With the ever-increasing use of adjunctive radiotherapy for a plethora of indications in the treatment of cancer, radiation dermatitis has been increasing in incidence. There are acute and chronic forms of radiation dermatitis, and their development is based on the total dose of radiation given. The skin is particularly sensitive to radiation damage, and it responds to the radiation in various ways. In the 1950s, the use of radiation to treat common skin conditions such as acne, tinea, and many common dermatoses was widespread. It was not until a better understanding of the long-term effects of radiation was achieved that this practice was discontinued. Localized or widespread radiotherapy is still used for some skin conditions, but it is most commonly reserved to treat malignancies such as tumor-stage mycosis fungoides or as an adjunctive therapy for melanoma, squamous cell carcinoma, Merkel cell carcinoma, or, uncommonly, unresectable basal cell carcinoma. External-beam radiotherapy can cause other complications depending on the location to which it is applied. Irradiation of the head and neck region often produces xerostomia and mucositis. Dysphagia is also a possibility. If care is not taken to protect the globe, vision alteration or blindness may occur.
The method by which the radiation dose is given (fractionated, hyperfractionated, or accelerated hyper-fractionated) is less critical in the development of radiation dermatitis than the total dose or the coexisting use of chemotherapy. Chemotherapy in combination with radiotherapy increases the chance of radiation dermatitis dramatically.
|EFFECTS OF RADIATION ON HUMANS|
Clinical Findings: Radiation dermatitis can be divided into an acute form and a chronic form. The acute form begins within weeks after the radiation therapy has started. There is a graded scale of acuity from grade I to grade IV. Almost all patients undergoing radiotherapy develop some symptoms of grade I radiation dermatitis. Grade I is defined as a slight erythema of the skin overlying the radiation site associated with xerosis of the skin. Grade II manifests with more inflammatory red patches and edema. Grade III shows evidence of bright erythema, edema, and desquamation of the epidermis. Grade IV, the most severe form of acute radiation dermatitis, manifests as full-thickness skin necrosis, erythema, and ulcerations. This is the least common form of acute radiation dermatitis but the most severe, and it requires immediate management.
Chronic radiation dermatitis is commonly seen many months to years after exposure to radiation. Poikilodermatous skin changes are most prominent, and there is a thickening and hardness to the exposed skin. Poikiloderma manifests as telangiectases, atrophy, and hyper- pigmentation and hypopigmentation. Hair loss is common, as is the loss of all appendageal structures such as eccrine glands and apocrine glands. The hair loss is permanent.
Treatment: Therapy for acute radiation dermatitis is grade dependent. There is no acceptable or reliable prophylactic method to prevent radiation dermatitis. Grade I acute dermatitis is treated with moisturizers, and the use of a low-potency cortisone cream can be considered. Grade II or III acute dermatitis should be treated with moisturizing creams such as zinc oxide paste. Strict sun protection is required. Medium-potency corticosteroids may be used, and care should be taken to avoid superinfection. If a cutaneous infection is suspected, culture and use of appropriate antibiotics is required. Grade IV dermatitis requires treatment by a team of wound care specialists adept at treating burns.
Chronic radiation dermatitis, in and of itself, does not require therapy unless the patient experiences severe tightness or hardness of the skin. In anecdotal reports, pentoxifylline has been successful in softening the areas of chronic radiation dermatitis. Topical moisturizers may help with the dryness. The most critical aspect is routine inspection of the area of chronic radiation dermatitis for the development of skin cancers, most commonly basal cell carcinoma and squamous cell carcinoma.