Introduction to MRI
A magnetic resonance imaging scan (MRI) allows your urologist an extremely clear picture of your prostate, including any enlargement, swelling, or even if the tumours have broken out of the prostate capsule itself. It is therefore important in assessing the stage of your prostate cancer – or how far the cancer has spread within the prostate gland.
The below video explains how MRI works and what you can expect during your scan.
MRI scan for prostate cancer patients
At Santis, our normal practice is to arrange an MRI scan prior to a prostate biopsy for newly referred patients. There is growing evidence that this is important for two main reasons:
- The needles used during a biopsy puncture the prostate and can cause minor bleeding. This bleeding can show up as ‘biopsy artefacts’ on the final MRI image, reducing the clarity of the image of your prostate.
- If an abnormality is seen on MRI scanning before a biopsy, it can be specifically targeted during the biopsy, increasing the detection rate for prostate cancer (if cancer is present).
Abnormalities seen within the prostate are classified using the PIRADS (Prostate Imaging Reporting And Data System) system with a score of 1 indicating the lowest suspicion of prostate cancer and 5 indicating the highest level of suspicion. PIRADS scores of 3 or more usually trigger a prostate biopsy if the prostate feels normal on digital rectal examination. If the DRE is abnormal then the prostate should always be biopsied.
Typically it takes around 2 weeks for an MRI scan to be arranged on the NHS, and then a further 2 weeks for the results to be available.
Your MRI scan will provide you with the stage of your prostate cancer
In patients who are subsequently diagnosed with prostate cancer, the MRI scan provides the stage of the cancer, with the letter T used to indicate the stage of the tumour. Stage means how far the cancer has spread. Although the stage can be assessed by digital rectal examination, it is more accurately assessed by an MRI scan.
Stage Description T1 T1 tumours are too small to be seen on scans, or felt during examination of the prostate. They may be discovered during a biopsy examination though. T1 tumours are not very serious.
T2 tumours are subdivided into three stages, T2a, T2b and T2c. Together they are commonly called localised prostate cancer. This is where the cancer is completely contained within the prostate. T2 tumours are more serious, but can be effectively treated.
Stage Description T2a T2a tumours are where tumours are found in only half of one of the two lobes that make up the prostate gland. T2b T2b tumours are where tumours are found in more than half of one of the two lobes. T2c T2c tumours are where tumours are found in both lobes, but the overall cancer is still contained within the prostate gland.
T3 tumours are subdivided into two stages, T3a and T3b. Put together, they are commonly called locally advanced prostate cancer. This is where the cancer has broken through the outer covering of the prostate, but has not spread to other organs. T3 tumours are fairly serious.
Stage Description T3a T3a tumours are where tumours have only broken through the outer covering of the prostate. T3b T3b tumours are where tumours have broken through the outer covering of the prostate and have also spread to the seminal vesicles.
T4 tumours have spread to other organs nearby, such as the rectum, bladder. It is also called metastatic prostate cancer. This is the most serious form of prostate cancer.
Whether you require treatment or not – as well as which treatment is most effective – is heavily dependent on the stage and grade of your prostate cancer.
T1 and lower grade prostate cancers might not require any treatment at all, while T2b and above is usually deemed as carrying a higher risk by urologists, and so usually require treatment – either radiotherapy, brachytherapy or surgery to remove the prostate itself.