Long-Term Follow-up of a Randomized Controlled Trial on Accelerated Radiation Therapy Versus Standard Fractionated Radiation Therapy for Early Glottic Cancer (JCOG0701A3).

Purpose: We previously reported the primary results of JCOG0701, a randomized, multicenter, phase 3, noninferiority trial comparing accelerated fractionation (Ax) to standard fractionation (SF) for early glottic cancer. In the primary results, although the similar efficacy of 3-year progression-free survival and toxicity of Ax compared with SF was observed, the noninferiority of Ax was not confirmed statistically. To evaluate the long-term follow-up results of JCOG0701, we conducted JCOG0701A3 as an ancillary study of JCOG0701.

Methods And Materials: In JCOG0701, 370 patients were randomly assigned to receive SF of 66 to 70 Gy (33-35 fractions; n = 184) or Ax of 60 to 64.8 Gy (25-27 fractions; n = 186). The data cutoff date for this analysis was in June 2020. Overall survival, progression-free survival, and late adverse events including central nervous system ischemia were analyzed.

Results: With a median follow-up period of 7.1 years (range, 0.1-12.4), progression-free survival of the SF and Ax arms were 76.2% and 78.2% at 5 years and 72.7% and 74.8% at 7 years (P = .44). OS of the SF and Ax arms were 92.7% and 89.6% at 5 years and 90.8% and 86.5% at 7 years (P = .92). Among 366 patients with a protocol treatment, the cumulative incidence of late adverse events of the SF and Ax arms were 11.9% and 7.4% at 8 years (hazard ratio, 0.53; 95% CI, 0.28-1.01; P = .06). Central nervous system ischemia of grade 2 or higher was observed in 4.1% for the SF arm and 1.1% for the Ax arm (P = .098).

Conclusions: After long-term follow-up, Ax showed comparable efficacy to SF and a tendency for better safety. Ax may be suitable for early glottic cancer because of its convenience in minimizing treatment time, cost, and labor.