Simple Blood Test To Reveal Cancer at Low Levels

The current tools for tracking cancer are not always sensitive enough to answer the most pressing question for doctors and patients: Is the cancer gone?

CBS News medical correspondent Dr. Jon LaPook reports that Harvard University medical researchers are developing a new test to make monitoring cancer in patients easier and more accurate. Those researchers have joined forces with health care giant Johnson & Johnson to bring the tests to the market.

Right now, Dr. Daniel Haber of the Massachusetts General Hospital Cancer Center says, "We're kind of shooting in the dark. We're treating patients based on what seems to work in our best guess."

Researchers believe a new test being developed at MGH Cancer Center - using just a teaspoon of blood - may be able to detect cancer before it shows up on scans.

Liquid Biopsy Blood Test: What It Would Mean

"it will give us a non-invasive, or a non-painful way of monitoring a cancer, following a cancer day to day, week to week, without having to do repeat biopsies," Haber said.

Cancers can shed cells that circulate in the bloodstream at extremely low levels, LaPook reports. This technology finds them by passing a blood sample through a microchip coated with antibodies that bind only to the cancer cells.

MGH Cancer Center's new test can recognize a single cancer cell among a billion normal ones.

"It would be most helpful for patients with prostate, bladder, colon, kidney and lung cancer, in addition to breast cancers," said Dr. Christopher Logothetis with the the University of Texas MD Anderson Cancer Center. "In many ways, it serves as a liquid biopsy."

In addition to detecting recurrences sooner, the test may allow doctors to examine the cancer cell itself and tailor therapies to a particular patient.

Four sites across the country are beginning to use the new test on patients. The research is supported by a $15 million grant from "stand up to cancer."

"If we only had a way to of measuring cancers as they are being treated, seeing how they respond relatively quickly and adjusting our treatment depending on how the treatment responds, then it would be a different day for treating cancer," Haber said.

If all goes well, the test is expected to become widely available in three to five years.

Although it is still in the early phase of testing, researchers hope this could eventually replace traditional tests like mammograms.

In addition to searching for the spread of cancer, the new tests will allow doctors to actually capture the cancer cell, study it, find the weak spots, and treat it accordingly.