hyperthermia, the local induction of heat via magnetic nanoparticles seems a fruitful strategy with promising preclinical results in different cancer modes [4,5]. The unique feature of magnetic nanoparticle hyperthermia is that the energy is transported in the body by means of an ac magnetic field.…”

Corrigendum to “Drug Delivery Nanoparticles in Skin Cancers”

“…The heat, generated by SPION, can be used for the selective destruction of tumor cells, which are more vulnerable to heating than normal cells [49,53] . Their surface can be functionalized by the attachment of polymers and capping agents, using biodegradable materials such as cellulose, dextran, PEG, or PLGA, enhancing their biocompatibility and biodegradability for several biomedical applications [54]. Recently, a prototype of carbon-coated superparamagnetic iron oxide nanoparticles (SPIO@C) for sentinel lymph node mapping in melanoma and breast cancer patients has been developed [55,56] .…”

Efficiency of magnetic hyperthermia in the presence of rotating and static fields

“…Let us also note, that magnetic hyperthermia or more general, the nonlinear dynamics of the magnetization in singledomain ferromagnetic nanoparticles receives increasing interest in various fields including data storage, biomedical engineering, spintronics, [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21], and as mentioned in the abstract in cancer therapy, [22][23][24]. A possible way to improve the efficiency of magnetic hyperthermia is to chose a proper type of applied field.…”