Prostate Biopsy

Prostate cancer is never diagnosed until you have had a prostate biopsy.

Why is a biopsy needed?​

Usually one or all of three reasons:

  • Abnormal or rising PSA levels.
  • Abnormal Multiparametric MRI , especially PI-RADS scores of 4 or 5.
  • Abnormal Digital Rectal Examination.
What is a Prostate Biopsy?​

A prostate biopsy involves using thin needles to take small samples of tissue from the prostate. The tissue is then examined under a microscope to check for cancer. If cancer is found, the biopsy results will also show how aggressive it is – in other words, how likely it is to spread outside the prostate.

How is this biopsy done?​

There are two methods of prostate biopsy. They are quite different.

  1. Trans-rectal ultrasound guided biopsy. (TRUS)
  2. Transperineal biopsy. (TP)

TRUS. Trans-rectal ultrasound guided biopsy

This is the traditional method, still the most common one performed in Ireland. You have the biopsy take through the lining of your back passage (rectum).

A simultaneous trans rectal ultrasound scanner shows where the biopsy needle goes. It is done in hospital, either with General or more commonly with Local Anaesthetic. Increasingly it is being performed by specialist radiologist – previously was done by urologists. Usually ten to twelve samples are taken.

The tissue removed has to be analysed by the laboratory, so you will always have to wait some time for the result.

Trans Perineal Biopsy

This is now the treatment of choice. Here, instead of passing the biopsy needles through the rectum (backside), they are passed through an area of skin called the Perineum. This is the small area behind the scrotum and in front of the rectum.

The number of samples taken usually depends upon the result of an MRI, and sometimes up to 50 samples can be taken. The average is 35.

There are two major issues with TRUS.

  • Infection risk
  • Inability to access all he prostate

Infection Risk

TRUS involves passing a number of needles through the lining of the rectum, and this is of course full of nasty bacteria. You are given an enema, and a high dose of antibiotics before the biopsy, but unfortunately, there is a worrying increase in the incidence of antibiotic resistant bacteria. So, the antibiotic may not work, and the biopsies then drive pathogenic bacteria straight into the prostate. Because they are already antibiotic resistant, they are very difficult to treat.

TP biopsy avoids this. The needles go through skin, which is far easier to sterilise. Also if an infection does happen, and they can, the bacteria responsible is far less likely to be antibiotic resistant.

It is estimated that the infection risk is 20 times higher with TRUS, and this figure is likely to increase with more antibiotic resistant bacteria appearing. The chance of dying is about 0.1% – that is one in a thousand – but the hospitalisation rate after TRUS approaches 5%.

TRUS Vs TP Biopsies

Most prostate biopsies performed in Ireland are still TRUS biopsies, but this is changing.

In Australia TRUS biopsies  have largely been replaced by TP. In the UK, most of the major teaching hospitals have replaced TRUS with TP. Indeed, Guys and St Thomas Hospitals in London state on their website ‘A Transperineal prostate biopsy is our standard test to diagnose prostate cancer. We do not offer transrectal biopsies. We believe a Transperineal biopsy is safer and more accurate than any other type of prostate biopsy.’

There are two major issues with TRUS:

  • Infection risk
  • Inability to access all the prostate.

Inability to access all the Prostate.

Approximately 20% of prostate cancers arise in the front part of the gland, but this is an area inaccessible by a TRUS biopsy, which approaches if from behind.
TP biopsies can access the whole gland, leading to far higher accuracy.

So, why is TRUS still being performed?

There are multiple reasons.
  • Many urologists and radiologists have not been trained in TP biopsy.
  • TP is more expensive, but only in the short term. When the cost of treating infections and missed diagnosis is factored in, costs are similar.
  • Previously TP biopsy needed a general anaesthetic, but now most are done with local anaesthetic.

What needs to be done?

Here we should follow the UK.

In 2017, Guy’s Hospital stopped all transrectal biopsies. By March 2019, all six of the hospitals in the South East London Cancer Network, a population of over 1.5 million, stopped transrectal ultrasound (TRUS) biopsies and converted to the Transperineal approach. They call it TRexit.

The European Association of Urology (EAU) has stated, in a position paper in January 2021  ‘Available evidence highlights that it is time for the urological community to switch from a transrectal to a Transperineal [prostate biopsy] approach despite any possible logistical challenges.’

The Mater Hospital in Dublin leads the way. All prostate biopsies – both private and public – are done with Transperineal. Other hospitals are gradually getting there.