Background: Hyperthermia is an intervention that uses microwaves to heat target tissue up to 41-45° Celsius. In clinical studies hyperthermia is evaluated as supplementary tumour therapy in combination with radiation therapy or chemotherapy is certain tumour stadiums. A comprehensive German assessment from 2005 (commissioned by the Federal Joint Committee of the German Health Care System – GB-A) concluded from their summary of the evidence, that hyperthermia is not recommended for routine use. The current assessment summarises the evidence after the 2005 German review for 11 (promising) tumour indications and evaluates, whether the status of evidence has changed since then.

Method: Medical databases and Health Technology Assessment databases were systematically searched for studies that evaluate hyperthermia. The selection process based on predefined inclusion criteria and is documented by a PRISMA Flowchart. For all studies the quality of evidence was assessed. Finally the evidence from the studies was summarised based on particular outcomes (using the GRADE method). This was the basis for a recommendation for the current use.

Results: 6 RCTs and a long-time follow up of an RC were included. No other prospective controlled studies could be identified. The studies report the application of hyperthermia within the following indications: rectal carcinoma (1 study and 1 long time result), breast cancer (1 study), cervical carcinoma (1 study), melanoma/superficial (2 studies) tumours and anal tumours (1 study). The quality of the collective evidence is moderate to low, because there was predominantly only one study per indication and the majority of the studies showed limitations. The majority of the studies do not show an advantage for the endpoints survival or quality of life. A few studies show an advantage in the endpoint local control, but this term was defined inconsistently and some criticisms exist whether the measurement of local control is convincing. Other studies show clear disadvantage of additional hyperthermia. The majority of studies report a high rate of acute toxicity.

Discussion: The results of studies assessing survival and quality of life do not show an advantage in adding hyperthermia. The result from local control based outcomes show a heterogenic picture and there relevance for patients is partially unclear. Acute side effects are reported frequently where hyperthermia is applied. The collective evidence is too low to conclude a beneficial effect for patients. Results of new studies are announced that may have an important impact to the evidence situation.

Conclusion: The use of hyperthermia can not be generally recommended, because the strength of the evidence (on time of this assessment) is too weak to conclude a net benefit. Hyperthermia should therefore only be applied within clinical studies.