Expert opinion document on the management of desmoid tumours in adult patients in Spain

Summary

Introduction: Desmoid tumours (DT), or aggressive fibromatosis are rare, nonmetastatic soft tissue neoplasms characterized by monoclonal fibroblast proliferation and infiltrative local behaviour that can affect organs and adjacent structures, resulting in sustained clinical burden and impacting patient's quality of life. Purpose: The aim of this work is to determine the current management of DT in Spain, including unmet needs and to propose the positioning of nirogacestat in the current treatment algorithm. Methodology: A literature review was conducted in June 2025 to identify published evidence on the epidemiology, diagnosis, management and unmet needs of DT in Spain. An expert panel of five Spanish oncologists specialized in sarcomas was convened. Each expert completed a questionnaire relating to research topics. Responses were consolidated and analysed, with a consensus threshold set at 80%. Findings were discussed and consensus reached at two virtual meetings. Results: The therapeutic approach to DT is currently based on an individualized strategy according to symptoms and tumour's biological behaviour. In asymptomatic patients, active surveillance represents the first recommended strategy, given the potential for spontaneous tumour stabilization or regression. Symptomatic, functionally limiting, or documented progression cases require active treatment. The current unmet needs include lack of systemic treatments with approved indication and favourable safety profile. Nirogacestat, the first treatment authorised for patients with progressing DT who require systemic therapy, should be positioned as standard of care in the treatment algorithm. Conclusions: This first Spanish expert opinion document on DT management addresses evidence gaps and proposes a treatment algorithm to harmonise clinical practice.