Real-world management of tuberous sclerosis complex-associated renal angiomyolipomas: the impact of mTOR inhibitors.

Background: Renal angiomyolipomas (AMLs) drive substantial morbidity in tuberous sclerosis complex (TSC) through haemorrhage and repeated invasive procedures. While mammalian target of rapamycin inhibitors (mTORis) reduce AML volume, long-term real-world data on clinically meaningful bleeding and procedure outcomes remain limited, particularly in cohorts enriched for high-risk imaging phenotypes. Methods: We conducted a multicentre observational study (2004-2020) in three French tertiary centres. Among 103 included patients, the 96 with TSC constituted the primary analysis set. We assessed AML-related haemorrhage and selective arterial embolization (SAE). For patients initiating mTORi, follow-up was split into pre- and post-initiation periods and incidence rate ratios (IRRs) were estimated using Poisson regression with patient-time offsets and patient-clustered robust standard errors; generalized estimating equation Poisson and negative binomial models were used as sensitivity analyses. Results: Total follow-up was 694.3 patient-years. Thirty-nine patients (40.6%) initiated an mTORi (everolimus 94.9%). Haemorrhage rates decreased from 0.061 to 0.007 events per patient-year after mTORi initiation {IRR 0.11 [95% confidence interval (CI) 0.02-0.62]} and SAE rates decreased from 0.197 to 0.020 sessions per patient-year [IRR 0.10 (95% CI 0.04-0.29)]. Therapeutic inertia remained substantial: among 57 never-treated patients, high-risk imaging features and active complications were frequent at the last assessment. Conclusions: In this long-term real-world cohort of TSC-associated renal AMLs, mTORi initiation was associated with markedly lower rates of AML haemorrhage and SAE. Despite these benefits, many high-risk patients remained untreated in routine care, supporting earlier nephrology referral, systematic risk stratification and timely treatment initiation to reduce preventable AML-related morbidity.