New evidence adds strength to arguments that doctors should be extremely cautious about using a procedure performed on about 50,000 women a year during surgery to remove the uterus because of the risk that it may spread cancer.
The procedure, power morcellation, uses a device to cut uterine tissue into pieces before removal through small incisions made during minimally invasive surgery. It also is used to remove fibroid tumors.
Recent reports indicate that some women have been harmed when the device, a morcellator, sliced into tumors they and their doctors did not know existed and spread cancer cells through the abdomen.
Now, a study, published Tuesday in the Journal of the American Medical Association, found that undetected tumors in women having hysterectomies are more common than many experts had previously thought, a conclusion that is likely to fuel calls to limit or eliminate the procedure.
The Food and Drug Administration said in April that the procedure should be discouraged and this month held hearings to evaluate morcellation.
The study analyzed a large insurance database that included 15 percent of hospitalizations nationwide from 2006 to 2012. The researchers found 232,882 cases in which women at 500 hospitals underwent minimally invasive hysterectomies using various approaches, including 36,470 women who had power morcellation.
Of those, 99 women had uterine cancer that was detected afterward. (If doctors had known about the cancer, they would not have used morcellation.) That means one in 368 women undergoing a hysterectomy had cancerous tumors that risked being spread by morcellation, said Dr. Jason Wright, the lead author and chief of gynecologic oncology at Columbia University College of Physicians and Surgeons.
Previous estimates suggested that unsuspected cancer was much rarer, ranging from one in 500 to one in 10,000 cases. But the FDA recently released an analysis estimating that one in 352 women undergoing hysterectomy or fibroid removal have sarcomas, aggressive, hard-to-detect cancers.
"The new numbers are coming all in the same ballpark -- higher than people anticipated," said Dr. Suzanne George, an oncologist at Dana-Farber Cancer Institute, who was not involved in the research.
The researchers found that age was the biggest risk factor for the uterine cancers, with cases increasing steeply from 50-year-old women to those 65 and older.
They also identified small numbers of other malignancies and several hundred women with a possible precancerous condition among those who underwent power morcellation. Dr. Kimberly Kho, an obstetrician-gynecologist at the University of Texas Southwestern Medical Center who was not involved in the research, said some of those can be detected with tests like Pap smears or endometrial screening, so "part of this research shows there are preventable complications we can find with a more systematic approach to preoperative testing."
The researchers could not determine how women fared after morcellation. But recent cases suggest it can spray pieces of tumor around, worsening the cancer. A review of cases at George's center found that cancer spread significantly faster after morcellation than after major abdominal surgery to remove the uterus.
George said another finding of the new study, that morcellation was used in only 16 percent of minimally invasive hysterectomies, means there are other options, including, in some cases, removing the uterus through the vagina. "Minimally invasive surgery does not equal morcellation," she said.