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

BACKGROUND: Over the past decade, various large observational studies have suggested an association between silicone breast implants (SBIs) and autoimmune and rheumatic diseases (ARDs), 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 SBIs and ARDs in a large multicenter cohort of women treated for breast cancer, part of whom received SBIs for reconstructive purposes. Clinical data and events of interest were identified through linkages with prospectively maintained nationwide- and institutional registries. Hazard Ratios (HRs) for ARDs were calculated using Cox proportional hazards regression models adjusted for potential confounders. RESULTS: Of 12,262 women in the cohort, 3,082 (25%) had received SBI-based breast reconstructions. Median follow-up time was 12.0 (IQR, 7.0) years. The event rate of ARD-diagnoses was 62.5 per 10,000 person-years. Compared with women without SBI-exposure, women with an implant-based breast reconstruction did not have an increased risk of ARDs (multivariably adjusted HR, 1.06, 95% CI [0.89 to 1.27]). In addition, no statistically significant association was found between SBI-exposure and inflammatory arthritis, systematic rheumatic disease, inflammatory dermatosis, inflammatory bowel disease or any specific condition. Sensitivity analyses in which SBI-exposure was analyzed as a time-dependent variable confirmed the results of the main analysis. CONCLUSION: The findings of this study indicate that SBI-exposure is not associated with an increased risk of ARDs 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 2nd 2022 (NCT05400954).