The capabilities of benzoporphyrin: In vivo study of canine malignant melanomas with photodynamic therapy

Human malignant melanomas are a kind of commonly occurring neoplasm with a clinical course of recurrence after surgical removal. This preliminary animal study seeks to evaluate the effect of benzoporphyrin derivative (BPD) in photodynamic therapy (PDT) for spontaneously arising melanoma in canines. Ten dogs with spontaneously occurring melanomas were treated with PDT using BPD as the photosensitizer. BPD was injected intravenously at a dose of 1 mg/kg. Six hours later the treatment of PDT with 690 nm light was taken. Some larger tumors (>1.5 cm deep) were surgically debulked prior to PDT. No significant systemic toxicity or skin photosensitization was observed. PDT with BPD led to a complete response in 70% (7 of 10) of these cases. 20% (2 of 10) had a partial response, and 10% (1 of 10) no response (<50% reduction of tumor size). BPD-PDT appears to have advantages in the treatment of canine melanomas, and systemic toxicity is almost nonexistent. Further studies of the long term results are necessary before BPD-PDT can be used in humans.