Risk of lymphoma in women with breast implants: analysis of clinical studies.

Large studies suggest that the overall rate of lymphoma in women with breast implants is no greater than in the general population; clinical reports suggest an association between breast implants and the rare non-Hodgkin lymphoma, anaplastic large cell lymphoma (ALCL). Observed cases of lymphoma reported in Allergan-sponsored breast implant clinical studies were compared with expected cases on the basis of the incidence of lymphoma among women in the National Cancer Institute's Surveillance Epidemiology and End Results program, using standardized incidence ratios (SIRs) and 95% confidence intervals (CIs). In clinical studies, there were 28 observed cases of lymphoma among 89 382 patients and 204 682 person-years of follow-up compared with 43 expected cases [SIR: 28/43=0.65 (95% CI: 0.43-0.94), P=0.02]. SIRs were calculated stratifying by baseline cancer history: women without prior cancer [SIR: 17/24=0.70 (95% CI: 0.41-1.13), P=0.17] and women with prior cancer [SIR: 11/14=0.79 (95% CI: 0.39-1.41), P=0.52]. SIRs were calculated by implant shell type: textured shell implants [SIR: 16/23=0.70 (95% CI: 0.40-1.13), P=0.16] and smooth shell implants [SIR: 12/19=0.63 (95% CI: 0.33-1.10), P=0.12]. Surveillance Epidemiology and End Results reported 12 cases of primary breast ALCL in women between 1996 and 2007 without a history of cancer, for an average annual incidence of 4.28 (95% CI: 3.51-5.05)/100 million women in the US - these women may or may not have breast implants. In clinical studies, three ALCL cases were reported in women with breast implants and a history of breast cancer, yielding a crude incidence rate of 1.46 (95% CI: 0.30-4.3)/100 000 person-years. Large clinical studies, based on over 200 000 person-years of follow-up, suggest no evidence of an increased risk of lymphoma among women who have received breast implants.