Ultrasound may help immune system detect cancer
High-intensity ultrasound beams aimed at tumours can cause them to 'leak', alerting the immune system to their presence, according to new research.
A study on mice, led by researchers at Duke University's Pratt School of Engineering, found that 'high-intensity focused' ultrasound (HIFU) can be used to physically shake tumour cells, causing the cell membranes to rupture and release their contents.
Once outside the cancer cell, the contents can be detected by the body's immune system, which can then produce anti-tumour white blood cells.
Although the technique has only been tested on mice so far, the researchers hope that it may provide a non-surgical treatment for humans that would induce the immune system to seek out and destroy cancer cells that have spread through the bloodstream into other parts of the body.
Pei Zhong, associate professor in the university's mechanical engineering and materials science department, commented: "In most cancers, what actually ends up killing the patient is the spread of the cancer from its original site to other parts of the body.
"If the patient has a tumour in the kidney or liver, several treatment options - including surgery, radiation or HIFU - can be used to get rid of the cancerous tissues. However, if the cancer cells spread to other vital organs such as the lung or brain, the outcomes are often much worse."
Dr Zhong revealed that HIFU is currently being tested in China, Europe and the US, where it is being used to kill tumours by heating them.
He explained that this method currently only enables doctors to treat the primary tumour, but said that using mechanical vibration to shake and break apart tumour cells "may have an even more significant impact in suppressing cancer metastasis by waking up the immune system".
"Our results show that while mechanical HIFU is not as effective as thermal HIFU in killing tumour cells directly, it has the potential to induce a stronger anti-tumour immune response," Dr Zhong said.
"These preliminary findings open up the possibility that we could use heat from HIFU to treat the primary tumour and HIFU-boosted immunotherapy for combating any residual and metastatic tumour cells."
The study is published in the Journal of Translational Medicine.