External beam radiotherapy with or without californium-252 neutron brachytherapy for treatment of recurrence after definitive chemoradiotherapy

We aimed to evaluate the application of external beam radiotherapy (EBRT) combined with californium-252 (252Cf) neutron intraluminal brachytherapy (NBT) in patients with local recurrent esophageal cancer after definitive chemoradiotherapy (CRT). Sixty-two patients with local recurrent esophageal squamous cell carcinoma after definitive CRT were retrospectively analyzed; 31 patients underwent NBT+EBRT, and 31 received EBRT alone. The response rate; 1-, 2-, and 3-year overall survival rates; and adverse event occurrence rates were compared between these two patient groups. The response rate was 83.87% (26/31) in the NBT+EBRT group and 67.74% (21/31) in the EBRT group (p < 0.001). The 1-, 2-, and 3-year overall survival rates were 80.6%, 32.3%, and 6.5%, respectively, in the EBRT group, with a median survival time of 18 months. The 1-, 2-, and 3-year overall survival rates were 83.8%, 41.9%, and 6.9%, respectively, in the NBT+EBRT group, with a median survival time of 19 months. The differences between the groups were not significant (p = 0.352). Regarding acute toxicity, no incidences of fistula or massive bleeding were observed during the treatment period. The incidences of severe and late complications were not significantly different between the two groups (p = 0.080). However, the causes of death for all patients differed between the groups. Our data indicate that 252Cf-NBT+EBRT produces favorable local control for patients with local recurrent esophageal cancer after CRT, with tolerable side effects.