Australian prostate-specific antigen outcome and toxicity following radiation therapy for localized prostate cancer

The objective of the present study was to examine prostate-specific antigen relapse free survival (PSA-RFS) and morbidity following 'conventional' radical radiation therapy for prostate cancer in two Australian regional treatment services. Four hundred and eighty men with clinically localized prostate cancer were treated between 1993 and 1997 at Liverpool and Westmead Hospitals using a standardized 4-field, CT-planned radiotherapy technique. Principal endpoints were PSA-RFS (American Society for Therapeutic Radiology and Oncology guidelines definition) and late rectal and urinary morbidity (Radiation Therapy Oncology Group/European Organisation for Research and Treatment of Cancer criteria). The median follow up of patients from the end of RT was 55 months. Prospectively, they were divided into three prognostic categories: (i) high risk T3 or 4 and/or PSA > 20 ng/mL and/or Gleason score 8-10 (40% of cohort); (ii) intermediate risk T1 or 2 and PSA 10-20 ng/mL and/or Gleason score 7 (33% of cohort); and (iii) low risk T1 or 2 and PSA < 10 ng/mL and Gleason score < 6 (27% of cohort). The 5-year actuarial PSA-RFS was 53% for the whole patient group. The 4-year rates were 32, 56 and 75% for high, intermediate and low risk groups, respectively. On multivariate analysis, T-stage, Gleason score, pre-RT-PSA were strong independent predictors of PSA-defined outcome. Late (grade 2) rectal and urinary morbidity occurred at some point in time in the post-RT period in 8.0 and 5.8% of patients, respectively. These results confirm that low Gleason score, low T stage, presenting PSA < 10 ng/mL and nadir < 1 ng/mL remain the strongest predictors of a good outcome. Long-term toxicity was very acceptable. However, further improvement in outcome is desirable, and with the adoption of new technology allowing escalation of radiotherapy doses such an expectation might be achieved.