Hi, I'm Dr. Scholz. Let's talk about prostate cancer.
We're going to cover perhaps one of the biggest technological breakthroughs in the prostate
cancer realm over the last 5-10 years: MRI imaging of the prostate.
This tool has a lot of potential to be used in many different roles and we're going to
cover them today in this video.
Let's talk about screening for prostate cancer. MRI can replace the standard 12-core random
biopsy. It's more accurate, it doesn't entail a risk of infection, it's not nearly as unpleasant,
and of course, it can be used for guidance if you need to do a biopsy as well. You should
be aware of something called the PI-RADS system where an expert assigns a number to a spot
that's detected from 1 to 5. The 5s being most consequential. So, a well-read MRI done
at a center of excellence will indicate whether or not prostate cancer is likely to be present
and it'll also indicate where in the prostate that suspicious area is located.
Historically, PSA has been blamed for all the problems of over-diagnosing prostate cancer
when in reality it was the random biopsy. Now that we have MRI scanning we're able to
look through the prostate without having to over-diagnose low-grade forms that no one
really wants to know about anyway.
So the second important role for MRI is to use the scan to guide a needle biopsy to the
correct location in the prostate. One big advantage of using MRI for screening is that
a certain percentage of individuals won't need any biopsy at all. If the MRI is clear,
there's no need to push ahead with any biopsy, but MRIs will detect spots in a certain percentage
of patients and when it becomes time to think about doing a biopsy of that abnormal area
consider that there are three different approaches called In-bore biopsy, cognitive fusion biopsy,
and ultrasound fusion biopsy. A cognitive biopsy means that the doctor looks at the
MRI scans and sort of figures out in his own mind where to stick the needle. And ultrasound
fusion biopsy uses fancy software with an ultrasound machine to take the MRI images
and guide the needle to the correct area. An in-bore MRI biopsy means that you go back
to the MRI center and while you're in the MRI the needle is directed to the appropriate
area with a robotic device. All three methods have different uses at different times. All
of them are dependent on skillful implementation—skillful doctors that have done this a lot and know
what they're doing.
The third important use for multiparametric MRI is to stage prostate cancer in men that
already know that they have the disease. How large the tumor is, what part of the prostate
it's located in, does it come through the edge of the gland or through the capsule,
and perhaps most importantly does it invade into the seminal vesicles which are immediately
adjacent to the gland? This information will guide treatment because more extensive disease
requires more aggressive therapy. The MRI gives the most accurate indication of the
size of the tumor, it's extent, and whether it's still contained inside the prostate or not.
The fourth way that MRI is utilized is in helping determine treatment for men that may
be having a relapse. Men that have had previous surgery or radiation and develop a rising
PSA have to be evaluated as to where the cancer is located. Sometimes it's where the prostate
used to be or in the case of radiation back inside the prostate. Multiparametric MRI can
help determine the location of the cancer in and around where the prostate used to be.
If the MRI detected a recurrence of the disease in the prostate after radiation, for example,
a cryosurgeon or a HIFU expert can direct treatment to that area and possibly cure the
relapsed cancer. In men that have had previous surgery, if a spot of cancer is seen where
the prostate used to be (called the prostate fossa) radiation to that area may be curative.
Most people are aware now that many types of prostate cancer are so low-grade they can
be safely monitored. The method most relied upon for monitoring these men is to do repeated
12-core random biopsies every two to three years. This policy has been in place for over
ten years and it's widely accepted. Progressive thinking doctors are now realizing that the
MRIs—[which] are more accurate than the biopsies and they're certainly far less dangerous—can
substitute for the random biopsies. When MRIs are used in this role sequential images can
be compared chronologically over time to determine if there are any abnormal spots and if those
spots are either getting larger or developing aggressive characteristics. If a change occurs
then a targeted biopsy can be done with far fewer cores required. But many doctors have
not incorporated MRI yet into the active surveillance protocol.
Multiparametric MRI scanning is a new technology. As you're no doubt aware, some doctors haven't
even heard about it. To get a good quality image you need good technicians to get the
right exposure on the film, you need great equipment (preferably a 3 Tesla magnet), and
you need highly trained physicians to read these. One expert told me that these doctors
need a thousand practice sessions before they're really competent to read these MRIs.
Lastly, when you have an MRI and they detect a spot, that's not the end of it. You could
still need a biopsy. The good news is that it might be far fewer cores, but you cannot
prove or disprove the presence of prostate cancer with an MRI. You can only be directed
to an area of suspicion that would require a targeted biopsy to prove or disprove the
presence of cancer.
As you can see, multiparametric MRI is groundbreaking technology for men with prostate cancer. We've
covered a broad range of subjects today. It is a little bit complicated, but this is such
a useful tool it's very important that you understand all it's potential.
For more information about MRI and different locations across the United States go to PCRI.org/prostateimaging.
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