Lone Star Mom: Histotripsy Clinical Cancer Trial

In 2014, Heather Hayenga, then 29, learned she had a rare type of tumor called a hemangiopericytoma, also known as a solitary fibrous tumor, located in her brain at the base of her skull. Treatment involved radiation therapy and surgery to remove it, all performed at a hospital near her home in Dallas. But in time, the cancer metastasized and tumors began popping up in other parts of her body, including her spinal canal, lungs and liver. 

Heather is an associate professor of bioengineering at the University of Texas in Dallas, a career that gives her useful insights into her cancer and treatment.

“I’m a researcher, so I look up medical doctors who have published in the cancer field,” she said.

Heather was reading about treatment options when she found research by Sarah White, MD, MS, a vascular and interventional radiologist and Medical College of Wisconsin faculty member. At Froedtert Hospital, the academic medical center of the Froedtert & MCW health network, Dr. White specializes in ablation, treatments that typically use heat to destroy liver tumors without removing them surgically. 

The Benefits of an Academic Medical Center

Heather contacted Dr. White, who was happy to share what she knew about emerging treatments for these tumors. Because the Froedtert & the MCW Cancer Network is anchored by an academic medical center, its physicians are especially knowledgeable about treatment advances and often conduct clinical research to test new therapies before they are widely available.

“It’s really helpful to have her guidance,” Heather said. “Dr. White goes above and beyond to help me figure out the best ways to treat the cancer, even if it’s with other doctors.” 

In 2021, Dr. White shared some good news. She and her colleague, Amanda Smolock, MD, PhD, vascular and interventional radiologist and MCW faculty member, were involved in a national clinical trial studying histotripsy, a new way to treat liver tumors. Heather was eligible for treatment with Dr. Smolock, who is part of a multidisciplinary specialty team within the Cancer Network’s Liver and Pancreatic Cancer Program. At the time, Heather had about 10 tiny tumors in her liver, and three of the tumors could be treated with histotripsy. 

What is Histotripsy?

“Histotripsy is a new, noninvasive treatment that uses focused ultrasound to mechanically destroy tissue,” Dr. Smolock said. “The ultrasound is applied by transducers placed on the patient’s abdomen, so there are no incisions, no needle sticks and no punctures. This may mean that patients experience less pain and recover faster than they do from other forms of ablation, although more research is needed to confirm this.” 

The focused ultrasound acts on gases found in human tissue, generating miniscule “bubble clouds” that rapidly form and collapse. The mechanical pressure created by the bubble clouds is strong enough to break apart tissue cells. This allows for very precise damage, destroying the tumor cells but sparing other nearby tissue. And ultrasound imaging allows the medical team to watch the tumor closely as it is destroyed.    

The Froedtert & MCW Clinical Cancer Center at Froedtert Hospital is one of only two Wisconsin sites where histotripsy is available. This trial includes patients with primary and metastatic liver tumors of all types.

Heather’s Experience

Because she lives in Texas, Heather’s first appointments with Dr. Smolock were held virtually. But in October 2021, Heather flew to Milwaukee to receive histotripsy treatment at Froedtert Hospital. One benefit of the Cancer Network is that a high number of patients are treated for primary and metastatic liver cancer. This is good news for patients like Heather because studies show that patients do better at centers that see many patients with a particular disease.

When she woke up after the histotripsy procedure, Heather said she felt great. She was happy when Dr. Smolock revealed the treatment dissolved all three tumors. She was observed overnight at the hospital and returned home to Texas the next day. Her medical team there performs regular diagnostic scans, which are sent to Dr. Smolock and Dr. White to review. 

Because Heather is a clinical trial participant, Dr. Smolock will follow her for the next five years.  As the technology evolves, Heather hopes to someday have histotripsy on the remaining tumors in her liver. 

Heather has received cancer treatment at multiple medical centers and is especially impressed by the team at Froedtert Hospital.

“Dr. Smolock has spent so many hours looking over my scans and really studying them,” she said. When Heather had questions about histotripsy, Dr. Smolock researched the answers with care.

“That’s what is so phenomenal about the Froedtert & MCW Cancer Network,” Heather said. “Not only are the physicians caring and able to treat you medically, but also, they are doing research, so they’re able to support their approaches scientifically. They are doing the latest, greatest things.”