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UC Davis Comprehensive Cancer Center

UC Davis Comprehensive Cancer Center

Rachel Pollard: A fascinating new way to treat cancer

Rachel Pollard
Rachel Pollard

Some of the most promising cancer research of our time involves treating cancer by cutting off the blood supply to solid tumors. Inhibiting the growth of new blood vessels, a process called angiogenesis, in tumors was shown to be effective in animal models and has begun to show promise in ongoing human clinical trials. However, scientists know little about how these antiangiogenic compounds really work in humans and do not have a good way of measuring their effectiveness.

That’s where UC Davis researcher Rachel Pollard comes in. Pollard is a radiologist and assistant professor at the UC Davis School of Veterinary Medicine. She is developing ways of measuring blood volumes in tumors using non-invasive imaging methods.

“We want to be able to measure blood flow to a tumor before and after treatment with an antiangiogenic compound,” Pollard said. “This technology has the potential to determine if these treatments are working much sooner than the watch-and-wait approach clinical researchers are using now.”

Pollard uses a host of imaging technology, including CT, MRI and ultrasound in her work.

“These imaging modalities have been around for a long time and give good anatomic information as they stand,” she said. However, to be useful to researchers interested in the effectiveness of antiangiogenic drugs, they must also provide information on the function of the tissues of interest — in this case, tumors. “It’s the difference between a snapshot and a video,” she explained.

Novel contrasting agents

Measuring blood flow in tumors requires Pollard to experiment with novel contrast agents, compounds used to improve the visibility structures in a diagnostic image. She must also compare different imaging methods to determine which will be better for measuring blood flow. In all cases, complicated mathematical procedures are applied to a series of images taken in the same location over time, giving measurements of blood flow.

Once fully tested, Pollard hopes these methods will allow scientists to determine whether antiangiogenic compounds are working in humans, in general. Ultimately, she hopes these imaging techniques will also allow physicians to test whether such treatments are working in individual cancer patients.

Pollard first tests her methods in laboratory animals. As a veterinarian, she also has the option of using these methods to treat pets, like a dog with a brain tumor, for example. This intermediate step allows for a more realistic application of the techniques.

“We’re in a unique position on this campus to move the medical science forward while helping save people’s pets at the same time,” she said.

Pollard attended the University of Washington in Seattle for her undergraduate work and Washington State University for her Doctorate of Veterinary Medicine. At UC Davis, Pollard completed a four-year residency in diagnostic imaging, later earning her Ph.D. in comparative pathology. She has held her current position since April 2005.

Cancer discovery as a team effort

Pollard spends much of her spare time in Lake Tahoe, where her husband owns a ski shop. She also goes backcountry backpacking once a year with a two of her best friends.

“One thing that you learn when you’re in the backcountry is that all you have to rely on is yourself and your companions,” Pollard said. Likewise, advancing the science of cancer treatment is a team effort. “In research, you have to have good collaborators that you can trust,” she added.

Pollard also believes that taking new approaches to how cancer is treated is essential for improving survival rates and quality of life for cancer survivors.

“Antiangiogenic agents are a fascinating new way to treat cancer,” she said. “As a radiologist, if I can understand how they really work, then I feel like I’ve made a contribution.”

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