New radiosensitization treatment (KORTUC I) using hydrogen peroxide solution-soaked gauze bolus for unresectable and superficially exposed neoplasms.

We developed a new radiosensitization treatment using a hydrogen peroxide solution (Oxydol)-soaked gauze named KORTUC I (Kochi Oxydol-Radiation Therapy for Unresectable Carcinomas) for superficially exposed and unresectable neoplasms, such as malignant melanoma and malignant fibrous histiocytoma (MFH), based on our experimental results which demonstrated hydrogen peroxide as a strong radiosensitizer for the highly radioresistant osteosarcoma cell line, HS-Os-1. Five patients entered our clinical trial, one of whom had unresectable malignant melanoma; one, unresectable MFH; one, unresectable extramammary Paget's disease; one, locally advanced breast cancer and one with locally recurrent skin cancer. These patients were treated with radiation therapy using a high-energy electron beam from a linear accelerator. The total dose was 48 Gy, and each fraction size was 4 Gy. Radiation therapy for these patients was performed three times per week. Each time the radiation therapy was carried out, the superficially exposed tumors of these patients were covered with hydrogen peroxide solution (Oxydol)-soaked gauze, and the lesion was gently massaged for several minutes so as to allow the hydrogen peroxide solution to soak deeply into the tumor. In the treatment results, two of these five patients showed a clinically complete response (cCR) two to three months following the end of the KORTUC I radiosensitization treatment. The other three patients showed a clinically partial response (cCR) showing a decrement of more than half of the pretreatment volume. KORTUC I was completed without any severe complications, excluding mild radiation-induced dermatitis/mucositis (Grade I). In conclusion, this newly developed radiosensitization treatment using hydrogen peroxide solution (Oxydol)-soaked gauze for superficially exposed unresectable/radioresistant neoplasms appears to be an effective and valuable method of radiosensitization in terms of the blockade of anti-oxidative enzymes such as peroxidases, resulting in local oxygen production. Moreover, the KORTUC I radiosensitization treatment is relatively inexpensive and the method can therefore be utilized worldwide for many patients suffering from superficially exposed and locally advanced radioresistant neoplasms such as malignant melanoma, malignant fibrous histiocytoma (MFH) and various types of sarcomas.