Access to Lymphangioleiomyomatosis Care Across Europe: An ERN-LUNG Survey of Clinical Practice and the Case for a European Registry and Trial Network

<title>Extract</title> Lymphangioleiomyomatosis (LAM) is a systemic, low grade, metastasizing neoplasm, that predominantly affects women of reproductive age, with an estimated prevalence of 20 cases per million females [1, 2]. LAM occurs either sporadically or in association with tuberous sclerosis complex (TSC), with clinical manifestations including diffuse cystic lung disease, chylothorax, spontaneous pneumothorax and renal angiomyolipomas (AMLs) [3]. Diagnostic criteria for LAM require computed tomography (CT) imaging displaying characteristic cystic lung disease and one or more of: TSC, AMLs, chylous effusions, lymphangioleiomyomas or a serum vascular endothelial growth factor D (VEGF-D) level greater than or equal to 800 pg·mL⁻¹ [4]. Beyond its diagnostic utility, serum VEGF-D also functions as a prognostic biomarker of severity and monitoring of treatment response [5]. Advances in understanding LAM pathogenesis have resulted in the development and approval of mechanistic target of rapamycin (mTOR) inhibitor agents, which demonstrated stabilisation of lung function decline in the landmark Multicenter International LAM Efficacy of Sirolimus (MILES) trial [6]. The beneficial impact of patient registries in the advancement of LAM research and patient care is evident in the National Heart, Lung, and Blood Institute (NHLBI) national LAM registry in the United States [7]. This comprehensive database has been instrumental in defining the natural history and key characteristics of patients with LAM [8].