Photodynamic therapy for breast cancer in a BALB/c mouse model

OBJECTIVE: Photodynamic therapy (PDT) has been used for superficial neoplasms and its usage has been recently extended to deeper lesions. The purpose of this study was to observe whether or not PDT can cure breast cancer in the solid tumor model, and to define the critical point of laser amount for killing the cancer cells. METHODS: Twenty four BALB/c mouse models with subcutaneous EMT6 mammary carcinomas were prepared. Mice were divided into eight groups depending on the amount of illumination, and the tumor size was between 8 mm and 10 mm. We began by peritoneal infiltration with a photosensitizer 48 hours prior to applying the laser light, and then we applied a non-thermal laser light. The energy was from 350 J/cm(2) to 30 J/cm(2) to the cancer. RESULTS: Regardless of the tumor size from 8 mm to 10 mm, all mice apparently showed positive results via PDT. We also did not find any recurrence over 90 J/cm(2). In all models, the color of the breast cancer lesions began to vary to dark on 2 days post PDT and the tumor regression began simultaneously. Also, we confirmed the complete regression of the breast cancer 21 days after PDT. CONCLUSION: We confirmed that PDT may treat breast cancers that are sized less 10 mm in mouse models. The moderate energy to destruct the breast cancer cells may be 90 J/cm(2). Therefore, we can expcect that PDT may be utilized to treat breast cancer, but we need more experience, skills and processing for clinical trials.