Objectives: To determine pattern of practice and outcomes for administration of androgen deprivation therapy (ADT) post radical prostatectomy (RP) comparing three approaches: administration of ADT alone, ADT with Radiation Therapy (RT), and RT alone.
Methods: From January 1995 to August 2015, 3451 patients with prostate cancer in British Columbia have been treated with RP. Data was extracted from the BC Cancer registry, charts were reviewed, and Kaplan-Meier analysis was performed to determine overall survival (OS) for each treatment modality. Patients were stratified based on pathological T stage and Gleason score.
Results: 1795 patients received ADT and RT, 781 received RT alone, 450 patients received ADT alone and 425 received no further therapy beyond RP. 48% received > 6 months of ADT, 33% received greater 12 months and 20% > 24 months. In 31% ADT was initiated prior to RP, in 47% following RP but prior to RT, and in 12% concurrent or after RT completion. Patients with ≥T3 disease and Gleason < 8 who received RT alone demonstrated prolonged OS compared to those who received ADT alone or ADT+RT (p=0.0192 and p = 0.001, respectively). OS benefit was not maintained in patients with ≥T3 disease and Gleason > 8. Pathological T stage did not result in a significant difference in OS between ADT+RT and ADT alone. Median OS was 24 years for RT alone, 21.1 years for ADT alone and 17.9 years for ADT + RT.
Conclusion: In appropriately selected patients, treatment of prostate patients following RP with RT alone appears to result in superior OS compared to ADT alone or ADT+RT while the administration of ADT remains important in patients with more aggressive biology. Multivariate analysis and extraction of PSA values for biochemical progression free survival following administration of each of the modalities will allow for recursive partitioning analysis in the future.
