Upfront androgen deprivation therapy with salvage radiation may improve biochemical outcomes in prostate cancer patients with post-prostatectomy rising PSA.

Abstract

The addition of androgen deprivation therapy (ADT) to definitive external beam radiation therapy (RT) improves outcomes in higher-risk prostate cancer patients. However, the benefit of ADT with salvage RT in post-prostatectomy patients is not clearly established. Our study compares biochemical outcomes in post-prostatectomy patients who received salvage RT with or without concurrent ADT.
Of nearly 2,000 post-prostatectomy patients, we reviewed the medical records of 191 patients who received salvage RT at the University of Pennsylvania between 1987 and 2007. Follow-up data were obtained by chart review and electronic polling of the institutional laboratory database and Social Security Death Index. Biochemical failure after salvage RT was defined as a prostate-specific antigen of 2.0 ng/mL above the post-RT nadir or the initiation of ADT after completion of salvage RT.
One hundred twenty-nine patients received salvage RT alone, and 62 patients received combined ADT and salvage RT. Median follow-up was 5.4 years. Patients who received combined ADT and salvage RT were younger, had higher pathologic Gleason scores, and higher rates of seminal vesicle invasion, lymph node involvement, and pelvic nodal irradiation compared with patients who received salvage RT alone. Patients who received combined therapy had improved biochemical progression-free survival (bPFS) compared with patients who received RT alone (p = 0.048). For patients with pathologic Gleason scores ≤7, combined RT and ADT resulted in significantly improved bPFS compared to RT alone (p = 0.013).
These results suggest that initiating ADT during salvage RT in the post-prostatectomy setting may improve bPFS compared with salvage RT alone. However, prospective randomized data are necessary to definitively determine whether hormonal manipulation should be used with salvage RT. Furthermore, the optimal nature and duration of ADT and the patient subgroups in which ADT could provide the most benefit remain open questions.