Advances in imaging have sparked a new debate in prostate cancer treatment: Now that oligometastases can be more precisely and sensitively identified, how should men with oligometastatic castrate sensitive prostate cancer be treated to provide the best long-term outcomes?
Some clinicians see better results using focal ablation to destroy the primary tumor and the limited number of systemic metastatic tumors that are identified outside the prostate in oligometastatic disease.
For other clinicians, greater benefit can be achieved from the most current systemic treatment that combines androgen deprivation therapy (ADT) with abiraterone. Abiraterone was initially indicated for use in castrate resistant prostate cancer, but two large trials published in 2017 showed the agent is also highly effective in castrate sensitive disease.
Still other clinicians see advantages in a blended approach that combines systemic therapy and focal ablation. And as of yet, there are no data showing clear superiority for one approach over the others.
“This is a new, emergent subtype of prostate cancer that can be better identified through imaging and for which we now have better tools to treat,” said Martin Gleave, MD, FRCSC, Director of the Vancouver Prostate Centre, Liber Ero British Columbia Leadership Chair in Prostate Research and Distinguished Professor and Chair of Urological Sciences at the University of British Columbia. “This group of patients with oligometastatic disease has historically been under identified and undertreated.”
Dr. Gleave will join three other leaders in prostate cancer therapy for a hotly contested international debate during Friday’s Prime Time plenary session. The debate topic for Crossfire: Controversies in Urology: Prostate Cancer, which begins at 11 am in the Esplanade Ballroom at Moscone South, is deceptively simple: Oligometastatic castrate sensitive prostate cancer is best treated by focal ablation, not ADT plus abiraterone.
The pro side will be argued by European urologists Francesco Montorsi, IV, MD, FRCS and David Dearnaley, MD. Dr. Montorsi is professor and Chair of Urology and Director of the Urological Research Institute at the University Vita-Salute San Raffaele in Milan, Italy. Dr. Dearnaley is professor of Uro-Oncology and Team Leader in Clinical Academic Radiotherapy at the Institute of Cancer Research in London.
Dr. Gleave will present the counter argument with North American colleague Robert Dreicer, MD, MS, FACP, FASCO, Section Head of Medical Oncology, Deputy Director of the University of Virginia Cancer Center, Co-Director of the Paul Mellon Urologic Cancer Institute and professor of Medicine and Urology at the University of Virginia School of Medicine.
“Focal therapy is only an option when you have a good systemic therapy,” Dr. Gleave said. “It’s only through the availability of more active systemic therapy that allows for control of systemic disease that we have the option for more focal therapy to the primary tumor and the oligomets.”
This is not the first time urologists have argued focal versus systemic therapy. Dr. Gleave likened castrate sensitive oligometastatic prostate cancer to regional salvage in testis cancer. Regional salvage is an appealing theory, but it only becomes practical in the setting of highly active systemic therapy and excellent imaging.
“Similarly, with active ADT plus abiraterone we are now able to prolong tumor control and any regional or oligometastatic disease, which is an additional source of relapse, may be controlled with focal therapy,” Dr. Gleave said. “But focal therapy, aside from palliation, is only an option for disease control when you have a good systemic therapy in place.”
The basic biology of castrate sensitive prostate cancer also argues against relying on focal therapy. In addition to systemic benefits, potent hormone therapy for prostate cancer acts to sensitize the tumor to radiation therapy.
“You need good androgen deprivation therapy to optimize the delivery of radiation therapy,” Dr. Gleave said. “This has been clearly documented in other areas. The activity of salvage radiation therapy is very clearly accentuated by androgen receptor pathway inhibition therapy.”