Hyperthermia is a cancer treatment that uses high temperatures to either destroy cancer cells directly, or to make the body hotter so that other cancer treatments can work better. It is a promising but experimental technique, and not in widespread use. When treating the tumour directly, there are issues in keeping the heating localised to the cancer so that healthy tissues aren’t damaged, as well as keeping the heat stable. We still need to test the technique in large clinical trials to work out exactly how effective it is. Some clinical trials have looked at using hyperthermia to treat bile duct cancer, but always in conjunction with other treatments like chemotherapy or radiotherapy. There have been some promising results, but these are preliminary studies.