Biochemical response after 3-d conformal radiotherapy of localized prostate cancer to a total dose of 66 gy 4-year results.

Background: Since the introduction of 3-D conformal radiotherapy (CRT) doses of
Patients And Methods: From January 1994 to February 1999 397 patients were treated for carcinoma of the prostate. In 279 patients a definitive curative treatment (T1 = 38, T2 = 165, T3 = 50, Tx = 11) with or without androgen deprivation was performed. 164 patients with radiotherapy of the prostate +/- seminal vesicles to a total dose of 66 Gy (n = 109) alone or in combination with a short-term hormonal treatment (n = 55) were included in this analysis. Biochemical relapse was defined as three rising PSA values or reintroduction of hormonal treatment. A low-risk subgroup was defined for patients with maximum serum PSA level
Results: The median follow-up of alive patients was 40 months (12-72 months). There was a total of 29/164 deaths, two were cause-specific and 27 were considered unrelated to prostate cancer. The 4-year rates of no biochemical evidence of disease for all patients was 58%. For the high-risk group the 4-year rates could be improved with borderline significance from 35% to 66% (p = 0.057) by additional neoadjuvant hormonal treatment. In contrast for the low-risk group no significant improvement was observed: 73% and 82%, respectively (p = 0.5).

Conclusion: Especially in high-risk patients doses /= 70 Gy should be considered. As a consequence of our earlier analysis a prospective multicenter treatment optimization protocol has been initiated in 1999. The protocol includes a risk-adapted dose increase from 70 Gy in low-risk patients to 74 Gy in high-risk patients including short-term androgen ablation.