Breast Implants Increase Cancer Risk, Large Lymphoma Study Shows

Breast implant
A picture taken on March 28, 2013 in Marseille, southeastern France, shows a breast implant produced by the implant manufacturer Poly Implant Prothese company (PIP). GERARD JULIEN/AFP/Getty Images

Breast implants are associated with an increased risk of a rare form of cancer, according to a new study published Thursday in JAMA Oncology. Although the issue has been known about for two decades, this is the largest study of the association between breast implants and lymphoma to date.

Scientists still sure how breast implants might be increasing a person's risk of cancer. As the paper describes, the implant may trigger an inflammatory response. Alternatively, a bacterial species could be hitching a ride on the implant's surface. Some women may even be genetically predisposed to develop this kind of cancer after a breast implant.

The statistics in this study appear alarming at first glance. In the new study, breast implants were associated with a 421 times greater risk of developing anaplastic large cell lymphoma. However, understanding what that number actually means is crucial.

That number, while astonishing, isn't necessarily the important piece of information for someone considering this type of plastic surgery. That's because it doesn't reflect the risk at a real-life scale, explained Dr. Daphne de Jong, a pathologist at VU University Medical Center. "What a person with breast implants wants to know is what is my individual risk," de Jong told Newsweek.

The more relevant number is this: if 7,000 women got breast implants, one of them would be diagnosed with this type of non-Hodgkin lymphoma. "That's extraordinarily low," said Dennis Deapen, a cancer epidemiologist at the University of Southern California's Keck School of Medicine who was not involved in the research. About 4 percent of American women have breast implants, according to a FiveThirtyEight analysis.

The 421-fold increase is what's known as the relative risk. The more palatable figure of one in 7,000 is the absolute risk. Why are these numbers so different? Understanding the distinction could be important for someone deciding whether or not to have breast implants.

breast implant court docs
A picture taken on March 28, 2013 in Marseille, southeastern France, shows a breast implant produced by the implant manufacturer Poly Implant Prothese company (PIP). The now-bankrupt PIP was shut down and its products banned in 2010 after it was revealed to have been using industrial-grade silicone gel that caused abnormally high rupture rates. GERARD JULIEN/AFP/Getty Images

The two figures are related, Deapen said. Anaplastic large cell lymphoma is rare. Only 4.3 percent of all cancers diagnosed in the United States fall into the category of non-Hodgkin lymphoma, according to the National Cancer Institute. Because the cancer is rare, even something that can increase the risk in a very significant way, like breast implants, will only result in a few people in a study group developing the cancer.

That small pool of people who are vulnerable to a rare cancer means that researchers studying the link between the risk factor and the disease need to look at a very large group of people in order to spot meaningful changes.

Could the type of implant matter when it comes to cancer risk? This study was conducted in the Netherlands, where about 45 percent of breast implants are textured. Among the women who developed lymphoma, about 82 percent had textured implants. Non-textured, smooth implants may be used more often in the United States than in the Netherlands, according to Dr. Hinne Rakhorst, a plastic surgeon and one of the authors of the paper.

Doing this study in the United States would most likely show very different results, Deapen said. And there's definitely not enough data to confirm that there's a particular brand of implant that's particularly risky.

Conducting a study like this in the U.S. would be nearly impossible because we don't collect the same data on a national level. A new breast implant registry in the United States could help address some concerns, Deapen noted. "That's not going to prevent disease, but that's going to at least monitor outcomes."

The first cases of anaplastic large cell lymphoma associated with breast implants were reported in 1997. Following a 2008 study, the FDA issued a report stating that breast implants were associated with an increased risk of non-anaplastic large cell lymphoma, a type of non-Hodgkin lymphoma, in 2011. The World Health Organization has a separate designation for this kind of breast-implant associated cancer.

This increased risk doesn't mean that we need to ban breast implants, de Jong said. But women should be aware of the risks and of the symptoms associated with this cancer, which include swelling or a lump in the breast with the implant. "Women should not panic," she said, "but they should be aware of it."