Once treatment for melanoma is underway, doctors determine whether the disease is responding via a biopsy, a procedure that is often expensive, time-consuming and physically unpleasant.

Now a new study suggests that a comparatively no-fuss, pain-free urine test could someday replace the skin biopsy as a method for tracking the progression of malignant melanoma.

Using a laboratory technique known as fluorescence spectroscopy, Ivana Špaková, PhD, and colleagues, all of Pavol Jozef Šafárik University in Košice, Slovakia, analyzed urine samples from melanoma patients and healthy volunteers for differences in the concentration of several metabolic molecules. These molecules, which are produced as a consequence of cancer metastasis, include the endogenous fluorophores (fluorescent chemical compounds) FAD, NADH and lipofuscin. The research was published in the journal Open Chemistry.

Almost without exception, the researchers found, the melanoma patients’ urine contained significantly higher numbers of metastasis-associated metabolic molecules than that of healthy volunteers. In addition, patient records and genetic analysis showed that these numbers were proportionate to cancer stage and the expression of genes that spur tumor growth.

“Our results show that we can successfully use urine, a simply and noninvasively collected biological material, to determine the progression and treatment response of malignant melanoma," said Špaková in a press release. Because many patients “do not seek medical assistance as soon as possible” for fear of the pain and the price of the diagnostic biopsy, the researchers wrote, it is possible that malignant melanoma outcomes could improve should the urine test be widely adopted.

One of the most aggressive forms of skin cancer, malignant melanoma accounts for only about 1% of all skin cancers but causes the majority of skin cancer deaths, according to the American Cancer Society. To learn more about melanoma diagnosis, see “Harnessing Artificial Intelligence to Detect Melanoma Earlier.” Find out more about melanoma from the Melanoma Research Alliance blog. And to learn which states have the highest rates of melanomas, click here.