Photoradiation therapy of cutaneous angiosarcomas in mice.

Abstract

Cutaneous angiosarcoma is a relatively rare but devastating malignant vascular tumor. It has a high incidence of recurrence following conventional therapeutic modalities applied either singly or in combination. The increased vascularity of cutaneous angiosarcomas, facilitating selective uptake and retention of a photosensitizing agent, such as hematoporphyrin derivative (HPD), suggests that these tumors would respond well to photoradiation therapy. To study the feasibility of this treatment modality, transplantable hemangiosarcomas were implanted in B6C3F1 female mice. Within 2.5 to 3.5 hours after intraperitoneal administration of HPD, fluorescence was recorded in the tumor as compared with surrounding normal skin. When these photosensitized tumors were exposed to 70 J/cm2 of laser energy from an argon-pumped dye laser at 630 nm, the tumors showed marked necrosis within 24 hours. In another series, the tumors were initially photosensitized with HPD for 3 hours and then treated with laser energy ranging from 0 to 96 J/cm2. A dual labeling procedure demonstrated a dose-related decrease in DNA synthesis rate in tumors that were exposed to 0 to 30 J/cm2 at 24 hours after treatment. Furthermore, tumor tissue exposed to laser energy in excess of 30 J/cm2 showed no significant cellular DNA synthesis. These data, supported by histologic evidence of tissue destruction, suggest that photoradiation therapy has a great potential as a therapeutic modality for cutaneous angiosarcomas.