Bladder cancer (urothelial carcinoma) is the sixth most common cancer worldwide. The treatment of the heterogeneous group of non-muscle invasive bladder tumours (NMIBC) with a combination of intravesical chemotherapy with regional hyperthermia (HT) -i.e. radiofrequency induced intravesical chemohyperthermia (RF-CHT)- was the subject of the systematic review of the LBI-HTA (since 03/2020 Austrian Institute for HTA, AIHTA). It was investigated whether RF-CHT is safer and more effective than other interventions. The most frequently used application is the Synergo® system, in which HT is administered by direct radiofrequency-induced irradiation of the urothelium. The treatment usually consists of two 20-30 minute sessions and aims to reach a temperature above 41°C for at least 20 minutes per session. There are prophylactic and ablative protocols, both consisting of a series of treatments. To evaluate the effectiveness of RF-CHT, four RCTs and one NRCT were included (503 patients*, 243 of them with RF-CHT). Conclusion: The technology is considered experimental and should only be used in clinical trials.