Application of invasive microwave hyperthermia for the treatment of gliomas.

Twenty five cases of gliomas of the brain were operated upon by debulking the tumour masses. Following this, microwave hyperthermia was given by heating a measured volume of Ringer's solution instilled into the tumour cavity. This was followed by a 'dry treatment' without Ringer's solution. The follow up of these cases revealed that 11 cases have died and 14 cases are alive post-operatively. For those that are alive, the follow up period ranges from 21 to 41 months with the mean survival period of 31.1 months; in this group, 12 cases have a Kanofsky scale of 80-100, i.e. they are fully independent. The other two cases have a score of 50 or under and they need institutional care. In this study, we believe that the first order effect of microwave hyperthermia is predominantly thermal and in the published literature, and in this investigation, there is no clear evidence that microwave radiation produces any other beneficial and quantifiable effect on the tissue.