Prostate Cancer - A Comprehensive USMLE Guide

Introduction

Prostate cancer is a common malignancy affecting the prostate gland in males. It is the second most common cancer among men worldwide. This guide aims to provide a comprehensive overview of prostate cancer, including its etiology, pathophysiology, clinical presentation, diagnosis, treatment, and prognosis.

Etiology

The exact cause of prostate cancer remains unclear, but several risk factors have been identified, including:

• Age (increased risk with advancing age)
• Family history of prostate cancer
• African-American ethnicity
• High dietary fat intake
• Hormonal factors (elevated levels of androgens)

Pathophysiology

Prostate cancer typically arises from the glandular cells of the prostate. It usually begins as an adenocarcinoma, which is a malignant tumor originating from glandular tissue. The development of prostate cancer involves multiple genetic mutations and alterations in cellular signaling pathways.

Clinical Presentation

The clinical presentation of prostate cancer can vary, but commonly includes the following:

• Lower urinary tract symptoms (e.g., urinary frequency, urgency, nocturia)
• Hematuria (blood in the urine)
• Erectile dysfunction
• Back pain (indicating bone metastasis)
• Weight loss and fatigue (in advanced stages)

Diagnosis

Screening

Prostate-specific antigen (PSA) testing is commonly used for screening purposes. Elevated levels of PSA may indicate the presence of prostate cancer, but further investigations are required for confirmation.

Diagnostic Tests

• Transrectal Ultrasound (TRUS): Used to visualize the prostate gland and guide biopsies.
• Prostate Biopsy: The gold standard for diagnosing prostate cancer. Tissue samples are obtained from suspicious areas and examined microscopically.
• Gleason Score: A grading system used to assess prostate cancer aggressiveness based on histopathological findings.
• Imaging: CT scan, MRI, and bone scan are used to determine the extent of disease and presence of metastasis.

Treatment

Localized Prostate Cancer

• Active Surveillance: Monitoring the cancer's progression without active treatment.
• Surgery: Radical prostatectomy to remove the prostate gland.
• Radiation Therapy: External beam radiation or brachytherapy (implantation of radioactive seeds).
• Focal Therapy: Targeted treatment of the cancerous area within the prostate.

Advanced Prostate Cancer

• Androgen Deprivation Therapy (ADT): Blocking the production or action of androgens to slow cancer growth.
• Chemotherapy: For hormone-resistant prostate cancer.
• Targeted Therapies: Medications targeting specific molecular pathways involved in prostate cancer growth and progression.

Prognosis

Prostate cancer prognosis depends on various factors, including:

• Tumor stage and grade
• PSA levels
• Age and overall health of the patient
• Response to treatment

Conclusion

Prostate cancer is a significant health concern, particularly in older males. Early detection through regular screening and prompt diagnosis are crucial for better treatment outcomes. Understanding the etiology, pathophysiology, clinical presentation, and available treatment options is essential for physicians preparing for the usmle exams and for providing optimal care to patients with prostate cancer.