Prostate Cancer

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Description

  • The prostate is a male reproductive gland that contributes seminal fluid to the ejaculate.
  • In an adult male, the prostate gland is approximately the size of a walnut, weighing 20 to 25 g and commonly enlarges after age 50 years.
  • Three distinct zones delineate the functional anatomy of the prostate: peripheral zone (largest, adjacent to the rectal wall, palpable on digital rectal exam [DRE] and the most common location for prostate cancer), central zone (contains the ejaculatory ducts), and transition zone (located centrally, adjacent to the urethra).
  • Prostatic epithelial cells produce prostate-specific antigen (PSA), which is used as a tumor marker and in screening.

Epidemiology

Incidence

Approximately 300,000 men in the United States will be newly diagnosed with carcinoma of the prostate (CaP) in 2025, representing approximately 15% of all new cancer diagnoses.

Prevalence

  • Approximately 35,000 men in the United States will die of CaP in 2025, representing 5.8% of all cancer deaths.
  • Median age at diagnosis is 67 years.
  • Autopsy studies find foci of latent CaP in 50% of men in their 8th decade of life.

Etiology and Pathophysiology

  • Adenocarcinoma: >95%; nonadenocarcinoma: <5% (most common transitional cell carcinoma)
  • Location of CaP: 70% peripheral zone, 20% transitional zone, 5–10% central zone

Genetics

The most strongly implicated genes are BRCA2, and BRCA1. HOXB13 mutations and DNA mismatch repair genes are associated with hereditary prostate cancer.

Risk Factors

Age >50 years, African American race, positive family history

General Prevention

Finasteride use associated with moderate risk reduction in low-grade CaP but associated with an increased risk of high-grade disease.

ALERT
  • Screening for prostate cancer is controversial:
    • U.S. Preventive Services Task Force (USPSTF): “for men aged 55 to 69 years, the decision to undergo periodic PSA-based screening for prostate cancer should be an individual one and should include discussion of the potential benefits and harms of screening with their clinician. Screening offers a small potential benefit of reducing the chance of death from prostate cancer in some men. However, many men will experience potential harms of screening” (1)[A]. USPSTF recommends against PSA screening for men ≥70 years old (1).
    • The American Urological Association (AUA) panel recommends for men 55 to 69 years old shared decision-making between physician and patient regarding PSA screening.
    • PSA screening is not recommended in men age <40 years or any man with <10 years of estimated life expectancy.
    • When providing informed consent, data shows if you screen 1,000 men between 55 and 69 years old:
      • 240 will have a positive result; only ~100 will truly have CaP; of the 100 with cancer, 80 will agree to treatment.
      • Treatment will result in one less person dying but 50 will develop erectile dysfunction (ED); 15 permanent incontinence

Commonly Associated Conditions

Obesity, hyperlipidemia, diabetes, hypertension

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