Ferroptosis in Differentiated Thyroid Cancer: Redox–Iodine Metabolism, Dedifferentiation, and Therapeutic Sensitization Beyond Anaplastic Disease

Differentiated thyroid cancer (DTC), including papillary and follicular subtypes, is generally associated with favorable prognosis; however, a subset of patients develops recurrent, metastatic, or radioiodine-refractory diseases with limited therapeutic options. Ferroptosis, an iron-dependent form of regulated cell death driven by lipid peroxidation, has recently emerged as a biologically relevant process in thyroid cancer, yet its role in differentiated disease remains incompletely defined. Unlike many other malignancies, thyroid cancer arises within an organ intrinsically shaped by iodine-dependent redox reactions required for thyroid hormone biosynthesis. This unique oxidative environment imposes selective pressure on tumor cells to adapt redox balance, lipid metabolism, and antioxidant defenses, all of which are central regulators of ferroptosis. Accumulating evidence indicates that ferroptosis susceptibility in DTC is dynamically modulated by differentiation status, oncogenic signaling, metabolic rewiring, and tumor microenvironmental interactions. Notably, progression toward radioiodine-refractory disease is accompanied by dedifferentiation and reinforcement of anti-ferroptotic programs, linking ferroptosis resistance to therapeutic failure. In this review, we synthesize recent original studies and contemporary reviews to provide a focused overview of ferroptosis in DTC, excluding anaplastic disease. We discuss thyroid-specific redox and iodine metabolism, genetic and metabolic determinants of ferroptosis sensitivity, lipid remodeling, and immune–microenvironmental interactions, and highlight translational opportunities for targeting ferroptosis in radioiodine-refractory DTC. By reframing ferroptosis as a context-dependent vulnerability rather than a universal death pathway, this review outlines a conceptual roadmap for integrating ferroptosis modulation into existing therapeutic strategies for DTC.