Photodynamic therapy in the management of metastatic cutaneous adenocarcinomas: case reports from phase 1/2 studies using tin ethyl etiopurpurin (SnET2).
BACKGROUND AND OBJECTIVES: Photodynamic therapy (PDT) using a photoreactive purpurin, tin ethyl etiopurpurin (SnET2, Purlytin, Miravant Medical Technologies, Santa Barbara, CA), was investigated as a treatment for cutaneous metastatic disease that had failed other treatment options. STUDY DESIGN/MATERIALS AND METHODS: Three patients with biopsy-proven metastatic adenocarcinoma of the skin were treated with a single dose of the study drug. Twenty-four hours later, the patients were exposed to a laser light at 664 nm in multiple light fields. Patients were followed for 6 months for safety, efficacy, recurrence, and palliative response. RESULTS: After PDT with SnET2, complete response was observed in all 13 treated lesions in three patients, with no evidence of recurrence at any treated site at the 6-month follow-up. Two patients subsequently died of distant metastatic disease. One patient with local chest wall recurrence after mastectomy was disease-free 24 months after PDT. CONCLUSIONS: PDT with SnET2 could be an effective treatment in locally advanced metastatic carcinoma of the skin.