Scientists have developed a tiny subdermal patch that monitors calcium levels in the bloodstream and creates a visible mole when cancer causes those levels to spike.

The concept is deceptively simple. Cancer causes calcium levels in the bloodstream to rise dramatically. The patch, implanted under the surface of the skin, merely releases melanin to create a small mole as soon as it detects levels high enough to indicate the presence of a developing tumor.

Swiss scientists of the ETH Zurich University in Switzerland claim that the patch already recognizes breast, colon, lung, and prostate cancers. Moreover, it does so even in the very early stages of development, giving potential victims a much higher chance of receiving successful treatment.

ETH Zurich Professor at the Department of Biosystems Science and Engineering Martin Fussenegger explains: “Nowadays, people generally go to the doctor only when the tumour begins to cause problems,” he said. “Unfortunately, by that point it is often too late.”

Since “early detection increases the chance of survival significantly,” the implant should represent hope more than dread. While “an implant carrier should see a doctor for further evaluation after the mole appears,” it is important to understand that this is a warning sign, not a death sentence. Fussenegger reminds that “the mole does not mean that the person is likely to die soon.”

According to experts, “1,688,780 new cancer cases and 600,920 cancer deaths” were projected to occur in the United States in 2017 alone. With something as simple as this calcium monitoring patch, those numbers could see a huge reduction. If the patch proves practical and effective, its implementation would mean another major step toward the eradication of one of humanity’s greatest plagues.