What are the signs and symptoms of an enlarged prostate (either cancer related or benign)?
The prostate gland in the adult male is normally about 20 to 25 cm3 in size. Over time, the prostate gland may grow as a result of benign enlargement of the prostate, known as benign prostatic hyperplasia (BPH), or as a result of prostate cancer. Enlargement of the prostate gland may cause changes in urinary symptoms; however, the severity of urinary symptoms does not correlate with the size of the prostate. In fact, some men with mildly enlarged prostates (for example, 40 cm3) may be more symptomatic than men with greatly enlarged (>100 cm3) prostate glands. The symptoms of an enlarged prostate are caused by the prostate's resistance to the outflow of urine and the bladder's response to this resistance. Common symptoms include:
• Getting up at night to urinate one or more times per night (nocturia).
• Urinating frequently (eight or more times per day).
• Feeling that you have to urinate, but when you attempt to, finding that it takes a while for the urine to come out (hesitancy).
• Straining or pushing to get your urine stream started and/or to maintain your stream.
• Dribbling urine near the completion of voiding.
• A urine stream that stops and starts during voiding (intermittency).
• Feeling of incomplete emptying after voiding such that you feel that you could void again shortly.
What is PSA? What is the normal PSA value? What is free total PSA?
PSA stands for prostate specific antigen. PSA is a chemical produced by prostate cells, both normal and cancerous. PSA is not produced significantly by other cells in the body. Normally, only a small amount of PSA gets into the bloodstream. However, when the prostate is irritated, inflamed, or damaged, such as in prostatitis and prostate cancer, PSA leaks into the bloodstream more easily, causing the level of PSA in the blood to be higher. The normal range is usually 0 to 4.0 ng/mL; however, in younger men a lower range is used (Table 1). The normal range for PSA varies with age and race.
Table 1. Age-Adjusted Normal PSA Ranges
Reprinted with permission from Oesterling et al. JAMA 1993; 270:860—864. Copyright © American Medical Association.
Once a baseline normal PSA has been obtained, the actual number becomes less important and the rate of change of the PSA over time becomes more important.
PSA is found in two forms in the bloodstream. PSA that is attached to chemicals (proteins) is bound PSA and PSA that is not attached to proteins is called free PSA. The amount of each form is measured, and a ratio of the free PSA to the free plus bound (or total) PSA is calculated.
The PSA present that is not bound to proteins is often expressed as a ratio of free PSA to total PSA. It's expressed as a percentage, which is the free PSA, divided by the total PSA x 100.
The higher this number, the less likely that prostate cancer is present. A free PSA value greater than 14—25% suggests that the presence of prostate cancer is less likely. This ratio may be helpful in individuals with mildly elevated PSAs in the 4—10 ng/mL range for whom the doctor is deciding whether to perform a prostate biopsy.
PSA density refers to the PSA per gram of prostate tissue and is calculated by dividing the PSA by the calculated prostate volume in grams estimated by transrectal ultrasound. A PSA density > 0.15 is felt to be suggestive of prostate cancer.
PSA velocity refers to the change in PSA level over time. As men get older the prostate tends to enlarge, thus it is expected that the PSA may increase slightly over time. In men with a PSA < 4 ng/ml it is felt that a PSA velocity > 0.35 ng/ml is cause for concern, whereas in men with a total PSA > 4 ng/ml a PSA velocity of > 0.75 ng/ml is cause for concern for the risk of prostate cancer.