Treatment is divided into skin-directed and systemic therapy.
Skin-directed therapy is the mainstay in early phases of disease and as an adjunct for systemic disease.
Therapeutic options for mycosis fungoides are listed in Table 66–3 and in Figure 66–4. Details of their use are described in Williams Hematology, 8th edition, Chap. 105, p.1601.
Therapeutic modalities produce remission in most patients, but cure is uncommon.
Topical glucocorticoids may be useful for pruritus, but they should not be used for long periods because they inhibit collagen synthesis and predispose to cutaneous infection. They should not be used on face, neck, or intertriginous areas. They can foster acne, glaucoma, and cataracts.
Topical nitrogen mustard for early cutaneous disease has low toxicity but is not curative. It is also inconvenient to use as it must be applied daily to large areas of skin and frequent allergic responses occur. In responders, treatment should be continued for a year (or until lesions disappear) and then can be decreased in frequency for an additional year or two.
Topical retinoids (e.g., bexarotene) can induce complete responses in 20 percent and improvement in an additional 40 percent. Approved for use in patients refractory to another topical therapy. Must not be used in pregnant women.
Phototherapy with ultraviolet (UV) radiation in the form of UVA or UVB spectrum can be useful in early disease, patches, and very thin plaques. Given at least three times per week for 4 to 8 weeks to achieve maximal response. May result in complete clearing of lesions. Acute cutaneous burning can occur and slight increase in long-term risk of other skin cancers.
Psoralen with ultraviolet A light (PUVA): Psoralen dose of 0.6 mg/kg, orally, 2 hours before ultraviolet A light therapy, three times per week, followed by maintenance therapy given every 2 to 4 weeks indefinitely.
PUVA results in 60 percent complete remission rate for patients with cutaneous plaques. Lower response rates for patients with generalized erythroderma or tumors. Adverse effects include mild nausea, pruritus, and sunburn-like changes.
PUVA is not curative.
Electron-beam therapy: 80 percent complete remission rate; 20 percent disease-free at 3 years; 4 Gy/week (total dose 36 Gy in 8 to 9 weeks). Can be given to specific lesions or to total skin surface.
Oral retinoids (e.g., bexarotene) 300mg/m2 per day induces overall response in about 50 percent of patients and a complete response in about 1 in 50 patients. Virtually all patients develop central hypothyroidism and hypertriglyceridemia. Requires treatment with thyroid replacement and lipid lowering agents. Headaches, leukopenia, pruritus may occur. Usually used in more advanced stages. Must not be given to pregnant women or those considering pregnancy.
Histone deacetylase inhibitors (e.g., vorinostat and romidepsin), interferon-α, a variety of single agent chemotherapy (e.g., pralatrexate, cyclophosphamide, fludarabine, doxorubicin), and combined agent chemotherapy have been used. Single agent therapy is occasionally effective but duration of response has been short, usually. Combined agent therapy is more toxic, about 25 percent of patients have a good response but long-term disease-free survival is extremely uncommon (see Williams Hematology, 8th ed, Chap. 105, p. 1603).
Several other therapies are under study.