Methoxsalen photochemotherapy for mycosis fungoides.

Methoxsalen photochemotherapy (PUVA; psoralen plus ultraviolet light) is effective in the treatment of mycosis fungoides (MF). The mechanism of this beneficial effect is unknown but probably involves covalent photo-binding of methoxsalen molecules to pyrimidine bases in DNA at the cellular level and impaired T-cell function or survival at the tissue level. Eleven patients (seven with plaques and four with erythroderma) were referred for PUVA therapy because of poor response to conventional therapy. Seven patients had complete clearing of skin lesions and three improved markedly. All ten of these patients experienced good to excellent control of the disease while receiving maintenance therapy, resulting in a virtual remission lasting for greater than 2 years in four patients. Of the six patients who discontinued PUVA during the followup period, three died within 1 year and three experienced progression of MF despite conventional therapy. The very promising results in this small patient group should encourage further studies of PUVA for cutaneous T-cell lymphomas.