Prostate cancer is the most common type of cancer in males, and statistics show that most of us will develop this condition.
It is the second most common cancer in the United States, and the incidence varies in different countries.
However, mean statistics show that more than half of men over 65 years have prostate cancer.
The risk keeps increasing as we grow older, with its peak at 80 years.
Some of these cases are not diagnosed, and their growth rate is usually very slow.
But we can find very aggressive cases, too, and prostate cancer was responsible for more than 30,000 deaths in 2018 only in the United States.
That’s why screening is important, and health authorities are constantly looking for new ways to make it more accurate.
MRI-guided prostate biopsy is one of those attempts.
It is a promising way to improve the outcomes of a biopsy, and we’ll cover what it is about in this article.
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What is an MRI guided prostate biopsy?
As the name implies, an MRI guided prostate biopsy is a type of biopsy in which the prostate is located through MRI technology.
MRI means Magnetic Resonance Imaging. It is more accurate than ultrasound scans, X-rays, and CT scans.
The difference is that an MRI scan uses very potent magnets to create images through radio waves. This makes a very detailed picture of the prostate gland.
Thus, the doctor can see particular areas that look suspicious and direct the biopsy needle more accurately.
But anyone who had an MRI done will know that you can’t have any metal objects around during the procedure.
If that’s the case, how can you perform a biopsy guided by MRI? They achieve this through a technology we call a fusion-guided biopsy.
You will go through an MRI, and then the doctor takes the image through high-tech software. They would then perform a prostate ultrasound, and the software merges the photos from the MRI and those of the ultrasound.
That’s how the doctor will see the trouble area very accurately, and the biopsy will have a more accurate result.
How does it work?
An MRI-guided prostate biopsy occurs in an MRI-positive prostate lesion.
In other words, if there is no highly suspicious lesion in an MRI, there’s no reason to spend extra money on a fusion biopsy.
With that in mind, the indications of this type of biopsy include (2):
- Patients who had previous transrectal ultrasound biopsies with a negative result but the suspicion is still very high.
- Patients with a diagnosis of prostate cancer under active surveillance.
After receiving the MRI image, doctors create a prebiopsy MRI map. They use a navigation feature that provides real-time feedback to guide needle location, the optimal patient position, and more.
The doctor may choose between a transperineal or transrectal approach depending on the prostate lesion.
The doctor will usually recommend the former if the patient is susceptible to infections or had a history of sepsis.
Fusion-guided biopsy uses a medical imaging software that works by:
- First, detecting and creating segmentation of the MRI image. In this step, the doctor outlines the prostate and the target lesions. The data is then transferred to a procedure workstation.
- Registering the image by sweeping the transurethral ultrasound probe until it automatically records the prostate gland.
- Rigid registration is activated, aligning both images when the patient or the probe moves. The doctor may also choose a manual alignment when necessary.
- Elastic registration remains an option if the doctor needs to stretch the MRI image to create a perfect overlap of prostate contours.
Advantages of an MRI guided prostate biopsy
If you read and understood how MRI works, you won’t be impressed to learn the benefits of this type of biopsy.
So, in a nutshell, this is why MRI-guided biopsies are becoming the modern screening method for prostate cancer (3,4):
Reduced number of samples
The standard prostate biopsy requires multiple prostate tissue samples (known as biopsy cores).
In other words, the needle will go through your prostate more than ten times in different areas.
This increases the accuracy of a prostate biopsy. But doing so increases the risk of rectal bleeding and other side effects.
MRI-guided biopsies require fewer samples and only take them from particular parts of the prostate.
Fewer side effects
This reduction in the number of samples makes MRI-guided biopsies more tolerable.
The rate of acceptance is higher, and there are fewer side effects.
There is significantly less pain, and the risk of bleeding and other complications is lower.
May reduce the rate of prostate cancer overdiagnosis
A common problem in screening is the overdiagnosis of prostate cancer.
In other words, to find lesions that do not require treatment and leave the patients with the side effects of a prostate biopsy.
Research suggests that using MRI-guided biopsies strategically may lead to a more accurate diagnosis of clinically significant prostate cancer.
Accurate detection of high-grade lesions
Other studies show that MRI-guided biopsies increase prostate cancer detection with a higher Gleason score.
In addition, the accuracy of this method to detect high-grade lesions is better than the standard.
Offers extra benefits for prostate cancer follow-up
This type of biopsy is advantageous in patients who require a repeat biopsy. They are more likely to tolerate the repeated procedure.
These patients sometimes need to be reclassified when cancer progresses.
A new classification means that the tumor is in a new stage, and the healthcare provider will adjust the treatment.
MRI-guided biopsies detect these changes more accurately, leading to a higher reclassification rate.
Drawbacks
Nothing is perfect, and MRI-guided prostate biopsies are not for everyone.
