MIT scientists have developed a tiny implantable sensor that can be used to track the progress of cancer therapy.

The device, detailed in the journal Lab on a Chip, could provide a new tool for doctors to monitor how well a patient’s cancer treatment is working, and make changes midstream to enhance its effectiveness, Medical News Today reports.

One of the device’s developers, Michael Cima, a professor in engineering at the Massachusetts Institute of Technology’s Koch Institute for Integrative Cancer Research, noted doctors now must rely on biopsies, MRIs, and other imaging technologies to monitor a cancer's response to treatment.

"We wanted to make a device that would give us a chemical signal about what's happening in the tumor,” he explained. “Rather than waiting months to see if the tumor is shrinking, you could get an early read to see if you're moving in the right direction."

The biosensor — which fits into the tip of a biopsy needle — works by monitoring two biomarkers: pH (a measure of acidity) and dissolved oxygen that indicate how well a tumor is responding to treatment. When chemotherapy begins to take effect, for instance, the tumor tissue becomes more acidic.

"Many times, you can see the response chemically before you see a tumor actually shrink," Cima said.

Tests of the device performed on laboratory rats showed the sensors could quickly detect accurate and reliable signals about pH and oxygen concentration in tissue.

"There are thousands of people alive today, because they have implantable electronics, like pacemakers and defibrillators," Cima noted. "We're making these sensors out of materials that are in these kinds of long-term implants, and given that they're so small, I don't think there will be a problem."