Cancer risk at sites other than the breast following augmentation mammoplasty

PURPOSE: There has been limited investigation of cancer risk other than bre ast cancer among patients with breast implants, despite some clinical and l aboratory evidence suggesting links with certain cancer sites, including he matopoietic and connective tissue malignancies. METHODS: A retrospective cohort study of 13,488 patients who received cosme tic breast implants at 18 plastic surgery practices in six geographic areas was conducted to assess long-term health effects. After an average of 12 y ears of follow-up, questionnaires were administered to subjects located and alive (78% of eligible population). Attempts were made to obtain death cer tificates for deceased subjects and medical verification for all reported c ancers. Expected numbers of cancers were derived using general population c ancer incidence rates and an internal comparison series of 3936 patients wh o received other types of plastic surgery at the same practices as the impl ant patients. RESULTS: A total of 359 malignancies was observed versus 295.95 expected ba sed on general population rates, resulting in a standardized incidence rati o (SIR) of 1.21 [95% confidence interval (CI) 1.1-1.4]. Individual malignan cies for which incidence was significantly elevated inducted cancers of the stomach (SIR = 2.65), cervix (SIR = 3.18), vulva (SIR = 2.51), brain (SIR = 2.16), and leukemia (SIR = 2.19). No excess risks were observed for other hematopoietic malignancies, including multiple myeloma. The internal analy ses, however, based on cancer rates derived among the comparison patients, showed no increased cancer risk among the implant patients [relative risk ( RR) = 1.00, 95% CI 0.8-1.2], as well as no statistically significant elevat ions for most individual sites. Cervical cancer continued to be elevated (R R = 1.78), although to a lesser extent than in the external analyses, while the risk for respiratory cancers was higher (RR = 2.40). Non-significant e levations in risk persisted in this analysis for liver cancer (RR = 2.65), brain cancer (RR = 2.83), and leukemia (RR = 1.83). Many of the cancers sho wing excesses were defined on the basis of death certificates, requiring ca ution in interpretation. The histologies of the leukemias were quite varied , which makes a biologic relationship appear unlikely. However, respiratory cancers showed some evidence of increasing risk with follow-up time and bo th respiratory and brain cancers were elevated in the mortality analyses. CONCLUSIONS: Although excesses of cervical and vulvar cancer among implant patients might he attributable to lifestyle factors, reasons for excesses o f respiratory and brain cancers were less apparent. Ann Epidemiol 2001;11:2 48-256. (C) 2001 Elsevier Science Inc. All rights reserved.