Last month the U.S. Food and Drug Administration (FDA) reaffirmed its warning concerning power morcellators used in gynecological surgery.

The spinning blades on morcellators bring with them the risk of spreading cancerous tissue within the abdomen, particularly in women with unsuspected uterine sarcoma.

As part of its warning, the FDA states there is “no reliable method for predicting or testing whether a woman with fibroids may have a uterine sarcoma.” There are, however, signs and symptoms to look for, such as:

The FDA estimated in its warning that “approximately 1 in 350 women undergoing hysterectomy or myomectomy for the treatment of fibroids is found to have an unsuspected uterine sarcoma.”

Women who are nearing or have reached menopause are particularly warned against undergoing laparoscopic surgery, as is any woman who requires a full hysterectomy. The risk involved with morcellation is too high when it comes to a patient’s survival.

Dr. Amy Reed became a patient advocate after morcellation spread leiomyosarcoma in her abdomen in 2013. Dr. Reed started the Slay Sarcoma Research Initiative with her husband, cardiac surgeon Hooman Noorchashm, after a post-surgery biopsy found a uterine sarcoma hidden in the fibroids, and the tumor had spread due to morcellation. Sadly, Dr. Reed passed away last year, but her campaign has resulted in declining morcellator use.

Though some gynecologists recommend morcellating tissue that’s first been enclosed inside a bag, Dr. William Maisel, chief scientist at the FDA’s Center for Devices and Radiological Health, said this was not a guaranteed approach to catching stray cancer cells.

Among the FDA’s recommendations for alternative procedures include traditional or laparoscopic surgical hysterectomy, and myomectomy without morcellation. Morcellators have been on the market since 1993, and remain so to this day, despite the FDA’s black box warning.