Management with topical nitrogen mustard in mycosis fungoides

Topical nitrogen mustard (mechlorethamine, NM) has been used as primary therapy for management of patients with mycosis fungoides (MF) since the 1950s. Many investigators have demonstrated the efficacy of topical NM in patch and/or plaque disease of MF. Updated results from Stanford also confirm the clinical efficacy. The complete response (CR) rates reported are 76-80% for patients with limited patch/plaque (stage IA), and 35-68% for those with generalized patch/plaque (stage IB) disease. Topical NM can be used as an aqueous (water) or ointment-based preparation. The efficacy results are similar in patients who were treated with aqueous versus ointment preparations. Maintenance regimens used are variable, but there is no data to suggest that a longer maintenance duration results in greater potential for long-term remission. Most patients who achieve initial CR with topical NM tend to require NM-only for disease management. Topical NM is equally effective when used as salvage therapy with disease relapse. The most common toxicity of topical NM therapy is contact irritant or allergic reaction. The potential for allergic reaction is significantly reduced (< 10%) when NM is used as an ointment preparation. The potential for secondary skin cancer development is increased in patients who have used multiple sequential topical skin-damaging therapies or NM in the genital skin, but not in patients who have used NM as monotherapy (avoiding genital skin application). Topical NM is used safely in pediatric patients and there is no evidence of any clinically significant systemic absorption of topically applied NM.