Low-intensity ultrasound: A novel technique for adjuvant treatment of gliomas

Glioma is the most common primary malignant tumor of the central nervous system. Although surgical treatment combined with radiotherapy, chemotherapy, and immunotherapy are commonly used for glioma treatment, the prognosis of glioma is still unsatisfactory. The poor effect of glioma treatment could be due to the blocking effect of blood-brain barrier (BBB) on most drugs and the multidrug resistance in tumor cells. In recent years, preclinical trials have shown that low-intensity ultrasound (LIUS) can reversibly open the BBB, inhibit the proliferation of tumor cells, and improve the delivery of drugs to brain tissue. This technology has also recently been used in clinical trials, and achieved encouraging preliminary results. In this review, the existing research results, the effect of LIUS on the adjuvant therapy of glioma under safe conditions, and the physical and biological mechanisms have been discussed. This review aims to show the potential and prospect of LIUS technique in the clinical treatment of glioma.