However, here’s what you need to know if you’re opting for this procedure (5):
It only works for MRI-positive lesions
If you don’t have lesions visible in the MRI, this type of biopsy does not provide any real advantage.
That’s why it is often not applicable in biopsy-naïve patients (patients who never had an initial biopsy done in the past).
Can reduce accuracy in BPH
This prostate biopsy method does not help treat an apparently normal prostate.
It may also reduce its accuracy in patients with benign prostatic hyperplasia.
It is more expensive than the average biopsy
This biopsy uses more complex technology and can be very expensive. Thus, if you’re not likely to benefit greatly, you might want to choose the standard biopsy instead.
It is not without side effects
It has fewer side effects, but not zero. You can still experience bleeding and pain.
Patients may also develop an infection due to bacterial migration from the rectum into the prostate.
What to expect
If you’re a patient and will soon have an MRI-guided biopsy done, you’re likely to have many questions. One of them is what will happen during this procedure.
First of all, this is an outpatient procedure. It means that you can leave the hospital after it’s over.
Still, you need to prepare for the biopsy with antibiotics and take them some time after. This reduces the rate of infections and other complications.
You will first have an MRI done. The doctor will analyze the data and call you back when it’s ready.
During the procedure, your doctor will use an ultrasound scanner and insert a transrectal probe.
The needle will be inserted alongside the probe, and local anesthesia will reduce the pain.
In some cases, the doctor may choose a transperineal approach. It is the same biopsy but goes through your perineal floor and requires sedation.
How does it compare to other prostate biopsies?
There are different ways to perform a biopsy, and an MRI-guided biopsy is only one type.
So how does it compare to other types of prostate biopsy? Here’s a brief review of each one:
Transrectal ultrasound guided systematic biopsy
This is the most common type of prostate biopsy. You could also find it as TRUS guided prostate biopsy or TRUS biopsy.
It is the standard procedure because it is applicable for most patients. TRUS biopsies are not only performed in patients with an MRI-positive lesion.
Thus, it could be better to use this biopsy instead of an MRI-guided biopsy in some patients who never had a prostate biopsy done in the past.
This type of biopsy does not feature a high-resolution 3D picture of the prostate. Thus, it requires a higher number of samples to diagnose prostate cancer accurately.
Transurethral biopsy
This method is rarely used, but you could be offered this option in some cases.
In a transurethral biopsy, a cystoscope is inserted through your urethra.
It is similar to catheter placement, except that it features a tube with a tiny camera.
The biopsy sample is taken from the urethral wall directly into the prostate.
This method is more accurate in anterior lesions and those located around the urethra.
Transperineal biopsy
The transperineal approach is through your pelvic floor.
Compared to the standard transrectal biopsy, this type is more accurate in anterior lesions of the prostate.
In other words, if cancer was far from the rectum, a transrectal biopsy won’t reach this area. A transperineal biopsy will.
This biopsy technique is also recommended in patients with a history of sepsis or very severe infections.
Compared to the usual transrectal approach, local anesthesia is not enough in this case.
Nerve block anesthesia is used instead. You could get an MRI-guided prostate biopsy using a transperineal method.
However, it is not the most usual and may not be available everywhere.
What to expect after the biopsy
After the biopsy, you can resume your usual activities. However, your doctor might advise you not to sit for extended periods and avoid lifting heavyweight.
You might stay sore for a few days, and it is normal to find traces of blood in your stools, urine, and semen.
Talk to your doctor if you experience abundant bleeding, high fever, and flu-like symptoms.
Your urologist may schedule a follow-up to see how you’re doing.
They may order a blood culture and urine culture to rule out infections after a biopsy.
Careful monitoring is always recommended, even if the biopsy result is negative.
Thus, you may still need to go back with your doctor every year for a prostate specific antigen (PSA) test, a digital rectal exam, and other evaluations.
Conclusion
As the name implies, this biopsy procedure is guided by an MRI scan. It is for patients with repeat biopsies and those with a visible prostate lesion in their MRI.
It is a targeted biopsy that goes directly to the trouble area.
Thus, it won’t require many samples to be accurate. It is recommended to detect progression in clinically significant prostate cancer. In these cases, it offers greater accuracy in the Gleason score progression.
Similar to ultrasound guided biopsy, this is a needle biopsy. But the risk of side effects is lower, and patients tolerate it more easily.
Thus, it is recommended in patients who need to repeat their biopsies frequently.
Depending on the location of the lesion, your doctor could take a transrectal prostate biopsy approach or go through your pelvic floor. The latter is a transperineal prostate biopsy.
MRI-guided prostate biopsies are not for everyone. Talk to your doctor if this approach interests you and to see if you’re a candidate.
It is essential to listen to your doctor’s recommendations before and after the procedure.
By doing so, the risk of complications reduces, and you will get appropriate management according to your case.
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