Treatment of canine hemangiopericytomas with photodynamic therapy

Background and Objectives: Canine hemangiopericytomas are a commonly occurr ing neoplasm with a clinical course of recurrence after surgical removal. T his study sought to evaluate Photochlor (HPPH) photodynamic therapy (HPPH-P DT) as an adjuvant therapy to prevent recurrence of tumor after surgical re moval. Study Design/Patients and Methods: Sixteen dogs with naturally occurring he mangiopericytomas were treated with surgical removal of the tumor followed by PDT using Photochlor as the photosensitizer. Photochlor was injected int ravenously at a dose of 0.3 mg/kg. Forty-eight hours later the treatment co nsisted of surgical removal of the tumor followed by HPPH-PDT. Results: Nine dogs (50%) had recurrence of tumor from 2 to 29 (median 9) mo nths after treatment. These results are comparable or not as good as other forms of therapy. Conclusion: Photochlor photodynamic therapy applied after surgery appears t o have no advantage over other forms of therapy in regards to preventing re currence. Delayed wound healing and infections are problematic and make HPP H-PDT an undesirable addition to surgery for the treatment of this tumor ty pe. (C) 2001 Wiley-Liss, Inc.