Therapeutic response to a novel enzyme-targeting radiosensitization treatment (KORTUC II) for residual lesions in patients with stage IV primary breast cancer, following induction chemotherapy with epirubicin and cyclophosphamide or taxane

Linac-based radiotherapy has a negligible effect on the majority of advanced neoplasms. Therefore, a novel radiosensitization treatment Kochi Oxydol Radiation Therapy for Unresectable Carcinomas II (KORTUC II), which utilizes hydrogen peroxide and sodium hyaluronate was developed. The effectiveness of KORTUC II for the treatment of chemotherapy-resistant supraclavicular lymph node metastases and recurrent breast cancers has previously been demonstrated. The present study evaluated the safety and efficacy of KORTUC II in patients with stage IV primary breast cancer. Seven patients (age range, 36–65 years) were enrolled. All patients received induction chemotherapy prior to KORTUC II treatment and underwent positron emission tomography-computed tomography (PET-CT) examinations prior to and 2–7 months following KORTUC II treatment, and every six months thereafter where possible. The radiotherapy regimen (x-ray irradiation) was 2.75 gray (Gy)/fraction, 5 fractions/week for 16–18 fractions with a total radiation dose of 44–49.5 Gy. Administration of the KORTUC II agent (3–6 ml: 3 ml for a lesion <3 cm in diameter and 6 ml for a lesion ≥3 cm) was initiated from the sixth radiotherapy fraction, and was conducted twice a week under ultrasonographic guidance. The therapeutic effects were evaluated by PET-CT examinations prior to and following KORTUC II treatment. Of the seven lesions from the seven patients, five exhibited complete responses, two exhibited partial responses and none exhibited stable disease or progressive disease. The overall survival rate was determined to be 100% at 1 and 86% at 2 years post-treatment. The mean duration of follow-up by December 2014 was 51 months. The results of the PET-CT studies indicated that KORTUC II treatment demonstrated marked therapeutic effects with satisfactory treatment outcomes and acceptable adverse effects.