Prostate-specific antigen

Overview of Treatment

Prostate-Specific Antigen (Prostate-Specific Antigen, abbreviated as PSA) is a protein secreted by prostate cells, primarily used for screening, diagnosis, and post-treatment monitoring of prostate cancer. This test measures PSA concentration through a blood test to assist physicians in assessing prostate health. Elevated PSA levels may be associated with benign prostatic hyperplasia, infection, or cancer, and should be interpreted in conjunction with clinical symptoms and other diagnostic results.

Types of Treatment and Mechanisms

PSA itself is not a treatment but an important biomarker. Its mechanism involves over-secretion by prostate cells (especially cancer cells), with increased blood levels serving as an indicator of disease. Clinically, PSA testing can be categorized into baseline screening, dynamic monitoring, and treatment evaluation. For example, after radical surgery, PSA levels should be near zero; a subsequent rise may suggest recurrence.

Indications

The main indications include:

• Routine screening for prostate cancer in men over 50 years old
• Early diagnosis in individuals with a family history of prostate cancer
• Monitoring efficacy after surgery, radiotherapy, or hormone therapy
• Adjunct diagnosis for suspected prostatitis or benign prostatic hyperplasia

Usage and Dosage

PSA testing is performed via blood draw, with no special preparation required. Recommended frequency includes:

• Healthy men over 50 years old: every 1-2 years
• High-risk groups (such as those with family history): starting at age 45
• Post-treatment follow-up: adjusted based on clinical condition, possibly every 3-6 months

Benefits and Advantages

The main advantages include:

• Non-invasive, high patient acceptance
• Early detection of precancerous changes or recurrence
• Enhanced diagnostic accuracy when combined with imaging techniques (such as MRI)

Additionally, long-term monitoring helps physicians evaluate treatment response and adjust strategies accordingly.

Risks and Side Effects

PSA testing has very low risks, but potential issues include:

• False positives: benign prostatic hyperplasia or inflammation can also elevate PSA
• False negatives: some cancer patients may have normal PSA levels
• Overdiagnosis risk: abnormal results may lead to unnecessary invasive procedures

Precautions and Contraindications

Precautions before testing:

• Avoid ejaculation or prostate massage within 48 hours prior to testing
• Inform your doctor if you have recently undergone digital rectal examination or cystoscopy
• Use of 5α-reductase inhibitors may affect PSA levels

Contraindications include acute prostatitis episodes, during which PSA may temporarily elevate; testing should be postponed until inflammation subsides.

Interactions with Other Treatments

PSA monitoring is often combined with imaging diagnostics (such as transrectal ultrasound, PET-CT) and tissue biopsy. In treatment, patients receiving androgen deprivation therapy may show PSA decline as an indicator of efficacy. Note that antibiotics for prostatitis should be administered for 2-4 weeks, and PSA should return to baseline before re-evaluation.

Treatment Outcomes and Evidence

Multiple large studies show that PSA screening increases early prostate cancer detection rates by 30-40%. The American Cancer Society recommends regular monitoring for specific risk groups. PSA has a half-life of about 3 days post-treatment, allowing rapid reflection of treatment effectiveness. However, over-reliance on PSA may lead to overdiagnosis; clinical judgment should be integrated.

Alternatives

Alternatives include:

• Digital rectal examination: physician palpates prostate shape and detects nodules
• Multiparametric MRI (mpMRI): accurately locates lesion areas
• Genetic testing: such as TMPRSS2-ERG fusion gene analysis

These methods can complement PSA testing and reduce misdiagnosis risks from relying on a single marker.

 

Frequently Asked Questions

What preparations are needed before PSA testing?

Before PSA blood testing, it is recommended to avoid vigorous exercise or digital rectal examination for at least 24 hours, and inform your doctor if you are taking steroids or 5-alpha reductase inhibitors that may affect PSA levels. If you have recently undergone prostate biopsy or urinary tract infection, inform the healthcare team in advance.

Does an elevated PSA level necessarily indicate prostate cancer?

An elevated PSA can be caused by prostatitis, benign hyperplasia, or malignancy, and should be interpreted with other indicators such as age, PSA density, and free PSA ratio. Further examinations like transrectal ultrasound or prostate biopsy are usually performed to confirm the cause; a single PSA value cannot diagnose cancer directly.

How to determine if active treatment is needed during PSA dynamic monitoring?

Doctors will assess the risk based on PSA velocity (e.g., increase of more than 2 ng/mL per year) and PSA doubling time. If the PSA curve rises sharply or imaging reveals lesions, biopsy or treatment may be recommended. Low-risk patients may opt for active surveillance with regular follow-up.

What dietary considerations should be taken during PSA-guided treatment?

During treatment, it is advisable to increase antioxidant-rich foods such as tomatoes and green tea to reduce oxidative stress, and reduce intake of high-fat and processed meats to help alleviate symptoms. Maintain hydration during recovery, avoid spicy foods that irritate the urinary system, and follow medical advice on calcium and vitamin D intake adjustments.

What does a continuously rising PSA after radical surgery indicate?

If PSA does not decline to undetectable levels or continues to rise after surgery, it may indicate residual cancer cells or recurrence. Imaging should be used to locate the lesion. Further options include additional radiotherapy, hormone therapy, or clinical trials, which should be discussed with the medical team.