Saturday, March 6, 2010

Prostate biopsy

The prostate is a walnut-sized gland that forms part of the male reproductive system. The gland is made of two lobes, or regions, enclosed by an outer layer of tissue. As the diagrams show, the prostate is located in front of the rectum and just below the bladder, where urine is stored. The prostate also surrounds the urethra, the canal through which urine passes out of the body.

The prostate enlarges as men grow older, and because small amounts of PSA are produced by the healthy prostate, its blood level tends to rise.
Benign prostate enlargement , is a common non-cancer condition causing PSA levels to rise. For this reason, age-based thresholds, shown in Table, can be used to decide if a test result is abnormal. The percentage Free to Total PSA (described below) also gives an indication whether raised PSA is due to benign enlargement.

A temporary rise in the PSA can be caused by a number of conditions . Urinary infection, prostatitis (inflammation of the prostate), or a biopsy of the prostate can cause large rises while small rises can be caused by ejaculation,Digital Rectal Examination and even pressure on the perineum(by trauma,bicycle riding).
Because of these non-cancer causes of PSA rises, it is not surprising that an abnormally high test result may not be due to prostate cancer. The chance that you have prostate cancer is only about one in three.

With the advent of prostate specific antigen the number of patients undergoing prostate biopsy has dramatically increased. The sextant biopsy technique(six core biospy) has been conventionally used for the diagnosis of prostate cancer.
Recently, concern has arisen that the original sextant method may not include an adequate sample of the prostate, hence it may result in high false negative rates.Usual protocol of ten core biopsy has been incorporated in many hospitals.Although saturation biopsy to the extent of 32 cores are sometimes taken.
Table 1 - Suggested upper limits of PSA for different age groups
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Age (years) Serum PSA (ng/ml)
40-49 2.0
50-59 3.0
60-69 4.0
70 -79 5.5



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Other ways of measuring PSA have been developed in an effort to make the test more specific for prostate cancer. One of these is called the "Free to Total" PSA. This is a ratio, expressed as a percent. Much of the PSA in the blood is bound to protein, including that produced by cancer cells. But men with benign prostate enlargement have higher levels of free (unbound) PSA and so a higher Free to Total ratio. If the total PSA level is abnormal, the Free to Total PSA ratio will give an idea of whether the rise is due to benign disease or cancer. Cancer is more likely if the Free to Total percentage is below 15% .

so,TRUS abnormal findings,abnormal digital rectal examination findings,abnormal PSA will necessitate TRUS guided biopsy.






Procedure:
It is a procedure in which small bits of prostate tissue are removed from a man's prostate gland to be tested for the presence of cancer. It is typically performed when PSA blood test rise to a level that is associated with the possible presence of prostate cancer.(Refer to Table)
The procedure is is an outpatient procedure.We usually do it under sedation(Keatmaine and midazolam combination) so that the patient tolerates the procedure without pain or discomfort. The most frequent complication of the procedure is bleeding in the urine for several days, some bleeding in the stool for several days, and hematospermia- blood in the ejaculate for several weeks afterwards.Rarely pateint can have sepsis after the procedure which may aggravate and become fatal.But with usual antibiotic precautions,this is rare to witnes.
The procedure is usually performed transrectally. Although it can be perofomed with tactile finger guidance; we do it with Trans-Rectal Guidance so that along with standard cores ,some biopsies from abnormal area also can be taken.

About 10 cores are taken from the prostate gland through a thin needle - equal from each side. The antibiotics are prescribed to prevent infection. An enema may also be prescribed for the morning of the procedure.


You Should consult a doctor?
When:
• Excessive bleeding from rectum/in urine
• High Grade fever
• Retention of urine

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