Post-Operative Radiotherapy Following Radical Prostatectomy

Abstract

Biochemical relapse will occur in 17–64% of men who undergo radical prostatectomy, and up to a third of men with biochemical relapse will progress to develop metastatic disease, and ultimately die of prostate cancer. Post-operative radiotherapy (RT) to the prostatic fossa is well-tolerated and potentially curative treatment, and should be considered for all men who have positive margins or biochemical relapse following prostatectomy. Gleason score <8, PSA doubling time >10 months and PSA re-emergence >2 years following surgery predict for a low risk of early metastatic failure, but even men with no favourable prognostic factors may have a long-term durable response to RT, and should not be excluded from consideration of treatment on the basis of these factors alone. Improvements in radiation delivery with modern 3D conformal RT techniques and the integration of advanced imaging techniques such as MRI into the treatment planning process may improve tumor targeting and reduce normal-tissue toxicity for post-operative RT, and these require investigation. A positive anastamotic biopsy does not predict response to RT, and routine biopsy is not recommended. PSA level at time of RT is a strong indicator of durable response to RT, but no one PSA cut-point level appears to be more significant, and early RT is likely more effective than late. Adjuvant RT for a positive margin with an undetectable PSA offers the best opportunity to eradicate microscopic disease while tumor is localized and the tumor burden is lowest, but it also risks over-treating some men. Contemporary PSA assays can detect biochemical relapse in the 0.01–0.2 range, and this may provide additional therapeutic advantage if treatment can be given once relapse is proven and when tumour burden is small. There is an urgent need for prospective data from randomised trials to optimally select patients for adjuvant or salvage RT, to determine the optimal time to initiate treatment and to determine the role of adjunctive hormone therapy, and all patients should be considered for entry into ongoing and future clinical trials.