Treatment of naturally occuring hemangiopericytoma and oral squamous cell carcinoma in dogs using surgery and photodynamic therapy with HPPH as a photosensitizer

摘要

Pyropheophorbide-a-hexyl ether (HPPH) is a new photosensitizer for use with photodynamic therapy (PDT) that has shown promise in laboratory animals. PDT, using this drug, is being used to treat canine patients afflicted with hemangiopericytoma and oral squamous cell carcinoma (SCC) at the University of Missouri-Columbia College of Veterinary Medicine. To date, 11 dogs with hemangiopericytoma and 5 dogs with oral SCC have been treated using a combination of surgery and PDT. Thus far, there have been no serious complications attributable to the treatment. Two dogs have had recurrences of the hemangiopericytoma and there have been no recurrences of SCC with a median follow time of 5 months. Both recurrent hemangiopericytomas were in patients with large tumors that had previous surgery. This study is ongoing and no conclusions have been reached; however several observations are noted. It appears that PDT using HPPH is safe is dogs, and may decrease the recurrence rate of Hemangiopericytomas. In dogs with oral SCC, the treatment is effective is causing necrosis and sloughing of the tumor tissue, and recurrences have not been noted on follow-ups up to 6 months.