Prostate Radiotherapy for Metastatic Hormone-sensitive Prostate Cancer: A STOPCAP Systematic Review and Meta-analysis

Area of Science:

• Oncology
• Radiation Oncology
• Clinical Trials

Background:

• Metastatic hormone-sensitive prostate cancer (mHSPC) management is evolving with numerous ongoing clinical trials.
• Androgen deprivation therapy (ADT) is a standard treatment for mHSPC.

Purpose of the Study:

• To systematically review and meta-analyze randomized controlled trials evaluating the efficacy of prostate radiotherapy in men with mHSPC.
• To assess the impact of prostate radiotherapy on survival and progression outcomes when added to ADT.

Main Methods:

• A prospective meta-analysis framework (FAME) was utilized, pre-specifying methods before trial results were known.
• Extensive searches identified eligible trials, and harmonized, pre-publication data were obtained from investigators.
• Fixed-effect meta-analysis combined hazard ratios for survival, progression-free survival (PFS), failure-free survival (FFS), and biochemical progression.

Main Results:

• Pooled analysis of 2126 men from the HORRAD and STAMPEDE trials showed no significant improvement in overall survival (HR=0.92) or PFS (HR=0.94) with prostate radiotherapy plus ADT.
• Prostate radiotherapy significantly improved biochemical progression (HR=0.74) and FFS (HR=0.76), translating to a ~10% benefit at 3 years.
• A significant interaction was observed based on metastatic burden (p=0.007), with a 7% improvement in 3-year survival for men with fewer than five bone metastases.

Conclusions:

• Prostate radiotherapy does not offer an overall survival benefit for men with mHSPC when added to ADT.
• Men with mHSPC and a low metastatic burden (fewer than five bone metastases) may benefit from the addition of prostate radiotherapy, showing improved survival.
• Consideration of prostate radiotherapy is recommended for select mHSPC patients with limited metastatic disease.