What is the initial treatment for a patient with metastatic prostate cancer and a Prostate-Specific Antigen (PSA) level of 16?

Initial Treatment for Metastatic Prostate Cancer with PSA 16

For patients with metastatic prostate cancer and a PSA level of 16, bilateral orchiectomy or luteinizing hormone-releasing hormone (LHRH) agonists are the recommended initial treatments. 1

Standard First-Line Treatment Options

• Androgen deprivation therapy (ADT) through surgical castration (bilateral orchiectomy) or medical castration (LHRH agonists) is the standard first-line treatment for metastatic prostate cancer 1
• When starting LHRH agonist therapy, an antiandrogen should be given for 3-4 weeks initially to prevent testosterone flare 1
• Continuous ADT is recommended over intermittent ADT for metastatic hormone-naïve prostate cancer 1

Treatment Considerations

• Combined androgen blockade (CAB), which is the combination of medical castration and an antiandrogen, may provide a small survival benefit but with increased toxicity 1
• Patients willing to accept the increased toxicity of CAB for a small benefit in survival should be offered a nonsteroidal antiandrogen in addition to castrate therapy 1
• Nonsteroidal antiandrogen monotherapy may be discussed as an alternative to castration, but steroidal antiandrogens should not be offered as monotherapy 1

Monitoring Response to Treatment

• PSA measurements should be performed every 3-4 weeks initially to assess response to therapy 2, 3
• Regular imaging follow-up with CT scans and bone scintigraphy should be considered to evaluate treatment response 2, 3

Advanced Treatment Options

• For patients who progress to castration-resistant prostate cancer (CRPC), additional treatment options include:
  • Abiraterone or enzalutamide for asymptomatic/mildly symptomatic men with chemotherapy-naïve metastatic CRPC 1, 4
  • Docetaxel chemotherapy for symptomatic patients with metastatic CRPC and good performance status 1
  • Radium-223 for men with bone-predominant, symptomatic metastatic CRPC without visceral metastases 1, 4

Important Clinical Considerations

• ADT is associated with significant side effects including hot flashes, sexual dysfunction, osteoporosis, metabolic syndrome, and cardiovascular complications 5, 6
• Regular exercise has been shown to reduce fatigue and improve quality of life in men on ADT 1
• Shared decision-making between patients and physicians is necessary for optimal use of ADT, as patients may weigh the balance between favorable and adverse consequences of palliative ADT differently 1
• Continuation of ADT is essential even when adding other therapies for disease progression 4

Treatment Algorithm

1. Confirm metastatic disease through appropriate imaging studies
2. Initiate ADT with either:
   • Bilateral orchiectomy (surgical castration), or
   • LHRH agonist with antiandrogen for the first 3-4 weeks to prevent testosterone flare 1
3. Consider adding nonsteroidal antiandrogen for combined androgen blockade if patient accepts increased toxicity for small survival benefit 1
4. Monitor PSA response every 3-4 weeks initially 2, 3
5. Continue ADT indefinitely (continuous rather than intermittent) 1
6. Upon progression to castration-resistant disease, add second-line therapies while maintaining ADT 1, 4

By following this treatment approach, patients with metastatic prostate cancer can achieve optimal disease control and symptom palliation while managing treatment-related side effects.