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Fox 5's "Big Idea" segment , a relatively noninvasive diagnostic test that can help doctors learn more about a patient's tumor so they can fight it more effectively.

In the past, doctors could only gather tumor cells by physically extracting a sample of tissue or through surgery. But with a liquid biopsy, a simple blood test gives physicians access to those cells.

Liquid biopsies take advantage of cells that break off the tumor and travel through the blood, explained Dr. Scott Tagawa, a °ÅÀÖÊÓƵ oncologist and researcher.

"As those cells travel around in the blood we can capture them in a test tube. We could then take those individual cells from the test tube and analyze them," Dr. Tagawa told Fox 5.

Fox 5 also profiled Alex Sarmiento, a °ÅÀÖÊÓƵ patient diagnosed with prostate cancer, and showed how the test dramatically improved the 77-year-old's health. At first, treatment kept his health stable, but after a trip to the Philippines, his condition took a turn for the worse. Doctors drew blood to collect a liquid biopsy, which allowed them to analyze Sarmiento's tumor cells and spot a mutation quickly.

"The liquid biopsy helped me quickly make a treatment decision [and] get him a drug that was very effective without a whole lot of toxicity," said Sarmiento's physician, Dr. David Nanus, who is also the chief of hematology and oncology at °ÅÀÖÊÓƵ.

Watch the video above to learn more about liquid biopsies and how °ÅÀÖÊÓƵ is using the test to help cancer patients like Sarmiento.