Background: To analyse the impact of radiation dose escalation and hormone treatment in prostate cancer patients according to risk groups.
Material and methods: Totally 494 prostate cancer patients received external beam radiation therapy, with or without androgen deprivation, between January 1990 and December 1999. The patients were divided into three risk groups, where the low risk group (stage T(1c), pretreatment prostate-specific antigen (PSA) level < or =10 ng/ml and WHO Grade 1) included 26 patients, the intermediate risk group (either stage T(2), PSA 10.1-20 ng/ml or WHO Grade 2) comprised 149 patients whereas the high-risk group (either stage T(3), PSA >20 ng/ml or WHO Grade 3) included 319 patients.
Results: In the intermediate risk group, the 5-years bNED rate was 92%, 69% and 61% after a radiation dose of 70 Gy, 66 Gy or 64 Gy, respectively (p < 0.001). In the high-risk group, the 5-year bNED rate was 79%, 69% and 34% for the same dose levels (p < 0.001). The 5-years CSS rates were not significantly different between the dose levels in the intermediate risk group while for the high-risk group it was 93%, 92% and 80% for the three dose levels (p < 0.001). Risk group and radiation doses were independent predictors of bNED, CSS and overall survival, for bNED also hormone treatment was independent predictors.
Conclusion: Radiation dose is important for the outcome in intermediate and high risk prostate cancer patients. A dose of 70 Gy should be considered the minimal dose for these patients.