New research published in the journal Cancer Discovery suggests a simple blood test may be effective in early detection of skin cancer relapse in patients with advanced melanoma.

A new study from the Cancer Research UK Manchester Institute collected blood samples from seven patients at The Christie NHS Foundation Trust with advanced melanoma and examined the DNA tumors shed into the bloodstream, known as circulating tumor DNA. Researchers found that by tracking levels of circulating tumor DNA, they could see when new genes appeared, indicating a relapse. When this happened, there was a good chance the tumor had become resistant to treatment.

Skin cancer is the most common cancer in the U.S., with 68,000 people being diagnosed in 2012, according to the Centers for Disease Control and Prevention. While most melanoma patients respond well to treatment initially, the cancer can become resistant within a year. Researchers from the Cancer Research UK Manchester Institute hope their approach will allow doctors to use the DNA shed by tumors into the bloodstream to tailor treatment for individual patients.

"Being able to spot the first signs of relapse, so we can rapidly decide the best treatment strategy, is an important area for research,” lead author Professor Richard Marais said in a statement. “Using our technique we hope that one day we will be able to spot when a patient's disease is coming back at the earliest point and start treatment against this much sooner, hopefully giving patients more time with their loved ones.”

According to the study, about 40 to 50 percent of melanoma patients have a faulty BRAF gene. For many of these patients, melanoma treatments like vemurafenib or dabrafenib don’t work or, if they do, the tumors develop resistance after a relatively short time. When this happens, patients are typically offered immunotherapy drugs including pembrolizumab, nivolumab, and ipilimumab. The new findings could make it possible for doctors to detect this resistance early, improving patient care and chance of survival.

“Being able to track cancers in real time as they evolve following treatment has huge potential for the way we monitor cancers and intervene to stop them growing back,” said Professor Peter Johnson, Cancer Research UK's chief clinician. “There's still some time until we see this in the clinic but we hope that in the future, blood tests like these will help us to stay one step ahead in treating cancer."

Marais said more research is needed to test the efficacy of this technique before it reaches melanoma patients in clinics.

Source: Girotti M, Marais R, Gremel G, et al. Application of Sequencing, Liquid Biopsies and Patient-Derived Xenografts for Personalised Medicine in Melanoma. Cancer Discovery. 2016.