Worldwide there have been 71 documented cases of patients with anaplastic large cell lymphoma (ALCL) in which researchers suspected breast implants to be the cause. ALCL is normally found in the lymph nodes, as well as in skin, lung, liver and soft tissue, but not usually in the breast. Cases in which ALCL developed in the breast region almost exclusively involved patients who have had breast surgery. In these cases, ALCL developed around ten years after the operation. The tumours grew in the scar tissue around the implant.
Breast implants are generally safe and studies have found no association between breast surgery and other forms of cancer. ALCL itself is also an extremely rare occurrence. Among three million breast implants, there are between one and six reported cases of ALCL.
ALCL is divided into two subtypes. In one subtype, the cancerous cells produce an abnormal form of the protein ALK (anaplastic lymphoma kinase). The other type does not express ALK in tumour cells at all. While patients with ALK-positive lymphoma have a better chance of survival, the cancer is considerably more aggressive in ALK-negative cases.
Implant-related ALCL appears to form a third group. The cells do not express ALK, but patients have good survival rates. "This is a previously unrecognized, new subtype of ALCL," Lukas Kenner explains. "We must now determine the exact causes behind its occurrence."
The search for causes
The actual reasons why implants can cause lymphoma remain unclear. While some patients were successfully treated with chemotherapy and radiation therapy, the lymphoma in many cases subsided on its own following removal of the implant and the surrounding tissue. An abnormal immune response from the body could therefore be a cause of the cancer. Kenner and his team are now preparing for further studies in which implants and dentures will be examined in other parts of the body.
Lukas Kenner from the Medical University Vienna, the University of Veterinary Medicine, Vienna and the Ludwig Boltzmann Institute for Cancer Research cooperated for this study with scientists from Cambridge, Liverpool, Swansea and Australia. The project was funded by the British organisation Leukaemia & Lymphoma Research.