Biopsy is the most common and painful way to diagnose cancer, where a piece of tissue or a sample of cells from a patient's body is removed so that it can be tested in a laboratory. But this pain could soon be a thing of the past. 

Scientists in the University of Michigan have developed a new wearable device that can capture live cancer cells directly from blood, saving millions of cancer patients from unnecessary pain.

"Nobody wants to have a biopsy. If we could get enough cancer cells from the blood, we could use them to learn about tumor biology and direct care for the patients. That's the excitement of why we're doing this," said Dr. Daniel F. Hayes, a professor of breast cancer research at the University of Michigan.

According to the research team, it's essential to measure cancer cells in the blood because those roving cells are most likely to spark new deadlier tumors. And as it is difficult for many cancer cells to  survive in the bloodstream, it is even more trickier to detect them.

Therefore, the gadget could help doctors to spot cancer in the blood and prevent biopsies. 

The new device, tested on animals, can capture 3.5 times more cancer circulating cells (CTC) than traditional blood tests and biopsies, enhancing accuracy and treatment efficiency.  

The watch-sized device, which measures 2×2.5×1 inches, is connected to a vein in an arm for capturing cancer cells. By applying an anticoagulant medicine, the device can function in a completely sterile environment while avoiding itself clogging up from the cells.

Hayes estimates the device could begin human trials in three to five years. It would be used to help optimize treatments for human cancers by enabling doctors to see if cancer cells are making the molecules that serve as targets for many newer cancer drugs.

"This is the epitome of precision medicine, which is so exciting in the field of oncology right now," he said.

Wearable health devices that are currently available in the market can only track vital health signs like blood pressure, heart rate, and blood sugar, but the advent of this new device could be a breakthrough in the field of cancer treatment worldwide.