Phase II trial of radiotherapy plus Huachansu in elderly or chemotherapy-ineligible patients with locally advanced esophageal squamous cell carcinoma

Background Preclinical studies have demonstrated that Huachansu, a traditional Chinese medicine derived from toad venom, exhibits radiosensitizing properties. This study aimed to explore whether Huachansu plus radiotherapy can improve the tumor control in elderly and chemotherapy-ineligible patients with locally advanced esophageal squamous cell carcinoma (ESCC). Methods Eligible patients were randomly assigned at a 1:1 ratio to receive either radiotherapy alone (RT) or combined Huachansu and radiotherapy (Huachansu+RT). The primary endpoint was locoregional control, and the secondary endpoints were overall survival (OS), progression-free survival (PFS), and treatment-related toxicities. Results From September 2015 to January 2020, 126 patients who met the eligibility criteria were randomly assigned to the Huachansu+RT group (n = 65) or the RT alone group (n = 61) from three hospitals. At a median follow-up of 64.8 months (IQR 37.8–78.3), the median locoregional control time was 12.9 months (95% CI 0–27.0) in the Huachansu+RT group and 22.0 months (95% CI 0–52.0) in the RT alone group (HR = 1.35, 95% CI 0.82–2.22; P = 0.235). The median OS time was 15.0 months (95% CI 10.3–19.7) in the Huachansu+RT group and 17.2 months (95% CI 11.3–23.1) in the RT alone group (HR 1.03 95% CI 0.71–1.51 P = 0.868). There was no significant difference between the two groups in the incidence of acute grade 3 or higher adverse events. Conclusions Compared with radiotherapy alone, concurrent radiotherapy with Huachansu injection did not improve the locoregional control rate or survival rate in elderly patients or chemotherapy-ineligible patients with locally advanced ESCC. The trial is registered with ClinicalTrials.org, NCT02647125.