The University of Michigan may have invented a new treatment that could improve the outcomes of cancer and neurological conditions; histotripsy, a noninvasive sound technology, focuses on ultrasound waves to destroy designated tissue with precision. This technique is currently used in Europe and the United States as a liver cancer trial.
Professor of biomedical engineering at the University of Michigan Zhen Xu created this research study. The engineering department at this University stated that “She [Xu] is one of the original inventors of histotripsy, a process that uses focused ultrasound to mechanically disrupt target tissue, as opposed to thermal ablation–or heating–of tissue.” The primary focus of Xu’s research is to use histotripsy to fight against cancer cells, including an eventual regression of the disease. Recently, the research group has continued their study to analyze the effects of histotripsy treatment for immunotherapy and brain cancer.
“Histotripsy is the first image-guided technique using focused ultrasound to destroy tissue noninvasively, without heating and without the use of ionizing radiation. It works by mechanically liquefying the target cancer tissue and demonstrates the potential to increase accuracy and reduce off-target damage for cancer treatment compared to radiation or thermal-based approaches,” Xu explained.
According to SciTechDaily, the University of Michigan used this treatment to break down liver tumors in rats, kill cancer cells and prevent the further spreading of disease. After this method dismantled 50% to 75% of the tumor volume, “the rats’ immune systems were able to clear away the rest, with no evidence of recurrence or metastases in more than 80% of the animals.” These results indicate that histotripsy stimulated the rats’ immune responses, contributing to the deterioration of tumors and the prevention of cancer spreading.
Standard ultrasounds produce images of the body’s interior, but the engineers of the University of Michigan have utilized this technique for treatment. “Our transducer, designed and built at U-M, delivers high amplitude microsecond length ultrasound pulses–acoustic cavitation–to focus on the tumor specifically to break it up. Traditional ultrasound devices use lower amplitude pulses for imaging,” Xu said.
The pulse from the transducer creates microbubbles within the targeted tissue. These microbubbles cause rapid expansion and collapse, creating mechanical stresses to separate the tumor’s structure.
Currently, in clinical situations, the entire cancerous tumor cannot be targeted due to its location, size or stage. To combat these issues, this study only focused on demolishing a portion of the mass. This strategy allowed the research team to show the treatment’s effectiveness in less-than-ideal conditions.
Doctoral student in biomedical engineering Tejaswi Worlikar described the potential benefits of this technology. “Histotripsy is a promising option that can overcome the limitations of currently available ablation modalities and provide safe and effective noninvasive liver tumor ablation. We hope that our learnings from this study will motivate future preclinical and clinical histotripsy investigations toward the ultimate goal of clinical adoption of histotripsy treatment for liver cancer patients,” Worlikar said.
Liver cancer continues to rank among the top 10 causes of cancer-related deaths in the United States. Although there are multiple treatment options, the survival rate for this diagnosis is less than 18%. Histotripsy could offer a technique that works without harmful side effects, like those involved with radiation and chemotherapy.
If histotripsy continues to be successful in clinical trials, this treatment could improve the outcomes of those with cancer or neurological conditions.
