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RADIOTHERAPY OF BENIGN SKIN DISORDERS
Background
The role of radiotherapy in treating benign cutaneous disorders has markedly diminished over the past several decades. It is no longer ethical to offer radiotherapy as a treatment for acne, warts, hirsutism, or tinea capitis. The role of radiotherapy in treating inflammatory skin conditions (e.g. dermatitis, psoriasis, lichen planus) is historical due to efficacious alternative treatments (e.g. corticosteroids, phototherapy, systemic immunomodulators), and the risk of exposing patients to ionizing radiation. Superficial radiotherapy has occasionally been used to treat recalcitrant Hailey-Hailey disease.
Keloids
Recurrent keloids, often refractory to re-excision and intralesional corticosteroid injections, can have significant cosmetic, functional, and psychologic sequelae for patients. The addition of low-dose (12โ20โGy) adjuvant radiotherapy delivered in three to five fractions, beginning within 24โ48โhours following surgery, can markedly and safely reduce the incidence of recurrence. A recent dose-response study involving 250 keloids concluded that 20โGy delivered in 5 fractions was the optimal postoperative regimen, when balancing relapse rate (2%) against adverse effects. A common site for keloids is the earlobe and patients can be treated with low-energy photons plus lead shielding of surrounding tissues. Young patients with keloids of the lower anterior neck (in close proximity to the thyroid gland) should not be irradiated.
Cutaneous Lymphoid Hyperplasia (Cutaneous Pseudolymphoma)
Cutaneous lymphoid hyperplasia (cutaneous pseudolymphoma) often arises on the face (see Ch. 121). When lesions fail to respond to intra-lesional corticosteroids, low-dose fractionated radiotherapy utilizing low-energy photons (10โ15โGy in five fractions) is an efficacious treatment option with minimal, if any, side effects.