Interstitial microwave thermal therapy and its application to the treatment of recurrent prostate cancer.

Interstitial microwave thermal therapy may be an effective alternative to surgery for the treatment of some solid tumours. Arrays of helical antennae can produce complex heating patterns which when combined with active cooling of normal tissue structures can provide conformal heating for thermal coagulation of tumours. The development of a clinical protocol involving phantom and animal model studies, treatment planning, tissue property measurement and methods for on-line treatment monitoring is reviewed. The technology developed has been applied to the problem of recurrent prostate cancer following failed radiation treatment where available curative options are associated with high normal tissue morbidity. The purpose was to develop a treatment option for this group of patients with a very low side-effect profile that would not preclude further treatment if the disease progressed. Results of a Phase I/II trial demonstrate safety, promising efficacy and a low complication rate. As the technology for delivering this treatment matures, larger multi-institutional trials should be considered.