Johnson & Johnson has begun to settle a group of legal claims alleging the company’s power morcellation devices can aggravate a patient’s cancer.

About 100 such power morcellation lawsuits have been filed or are ready to be filed in a multidistrict litigation set up by the federal Judicial Panel on Multidistrict Litigation.

The panel created the MDL in October 2015 by transferring 15 claims to a federal court in Kansas. Some plaintiffs’ attorneys allude to hundreds of more such cases still under investigation.

J&J has reportedly settled dozens of these claims already. One estimate projects a total payout in the hundreds of millions once all settlements are completed.

The lawsuits generally name as defendants J&J and its subsidiary Ethicon Inc., the maker of these devices used in morcellation hysterectomy and uterine fibroid surgery.

Ethicon commands the lion’s share of the morcellator market, having manufactured and sold over 70 percent of devices in use. Ethicon had suspended sales of its Morcelex power morcellators in April 2014, then issued a worldwide recall of the devices in July 2014.

The Controversy Behind Power Morcellation Lawsuits

Power morcellators, the devices at the heart of the controversy, have been used in laparoscopic surgery to cut tissue into smaller pieces that can be more easily removed. The devices were created to allow the removal of larger masses of tissue through smaller incisions.

In recent years, the technique had seen frequent use in gynecological procedures like morcellation hysterectomy and uterine fibroid surgery. Hundreds of thousands of procedures each year have used power morcellation.

It’s been a popular choice because it comes with the advantages generally associated with laparoscopic surgery, such as shorter recovery time and a reduced risk of infection.

The problem with power morcellation, as described in FDA warnings issued in April and November 2014, is that it may spread and upstage cancerous tissue that went previously undetected prior to the surgery.

The federal agency says that about 1 in 350 women undergoing hysterectomy or uterine fibroid surgery has some form of uterus cancer that goes undetected before the surgery.

The FDA notes that there is no reliable way to determine prior to surgery whether a woman with fibroids also has uterus cancer. These cases of cancer often are not diagnosed until surgically removed tissue can be analyzed in a lab.

A woman who undergoes power morcellation in the presence of such undetected cancer is at risk for advancing the cancer in a way that significantly worsens her odds of long-term survival, the agency says. Morcellation cancer has an approximately 5 year survival rate and may not respond well to chemotherapy.

Plaintiffs in the MDL include the surviving family members of women who did not survive their morcellation cancer. At the core of many plaintiffs’ arguments is the allegation that J&J knew about the risks but failed to address them properly. They argue that these devices are inherently defective due to the unavoidable difficulty of discerning benign fibroids from deadly cancer.

The Ethicon Power Morcellation MDL is In Re: Ethicon, Inc., Power Morcellator Products Liability Litigation, MDL No. 2652, in the U.S. District Court, District of Kansas.