Tumors partially destroyed with sound don't come back

Date:
April 18, 2022
Source:
University of Michigan
Summary:
Noninvasive sound technology breaks down liver tumors in rats, kills
cancer cells and spurs the immune system to prevent further spread
-- an advance that could lead to improved cancer outcomes in humans.



FULL STORY ========================================================================== Noninvasive sound technology developed at the University of Michigan
breaks down liver tumors in rats, kills cancer cells and spurs the
immune system to prevent further spread -- an advance that could lead
to improved cancer outcomes in humans.


==========================================================================
By destroying only 50% to 75% of liver tumor volume, the rats' immune
systems were able to clear away the rest, with no evidence of recurrence
or metastases in more than 80% animals.

"Even if we don't target the entire tumor, we can still cause the tumor
to regress and also reduce the risk of future metastasis," said Zhen Xu, professor of biomedical engineering at U-M and corresponding author of
the study in Cancers.

Results also showed the treatment stimulated the rats' immune responses, possibly contributing to the eventual regression of the untargeted
portion of the tumor and preventing further spread of the cancer.

The treatment, called histotripsy, noninvasively focuses ultrasound waves
to mechanically destroy target tissue with millimeter precision. The
relatively new technique is currently being used in a human liver cancer
trial in the United States and Europe.

In many clinical situations, the entirety of a cancerous tumor cannot be targeted directly in treatments for reasons that include the mass' size, location or stage. To investigate the effects of partially destroying
tumors with sound, this latest study targeted only a portion of each
mass, leaving behind a viable intact tumor. It also allowed the team,
including researchers at Michigan Medicine and the Ann Arbor VA Hospital,
to show the approach's effectiveness under less than optimal conditions.



========================================================================== "Histotripsy is a promising option that can overcome the limitations of currently available ablation modalities and provide safe and effective noninvasive liver tumor ablation," said Tejaswi Worlikar, a doctoral
student in biomedical engineering. "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." Liver cancer ranks
among the top 10 causes of cancer related deaths worldwide and in
the U.S. Even with multiple treatment options, the prognosis remains
poor with five-year survival rates less than 18% in the U.S. The high prevalence of tumor recurrence and metastasis after initial treatment highlights the clinical need for improving outcomes of liver cancer.

Where a typical ultrasound uses sound waves to produce images of the
body's interior, U-M engineers have pioneered the use of those waves
for treatment.

And their technique works without the harmful side effects of current approaches such as radiation and chemotherapy.

"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," Xu said. "Traditional ultrasound devices use lower amplitude pulses for imaging." The microsecond long
pulses from UM's transducer generate microbubbles within the targeted
tissues -- bubbles that rapidly expand and collapse. These violent but extremely localized mechanical stresses kill cancer cells and break up
the tumor's structure.

Since 2001, Xu's laboratory at U-M has pioneered the use of histotripsy
in the fight against cancer, leading to the clinical trial #HOPE4LIVER sponsored by HistoSonics, a U-M spinoff company. More recently, the
group's research has produced promising results on histotripsy treatment
of brain therapy and immunotherapy.

The study was supported by grants from the National Institutes of Health, Focused Ultrasound Foundation, VA Merit Review, U-M's Forbes Institute
for Discovery and Michigan Medicine-Peking University Health Sciences
Center Joint Institute for Translational and Clinical Research.


========================================================================== Story Source: Materials provided by University_of_Michigan. Note:
Content may be edited for style and length.


========================================================================== Journal Reference:
1. Tejaswi Worlikar, Man Zhang, Anutosh Ganguly, Timothy L. Hall,
Jiaqi Shi,
Lili Zhao, Fred T. Lee, Mishal Mendiratta-Lala, Clifford S. Cho,
Zhen Xu.

Impact of Histotripsy on Development of Intrahepatic Metastases
in a Rodent Liver Tumor Model. Cancers, 2022; 14 (7): 1612 DOI:
10.3390/ cancers14071612 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/04/220418093955.htm

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