High dose combination radiotherapy for the treatment of localized prostate cancer.

PURPOSE: We evaluate the efficacy of high dose combination radiotherapy for the treatment of localized prostate cancer.
MATERIALS AND METHODS: A total of 212 patients with localized prostate cancer (T1-T3) were treated with transperineal radioactive seed implantation followed by 45 Gy. external beam radiation therapy. Patients with Gleason scores of 2-5 were treated with 125iodine at a minimum peripheral dose of 120 Gy., while 103palladium at a minimum peripheral dose of 90 Gy. was used for those with Gleason scores of 7-10. Patients with Gleason 6 diploid tumors were treated with 125iodine and those with aneuploid tumors were treated with 103palladium. Biochemical failure was defined as inability to achieve a prostate specific antigen nadir value of 0.5 ng./ml. or less. No patient was treated with androgen deprivation therapy.
RESULTS: The 212 patients have a minimum of 24 months of followup (mean 33 months). Prostate specific antigen 0.5 ng./ml. or less was reached by 72% of the patients (152 of 212) and positive biopsies were detected in 13.9% (20 of 144). Using life table survivorship analysis the probability of initial biochemical success at 5 years was 91% (95% confidence interval, 83 to 97). The probability of subsequent failure following an initial success was 11% (95% confidence interval, 6 to 20) at 24 months. The complications of combination therapy included proctitis in 21.4% (47 of 212 men), impotence in 38% (38 of 100), urinary retention in 1.5%, incontinence in 2.8%, rectoprostate fistula in 2.4%, rectal wall breakdown in 0.5% and urethral stricture in 0.5%. Six patients (2.8%) required colostomy and urinary diversion.
CONCLUSIONS: Short-term responses to high dose combination radiotherapy for localized prostate cancer are promising. The morbidity is acceptable. Further long-term followup is warranted to assess this treatment.