D

Cartilage (or perichondrial) involvement upgrades a glottic tumour to at least T4a. Tumours that have invaded the thyroid cartilage respond poorly to organ-preserving radiotherapy or chemoradiotherapy; standard guidelines therefore recommend primary total laryngectomy followed by adjuvant radiotherapy for optimal local control [Biau, 2022, PMID 34953705]. Studies of patients who develop perichondritis after radiation show a high rate of residual or recurrent cancer, underscoring the need for definitive surgical removal rather than additional radiation alone [Mintz, 1981, PMID 6793963].