You're probably familiar with traditional biopsies -- a tissue sample taken from a patient for analysis of a tumor. But you may not have heard of liquid biopsies, which are noninvasive and may have the potential to become the standard of care for evaluating patients and guiding cancer treatments.

"A liquid biopsy is essentially a simple blood draw, which is much easier on patients than tissue biopsies," Michael Cher, M.D., chair of the Wayne State University School of Medicine Department of Urology and chief of Urology for the Barbara Ann Karmanos Cancer Center. "Cancer cells or fragments of cancer cells may be present in a patient's bloodstream. Liquid biopsies are a technique for finding tiny numbers of circulating tumor cells, which hide like a needle in a haystack. We have techniques for isolating CTCs so we can count them and perform a genetic analysis."

Doctors examine CTCs for genetic changes or expressions of certain proteins that can promote cancer. These data can help doctors select certain cancer-fighting drugs for treatment or help determine the patient's prognosis. A liquid biopsy can be performed with any type of cancer, but the information provided has limitations, Dr. Cher said.

"Because the tumor cells can be difficult to find in a liquid biopsy, they are usually performed on patients with disease that has spread rather than for early diagnosis or small tumors," he said. "Tumors also evolve genetically over time, especially in response to treatment. An advantage of liquid biopsies is the ability to obtain serial samples over extended periods of time. These samples can be analyzed to detect changes in order to adapt treatment plans."

Liquid biopsies are reasonably accurate, but the genetic changes found in tumor cells in the bloodstream may not completely match those found in the tumor tissue.

"In many cases, there is high degree of overlap but still with some differences. That makes it challenging to find the perfect drug for treatment," Dr. Cher said.

He is collaborating with other WSU and Karmanos researchers on a clinical trial involving patients with prostate cancer that has spread to their bones. Each patient provides a bone and liquid biopsy. The researchers examine the similarities and differences between the samples. That data will help further refine cancer treatments for future prostate cancer patients.

"Studies like ours are paving the way for more personalized selection of cancer-fighting medications," Dr. Cher said. "We're very grateful to our patients for helping to advance cancer treatments. Liquid biopsies have the potential to allow less invasive analysis of a patient's cancer status. In some cases, depending on the tumor type, a liquid biopsy could become the standard of care."

For more information about a cancer diagnosis or treatment, call 1-800-KARMANOS (1-800-527-6266) or visit karmanos.org.