After treatment for metastatic prostate cancer, a decline in prostate-specific antigen (PSA) levels is an indicator that the treatment is effective. Findings from a recent real-world study published by Freedland et al in the journal Cancer indicate that reaching a PSA level below 0.2 ng/mL is an indicator of improved patient survival.
Multiple phase III clinical trials have shown that a PSA level below 0.2 ng/mL is an appropriate cut-off for determining a patient’s prognosis. Real-world data are lacking, however, and physicians often use other metrics to assess treatment response, such as the percentage of PSA decline.
To determine whether there is a PSA response target associated with a favorable outcome, investigators analyzed Veterans Health Administration data on 4,890 patients with metastatic hormone-sensitive prostate cancer who received testosterone deprivation therapy with or without other treatments during 2018 to 2023.
Over a median follow-up of approximately 2 years, 896 patients died. Patients whose PSA levels dropped below 0.2 ng/mL within 9 months of starting treatment were 54% less likely to die than patients whose levels did not decline this low. No improvement was noted in patients who had at least a 90% PSA decline but did not achieve a PSA of less than 0.2 ng/mL.
The findings suggest that patients who do not experience a PSA drop below 0.2 ng/mL could be candidates for more aggressive treatments. Also, patients who received testosterone deprivation therapy plus another drug to further block testosterone were more likely to achieve a PSA below 0.2 ng/mL.
“These data show that we need to target a PSA below 0.2 ng/mL as our metric of success to optimize outcomes for our patients with metastatic prostate cancer,” said corresponding author Stephen J. Freedland, MD, Professor of Urology at Cedars-Sinai and Staff Physician at the Durham VA Medical Center.
DISCLOSURE: For full disclosures of the study authors, visit acsjournals.onlinelibrary.wiley.com.
