Therapeutic response to a novel enzyme-targeting radiosensitization treatment (Kochi Oxydol-Radiation Therapy for Unresectable Carcinomas) in patients with recurrent breast cancer

Linear accelerator-based radiotherapy has little effect on the majority of locally advanced neoplasms. Thus, the novel radiosensitizer Kochi Oxydol Radiation Therapy for Unresectable Carcinomas, Type II (KORTUC II), which contains hydrogen peroxide and sodium hyaluronate, was developed. The effectiveness of KORTUC II for the treatment of chemotherapy-resistant supraclavicular lymph node metastases has been previously demonstrated. The present study evaluated the safety and effectiveness of KORTUC II in patients with recurrent breast cancer. A total of 20 patients (age range, 39–84 years) were enrolled in the study. The majority of patients underwent positron emission tomography (PET)-computed tomography (CT) examinations prior to and 1–7 months following KORTUC II treatment, and every 6 months thereafter when possible. The radiotherapy regimen was 2.75 Gy/fraction, 5 fractions/week, for 16–18 fractions, with a total radiation dose of 44.00–49.50 Gy (X-ray irradiation), or 4.00 Gy/fraction, 3 fractions/week, for 10–12 fractions, with a total radiation dose of 40.00–48.00 Gy (electron beam irradiation). The injection of 3–6 ml of the KORTUC II agent was initiated at the fifth radiotherapy fraction, and was performed twice/week under ultrasonographic guidance. The therapeutic effects were evaluated by PET-CT examinations prior and subsequent to KORTUC II treatment, which was observed to be well tolerated with minimal adverse effects. Of the 24 lesions presented by the 20 patients, 18 exhibited complete response, 5 partial response, 0 stable disease and 1 progressive disease. The overall survival rate was 100% at 1 year and 95% at 2 years. The mean duration of follow-up at the end of June 2014 was 51 months. Based on the results of the PET-CT studies conducted, KORTUC II treatment demonstrated marked therapeutic effects, with satisfactory treatment outcomes and acceptable adverse events.