WASHINGTON (AP) — The Food and Drug Administration is warning women that a surgical procedure used to eliminate growths in the uterus could inadvertently spread cancer to other parts of the body.

The agency is discouraging doctors from performing the procedure, which uses an electronic device to grind and shred uterine tissue so it can be removed through a small incision in the abdomen. Known as laparoscopic power morcellation, the technique is widely used to treat painful fibroids, either by removing the noncancerous growths themselves or the entire uterus.

Doctors have long recognized the risk of accidentally spreading cancer from undetected tumors, but FDA officials said Thursday the problem now appears far more common than previously thought. An FDA analysis estimates that 1 in 350 U.S. women who undergo fibroid procedures each year have a form of cancer called uterine sarcoma.

“There is a risk that the procedure will spread the cancerous tissue within the abdomen and pelvis, significantly reducing the patient’s likelihood of long-term survival,” said Dr. William Maisel.

, the FDA’s director for medical devices. He added that there is no reliable way to spot cancerous uterine tumors before removing them.

The agency did not give estimates for the number of cancers affected by the problem, but at least 50,000 U.S. women undergo the procedure each year for hysterectomy — removal of the uterus.

Electronic uterine procedures were developed as a less invasive alternative to traditional surgery, in which the uterus or fibroids are removed through the vagina or a large incision in the abdomen. Studies suggest the device-assisted approach results in faster recovery and smaller scars.

Fibroids can grow to the size of cantaloupes, causing severe pain, heavy bleeding, and bladder and bowel dysfunction, mostly among women in their late 30s and 40s. It’s unclear what causes the tumor-like growths, but they are blamed for an estimated 240,000 of the 600,000 annual hysterectomies in the U.S.

Surgically removing the uterus is a key treatment because it is the only way to ensure fibroids do not return. Myomectomy, surgery that removes fibroids while leaving the uterus intact, is recommended for women who still want to become pregnant.

The risk of disturbing undetected uterine tumors has long been debated by reproductive specialists. Previous figures in the medical literature estimated anywhere from 1 in 500 to 1 in 10,000 women would have their cancer spread by the electronic fibroid procedures. FDA officials said they decided to take action after realizing the risk is much higher.

“What is new is that the magnitude of the risk appears to be greater than was appreciated by the clinical community,” Maisel said. He added that the agency has received a dozen reports of cancers spread due to the procedures, but that only represents cases submitted by concerned physicians.

The FDA approved the first electronic morcellators in 1995 and about two dozen are now available in the U.S. The devices were cleared through an abbreviated review process because they were deemed similar to manual surgical devices long on the market. Even with more rigorous testing, Maisel said the cancer risk would probably have not been detected because cases of uterine cancer are so rare.

Despite the risks outlined in a press teleconference, agency officials said the devices will remain on the market because there still may be patients who benefit from the procedure.

Patients should discuss all options for treating fibroids with their physician, including traditional surgery and less-invasive procedures that do not use power morcellators.

The agency plans to convene a meeting later this year to discuss how the devices should be used going forward. Among other options, the FDA will discuss the use of protective bags to collect the uterine tissue so it doesn’t spread to other parts of the body. Some surgeons already use this method, though the FDA said Thursday the technique does not eliminate the risk of cancer spread.