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Scientists have been working on noninvasive solutions to measure tumor growth. Westend61/Getty Images
  • Current methods to measure cancerous tumors can have certain limitations.
  • A research team from Stanford University has developed a wearable device that measures size changes in tumors under the skin in mice.
  • Researchers believe their new technology can provide a new way to test potential cancer drugs, and that may eventually impact cancer treatment in the future.

Over the past few years, wearable health monitoring devices have become very mainstream. Although smartwatches that monitor your daily activity and heart rate are more commonplace, researchers have developed wearable devices that track glucose levels, breathing rates, and epileptic seizures.

Now, researchers from Stanford University have created a small wearable device capable of measuring size changes in cancerous tumors under the skin.

A study testing this new device via a mouse model was recently published in the journal Science Advances.

When cells in your body’s tissues divide and grow more than they should, a tumor may form. Not all tumors are cancerous. A noncancerous tumor is called a benign tumor and a cancerous tumor is called a malignant tumor.

During cancer diagnosis, a doctor will measure the size of the tumor. The doctor will then continue to measure tumor size during the course of cancer treatment to monitor whether the tumor grows or shrinks. Doctors also use tumor size to help determine what stage the cancer is in.

Traditionally, medical professionals use diagnostic imaging, such as x-rays, CT (computed tomography), or MRI (magnetic resonance imaging) scans to determine the size of a tumor inside the body. A doctor may also use a caliper to measure a tumor that is on top of or right below the skin.

Measuring tumor size is also central for the research of novel cancer treatments by assessing the efficacy of potential cancer therapeutics in animal models.

“Current methods for detecting tumor progression or regression, such as caliper or imaging-based measurements, require significant human intervention and also have limitations in their time- and length-scale dimensions,” Dr. Alex Abramson, first author of this study, assistant professor in the chemical and biomolecular engineering department at The Georgia Institute of Technology, and a recent post-doc in the lab of Zhenan Bao at the Stanford School of Engineering, explained to Medical News Today.

“Often these measurements only can be taken every few days, due to the labor and costs associated with the procedures,” he added.

Known as FAST — “Flexible Autonomous Sensor measuring Tumors” — the wearable device developed by Dr. Abramson and his team consists of a stretchy skin-like polymer membrane embedded with a layer of gold circuitry. The sensor adheres to the skin above where a cancerous tumor is currently located. The sensor also has a small electronic “backpack” holding its battery.

The device, however, only measures cancerous tumors and not those of benign origin.

As the tumor grows or shrinks, the sensor stretches or contracts along with it. The device measures how much strain the sensor experiences. Data transmits through a cell phone app, through which doctors can obtain both live and historical measurement data.

According to Dr. Abramson, the wearable sensor automates the entire process of measuring tumor volume regression, meaning a doctor could perform measurements continuously without any added cost or labor.

“It is the first tool to provide real-time analysis of tumor regression in vivo.”
— Dr. Alex Abramson

Additionally, Dr. Abramson said the device has a resolution of 10 micrometers. “That resolution is on the order of the size of a single cell,” he explained.

“This tool allows us to detect the response of a tumor to a given drug within a few hours following treatment initiation. We hope that it will allow us to better understand the short-term effects of drugs on tumors and allow scientists and healthcare professionals an easier method to screen drugs that could become therapies in the future,” he told MNT.

As researchers used a mouse model for this study, Dr. Abramson said the team is still working on bringing the new device into the clinical setting. Until then, he said researchers can build the device themselves using the instructions in their study.

“The sensor currently costs about $60 to fabricate on an individual basis, although mass manufacturing would bring the costs down significantly,” he added. “It costs a few cents per day to run.”

For the next steps on this device, Dr. Abramson stated they plan to test the device on more cancer models.

“This will help us to understand the relationship between the tumor’s short-term and long-term responses to a drug. Eventually, this understanding will help us choose the optimal therapy regimens and doses for a given tumor type,” ehe said.

MNT also spoke with Dr. Anton Bilchik, surgical oncologist and division chair of general surgery at Providence Saint John’s Health Center and chief of general surgery at Saint John’s Cancer Institute in Santa Monica, CA, about this new wearable device. He said the study was “very intriguing” as it is extremely important to develop new techniques and technology to evaluate tumor response.

“This is a noninvasive piece of equipment that may be able to evaluate response to treatment without requiring a blood draw or without requiring additional scanning. The major issue with it is that it’s very much investigational. The studies have been performed in a mouse model. So, I think all we can say at this point is that it’s very intriguing and certainly relevant to what we deal with every day, which is to evaluate tumor growth and response to therapy,” he said.

Dr. Richard Reitherman, medical director of breast imaging at MemorialCare Breast Center at Orange Coast Medical Center in Fountain Valley, CA, also found this study thought-provoking as the wearable device can monitor the different parameters it measures and the results demonstrated a correlation with the final pathological findings.

“That’s called concordance in medicine,” he detailed. “In other words, X agrees with Y. So, the measurements agreed with the final pathology and pathology is the final arbiter of how big tumors are and how much they’ve responded to the chemotherapy.”

For the next steps in this type of research, Dr. Bilchik stressed the need for additional studies on this type of technology.

“This is very much preliminary — more studies needed to be done in animals. And then clearly the million-dollar question is will these mouse model studies translate to humans? So often studies are successful in mouse models and turned out to be less successful in humans, so human clinical trials would be the next step.”
— Dr. Richard Reitherman