Topical diphencyprone immunotherapy for cutaneous metastatic melanoma.

Topical immunotherapy with contact sensitizers for metastatic melanoma was first reported more than 30 years ago. Diphencyprone (DPCP) immunotherapy is frequently used to treat cutaneous warts and alopecia areata, and we have previously reported the use of DPCP as a single agent to successfully treat extensive, radiotherapy-resistant melanoma metastases on the scalp. We now report DPCP treatment of a further six patients with cutaneous metastatic melanoma. Of seven patients treated with DPCP thus far, four have demonstrated complete responses of their cutaneous lesions and three have had partial responses. The treatment was well-tolerated by all patients. Topical immunotherapy with DPCP is inexpensive and relatively non-invasive and should be considered in patients with locally advanced skin metastases that are unsuitable for other therapies.