Latin American Thyroid Society expert panel consensus on anaplastic thyroid cancer

Anaplastic thyroid cancer (ATC) is a highly aggressive histologic subtype of thyroid malignancy. Its rarity, rapidly progressive clinical course, along with limitations in health-care resources make management particularly challenging in Latin America. In recent years, substantial advances in the understanding of ATC biology have led to modifications in therapeutic strategies. This consensus aims to raise awareness and provide practical, evidence-based guidance for the diagnosis and management of ATC, summarizing current diagnostic and therapeutic advances while offering an accessible framework tailored to the Latin American context. A multidisciplinary panel of experts in endocrinology, surgery, oncology, pathology, and genetics from Latin American countries developed a series of recommendations. Each recommendation is accompanied by its rationale and supporting evidence, adapted to the regional context to facilitate implementation. All recommendations were reviewed and voted on through a non-anonymous process. Recommendation wording was pre-specified and linked to voting thresholds: "should" indicated unanimous agreement (100%); "is recommended" indicated ≥70% agreement; and "may be considered" was used when agreement was <70% and/or when applicability depended on local availability, feasibility, or patient-specific clinical context. The consensus includes 37 recommendations covering the initial approach, diagnosis, and management of locoregional and advanced disease. By integrating current evidence with expert consensus and accounting for regional resource variability, this document aims to harmonize clinical practice, support multidisciplinary care, and facilitate timely diagnosis and treatment. These recommendations may also serve as a foundation for future research initiatives and the development and updating of regional health policies for this highly lethal disease.