Doctors are now able to better identify breast cancers at higher risk for recurrence and track the success or failure of treatment – via asimple blood test. This is thanks to the discovery of a new biomarker, called cMethDNA, discovered in the blood of women with advanced breast cancer by scientists at the Johns Hopkins Kimmel Cancer Center.

“There’s a great need in cancer patients to be able to quickly and easily assess if a particular treatment is working in order to switch to another if it’s not, thus avoiding wasted time, potential side effects and cost,” says Kala Visvanathan, MD, MHS, professor of epidemiology at the Johns Hopkins Bloomberg School of Public Health. “Our study results, although preliminary, suggest that cMethDNA has the potential to be an effective way to do this for breast cancer patients.”

The researchers made their discovery after analyzing the blood collected from 141 women with advanced breast cancer. They collected the samples at the start of therapy, four weeks later and when the women’s cancers were “re-staged,” which was usually after 12 weeks.

What's the science? The marker, found in the blood serum, suppressesgenes that keep runaway cell growth in check, and its appearance in the DNA code of breast cancer-related genes shed into the blood may indicate that a patient’s cancer growth is increasing and the disease has gotten worse.

Among 128 of the 141 patients, the researchers found that the median progression-free survival of 71 patients identified with high levels of the marker in their blood was 2.1 months, compared with 5.8 months for 57 patients with low levels. In 129 patients, median overall survival for 62 patients identified with high levels of cancer DNA in their blood was 12.3 months, compared with 21.7 for 67 patients with low levels.

“What we see is an association between shorter periods of progression-free survival and overall survival in patients whose blood has higher levels of hypermethylated DNA, and we can see this very early on, after just four weeks of treatment,” says Sara Sukumar, PhD, professor of oncology at the Johns Hopkins University School of Medicine and member of the Kimmel Cancer Center, who developed the test with Johns Hopkins scientist Mary Jo Fackler, PhD, and others.

Next steps? More research to determine the blood test’s predictive ability among women with earlier-stage disease is already underway.

The study was published in Clinical Oncology.