Skin cancer occurs as late somatic damage caused by skin exposure to ionizing radiation.
In fact, people in the past used ionizing radiation (dose > 10Gy) in treating benign skin conditions like acne, psoriatic keratoses, hemangiomas. This ionizing radiation causes radiodermatitis (skin disease associated with prolonged exposure to ionizing radiation).
Radiodermatitis is characterized by cutaneous atrophy, depigmentation, telangiectasias (widened venules), alopecia (hair falling), and keratosis. After a long period of time, 20 to 40 % of these patients develop planocellular (or basocellular if the lesion is on the face) skin cancer.
Also, the occurrence of planocellular skin cancer is noticed on the hands of radiological technicians and dentists, due to improper care and skin (hands) exposure to radiation.
Modernization of radiation equipment and implementing adequate protection against ionizing radiation drastically reduced the risk of skin cancer caused by ionizing radiation.