Ultrasounds in cancer therapy: A summary of their use and unexplored potential

Abstract

Ultrasounds (US) are a non-ionizing mechanical wave, with less adverse effects than conventional pharmacological or surgical treatments. Different biological effects are induced in tissues and cells by ultrasound actuation depending on acoustic parameters, such as the wave intensity, frequency and treatment dose. This non-ionizing radiation has considerable applications in biomedicine including surgery, medical imaging, physical therapy and cancer therapy. Depending on the wave intensity, US are applied as High Intensity Ultrasounds (HIUS) and Low Intensity Pulsed Ultrasounds (LIPUS), with different effects on cells and tissues. HIUS produce thermal and mechanical effects, resulting in a large localized temperature increase, leading to tissue ablation and even tumor necrosis. This can be achieved by focusing low intensity waves emitted from different electrically shifted transducers, known as HIFU (High Intensity Focused Ultrasounds). LIPUS have been used extensively as a therapeutic, surgical and diagnostic tool, with diverse biological effects observed in tissues and cultured cells. US represent a non-invasive treatment strategy that can be applied to selected areas of the body, with limited adverse effects. In fact, tumor ablation using HIFU has been used as a curative treatment in patients with an early stage pancreatic tumor and is an effective palliative treatment in patients with advanced stage disease. However, the biological effects, dose standardization, benefit-risk ratio and safety are not fully understood. Thus, it is an emerging field that requires further research in order to reach its full potential.

Radiation combined with ultrasound and microbubbles: A potential novel strategy for cancer treatment

“…Collectively, these studies strongly suggest that the acoustic cavitation that occurs upon high ultrasound pressure causes microbubbles disruption, enhancing the tumor effect. Another proposed mechanism for greater tumor response following high-intensity focused ultrasound (HIFU) is the mechanical disruption caused to the tumor tissue using repeated short-duration pulses with low-duty cycles [67] . Together, all these abovementioned findings provide strong evidence that the permutations of ultrasound pressure and microbubble concentrations might be an essential factor to consider while treating tumors.…”

Ultrasound-Induced Drug Release from Stimuli-Responsive Hydrogels

“…Ultrasound has successfully been used as a minimally invasive diagnostic tool for the detection and follow-up of cancer patients [ 26 , 107 , 121 ] and for analyte detection [ 122 , 123 , 124 , 125 ]. Ultrasound has also been used for cancer treatment due to its effective real-time capabilities in imaging and has more recently been used for drug delivery from responsive hydrogel systems [ 126 , 127 , 128 , 129 , 130 , 131 ]. Like the hydrogel systems used for drug delivery in tissue engineering, these hydrogels were chosen due to their high loading efficiencies, stability, and flexibility [ 17 ].…”

Ultrasound-Triggered Amoxicillin Release from Chitosan/Ethylene Glycol Diglycidyl Ether/Amoxicillin Hydrogels Having a Covalently Bonded Network

“…Such DDS systems in combination with external stimulation have become popular because of their superior drug release efficiency and more precise control of their characteristics. , Among these stimulants, US retains the advantages of deep penetration, noninvasiveness, and nontoxicity to the human body, as well as simple operation and low cost , compared to other DDSs. The efficient penetration from the outside to the inside of the body is a major feature not found in other external stimuli and the release of the drug toward the outside of the drug matrix can be controlled by changing the US intensity without loading the specimen. , In fact, US waves can be transmitted through water and induce oscillatory motion of the surrounding fluid, acoustic streaming, cavitation, and thermal effect. , US treatment has been proven to be beneficial in a variety of cases, including treatment of diabetes, stroke, cancer, infections, skin dehydration, and bone fractures . On the other hand, we have investigated US-stimulated drug release of biocompatible cellulose hydrogel drugs.…”

“…24,25 In fact, US waves can be transmitted through water and induce oscillatory motion of the surrounding fluid, acoustic streaming, cavitation, and thermal effect. 26,27 US treatment has been proven to be beneficial in a variety of cases, 28 including treatment of diabetes, 29 stroke, 30 cancer, 31 infections, 32 skin dehydration, 33 and bone fractures. 34 On the other hand, we have investigated US-stimulated drug release of biocompatible cellulose hydrogel drugs.…”