Projecting the clinical benefits of adjuvant radiotherapy versus observation and selective salvage radiotherapy after radical prostatectomy: a decision analysis.

Our purpose was to project and compare clinical and quality-adjusted life year (QALY) outcomes of adjuvant radiotherapy (ART) versus salvage RT (SRT) after radical prostatectomy for men with locally advanced prostate cancer. We constructed a Markov model to simulate the randomized studies of observation versus ART, assuming 75% of observation patients would receive SRT at PSA recurrence. Transition probabilities and utility inputs were drawn from randomized trials of ART and cohort studies of SRT. We projected 10-year PSA recurrence-free survival, metastasis-free survival and overall survival. We found that observation with selective SRT yielded slightly worse outcomes than ART for post-RT PSA recurrence-free survival (47 and 52%), metastasis-free survival (69 and 70%) and overall survival (72 and 73%). Findings were robust to sensitivity analyses. After adjusting for the disutility of RT, observation plus SRT yielded better QALYs at 10 years than ART (6.80 and 6.13 QALYs). Thus, observation plus SRT may be optimal for men likely to comply with surveillance who wish to minimize side effects of the treatment. These findings reflect outcomes for the average patient given the current level of evidence and are meant to help inform current decision-making as we await future clinical studies of comparative effectiveness.