Prostate cancer is a notoriously tricky disease to diagnose and is now a bigger killer than breast cancer.
If someone is at risk of having prostate cancer, a GP may suggest they have a biopsy. However, the most commonly used diagnostic test, the trans-rectal ultrasound guided (TRUS) prostate biopsy, can miss up to one in five cancers according to the NHS.
There have been huge improvements in the diagnosis of prostate cancer in recent years, the most significant being the introduction of multiparametric MRI scans (mpMR). The advantages of mpMR have been demonstrated by the PROMIS Trial which compared MRI with the standard TRUS biopsy. A summary of this trial can be found in The Lancet. In this study, all scans were performed using a 1.5T MRI.
What this trial showed is that multiparametric MRI has a high sensitivity (good at identifying significant cancer) and low likelihood of a false negative result when the scan is reported as normal but in reality, prostate cancer is present. MRI is, therefore, a justifiable test which should be part of the prostate cancer diagnostic pathway.
What is a 3T MRI scan?
A 3-Telsa (3T) MRI scanner is significantly more powerful than the more common 1.5T scanners and the 3T magnetic field provides exceptional anatomic detail.
The increased image clarity revealed by 3T is particularly beneficial for prostate imaging and this high quality enables specialist experienced radiologists to differentiate between benign and potentially malignant conditions with confidence. Working collaboratively, the radiologist and urologist will be able to provide you with earlier diagnosis and more effective treatment allocation, with subsequent improvements in treatment outcome. Those with a negative or normal scan will also be reassured that there is no cancer present and therefore no cause for concern.
The importance of an accurate diagnosis
Most men as they get older will have some low-grade prostate cancer. These are often small and difficult to see on imaging or find on biopsy. The reason that an accurate diagnosis is so important is that it will enable us to offer the best possible advice for our patients. A pre-biopsy MRI will enable targeted sampling of any areas of concern and will, therefore, improve the quality of the biopsy samples. This, in turn, will enable better decision-making. Some cancers will be safely monitored and others will require treatment.
No significant cancer
Following their multiparametric MRI, many men will be told that they do not have any significant prostate cancer, and will be returned to the care of their GP or urologist for regular follow-up.
Some men will have changes which might be significant cancer and will subsequently undergo a prostate biopsy. The cancer may be low grade and the resultant recommendation be a follow-up MRI 9-12 months later to reassess the lesion. Men can remain on active surveillance for many years with no significant changes to the cancer.
Some men may have a significant cancer which is restricted to one part of their prostate. This may lead to that part of their prostate being treated using one of the following technologies:
High Intensity Frequency Ultrasound (HIFU)
With a greater understanding of the location and volume of the prostate cancer, urologists can also consider treating the affected part of the prostate rather than having to destroy it all. If carefully selected, this can result in a safe alternative to the traditional more radical approaches which are more likely to result in side effects.
Some patients will need to have the whole prostate treated. This can be done surgically or with radiotherapy or by brachytherapy. Having high-quality MR images of the prostate enables the specialist to determine the most appropriate and effective treatment and to plan the treatment itself; often resulting in a better outcome.
If you are worried about prostate cancer you should see your GP and discuss having a blood test and examination. They can refer you to a consultant urologist if appropriate. The urologist will discuss all options with you and can refer you for a multiparametric Prostate MRI scan. After the scan, a decision can be made regarding the need for a biopsy. At least 30 percent of men will have a completely normal scan and so will not proceed to biopsy.