Phase I fractional dose escalation study of equipotent stereotactic radiotherapy regimens for early-stage glottic larynx cancer
Mené sur 29 patients atteints d'un carcinome épidermoïde du larynx glottique de stade Tis à T2 (durée médiane de suivi : 39,2 mois), cet essai de phase I évalue la toxicité d'une radiothérapie stéréotaxique hypofractionnée en fonction de la dose de rayonnements administrée et de son fractionnement
Background : Early-stage glottic larynx squamous cell carcinoma (GLC) is a relatively common disease with excellent oncologic control, but treatment is associated with acute dysphagia and long-term voice quality changes. This phase I study of hypofractionated radiotherapy for early-stage GLC increased the fraction size while reducing the number of fractions until 5 fraction stereotactic ablative radiotherapy (SAbR) was delivered. Methods : Eligible patients were diagnosed with stage Tis to T2 GLC. Patients with prior curative-intent surgery were excluded. The equipotent dose levels were: level 0, 50 Gray (Gy)/15 fractions (n=4); level 1, 45 Gy/10 fractions (n=13); level 2, 42.5 Gy/5 fractions (SAbR level, n=12). Grade 3 or 4 laryngeal edema, voice, dyspnea, stridor, or cough were the pre-defined dose-limiting toxicities (DLT). Results : Twenty-nine patients were enrolled from November 2013 to March 2017. The median and minimum follow-up times were 39.2 and 13 months, respectively. Two actively smoking patients developed a DLT, one treated in level 1 (grade 4 laryngeal edema, grade 3 dysphagia), and one treated in level 2 (grade 3 laryngeal necrosis, dysphagia). The former patient soon developed a local recurrence, and the latter patient recovered. There were a total of 5 local recurrences, 2 in level 0 and 3 in level 1. The Voice Handicap Index results showed robust long-term voice quality, with median values of 7 and 0 at 6 and 12 months, respectively. Conclusions : Given the tolerability, excellent voice outcomes, and preliminary efficacy data of 5 fraction glottic larynx SAbR, this regimen warrants further study.