PSA Levels and Outcomes in High-Risk Prostate Cancer Treated With ADT and Radiotherapy
Posted: Friday, January 8, 2021
Abdenour Nabid, MD, of the Centre Hospitalier Universitaire de Sherbrooke, Quebec, Canada, and colleagues conducted a study to evaluate whether prostate-specific antigen (PSA) response measured at 6 months after treatment initiation may predict better clinical outcomes in patients with localized high-risk prostate cancer who received androgen-deprivation therapy (ADT) and radiotherapy. The phase III PCS4 trial results were presented during the 2020 American Society for Radiation Oncology (ASTRO) Annual Meeting (Abstract 3993).
“A PSA response of less than 0.1 or 0.2 ng/mL at 6 months after ADT predicts fewer biochemical failures and lower prostate cancer progression,” the investigators commented. “These data suggest that patients remaining with a higher PSA level after 6 months of ADT may harbor a more aggressive genetic phenotype and should be considered for trials testing new therapeutic strategies earlier on.”
A total of 547 patients were enrolled. At 6 months, a PSA response of less than 0.1 ng/mL was observed in 34.4% of patients. They seemed to experience lower biochemical failure rates (17% vs. 35.9%; P ≤ .001) and prostate cancer progression (8.5% vs. 17.3%; P = .006) than those with a higher PSA level. According to the investigators, 58% of patients achieved a PSA response of less than 0.2 ng/mL at 6 months. They also appeared to experience decreased prostate cancer progression rates and fewer biochemical failures than those with a higher PSA level (P ≤ .001 for both).
Based on the multivariate analysis, the association of PSA level at 6 months for either cutoff level seemed to remain significant for biochemical failure and prostate cancer progression. Neither PSA cutoff level seemed to be significantly associated with metastasis-free survival or overall survival.
Disclosure: For full disclosures of the study authors, visit redjournal.org.