Liquid Biopsy

From Science Daily:

Cancer cells obtained from a blood test may be able to predict how early-stage lung cancer patients will fare, a team from the University of Michigan has shown.

This information could be used to determine which patients are most likely to benefit from additional therapies to head off the spread of the cancer to other areas of the body.

With a new single cell analysis service in U-M’s Comprehensive Cancer Center, the researchers are making the necessary technology more widely available in the university system. They hope these “liquid biopsies” will be offered to patients within the next five years.

Circulating tumor cells, representing only about one in a billion cells in the bloodstream, are largely untapped sources of information about tumors, but new methods are bringing their diagnostic value ever closer to patient care.

Sunitha Nagrath, U-M professor of chemical engineering who designs devices that can capture these rare cells, led a team including oncologists and surgeons to explore how cancer cells escape tumors and travel through the body in the bloodstream. This is how metastases, or satellite tumors elsewhere in the body, are thought to form.

“The tumors were constantly shedding cells even when they were small — that’s one thing we learned,” Nagrath said. “Although we define the tumors as early stage, already they are disseminating cells in the body.”

Early-stage lung cancer patients, whose tumors may only measure a few millimeters in diameter, are typically treated with surgical removal of the tumor, but the study results suggest that this may not be enough. A handful of patients had tumors that were shedding hundreds or thousands of tumor cells into the lung.

“Even though you removed the tumor, you left behind these hundreds and hundreds of cells,” Nagrath said. “If you know this patient walking out of the clinic is going to relapse after less than a year because of these cells, why don’t we treat them now?”

With a relatively small sample of 36 patients, the team can’t definitively say that an actively shedding tumor will lead to metastasis within a year, but Nagrath is exploring the predictive power of cancer cells drawn from the blood. In particular, the study showed that clusters of two or more tumor cells indicated shorter survival times. Six of the nine patients whose cancer returned during the two to 26 months of follow-up had circulating tumor cells appearing in clusters.

“Ultimately, this method will help us look for and find potential markers for either metastatic spread or cancer detection,” said Rishindra Reddy, U-M associate professor of surgery who coordinated the blood samples and designed the study with Nagrath and Nithya Ramnath, an associate professor of medical oncology at the U-M Medical School.

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