Prostate cancer is the most frequent malignant neoplasm in men and the second most common cause of cancer death among American men.

Epidemiology

• Incidence - >218,000 new cases/year in U.S.; 6th most common cancer in the world
• Age - risk rises steeply with age
  • <50 years - low risk
  • 75% of cases occur in men greater than or equal to 65 years

Risk Factors

• Ethnicity - Black race has higher occurrence
• Family history - 5-11 fold increase in risk when there is a first degree relative who was diagnosed with prostate cancer <age 65
• Age - common malignancy in elderly males

Pathophysiology

• Tumors are usually adenocarcinoma and depend on androgen for growth
• Epithelial cells of prostate produce prostate specific antigen and acid phosphatase
  • Production increased with tumors
• Most tumors develop in peripheral zone of prostate

Clinical Presentation

• May have signs and symptoms of enlarged prostate - urgency, frequency of urination
• Frequently asymptomatic
• Metastatic disease
  • Bone pain - pelvis, spine

Diagnosis

• Laboratory testing
  • Prostate specific antigen (PSA) - elevated >4 ng/mL in majority of patients
    • Normal PSA values do not rule out prostate cancer as substantiated by the Prostate Cancer Prevention trial
      • <0.5 ng/mL - 6.6% had cancer
      • 0.6-1.0 ng/mL - 10.1% had cancer
      • 1.1-2.0 ng/mL - 17% had cancer
      • 2.1-3.0 ng/mL - 23.9% had cancer
      • 3.1-4.0 ng/mL - 26.9% had cancer
    • PSA can be elevated in benign conditions
  • Free PSA - helps in distinguishing prostate cancer from benign disease - use when PSA 4-10 ng/mL
    • >25% associated with low risk

• • • PSA kinetics (PSAV) - (PSA #2 - PSA #1)/time lapsed for PSA >2.5 ng/mL for PSA and PSAV >3.5 ng/mL per year should have biopsy (National Comprehensive Cancer Network 2007 guidelines)
• Biopsy
  • Sonographically guided biopsy is current means of diagnosis
    • Tumors assigned Gleason score
    • Recommended if PSA >4 ng/mL, significant increase in PSA, or abnormal digital rectal exam
• Imaging
  • Transrectal ultrasound - measure prostate volume (PV)
    • Can derive PSA by PV to obtain PSA density

Disease Monitoring

• Laboratory testing
  • Prostatic specific antigen (PSA) - monitoring progression of disease
  • Circulating tumor cell count - in metastatic tumors, monitor disease progression and response to therapy
• Successful surgical resection should lead to PSA concentrations <0.05 ng/mL
• Radiation therapy may not result in levels this low
  • Subsequent rise is indicative of residual disease or metastasis

Disease Screening

• PSA is the only tumor marker available that has been approved for use as a screening test for prostate cancer
  • Prostatic acid phosphatase has little value in screening for prostate cancer
• Screening recommendations
  • Screening not recommended in the following cases
    • If patient is younger than 50 years of age unless patient has first degree relative with prostate cancer
    • If patient is older than 65 years of age and has a life expectancy less than10 years
    • If patient is older than 75 years of age since the average life expectancy at 75 years of age is less than 10 years
  • Screening should be yearly if decision is made to screen
  • Screening should be performed in conjunction with digital rectal exam
  • PSA screening favored by American Cancer Society, American Urological Association and National Comprehensive Cancer Center Network; however the US Preventive Services Task Force concludes that the current evidence is insufficient to assess the balance of benefits and harms of prostate cancer screening in men younger than age 75 years. 
  • The ACS and AUA recommend using the free PSA test only in cases where total PSA is between 4.0 ng/mL (or 2.5 ng/mL, depending on physician and patient preference) and 10.0 ng/mL.  No interpretive guidelines are available for free PSA when the total PSA is less than 2.5 ng/mL or greater than 10 ng/mL)

Prognosis

• Higher initial PSA is correlated with increased risk of 10 year progression of disease as well as less organ confined disorder

Differential Diagnosis

• Prostatitis  - bacterial, fungal, tuberculosis
• Benign prostatic hypertrophy