Thermoradiotherapy using interstitial self-regulating thermoseeds: An intermediate analysis of a phase II trial

Objective: Thermoradiotherapy in the treatment of prostate cancer is based on a variety of experimental and clinical phase I data which have proven the synergistic effects of this combination. We report on a phase II trial in a special hyperthermia research group (SFB 273) of the German Research Foundation (Deutsche Forschungsgemeinschaft, DFG) to determine feasibility, acute toxicity and efficacy of this combination for prostate cancer. Methods: 57 patients with localized prostate cancer were treated with interstitial hyperthermia using cobalt-palladium thermoseeds and conformal radiation between July 1997 and December 2000. Thermoseeds were placed into the prostate homogeneously. Hyperthermia was created using a magnetic field and was delivered in six sessions once weekly for one hour. 3D-conformal radiotherapy of 68.4 Gy was given simultaneously in daily fractions of 1.8 Gy. Results: Intraprostatic temperatures were between 42 and 46 degreesC. No major side effects were observed during hyperthermia. Median follow-up was 36 months (range 3-72 months). Median PSA value decreased from 11.6 ng/ml to 2.4 ng/ml 3 months after treatment, to 1.3 ng/ml 12 months after treatment and to 0.55 ng/ml 2 years after therapy. Conclusion: Interstitial hyperthermia is feasible, well tolerated and led to a steep decrease of PSA values. Combining effective interstitial hyperthermia with conformal radiotherapy may be an exciting innovative treatment option for prostate cancer. (C) 2003 Elsevier B.V. All rights reserved.