There is a device the US FDA approved for brain tumors (Optune by Novocure)that uses alternating electrical fields. It surprised the field when it got approved

There is a device the US FDA approved for brain tumors (Optune by Novocure)that uses alternating electrical fields. It surprised the field when it got approved as its mechanism wasn't conventional or well understood. There were also some confounding factors in the study design. That said, it's in a bunch of other tumor types now in more studies.