Certainly, data support adjuvant radiotherapy compared to a 'wait-and-watch' strategy to reduce recurrence rates, however uptake of adjuvant radiotherapy has been low amongst clinicians. Considering there are no randomized, controlled trials (RCTs) comparing adjuvant radiotherapy with salvage radiotherapy (administered at the time of recurrence), the objective of this study was to provide further insight into the timing of radiotherapy after radical prostatectomy using a decision analysis approach.
For this study, the authors constructed a Markov (health state transition) model to compare the quality adjusted survival associated with postoperative strategies using adjuvant or salvage radiotherapy. Transition probabilities and utilities for disease states were derived from a literature search of MEDLINE and expert consensus. Prior to analysis, the model was calibrated and validated using results of previous RCTs. Clinically important oncological health states were considered from immediately postoperative to prostate cancer-specific death, commonly described complications from prostate cancer treatment, and other causes of mortality. Examining recurrence rates, the model demonstrated validity compared to available RCT data. Salvage radiotherapy was associated with increased quality-adjusted life expectancy (QALE) (58.3 months) as compared to adjuvant radiotherapy (53.7 months), a difference of 4.6 months (SD 8.8 months). Additionally, salvage radiotherapy had higher QALE in 53% of hypothetical cohort analyses, with a small difference in overall life expectancy (-0.1 months).
The authors concluded that based on this decision analysis, salvage radiotherapy appears to provide improved QALE for patients with adverse pathological findings following radical prostatectomy compared with adjuvant radiotherapy. Since these findings reflect population averages, specific patient and tumor factors, and patient preferences remain central for individualized management. In the absence of high quality clinical trial level data, these decision analyses should be strongly considered when discussing treatment options with patients.
Speaker: Christopher JD. Wallis, PhD, University of Toronto, Toronto, ON, Canada
Co-Authors: Gerard Morton, Angela Jerath, Raj Satkunasivam, Ewa Szumacher, Sender Herschorn, Ronald T. Kodama, Girish S. Kulkarni, David Naimark, Robert K. Nam
Written By: Zachary Klaassen, MD, Urologic Oncology Fellow, University of Toronto, Princess Margaret Cancer Centre Twitter: @zklaassen_md at the 72nd Canadian Urological Association Annual Meeting - June 24 - 27, 2017 - Toronto, Ontario, Canada