Machines with rotating blades used to slice and dice tissue inside the body have been deemed too dangerous to use on patients, because it turns out they may be increasing the risk, spread, and speed of cancer development. Johnson & Johnson announced on Wednesday the company was recalling its power morcellators, a surgical tool that is capable of spreading cancer in women, and urging doctors to stop using it.

The sale of Johnson & Johnson’s devices used to perform hysterectomies and fibroid-removal surgery, known as laparoscopic power morcellators, were halted after the Food and Drug Administration (FDA) issued a warning in April. Two recent studies from the FDA and researchers from Columbia University found that roughly one in 350 women had cancer when treated for fibroids. Women who underwent minimally-invasive hysterectomies had a risk of one in 368. If doctors were aware of the cancer, they wouldn’t have used morcellation as a treatment approach.

Gynecologists use power morcellators when they perform procedures such as a hysterectomy or a myomectomy. Morcellators are tiny devices with rotating blades that break large tissue masses into small fragments that are then vacuumed out of the body. This allows surgeons to only have to make incisions less than 2 centimeters in size, instead of performing a major surgery.

Hysterectomies are surgical operations performed to remove all or part of the uterus. If there are any cancerous cells in the tissue that’s broken up and it isn’t 100 percent removed during vaccumming, the cancerous cells can spread to other areas.

Recent cases suggest morcellation can spray pieces of the tumor around and actually worsen the cancer, and in a few cases, it actually sped up the spread of cancer faster than the patient undergoing abdominal surgery to remove the uterus. In the study group, several hundred women also had precancerous conditions when they underwent power morcellation.

“You don’t even have to be a doctor to recognize that if tissue or a tumor has malignant potential, you should not mince it up inside someone’s body,” Dr. Hooman Noorchashm, a Harvard-based cardiothoracic surgeon, told The Washington Post. “That’s just bad medicine.”

Johnson & Johnson’s decision to pull back the device and urge those who have purchased it to return it makes a large impact on the industry, considering they represent 72 percent of the market for the morcellation device.

"Due to this continued uncertainty, Ethicon believes that a market withdrawal of Ethicon morcellation devices is the appropriate course of action at this time until further medical guidelines are established and/or new technologies are developed to mitigate the risk," a spokesman from Johnson & Johnson said in an email to Reuters.

The morcellation device is not the only way to treat women with minimally-invasive hysterectomies. In fact, it was only used in 16 percent of the procedures, which means there are other options, including removing the uterus through the vaginal canal.