This test is commonly performed because either a blood test called PSA is abnormally high or the examination of the prostate through the back passage is abnormal. Sometimes though the prostate feels normal and the PSA is within the "normal" range, it starts to rise quickly. MRI of the prostate is also being used as a diagnostic tool and in some cases this is abnormal and may result in the need for a biopsy. A biopsy is where a sample of cells is taken for examination under the microscope by a pathologist.
There are three ways a prostate biopsy can be performed:
- Transrectal - In this approach, at least 12 needle samples are taken through the rectum and into the prostate. However, I stopped doing this technique over three years ago because I became concerned about the risk of serious infection which can be up around 5%. In addition, I became concerned about the accuracy of this technique.
- Transperineal - In this approach, the needles are inserted through the skin between the scrotum and the anus. The risk of infection is very much lower than that with the transrectal approach and is much less than 1%. It also provides much more thorough sampling of the prostate and we have found that it is potentially more accurate than the transrectal approach. (Scott S, Samaratunga H, Chabert C, Breckenridge M, Gianduzzo T. Is transperineal prostate biopsy more accurate than transrectal biopsy in determining final Gleason score and clinical risk category? A comparative analysis. BJU Int. 2015 Oct;116Suppl 3:26-30.)
- MRI-guided biopsy - In some cases an MRI of the prostate will have been performed and will show an abnormal area. In some of these cases we can do the biopsies with the patient actually in the MRI machine. This is a very accurate technique but is more expensive and its exact place in prostate cancer diagnosis is still being defined. In this technique, the patient lies face down in the MRI machine and generally 2 or 3 needle samples are taken through the rectum in to the prostate. Even though the samples are taken through the rectum, the risk of infection is very low as only 2 or 3 samples are taken.
Transperineal biopsy - Preparation for the test
You do not need any antibiotic before or after the biopsy. You will be given a general anaesthetic for the procedure so you will need to fast (nothing to eat or drink) for 6 hours before the test. So if the test is in the morning you should have nothing by mouth from midnight the night before. If your test is in the afternoon, then you can have a light breakfast at around 6 AM and then nothing after that. Please let Dr Gianduzzo and the staff know if you are on any blood thinners as you may need to stop these before the test. You will be advised of this at your appointment when the test is scheduled.
Transperineal Biopsy - Procedure
A probe-like instrument about 2.5 cm in diameter is gently inserted into the back passage. This is an ultrasound probe that allows visualisation of the prostate beyond what can be felt by the finger alone. More importantly, it allows the placement of a special biopsy needle that collects samples of your prostate. You will have a general anaesthetic for the procedure. You will receive one dose of antibiotic intravenously at the start of the procedure. A number of specimens are collected by inserting the biopsy needle through the skin between the scrotum and the anus. The procedure takes about 40 minutes. You will need someone to drive you home as you will have been given a light anaesthetic.
MRI-guided biopsy -Preparation for the test
An earlier MRI of your prostate has shown abnormalities. Your urologist has requested a second MRI in order to find out exactly what is the matter. During this scan any visible abnormalities will be biopsied with a needle.
For this second MRI scan the same precautions should be taken as for your previous MRI. You may eat and drink up to 6 hours before the test. We also ask that you refrain from intercourse and ejaculation in the 4 days before the test.
You also need to have an empty rectum, so we ask you to use 2 Microlax Enemas (available over the counter from the pharmacy) - one the night before the examination, and one on the morning of the examination. You will also be given two (2) tablets of antibiotics in the form of Ciproxin (250mg). Take two (2) of these with a sip of water 1 hour before the biopsy. If you have a known allergy for antibiotics, then you should inform your urologist. You cannot drive after the procedure.
MRI-guided biopsy -Procedure
You will receive an intravenous antibiotic injection (typically Gentamycin – this antibiotic has a very rare risk of permanently affecting your hearing and/or balance). You will receive a mild sedative. You will lie on the table of the MRI scanner, on your front with your head facing forwards. The doctor will then insert a thin tube, called the needle guide, into your rectum. A gel will be applied to the needle guide before it is inserted. This gel has pain relieving properties and makes insertion easier. The doctor will connect the needle guide to a biopsy apparatus, which is placed between your legs. The doctor can use this apparatus to adjust the position of the needle guide. A coil in the form of a plate is then placed on your back. The procedure takes about 40minutes.
Firstly, a number of longer scans are done to produce an image of your prostate. The doctor will then determine the exact location at which he/she will insert the needle. You will be slid in and out of the tunnel a few times to adjust the position of the needle guide so that it is directed at the suspicious region of your prostate. The sample will be taken once the needle guide is directed at the suspicious region. Taking the sample can be uncomfortable.
Following this, further scans are done to check that the needle is in the correct position. It may be necessary to take more samples from the same region or from other regions. In this case the needle guide will be moved to a new position. In general, the doctor will take about 2-3 samples from the most suspicious region.
Following a prostate biopsy, you can expect to see some blood in the urine, bowel motions and semen. Any blood in the urine or bowel motions usually settles by a week although brownish discoloration of the semen can last for up to a couple of months. Uncommonly, you may develop an infection but this risk is minimised by the antibiotics administered. If you develop fevers and begin to shake, which is rare, you should go to the nearest emergency department to be assessed. Infections can be very serious after a biopsy so it is important that you seek medical attention if you have symptoms of infection even if it is in the middle of the night! Other risks such as bleeding and not being able to urinate after the procedure etc. will be discussed with you prior to your procedure.
It generally takes a few days to obtain the results of your biopsy. We will contact you by phone as soon as the results come through. If there is cancer present then we will send you some information about prostate cancer to read and some forms for a bone scan and a CT scan, or perhaps a PSMA scan. You will then be seen in around 2 weeks for the results of those scans and to discuss your management options for the cancer. If the test is negative, you will be sent a form for another PSA test and you will need another appointment in around 3 months with a repeat PSA test. We may also ask that you come in earlier if there are other issues that we need to discuss with you or that need to be checked. If you have not been called with your results within 1 week of our biopsy, please contact the rooms.
Anticoagulants and Blood-Thinning Medication
If you are taking any of the following anticoagulants: Warfarin, clopedigrol (Plavix, Iscover), Pradaxa, or any other blood-thinning medication, you should tell your attending physician. If you are going to have a biopsy, then you should discuss with your attending physician about when to stop taking these drugs. Aspirin need not to be stopped.
If you are on Warfarin, then you must also tell your thrombosis service that your INR must be 1.5 or lower on the day of your biopsy. Inform the medical staff at the thrombosis service of the reason for this: you will be having a biopsy on that day. You yourself are expected to make an appointment with the thrombosis service to have your INR measured. Bring the written test report with you to the biopsy to show the doctor taking the biopsy. If your blood is too thin then the biopsy cannot go ahead.