DNA Detector May Help Predict Recurrence in Women With Metastatic Breast Cancer

A new experimental blood test may be able to help better guide clinicians who are managing women with metastatic breast cancer (MBC). Researchers at Johns Hopkins Kimmel Cancer Center have been studying the ability of a novel panel of cell-free DNA methylation markers to predict survival in women with MBC. They evaluated a quantitative multiplex assay (cMethDNA) and found it could be used to help predict survival outcomes in MBC and may have clinical usefulness in risk stratification and disease monitoring.

This study was published in the November 2016 issue of Journal of Clinical Oncology.  

“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,” said Kala Visvanathan, MD, MHS, who is a professor of epidemiology at the Johns Hopkins Bloomberg School of Public Health and a professor of oncology at the Johns Hopkins University School of Medicine in Baltimore.

Hypermethylation often silences genes that keep runaway cell growth in check. 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 worsened. The researchers tested in duplicate serum samples on 10 genes from 141 women with MBC at baseline, at week 4, and at first restaging (usually after 12 weeks).

They looked at progression-free survival (PFS) and overall survival (OS) and used statistical models to evaluate the distribution of cancer-linked DNA in the patients’ blood samples over the 7-year study to find the largest degree of differences between patients with low and high levels of evidence of hypermethylation in their DNA. 

Among 128 of the 141 patients, the scientists found that the median PFS of 71 patients identified with high levels of cancer DNA in their blood was 2.1 months, compared with 5.8 months for 57 patients with low levels. In 129 patients, median (OS) 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. Median follow-up of the women in the study was 19.5 months (range 0.8–86.3 months).

The study showed that this test may be valuable very early on in the course of the disease. Dr. Visvanathan said the current study did not look at the test’s benefits with regard to specific anticancer therapies. Currently, the researchers are also looking at the test in women with earlier stage breast cancer.