Sherar MD et al. (2004) Interstitial microwave thermal therapy and its application to the treatment of recurrent prostate cancer. Int J Hyperthermia 20: 757–768

Interstitial microwave thermal therapy has been investigated as a treatment for certain solid tumors. Sherar et al. have applied this technology to the field of prostate cancer and have recently reported on their experience.

Thermal therapy is based on the selective coagulation of the tumor tissue; protection of the surrounding, normal tissue is crucial. Interstitial microwave therapy allows relatively precise control of the zone of thermal damage. Indeed, treatment simulations using phantom materials showed that the prostate can be targeted whilst the urethra is protected using a cooling mechanism. A Phase I/II trial examined the safety and efficacy of interstitial microwave therapy as an alternative to prostatectomy or hormone therapy in 41 patients with prostate cancer. All patients had recurrent disease following external beam radiation therapy. Disease-free survival was similar to that found using cryotherapy but, importantly, complication rates were lower.

The authors explain that the development of this technology will focus on the prediction of changes in tissue properties and blood flow during the heating process. It will also be important to determine the optimal level of protection of the normal tissue and to reduce cost and risk. Noting that the treatment might be appropriate for other patient groups, including those who have failed primary brachytherapy, Sherar et al. call for larger, multicenter trials in this area.