Smart Watches Long Ago Earned Their Keep on Heart Rates; Now May Even Help to Save Limbs of Cancer Patients

In the medical world, “Smart” watches have earned their name honestly through their ability to detect and evaluate an impressive list of problems.

As early as 2014, researchers at Harvard’s T.H. Chan School of Public Health and Yale’s School of Medicine were beginning to investigate using these watches to monitor cardiac arrhythmias. In the last three years, Harvard researchers have turned to using the watches to track reproductive cycles. At the same time, Mt Sinai’s elegantly named Warrior Watch Study found that subtle changes in a person’s heart rate measured by an Apple Watch were able to catch a COVID infection up to seven days before actual diagnosis via nasal swab. Late last year, an international team of surgeons from the University of British Columbia in Vancouver, Iran’s Tehran University and Torbat Heydariyeh University of Medical Sciences, toted up 761 studies including six on stress monitoring, six on movement disorders, three on sleep tracking, three on blood pressure, two on heart disease, six on covid pandemic, plus an additional nine to measure how safe and accurate the devices were.

Now the experts at Ohio State’s James Cancer Hospital in Columbus are going an important stop farther with Project Limb Rescue, a clinical trial designed to find out if smart watches can also be employed to help save a cancer survivor’s limbs.

Lymph nodes are small vessels that allow fluid to move through your body’s tissues. During cancer surgery, surgeons may remove lymph nodes adjacent to the tumor to see if the cancer has spread. The more lymph nodes they take out, the more likely it is that fluid will build up in that area, eventually causing lymphedema, a painful swelling of the affected area. When found, most commonly in arms and legs, the swelling is reduced with exercise, compression garments, massage and pumps that manually stimulate movement of fluid away from the affected area. This therapy is effective, but it’s also a continuing and lengthy procedure that can diminish the quality of life and might, in extreme cases, fail to prevent the loss of the affected limb.

As Carlo Contreras, the surgical oncologist who’s leading the Ohio trial explains, right now, doctors can detect early lymphedema only by examining a patient in person at a medical facility. His team proposes to recruit up to 35 men and women of ages 19-90 who have lymphedema in one arm and substitute a custom smartwatch developed with the help of the University’s engineering students. Each watch will come with adhesive-based sensors that use photoplethysmography (PPG) and bioimpedance (BI), two multi-syllable methods to detect blood-volume changes in tissue.

The first is an optical technique; the second evaluates how tissue responds to an externally applied electrical current. Taken together, this combination provides clues that can help doctors detect rising fluid retention indicative of early lymphedema, allowing them to catch a problem before it’s a problem.

Clearly, the wearable device, measuring changes in real-time, could be a game changer. “We may be able to take steps to avoid lymphedema altogether or slow down the pace at which it accumulates over time, and that is so important for our cancer survivors’ quality of life,” says Ohio State oncology clinical nurse specialist nurse Lynne Brophy.