Transrectal ultrasound–guided prostate biopsy

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Transrectal ultrasound–guided prostate biopsy is considered the standard approach for prostate biopsy and is most commonly performed on an outpatient basis following positive screening for prostate cancer.  It is not a targeted biopsy procedure.

Nowadays it is possible to perform targeted sampling of prostate lesions guided by real-time MR imaging.

Indications

Prostate cancer screening consists of prostate specific antigen (PSA) measurement in the serum and a digital rectal examination. Positivity in one of these tests make patients candidates for further diagnostic evaluation with a transrectal ultrasonography–guided prostate biopsy.

Contraindications

The most important contraindications are:

  • uncooperative patient
    • sedation with a hypnotic agent (e.g. propofol or midazolam) might be required +/- monitoring by an anesthesiologist
  • uncorrectable bleeding diathesis (abnormal coagulation indices)

Procedure

Preprocedure

Antibacterial prophylaxis is recommended and may follow institutional protocols. The recommended antibiotics for transrectal prostate biopsies published by the American Urology Association include: quinolones, 1st / 2nd / 3rd generation cephalosporins, aminoglycoside and metronidazole or clindamycin, and aztreonam and metronidazole or clindamycin.

In some institutions, an enema is performed before the procedure to clean out the bowels and clear the rectum of feces. However evidence shows that there is no significant difference in rates of infectious complications between patients having/not having formal bowel prep if they are on antibacterial prophylaxis .

Laboratory parameters for a safe procedure

Many patients that undergo prostate biopsy have increased cardiovascular risk and are on anticoagulants or antiplatelet medication. The decision to suspend or maintain these therapies must be taken together with the patient's physician, taking into account the risks of bleeding and of a cardiovascular event.

In patients without disease or use of antibleeding agents, pre-procedure laboratory exams may not be necessary. Although, in some institutions it is standard protocol to obtain blood tests in all cases.

Complete blood count: platelets >50000/mm (some institutions use other values between 50000-100000/mm)

Coagulation profile: studies show that having a normal INR or prothrombin time is no guarantee that the patient will not bleed after the procedure.

  • international normalized ratio (INR) ≤1.5
  • normal prothrombin time (PT), partial thromboplastin time (PTT)
Positioning

Patient may be placed in the left lateral decubitus position with semiflexed knees.

Biopsy
  • the lubricated ultrasound transducer is inserted into the patient’s rectum. A lidocaine preparation may be used as ultrasound gel.
  • regional block is administered around both neurovascular bundles (lidocaine).
  • biopsy needle is introduced
  • the prostate sampling technique is based on the sextant protocol, described by Hodge et al. and modified later, in which samples are obtained of the more peripheral zone (where the diagnostic yield is higher) from the base through the middle to the apex of the gland, bilaterally. Usually 12 samples are taken, two per sextant.
    • Post-procedure care

    The recovery process will vary depending on the type of anesthesia that is used. In the usual technique, with only local anesthetic, the patient may resume their normal activities and diet.

    Patient should be consented about possible light bleeding from the rectum, mild hematuria and/or hematochezia for a few days and that his semen may have a red or rust-colored tint caused by a small amount of blood.

    It should be re-emphasized the continued use of antibiotic, as institutional protocols.

    Complications

    Minor complications are frequent, such as limited hematuria and hematospermia (may persist as long as 1 week after the biopsy). Reported infection rates are variable but low with the use of prophylactic antibiotics (septicemia requiring hospitalization occurred in less than 4% of patients ).