Bridget F. Koontz, MD, radiation oncologist, Duke Cancer Institute, discusses the next steps for the phase II trial of 6 months of androgen deprivation therapy/abiraterone acetate (Zytiga) plus prednisone and definitive radiotherapy for men with intermediate- to high-risk localized prostate cancer.

This single-arm study was hypothesis generating, as many believe it would be interesting to look at a comparison with the current standard of care, explains Koontz. This study evaluated patients with aggressive cancer, but included higher-risk and intermediate patients. Investigators aimed to accrue patients who had localized but aggressive cancer so that there was no risk of metastatic disease, Koontz adds.

There are 2 current standards of care for these patients—intermediate-risk patients get 6 months of hormonal therapy, and the long-term patients get 2 years. Koontz believes it would be interesting to compare the outcome of this study with patients on those trials.

Additionally, physicians are investigating next-generation hormone actors, which is in line with the idea of having potent androgen blockade. This could sensitize cancer cells with radiation but limit the overall length of the hormone deprivation to maintain quality of life.

Videos

Dr. Koontz on Next Steps for Study of LHRH in Prostate Cancer

Bridget F. Koontz, MD, radiation oncologist, Duke Cancer Institute, discusses a phase II trial of 6 months of androgen deprivation therapy/abiraterone acetate (Zytiga) plus prednisone and definitive radiotherapy for men with intermediate- to high-risk localized prostate cancer.

According to Koontz, this trial was a single-arm phase II study where patients received 6 months of concurrent LHRH therapy with abiraterone and prednisone. Concurrent with that was 6 months of hormone manipulation. Patients received radiation months 3 and 4. Those patients have been monitored for prostate-specific antigen (PSA) and testosterone maintenance.

The trial was well tolerated with a low grade III toxicity rate mostly related to abiraterone hypertension, explains Koontz. All 33 patients were able to finish the therapy. Overall, patients had a high testosterone recovery rate. At 1 year, half the patients had full testosterone recovery.

There were low scores of PSA, suggesting that low PSA with radiation is prognostic for late outcome. In the men who had testosterone recovery, 95% of the men had a PSA under 0.5.

Bridget F. Koontz, MD

Articles

Dr. Koontz on Next Steps for Study of LHRH in Prostate Cancer

Dr. Koontz Discusses LHRH in High-Risk Prostate Cancer