[Conformal radiotherapy for patients with clinical stage T1-T3 prostate cancer].

Purpose: The purpose of the study is the evaluation of the efficacy and morbidity of conformal radiotherapy in patients with clinical stage T1-T3 prostate cancer.

Material And Methods: The study group comprises 71 patients with clinical stage T1-T3, N0, M0 prostate cancer, treated with conformal radiotherapy between 1998 and 2000. The planned target volume included in all patients prostate a margin (PTV1). Forty patients (56%) were initially irradiated for the pelvic region (PTV2). The mean total radiation dose delivered to prostate was 68 Gy, and to the pelvis--44 Gy. Radiation morbidity was scored by the RTOG/EORTC system, and it was analysed in relation to the total dose. The 2-year biochemical relapse-free survival and 2-year metastatic control rates were compared by clinical T-stage and histologic grade. The probability of biochemical relapse and the probability of distant metastases were estimated as a function of clinical T-stage, histologic grade, the planned target volume (PTV1 vs PTV1+PTV2) and total radiation dose.

Results: There were no acute > or = grade III bladder toxicity, and only 3 patients (4%), who were irradiated for the pelvis had acute grade III bowel toxicity. No patient had late grade > or = III toxicity. The actual 2-year biochemical relapse-free survival and 2-year metastatic control according to T-stage were respectively: T1c--89% and 100%, T2a--90% and 100%, T2b--77% and 85%, T2c--62% and 83%, T3--58% and 65%, and by histologic grade they were respectively: G1--100% and 100%, G2--79% and 96%, G3--36% and 50%. Statistically significant relationships were found between the probability of distant metastases or biochemical relapse and histologic grade (p<0.00, p=0.005). Clinical T-stage had significant influence on the probability of distant metastases and borderline influence on the probability of biochemical relapse (p=0.004 and p=0.056). In the multivariate analysis, only histologic grade remained significant.

Conclusions: Conformal radiotherapy for prostate cancer is well tolerated, and it yields satisfactory results which depend on histologic grade and clinical T-stage.