Skin Cancer Incidence among Children Irradiated for Ringworm of the Scalp

Abstract

A series of about 2200 children who received X-ray treatment for ringworm of the scalp (tinea capitis) during the 1940s and 1950s, and a comparable group of 1400 treated without X ray, have been followed by mail questionnaire for an average of 26 years since treatment to tabulate the incidence of skin cancer. The X-ray treatment consisted of 300-380 R to five overlapping fields on the scalp, to cause complete depilation. This delivered doses of 300-600 rad to various portions of the scalp, with lower doses to the skin of the face and neck. In the irradiated group, 41 persons have had one or more basal cell carcinomas of the scalp or face while only three have been diagnosed in controls. There was a high prevalence of multiple skin cancers in the irradiated group (80 lesions among 41 cases). The minimum latent period for radiation-induced skin cancers was long--about 20 years--and this may be attributable to the young age of the population. The skin cancer risk was particularly pronounced on the face, where there would be more UVR exposure in addition to X-ray exposure. Lightness of complexion proved to be an important factor in the skin cancer risk. In addition, skin cancers were found only among caucasians, even though 25% of the study population were blacks. These findings suggest that UVR exposure levels or sensitivity to such exposure interact with ionizing radiation exposure in defining skin cancer risk.

Squamous Cell Carcinoma – 70 Years after Irradiation

“…In one study, the incidence of skin cancer in 306 patients, irradiated over a time span of 19-48 years previously, was 30 tumors in 21 patients [9], In another study [8], two groups of patients were examined. Out of 2,200 patients irradiated for ring worm of the scalp in childhood.…”

“…has been used for tinea capitis for 50 years [3]. Many studies and reports have been published of skin tumors induced by ionizing radiation [4][5][6][7][8][9]. This is the first report of carcinoma which appeared 70 years after irradiation.…”

Therapeutic Ionizing Radiation and the Incidence of Basal Cell Carcinoma and Squamous Cell Carcinoma

“…2,14,16 However, it is difficult to separate the effects of latency from those of age at treatment and type of therapy received. In our data, risks of BCC and SCC were highest among those treated 40 years or longer before diagnosis.…”

Radiotherapy for benign disease; assessing the risk of radiation-induced cancer following exposure to intermediate dose radiation

“…Several studies show an increase in non-melanoma skin cancer (NMSC) caused by occupational exposure to IR 85 and during RT for a range of benign indications, e.g. tinea capitis, 52,53,86 acne and other skin disorders. 54,55 Other reports have failed to confirm this.…”