Single vocal cord irradiation (SVCI) vs whole laryngeal radiotherapy in the treatment of T1aN0 glottic cancer A prospective randomized trial.

Abstract

Both Transoral laser surgery (TLS) and radiotherapy are used in the treatment of T1aN0 glottic cancer with similar oncological outcomes. Retrospective studies suggest excellent local control with single vocal cord irradiation that targets only the affected vocal cord. So, the aim of this study was to compare the treatment outcome and toxicity of the classic radiotherapy field vs single vocal cord irradiation (SVCI) technique. This is a prospective phase 2 randomized study (clinicaltrial.gov registration NCT05679856). A total of 57 patients with T1aN0 glottic cancer were randomized. 28 were assigned to standard of care whole larynx radiotherapy that covers the whole larynx with a prescription dose of 63 Gy/28 Fractions (Fs) The remaining 29 patients were randomized to single vocal irradiation with a prescription dose of 58.08 Gy/16Fs. The primary endpoint was to prove superiority of SVCI in terms of voice quality by comparing voice handicap index (VHI) between the 2 study arms. Baseline VHI was recorded before treatment, at end of radiotherapy, then during each follow up visit. Demographic and patients' characteristics were comparable between the 2 arms. The doses to different organs at risk were statistically lower in the SVCI arm. 2-year local control rate was 100% in SVCI arm and 96% in the whole larynx arm, with no significant difference. No grade 3 or 4 toxicities were reported in both treatment arms. Patients in the SVCI arm demonstrated lower VHI scores at 2 months and 1-year post-treatment, with median scores of 4 and 0, respectively, compared with 22 and 21 in the whole-larynx arm. SVCI is effective and safe treatment for T1aN0 glottic cancer with comparable local control rates and safe toxicity profile. SVCI was associated with superior voice outcome as evidenced by significantly improved VHI scores compared with whole larynx radiotherapy.