A Phase 2 Randomized Trial Comparing Radiation Doses in Concurrent Chemoradiotherapy With TS-1/Nedaplatin for
Hideomi Yamashita1, Subaru Sawayanagi1, Mei Kono1
1Department of Radiology, University of Tokyo Hospital, Tokyo, Japan.
Purpose:
To evaluate and compare progression-free survival (PFS) between 50.4-Gy and 60-Gy radiation doses in definitive chemoradiotherapy (CRT) for patients with esophageal cancer, and to confirm that 50.4 Gy is noninferior to the 60-Gy irradiation method in terms of PFS.
Methods And Materials:
Patients with medically inoperable (including patient refusal), unresectable, and/or recurrent esophageal carcinoma referred for definitive CRT were randomly assigned to either the group receiving a total dose of 50.4 Gy in 28 fractions (1.8 Gy/d) for 5.5 weeks or the group receiving a total dose of 60 Gy in 30 fractions (2.0 Gy/d) using involved-field radiation therapy. Chemotherapy consisted of 2 courses of concurrent nedaplatin (80 mg/m2) and tegafur, gimeracil, and oteracil potassium (S-1) (80 mg/m2) in both arms every 4 weeks. The primary end point was PFS.
Results:
Between December 2015 and February 2025, 97 patients with squamous cell carcinoma were included. Radiation treatment was completed in 98% of patients. The median follow-up time for surviving patients was 33.2 months. The 3-year PFS was 45% in the 50.4-Gy group versus 26% in the 60-Gy group (P = .017). The 3-year cumulative local control rate was 65% and 46% for the 50.4-Gy and 60-Gy groups, respectively (P = .047). The 3-year overall survival was 73% and 42% for the 50.4-Gy and 60-Gy groups, respectively (P = .018). Overall, grade 3-4 toxicities were observed in 53% of the 50.4-Gy group versus 51% of the 60-Gy group. The PFS and overall survival differences between the 50.4-Gy and 60-Gy groups were no longer statistically significant after adjustment for key covariates using multivariable analysis.
Conclusions:
A radiation dose of 50.4 Gy remains the standard dose in concurrent CRT for esophageal squamous cell carcinoma.
