A link has been found between breast implants and a rare form of cancer, which has killed at least nine people, the U.S. Food and Drug Administration (FDA) announced Tuesday.

The cancer, called anaplastic large cell lymphoma (ALCL), is a rare type of non-Hodgkin’s lymphoma involving cells in the immune system that can develop following breast implants.

The FDA first identified a possible link between breast implants and the development of ALCL in 2011. At the time, the FDA said women with breast implants “may have a very small but increased risk of developing” anaplastic large cell lymphoma. However, because there were so few reported cases, it was unclear which factors contributed to increased risk.

Earlier this week, the FDA issued an update on its understanding of breast implant-associated ALCL cases. “All of the information to date suggests that women with breast implants have a very low but increased risk of developing ALCL compared to women who do not have breast implants,” the FDA said in a statement.

As of February 1, more than 350 cases of breast implant-associated ALCL, including 9 deaths, have been reported to the FDA. The cancer seems to develop more frequently in women with textured implants than in women with smooth-surfaced implants. Of the 231 reports that contained information about the implant, 203 had textured surfaces and 28 had smooth surfaces. Both saline- and silicone-filled implants were included in the reports.

Though an exact number of cases has been difficult to determine “due to limitations in world-wide reporting and lack of global implant sales data,” the FDA says breast implant-associated ALCL is an extremely rare condition that most frequently occurs in patients undergoing implant revision operations for late-onset, persistent seroma.

The cancer, which is found in the skin or lymph nodes around the breast implant, appears to progress slowly and is treatable when detected early. “Most cases of breast implant-associated ALCL are treated by removal of the implant and the capsule surrounding the implant and some cases have been treated by chemotherapy and radiation,” the FDA said.

The FDA recommends patients do their research before getting breast implants and talk with their surgeon about the risks and benefits of textured- versus smooth-surfaced implants. For the 10 to 11 million women world-wide who already have implants, the FDA says “there is no need to change your routine medical care and follow-up,” though it is advised to be aware of symptoms such as fluid buildup, hardening or mass around the implants, or swelling and redness near the implants.

Any noticeable changes should be reported to a health care provider immediately.