A new investigation by the Food and Drug Administration will look into a possible link between breast implants and the risk of cancer.
According to 60 cases reported to the FDA over the past 13 years, a rare cancer known as anaplastic large cell lymphoma that attacks lymph nodes has been found in the scar tissue that surrounds the breast implant.
An estimated 5 to 10 million women worldwide have breast implants. The FDA is asking doctors to report all cases of the cancer so the agency can better understand the association.
Scientific literature going back to 1997 will be reviewed, along with information provided by international governments and manufacturers.
Most of the cases were reported after patients sought medical care for pain, lumps, swelling and other problems around the surgical site.
Breast implants come in both saline and silicone-gel filled formulations and are marketed in the U.S. by Allergan Inc. and Johnson & Johnson's Mentor Corp. Those companies will be required to update the labeling for their products to reflect the cancer cases.
"Women should monitor their breast implants and contact their doctor if they notice any changes," the agency said in a statement.
The FDA pulled silicone breast implants off the market in 1992, saying manufacturers had not provided medical data showing their safety and effectiveness. At the time, there were worries about a connection to a variety of diseases, including cancer and lupus. Alarming cases of ruptures also added to the concern.
But in 2006 the agency returned the implants to the market after most studies failed to find a link between silicone breast implants and disease.
The approval came with conditions, including a requirement that the companies complete 10-year studies on women who have already received the implants to study leaks, as well conduct new decade-long studies of the safety of the devices in 40,000 women.
The Associated Press contributed to this report.