HONG KONG - Biomedical engineer Zhen Xu has spent a quarter of a century developing a non-invasive, ultrasound-based technique to treat tumor cells, in what is potentially a breakthrough treatment of cancer.
Xu co-invented the histotripsy technique, which can target and liquefy tumor cells while leaving surrounding tissue unharmed. Unlike conventional invasive cancer procedures, no incision is required.
HistoSonics, a start-up she co-founded in 2009, was named by Time magazine this year as one of the world's 10 most influential health and life science companies. In August, a consortium of investors valued the company at $2.25 billion after acquiring a majority stake. Xu herself received the Sony Women in Technology Award in Japan in February.
A China-born scientist now based in the United States, Xu is determined to be a role model, demonstrating how an Asian woman can succeed in the country's male-dominated industry while raising three children.
"It can be really frustrating when you don't see anybody like you in the field," said Xu in a recent interview with Kyodo News. "You don't know if it is even possible to get to a certain stage."
After graduating in China, Xu began her doctoral studies at the University of Michigan in 2001, focusing on medical applications of ultrasound beyond sonography, which is most commonly associated with monitoring fetal development.
It was at the university's ultrasound lab that the then doctoral candidate chanced upon one of her first practical challenges when she was approached by a child specialist who had to perform surgeries on babies with structural heart problems present at birth.
"Those kids were so sick, dying on the surgical table," she recalled.
Xu said she saw an opportunity to perform procedures using ultrasound technology instead, since physicians at the time had relied mainly on radiation or heating as the standard treatment, which might cause long-lasting side effects for patients.
Given the small population of congenital heart defect patients, Xu worked to explore the use of histotripsy in other diseases while trying to commercialize the technique, during which she took inspiration from a student of hers whose mother died of liver cancer when he was 3.
Xu herself was no stranger to cancer because both of her in-laws succumbed to the condition, making her husband her "biggest supporter and cheerleader" because he believed he faced a heightened risk of developing the disease himself.
"He said, 'I think I will get cancer. I just don't know which one I will get,'" Xu said.
The World Health Organization in 2024 projected that around a fifth of the world's population would develop cancer at some point in their lifetime, with a "rapidly growing" cancer burden coinciding with population ageing and growth worldwide.
Histotripsy for liver cancer received approval from the U.S. Food and Drug Administration in October 2023, followed by green lights from jurisdictions such as Britain, the United Arab Emirates and Hong Kong.
Earlier this month, HistoSonics applied to the U.S. health authorities for extending the use of the technique to kidney tumors following a trial involving 67 patients, which is the first attempt in authorized application beyond liver tumors.
Some 4,000 patients have received histotripsy treatment globally, of whom around three-fourths are from the United States, according to Xu.
Earlier in April, Hong Kong's Gleneagles Hospital used histotripsy on two pancreatic cancer patients, while clinical trials on tumors in the kidney, prostate and fat and muscle tissue are underway.
Its clinical application in Japan, however, is still awaiting approval, though Xu said she hopes to secure support from health officials "in the near future."
Sony Group Corp. has collaborated with HistoSonics, which aims to refine the histotripsy technique's imaging capabilities through the Japanese conglomerate's high-end 3-dimensional visualization tools.
Xu envisioned that the future of medicine would become less invasive and toxic, as "pretty much every 60 years, there is a technology breakthrough."
"In the 1900s, Marie Curie developed radiation therapy. In the 1960s, people invented optics, which you make small holes and operating through them," she said.
"It's another 60 years now. The future of medicine as a whole and cancer treatment will eventually become non-invasive and, hopefully, non-toxic," Xu added.
