Trans Rectal Ultrasound Prostate Biopsy (TRUS-Bx) 

Indications for the initial biopsy
TRUS alone should not be used as a fi rst-line screening study as it lacks acceptable specifi city, is relatively expensive when compared with digital rectal examination (DRE) and prostate specifi c antigen (PSA) testing and adds little information to that already gained by the use of serum PSA and digital rectal examination. The most important role for TRUS is to provide visual guidance for biopsy. In general, most agree that TRUS guided prostate needle biopsy should be performed in men with an abnormal DRE, an elevated PSA (>4.0 ng/ml) or PSA velocity (rate of PSA change) >0.4 to 0.75ng/ml/yr. Also, men who were diagnosed with high-grade prostatic intraepithelial neoplasia (PIN) or atypia on a previous prostate needle biopsy should undergo a repeat biopsy 3 to 12 months later. Less commonly agreed upon recommendations for TRUS guided prostate needle biopsy include, age-specifi c PSA elevation, low percentage free PSA (< 22% to 25%), and prostate specifi c antigen density (PSAD) > 0.15, which is a measure of the amount of PSA relative to the overall prostatic volume (PSA ÷ Prostate Volume in cubic centimeters).
In patients previously treated with curative intent for prostate cancer (i.e. radical prostatectomy, radiation therapy, and cryotherapy) relative indications for TRUS guided prostate needle biopsy includes a palpable abnormality on digital rectal examination or a rising PSA suggestive of local, rather than distant, recurrence.

Technique
Patient preparation
At our institution, we routinely use a three-day course of an oral fl uoroquinolone starting before the biopsy is performed. We instruct the patient to give a self-administered cleansing enema (sodium phosphate and dibasic sodium phosphate) prior to the biopsy to eliminate gas and remove feces. We also recommend that aspirin and non-steroidal anti-infl ammatory (NSAIDS) be discontinued for seven and three days respectively prior to the scheduled prostate needle biopsy. Patients on anticoagulation therapy are not biopsied until the anticoagulant dosage is adjusted or held to allow the coagulation status to normalize.

Transrectal ultrasound procedure
The patient is positioned in either the right or left lateral decubitus position (lying on left side). This allows for easier insertion of the rectal probe. A topical anesthetic ointment is applied to the index fi nger prior to performing the DRE. A 5.0 to 7.5mHz transducer is used for transrectal imaging of the prostate. The probe is gently advanced into the rectum, to the base of the bladder until the seminal vesicles are visualized. Transverse images are then obtained as the probe is moved back from the prostate base to the prostate apex. Hard copy images are made at the level of the seminal vesicles, base, mid-prostate and apex. With the transducer at the largest cross-sectional image in the transverse plane and in the mid-sagittal plane, prostate volume can be calculated. A simple prorated ellipsoid formula is commonly used to calculate prostate volume: (anterior-posterior diameter) x (transverse diameter) x (superior-infereior diameter) x ?/6 (approximately 0.52) is accurate and reproducible.

Information by Peter Carroll, MD and Katsuto Shinohara, MD, see here for full article.

Prostate Biopsy

A prostate gland biopsy is a test to remove small samples of prostate tissue to be examined under a microscope. See an illustration of the prostate gland.

For a prostate biopsy, a thin needle is inserted through the rectum (transrectal biopsy), through the urethra, or through the area between the anus and scrotum (perineum). A transrectal biopsy is the most common method used. The tissue samples taken during the biopsy are examined for cancer cells.

A biopsy may be done when a blood test shows a high level of prostate-specific antigen (PSA) or after a digital rectal examination finds an abnormal prostate or a lump.
Why It Is Done

A prostate biopsy is done to determine:

* If a lump found in the prostate gland is cancer.
* The cause of a high level of prostate-specific antigen (PSA) in the blood.

How To Prepare

Tell your doctor if you:

* Have had any bleeding problems.
* Are allergic to any medications, including anesthetics.
* Take any medications regularly. Be sure your doctor knows the names and doses of all your medications.
* Are taking any blood-thinning medications, such as warfarin (Coumadin), heparin, enoxaparin (Lovenox), aspirin, ibuprofen, or other nonsteroidal anti-inflammatory drugs (NSAIDs).

You will need to sign a consent form that says you understand the risks of a prostate biopsy and agree to have the biopsy done. Talk to your health professional about any concerns you have regarding the need for the biopsy, its risks, how it will be done, or what the results will indicate. To help you understand the importance of the biopsy, fill out the medical test information form(What is a PDF document?).

If a prostate biopsy is done under local anesthesia through the area between the anus and scrotum (perineum), no other special preparation is needed.

If the biopsy is done through the rectum, you may need to have an enema before the biopsy.

If the biopsy is done under general anesthesia, do not eat or drink anything for 8 to 12 hours before the biopsy. During preparation for the biopsy, an intravenous line (IV) is inserted in your arm, and a sedative medication is given about an hour before the biopsy.
How It Is Done

This biopsy is done by a doctor who specializes in men’s genital and urinary problems (urologist) in the doctor’s office, a day surgery clinic, or a hospital operating room.

Before your prostate biopsy, you may be given antibiotics to prevent infection. You may be asked to take off all of your clothes and put on a hospital gown.

Your skin at the biopsy site is cleaned with an antiseptic solution, and the area around it is covered with sterile cloth. Your doctor will wear sterile gloves. It is very important that you do not touch this sterile area.

This information is from WebMD, see full article here.