Electron beam radiotherapy for Kaposi's sarcoma of the toe and web

Kaposi's sarcoma (KS) is an uncommon neoplastic vascular disease. The standard treatment for localized classic KS lesions is surgical excision or radiation. Superficial skin lesions are generally treated with electrons or low-energy photon fields using boluses. Radiotherapy (RT) can be used for poor surgical candidates or when surgery is expected to result in a poor cosmetic or functional outcome. This study is the first to describe a case of KS of the toe and web treated with electron RT, which precisely targeted the irregular skin lesion with a markedly higher presided effective treatment. An electron field is often limited in its effectiveness to deliver a homogeneous dose in cases with irregular contours. Here, we report our successful experience using low-energy electron beam radiation to treat KS of the toe and web. The patient was a 78-year-old woman who was diagnosed with KS located on the first and second toe and web, based on radiology, pathology, and immunohistochemical examinations. KS was located on the left foot and measured more than 2.5 cm. No regional nodal or distant organ metastasis was observed. She was medically inoperable. RT was performed using a 6-MeV electron with a 0.5-cm bolus and a dose of 50 Gy delivered in 25 fractions. Follow-up computed tomography 2 months after RT revealed a complete tumor response. Toxicity was limited to mild skin desquamation during treatment. The patient remains alive and has shown no evidence of disease for 2 years. This study suggests that electron RT is a safe and effective treatment option for skin lesions located on the toe and web.