Autoimmune/Inflammatory Syndrome Induced by Adjuvants in Silicone Breast Implant Recipients: A Systematic Review and Meta-Analysis of Prevalence, Risk Factors, and Clinical Outcomes

Background Silicone breast implants remain among the most frequently performed cosmetic procedures worldwide, yet concerns persist regarding potential associations with autoimmune and inflammatory conditions. The Autoimmune/Inflammatory Syndrome Induced by Adjuvants (ASIA) has emerged as a framework for understanding immune-mediated responses to silicone, though evidence remains fragmented and inconsistent. Objective To systematically review and quantitatively synthesize existing literature on ASIA syndrome associated with silicone breast implants, estimating pooled prevalence and identifying potential risk factors. Methods Following PRISMA 2020 guidelines, we searched multiple databases through October 2024 for observational studies evaluating ASIA syndrome in silicone breast implant recipients. Two independent reviewers conducted study selection, data extraction, and quality assessment using the Newcastle-Ottawa Scale. Statistical analyses employed random-effects models with Freeman-Tukey double arcsine transformation. Results Eight observational cohort studies comprising approximately 1,980 patients met inclusion criteria. ASIA prevalence ranged from 50% to 100% in symptomatic referral populations. Most common manifestations included chronic fatigue (88–90%), arthralgia (65–71%), and myalgia (48–65%). Pre-existing allergies were present in 56–75% of symptomatic cohorts. Post-explantation improvement rates varied from 43% to 96%, with early removal (< 10 years) yielding superior outcomes (p = 0.007). Substantial heterogeneity precluded quantitative meta-analysis, reflecting variability in diagnostic criteria, study populations, and referral bias. Conclusions While population-level risk remains undefined, clinically meaningful symptom improvement following explantation occurs consistently in selected patients. Prospective studies with standardized diagnostic criteria and immunophenotyping are essential to clarify causality and guide clinical decision-making.