PSA levels are commonly used as a marker for which of the following?

• A. Screening prostate cancer
• B. Monitoring the diagnosed patients for response to therapy
• C. Recurrence of the tumor after remission
• D. All of the above

Answer: (D)

PSA is a blood-based biomarker used in several ways to manage prostate cancer. For screening, an elevated PSA can prompt further evaluation to look for cancer. For monitoring therapy, PSA levels tend to rise or fall with the tumor burden, so tracking changes helps gauge how well treatment is working. For detecting recurrence, after definitive treatment PSA should become undetectable; a rising PSA can signal that the cancer has returned, often before symptoms arise. Because PSA can be affected by benign prostate conditions and age, clinicians interpret it in the full clinical context, including baseline levels and how quickly PSA changes over time. With all these roles, PSA serves as a marker in screening, treatment monitoring, and recurrence detection, so all of the above is the best answer.