Background and purpose: Since long-term results of the standard treatment of locally advanced or recurrent prostatic carcinoma are unsatisfactory, the role for additional regional hyperthermia was evaluated in a phase I/II study.
Patients and methods: From 08/1996 to 03/2000, 22 patients were treated by a standard irradiation regimen (68.4 Gy) in combination with regional hyperthermia (weekly, five to six times), and five of 22 patients received short-term (neoadjuvant) hormonal treatment. Of these, 15 patients had primary prostatic carcinoma T3 pN0 M0 and seven a histologically confirmed local recurrence after radical prostatectomy. Feasibility of hyperthermia, and acute/late toxicity as well as long-term follow-up (prostate- specific antigen [PSA] control, overall survival) were analyzed. Clinical endpoints were correlated with thermal parameters.
Results: Mean maximum temperatures along the urethra of 41.4 degrees C (41.0 degrees C for the recurrences), and mean T(90) values of 40.7 degrees C could be achieved. Severe acute toxicity of grade 3 occurred at the rectum in three, at the urethra in four, at the intestine in one, and a burn induced by hyperthermia in one of 22 patients. Late toxicity was only observed rectally in one patient (grade 3) and at the urethra in two patients (grade 2). There was no correlation between thermal parameters and any toxicity. The survival curves showed a PSA control for primary prostatic carcinoma > 50% after 6 years, but no long-term PSA control for the recurrences. Overall survival after 6 years was 95% for primary carcinoma, and 60% for the recurrences. There was a clear correlation between higher temperatures or thermal doses with long-term PSA control.
Conclusion: Regional hyperthermia might be a low-toxicity approach to increase PSA control of common treatment schedules. Further evaluation, in particular employing improved hyperthermia technology, is worthwhile.