[Radiotherapy in dermatology].

Ionizing radiation causes cell death through DNA damage and has a stronger effect on undifferentiated tumor cells with a high mitotic rate. The use of a fractionated radiotherapy regimen improves both efficacy and tolerance. In addition, greater fractionation, with lower doses per session, minimizes adverse effects. In the majority of tumors treated with radical radiotherapy, the tumor cells do not disappear immediately after treatment, and assessment of the final response to treatment before three months is premature. Radiotherapy is an important treatment modality in selected patients with skin cancer. Modern radiotherapy equipment and techniques achieve excellent rates of tumor control, associated with good cosmetic results, preserved function, and a low rate of complications. The choice of technique is determined by tumor size and site and the thickness. The techniques most widely used at the present time include external beam radiotherapy with linear accelerators and high-dose-rate brachytherapy.