High-risk prostate cancer (PCa) is well defined, but opinions vary on whether radical prostatectomy or radiation therapy is the best treatment approach.
According to Suneil Jain, MD, from the Centre for Cancer Research & Cell Biology at Queen's University Belfast in Belfast, Northern Ireland, only 2% of patients in the ProtecT study had high-risk disease, so no conclusions can be drawn from it. Still, he believes the evidence for the use of radiotherapy to treat high-risk PCa is stronger than for surgical treatments. “Well-powered clinical trials have clearly demonstrated that radiation plus ADT improves overall survival compared to ADT alone,” Dr Jain said.
Retrospective and population-based studies are subject to multiple biases, including gatekeeper bias, he said. Data from the STAMPEDE study presented at the European Society for Medical Oncology (ESMO) 2017 conference in September demonstrated the best results for high-risk localized PCa to date. Investigators reported data from patients with high-risk localized PCa randomized to radiotherapy and ADT or radiotherapy, ADT, and 2 years of abiraterone with prednisone. “Amazingly, 3-year failure free survival improved from 80% to 98% with the addition of abiraterone,” Dr Jain said.
Michael Zelefsky, MD, professor of radiation oncology and chief of brachytherapy at Memorial Sloan Kettering Cancer Center in New York, said there is no Level I evidence to support one form of therapy over the other for patients with high-risk disease. “Nevertheless, the retrospective data comparing surgery and radiotherapy suggesting inferior survival outcomes among patients receiving radiotherapy are flawed because of the very different patient populations and their co-morbidities and age as well as the less intense radiation dose levels used years ago,” Dr Zelefsky said.