— OS, PFS, cancer-specific survival all improved, with no increase in toxicity
by
Charles Bankhead, Senior Editor, MedPage Today
January 26, 2024
SAN FRANCISCO — Men with high-risk localized prostate cancer lived significantly longer with dose-escalated radiation therapy (RT) plus long-term androgen deprivation therapy (ADT), according to long-term follow-up from a randomized trial.
After a median follow-up of 9.5 years, the 10-year overall survival (OS) rate increased from 65.9% with standard-dose (70 Gy) RT plus 3 years of ADT to 77% with 80 Gy RT. Cancer-specific survival (CSS) and progression-free survival (PFS) at 10 years also improved significantly with the higher dose of RT.
Late-occurring genitourinary (GU) and gastrointestinal (GI) toxicity did not increase with the higher RT dose, and quality of life was similar between treatment groups, reported Christophe Hennequin, MD, PhD, of Saint-Louis Hospital in Paris, at the Genitourinary Cancers Symposium.
“Even if we use long-term ADT, high-dose RT improved progression-free survival, cancer-specific survival, and overall survival in high-risk prostate cancer without increasing toxicity,” said Hennequin. “However, IMRT [intensity-modulated RT] is required to obtain these results.”
“We now have level-one evidence that high-dose RT with long-term ADT must be a standard of care in high-risk prostate cancer,” he added.
Accumulating Data
The findings, from the French Genito-Urinary Tumor Group (GETUG) 18, added to and extended existing evidence that high-dose RT plus long-term ADT yields better outcomes for high-risk prostate cancer. RT and ADT have biologic synergy and co-dependent, complex cytotoxic interactions. Finding the right RT dose to achieve the best outcomes has been a major challenge, according to invited discussant Neha Vapiwala, MD, of Penn Medicine in Philadelphia.
Several studies evaluated long- versus short-course ADT with an RT dose of 70 Gy. In general, long-term ADT achieved better or non-inferior OS.
The Duration of Androgen-Deprivation Therapy (DART) trial pushed the envelope a little further, comparing 4 versus 28 months of ADT and dose-escalated RT ranging between 76 and 82 Gy. Vapiwala pointed out that the DART population was not purely high risk, but a mix of intermediate- and high-risk prostate cancer.
Nonetheless, the primary analysis showed better 5-year OS with long-term ADT, no increase in lat