[Treatment of prostate cancer by radiotherapy]

Fifty-seven patients with clinically localized prostate cancer were treated by radical prostatectomy or external radiation therapy following pelvic lymphadenectomy. Comparing the outcome of radiotherapy with that of prostatectomy in 42 T2 patients without lymph node metastasis, the 5-year cause-specific survival did not differ between the radical prostatectomy group (n = 31) and radiotherapy group (n = 11). The 5-year disease-free survival of the prostatectomy group, however, was superior to that of radiotherapy group (p = 0.01). To cure patients with T2 prostate cancer, therefore, it is supposed that radical prostatectomy should be performed. To improve the treatment outcome after radiotherapy, stereotactic radiosurgery for prostate cancer has been attempted in our institution. Phantom experiments using a linear accelerator demonstrated a round dose distribution, and high reproducibility of prostate positioning was confirmed by CT when a thermoplastic immobilization device was used to fix the pelvis. In one patient with localized prostate cancer treated by radiosurgery, acute complication has not been recognized during the 5 week follow-up. Radiosurgery may be available to treat clinically localized prostate cancer.