Researchers have identified a new blood test that can closely track metastatic melanoma. The test, which monitors the blood levels of DNA fragments from dead cancer cells, helps in tracking the severity and potential spread of the skin cancer.

“Our study results show that circulating tumour DNA is a superior blood test for evaluating and tracking progression of metastatic melanoma,” says Dr David Polsky, dermatologist at NYU Langone Medical Center, in New York.

Currently, a test that measures blood levels of an enzyme called lactate dehydrogenase (LDH) is done to guide management of the cancer. The new test looks at levels of circulating tumour DNA (ctDNA), released into the blood when tumour cells die. Thirty-one patients with inoperable metastatic melanoma were involved in the study. The study found that blood levels of ctDNA were elevated in 80% of patients about to undergo treatment for advanced melanoma. Blood levels of LDH were elevated in just 30% of such patients, the study showed. 

Also, the ctDNA blood test detected cancer recurrence – confirmed by x-ray or CT scan – in 85% of patients tested and undergoing treatment. The LDH blood test detected 54% of such cases, the researchers said.