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- The prostate is a male reproductive organ that contributes seminal fluid to the ejaculate.
- The prostate gland is about the size of a walnut, averaging 20 to 25 g in volume in an adult male; tends to enlarge after age 50 years
- Three distinct zones delineate the functional anatomy of the prostate: peripheral zone (largest, neighbors rectal wall, palpable on DRE, 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.
According to the National Cancer Institute SEER data, an estimated 164,690 men in the United States will be newly diagnosed with carcinoma of the prostate (CaP) in 2018 (1).
- About 3 million men are living with CaP in the United States (1).
- An estimated 29,430 men in the United States will die of CaP in 2018 (1).
- Mean age at diagnosis is 66 years.
- Prostate cancer is the most commonly diagnosed nonskin cancer in men in the United States (~11.6% lifetime risk) and second leading cause of cancer death in men (only ~3% of all CaP results in CaP-related death) (1).
- Autopsy studies find foci of latent CaP in 50% of men in their 8th decade of life.
- Probability of clinical CaP 10.9% (1 in 9) in men aged ≥70 years
Etiology and Pathophysiology
- Adenocarcinoma: >95%; nonadenocarcinoma: <5% (most common transitional cell carcinoma)
- Cells generally stain positive for PSA and prostatic acid phosphatase (PAP).
- Location of CaP: 70% peripheral zone, 20% transitional zone, 5–10% central zone
Elevated risk if first-degree relative diagnosed with CaP suggesting genetic component; specifics unclear
- Age >50 years
- African American race
- Positive family history
- Poorly understood environmental factors
There are no FDA-approved drugs or diet modifications to prevent CaP.
- Finasteride has been studied for this purpose in a phase III trial called the Prostate Cancer Prevention Trial. A moderate risk reduction associated with an increased risk of high-grade disease was encountered. Therefore, it has not been FDA-approved for prevention (2).
Screening for prostate cancer is controversial:
- U.S. Preventive Services Task Force (USPSTF) final recommendation statement states “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. (Grade B). (3)[A].
- USPSTF recommends against PSA screening for men ≥70 years old (3)[A].
- For men ages 55 to 69 years, the AUA panel recommends 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, the data shows if you screen 1,000 men between 55 and 69 years:
- 240 will have a positive result.
- ~100 will have prostate cancer.
- Of the 100 with cancer, 80 will agree to treatment.
- Only one person will avoid dying from screening.
- 50 will develop erectile dysfunction (ED); 15 permanent incontinence