The efficacy and safety of low-dose radiotherapy on pain and functioning in patients with osteoarthritis: a systematic review.

Low-dose radiotherapy (LD-RT) has been widely used for treatment of non-malignant disorders since its introduction and animal studies show anti-inflammatory effects in osteoarthritis (OA). However, the evidence for its effect in clinical practice remains unclear. Therefore, the aim of this study is to systematically summarise the literature on effectiveness of LD-RT on pain and functioning in patients with OA and its safety. Broad search terms were used to search PubMed, EMBASE and Web of Science. Primary inclusion criteria were osteoarthritis as indication, radiotherapy as intervention, written in English, German or Dutch and published since 1980. Study quality was assessed using the EPHPP Quality Assessment Tool for Quantitative Studies (scale: strong, moderate, weak). Seven studies were suitable for inclusion, all with retrospective uncontrolled observational design. Methodological quality of all studies was judged as weak. Most studies used 2-3 RT sessions per week for 2 weeks, some with booster session after 6 weeks. Generally, non-validated single-item measurement instruments were used to evaluate the effect of LD-RT on pain and function. Across the studies, in 25-90 and 29-71 % of the patients pain and functioning improved, respectively. Side effects were described in one study, none were reported. Our results show that there is insufficient evidence for efficacy or to confirm the safety of LD-RT in treatment of OA, due to absence of high-quality studies. Therefore, a well-designed, sham-controlled and blinded randomised trial, using validated outcome measures is warranted to demonstrate the value of LD-RT for OA in clinical practice.