Risk of autoimmune and rheumatic diseases in breast cancer patients with silicone breast implants

Abstract Background Over the past decade, various large observational studies have suggested an association between silicone breast implants and autoimmune and rheumatic diseases, rekindling long-standing breast implant safety concerns among breast cancer survivors with breast reconstructions and newly diagnosed breast cancer patients. Methods We investigated the association between silicone breast implants and autoimmune and rheumatic diseases in a large multicenter cohort of women treated for breast cancer, part of whom received silicone breast implants for reconstructive purposes. Clinical data and events of interest were identified through linkages with prospectively maintained nationwide and institutional registries. Hazard ratios (HRs) for autoimmune and rheumatic diseases were calculated using Cox proportional hazards regression models adjusted for potential confounders. Results Of 12 262 women in the cohort, 3082 (25%) had received silicone breast implant–based breast reconstructions. Median follow-up time was 12.0 years (IQR = 7.0 years). The event rate of autoimmune and rheumatic disease diagnoses was 62.5 per 10 000 person-years. Compared with women without silicone breast implant exposure, women with an implant-based breast reconstruction did not have an increased risk of autoimmune and rheumatic diseases (multivariably adjusted HR = 1.06, 95% CI = 0.89 to 1.27). In addition, no statistically significant association was found between silicone breast implant exposure and inflammatory arthritis, systemic rheumatic disease, inflammatory dermatosis, inflammatory bowel disease, or any specific condition. Sensitivity analyses in which silicone breast implant exposure was analyzed as a time-dependent variable confirmed the results of the main analysis. Conclusion The findings of this study indicate that silicone breast implant exposure is not associated with an increased risk of autoimmune and rheumatic diseases in women with breast cancer and challenge the results of earlier studies in women with cosmetic implants. Registration This study is registered at ClinicalTrials.gov on June 2, 2022 (NCT05400954)