RSS feedEnhanced prostate cancer MRI
Harley Street Urology works in partnership with specialists in enhanced prostate MRI scans, also known as prostate mapping, used before and as an alternative to standard biopsy. This technology is called multiparametric technology called the 3T Verio MRI scanner. In this section we explain what this technology is, how it is used and why it is beneficial.
Why do an MRI scan before a biopsy?
The majority of men over the age of 60 will have some degree of prostate cancer, but for the vast majority, this will not be clinically significant disease. This means their prostate cancer will be slow-growing and therefore very unlikely to have an impact upon health during their lifetime. The task of the urologist is to judge where there is a small amount of slow-growing disease and avoid over-treating, but identify harmful, fast-growing cancer. This is sometimes described as “telling the prostate cancer tigers from the pussy cats.”
Traditionally, MRI has been used after the biopsy has confirmed prostate cancer to stage the disease. This means the scan takes place to help assess what extent the disease has progressed and whether it has moved beyond the prostate. As a result of better understanding of how prostate cancer develops, combined with improvements in MRI technology, there is now a new and important role for MRI before considering a biopsy and in combination with other assessments.
The anatomy of the prostate and what it means for detecting cancer
Between two thirds and three quarters of prostate cancer develops in what is known as the peripheral zone (or back) of the prostate. The traditional biopsy, medically known as the TRUS biopsy, involves taking samples from the back of the prostate. Therefore, because of the position patients lie in during the biopsy and the place of insertion, most peripheral zone cancers are found during a standard biopsy.
However it is more difficult for biopsy needles to reach anterior (or frontal) prostate cancers during a TRUS biopsy. This location is where at least a quarter of prostate cancers occur and there are many examples of anterior cancers being missed on standard biopsy.
Improvements in MRI technology
Harley Street Urologists are referred to Harley Street radiologists who use advanced MRI technology to ensure the most accurate results are achieved. The technology involves:
- Adding dynamic contrast enhancement
- Diffusion-weighted imaging
- Using a 3T scanner (compared with older T1 and T2 weighted sequences). This means the scan has a higher signal which enables the radiologist to scan faster and use a higher resolution
- There is no need for an endorectal coil (used widely in the US) which patients find uncomfortable and sometimes painful. The quality of 3T scanners and improvements in surface coils means there is no need for patients to have an endorectal coil fitted
How are 3T MRI prostate scans used?
For between a third and a half of all patients, the 3T MRI is so convincingly negative, that we can say more reliably than with biopsy that there is unlikely to be significant disease in the gland . Therefore an invasive biopsy is not needed.
If a biopsy is required as a tumour has been identified, the MRI scan can be targeted to a specific location within the prostate. This is often the case for anterior tumours (located in the front of the prostate) which accounts for a quarter of all prostate cancers.
With patients undergoing active surveillance, enhanced prostate MRI scans, also known as prostate mapping, can be used in combination with other assessments, such as PCA3 and PSA, to check how the disease is progressing and judge whether a biopsy is also needed.
