Histotripsy stimulates the immune system to attack cancer cells outside the liver

After FDA approval in late 2023, the non-invasive liver tumor treatment histotripsy has been used at University of Michigan Health since early 2024.

As the use of histotripsy expands across the state of Michigan and to surrounding states, U-M researchers are continuously observing the body’s immune response to histotripsy treatment.

Anutosh Ganguly, Ph.D., an assistant research scientist at University of Michigan Health, led a team of researchers looking to extend beyond the characterization of immune responses following liver cancer treatment, in hopes of expanding the understanding of how histotripsy could impact other tumor types such as those found in pancreatic cancers and melanoma.

The technology, pioneered by biomedical engineers at U-M, uses ultrasound waves to destroy tumors within the liver without the major side effects experienced in other forms of cancer treatment such as chemotherapy and radiation.

The paper is published in the journal Molecular Cancer Therapeutics.

The data collected by Ganguly and the team showed that immunomodulatory effects of histotripsy are most likely triggered by a reduction of tumor hypoxia, also known as very low oxygen levels within the tumor. These low oxygen levels are no longer present after histotripsy treatment.

“The relief from hypoxia after histotripsy treatment facilitates a rise in anti-tumor CD8⁺ T cells that move to the site of the procedure but also to the distant tumors within other parts of the body to oppose their growth,” said Ganguly. “So, in addition to physically destroying tumor cells, histotripsy stimulates the patient’s own immune system to fight cancer more effectively throughout the body.”

Understanding that histotripsy treatment can alter how the body reacts to cancer cells located outside the liver gives better insight into how metastases in other areas of the body may respond to direct histotripsy treatment.

“The additional effect of activating the patient’s own immune system against cancer cells by histotripsy can help the patient’s body respond better to other types of cancer treatment they may be receiving in addition to the histotripsy such as radiation and chemotherapy,” Ganguly added.

“Our work to continue understanding the ways that histotripsy impacts the whole body can open doors for new and potentially more effective ways to treat cancer that have fewer patient side effects.”

Ganguly and his team plan to continue their study to gather further data on how histotripsy treatment impacts cancer cells within the entire body and the immune system of the patient, and what additional therapies can enhance the results of histotripsy treatment.