Robert G. Bristow, MD, PhD

FORMAL DISCUSSANT Robert G. Bristow, MD, PhD, of the Manchester Cancer Research Centre, Manchester, United Kingdom, called this trial “an exemplar.”

“Radiation to the prostate should be considered standard of care in the setting of hormone-sensitive low-metastatic burden. The treatment is well tolerated, especially for the elderly, and it is relatively inexpensive. Building on the strength of numerous retrospective studies and extrapolating from this study, men with node-positive disease should also be treated with local radiotherapy to improve outcome. The biology behind the clinical observation is currently unknown, so we look forward to seeing whether similar results occur when surgery is used to remove the primary and whether additional benefit will come from also treating the synchronous metastases in the M1 setting.”

Ignacio Duran, MD

Commenting on this study at a European Society for Medical Oncology (ESMO) press conference, Ignacio Duran, MD, of the Hospital Universitario Marques de Valdecilla, Santander, Spain, said: “These data are provocative. About 10% of men diagnosed with prostate cancer present with metastatic disease. We were used to handling these patients by ‘cutting down the fuel’ that drives their cancer using androgen blockade. We did consider treating the local tumor with focused treatment. These results show you can impact the cancer with radiation to the prostate in patients with low disease burden. Now we need to understand the role of docetaxel and abiraterone [Yonsa, Zytiga].”

Karim Fizazi, MD

In a news release from ESMO, Karim Fizazi, MD, of the Gustave Roussy Institute and University of Paris-Sud, France, said: “For the first time, this study provides evidence that treating the local primary tumor is associated with improvement in overall survival in men with metastatic prostate cancer and minimal disseminated disease.” He added that the finding of no significant increase in overall survival among men with a higher burden of disease was consistent with the previously reported HORRAD trial.¹

“For men with newly diagnosed oligometastatic prostate cancer, it is quite likely that these data are practice-changing,” Dr. Fizazi stated. However, benefits are not proven in men with a higher disease burden. “More data are needed as to whether radiation to the prostate is justified in this setting in the absence of an overall survival benefit.”

Although this study was a large, randomized phase III trial, Dr. Fizazi pointed out that only 18% of patients were treated with early docetaxel, and no patient received early abiraterone (Yonsa, Zytiga), which are current standards of care for newly diagnosed metastatic prostate cancer. ■

DISCLOSURE: Dr. Bristow has received research funding from GenomeDx. Dr. Duran has received research funding from AstraZeneca, Astellas Pharma, and Roche/Genentech; honoraria from Janssen, Sanofi, Astellas Pharma, Pierre Fabre, MSD, and Roche/Genentech; is a consultant/advisor for Janssen Oncology, Bayer, Astellas Pharma, Sanofi, AstraZeneca, Bristol-Myers, Squibb, Roche/Genentech, and Pharmacyclics; and has received reimbursement for travel/accommodations/ expenses from AstraZeneca, and Roche/Genentech. Dr. Fizazi has received honoraria from Janssen, Sanofi, Astellas Pharma, Takeda, Merck, and Amgen; is a consultant/ advisor with Janssen Oncology, Bayer, Astellas Pharma, Sanofi, Orion Pharma GmbH, CureVac, AstraZeneca, Essa Pharma, Roche/Genentech, and Clovis Oncology; and has received reimbursement for travel, accommodations, or expenses from Amgen.

REFERENCE

1. Boevé LMS, et al: Effect on survival of androgen deprivation therapy alone compared to androgen deprivation therapy combined with concurrent radiation therapy to the prostate in patients with primary bone metastatic prostate cancer in a prospective randomised clinical trial. Eur Urol. September 25, 2018 (early release online).