The Role of Radiotherapy in Orbital Pseudotumor: A Systematic Review of Literature.

Orbital pseudotumor (or pseudotumor orbitae) is a benign entity, also known as idiopathic orbital inflammatory syndrome (IOIS), which encompasses a wide range of non-tumoral, space occupying lesions of the orbit. In selected cases of refractory disease or presence of side effects or even comorbidities that limit systemic therapies, radiotherapy could play a role in the management because it has been demonstrated that irradiation is effective in suppressing the inflammatory process. A systematic review of the literature about the main scientific databases was launched and the time interval included all published articles present in the databases from their inception until September 2020. We were able to identify 19 studies eligible for inclusion in this review from 1978 to 2018. Overall the data of 241 patients were collected and are presented in this systematic review. The response rate varied between 74% and 100% with a median recurrence rate of 10%. The median total dose was 20 Gy whereas the mean total dose was 21 Gy with a range from 4 to 36 Gy. Regarding the fractionation, 2 Gy/fraction daily was the most widely used. Radiotherapy seemed to achieve good response rates however, in most of the studies, inclusion criteria and outcome parameters are not uniform and therefore the results are difficult to compare. Often important parameters such as chronic pain and permanent functional deficits are not assessed in the outcome. Therefore, prospective studies, with good cohort characteristics and a clear definition of the outcome, are required.