Radiotherapy for benign diseases is gaining increasing significance. In 2016, about 55% of radiation treatments in Germany were used for benign conditions, including inflammatory diseases or benign tumors.1

Historically, the first benign condition treated with irradiation was juvenile arthritis in 1897, reported by Nikolai Sokoloff.2 Although low-dose radiotherapy is no longer used for childhood arthritis, osteoarthritis in adults continues to be one of the most common indications. A pattern of care study conducted 2014 in Germany, involving 116 participating institutions and treating 36,830 patients, found that most institutions focused on treating patients with degenerative diseases (eg, peritendinitis humeroscapularis, epicondylitis humeri, heel spur) and osteoarthritis (including coxarthrosis, gonarthrosis, omarthritis, rhizarthrosis, and polyarthrosis). Less common indications included hyperproliferative conditions such as Dupuytren’s disease, Ledderhose disease, keloids and functional disorders like Graves' disease, or prophylaxis for heterotopic ossification. It should be noted that only one-third of the invited institutions participated in the pattern of care study; hence, the number of treatments performed will therefore be significantly higher.3 In this review, we aim to highlight rare indications and their evidence.