Gene-Based Blood Test for Melanoma Spread Evaluates Treatment Progress

  A test that monitors blood levels of DNA fragments released by dying tumor cells may serve as an accurate early indicator of treatment success in people in late stages of one of the most aggressive forms of skin cancer, a new study finds.

Led by NYU Grossman School of Medicine and Perlmutter Cancer Center researchers, the investigation looked at adults with undetectable levels of freely circulating tumor DNA (ctDNA) four weeks into drug treatment for metastatic melanoma tumors that cannot be removed surgically (unresectable). The study showed that these patients, all of whom had common genetic changes (BRAFV600 mutations) linked to cancer, were living nearly twice as long without cancer growth as those who continued to have detectable levels.

Normally, the study authors say, physicians would have to wait three months before an X-ray, CT scan, or other measures could reveal whether a tumor is growing or shrinking in response to treatment.

"Our findings suggest that levels of ctDNA may serve as a fast and reliable tool to gauge whether an anticancer medication is working," says study senior author David Polsky, MD, PhD. "The blood test results could help support continuing the current treatment strategy or else encourage patients and physicians to consider other options," adds Polsky, the Alfred W. Kopf, M.D. Professor of Dermatologic Oncology at NYU Langone Health and its Perlmutter Cancer Center.

Polsky notes that swift treatment modification could potentially be helpful in a disease as aggressive as melanoma, which kills nearly 7,000 Americans a year and is notoriously difficult to treat once it spreads to other body parts. Early feedback from a blood test might save lives, he says.

Researchers have long searched for better ways to monitor certain cancers using blood tests, or so-called biomarkers, which can be performed more easily, more often, and less expensively than imaging scans or surgical procedures and provide a clearer picture of tumor behavior over time. With melanoma, one frequently used option, a test for the presence in blood of an enzyme called lactate dehydrogenase (LDH), has had only limited success as such a tool, because non-cancer ailments such as liver injury and bone damage can also cause levels to spike. Although more specific biomarkers have been identified in cancers of the prostate, breast, and colon, the study investigators say a reliable signpost for melanoma has until now remained elusive.

According to Polsky, also a professor in the Department of Pathology at NYU Langone, early research by the same team had pointed to ctDNA as a promising candidate. This method works by targeting the most common mutations in the DNA code found in melanoma cells. This mutated DNA spills into surrounding blood as the cancer cells break down. In previous small studies, the blood test was shown to outperform LDH in predicting melanoma recurrence, as well as tracking progression of other forms of cancer.

The new investigation, publishing Feb. 12 in the journal The Lancet Oncology, was conducted over two years and is the largest analysis to date of the potential utility of this blood test for skin cancer, says Polsky.

https://www.biospace.com/article/releases/gene-based-blood-test-for-melanoma-spread-evaluates-treatment-progress/