Homing in on prostate cancer with fusion biopsy

Left Image: The target from an MRI is merged with an ultrasound image for targeting. Right Image: The biopsy locations are captured by the MRI-Ultrasound fusion technology.

Ideally, doctors would catch every case of prostate cancer early, before it has time to grow and spread. Early detection gives men more options, whether that involves treatment or active surveillance to make sure the cancer doesn’t continue to develop.

But standard approaches can’t always locate the prostate cancer. That’s an issue for many of my patients. One man had previously had five standard biopsies, all of which were negative for prostate cancer. But he still had high levels of PSA, or prostate-specific antigen, which is a potential indicator of prostate cancer. I told him, “You really should get an MRI.”

The patient’s MRI (magnetic resonance imaging) test showed there was an abnormality in an area of the prostate where we don’t usually see tumors—one that’s difficult for us to access during a standard biopsy. So we used an advanced technique called an MRI/ultrasound fusion biopsy, which uses both MRI and ultrasound, to help detect this patient’s prostate cancer.

This patient would not have been diagnosed as early as he was without having an MRI/ultrasound fusion biopsy. And this is just one of the many examples I’ve seen of this technology’s value to patients.

The benefits of MRI/ultrasound fusion biopsy

Prostate cancer is a serious problem, both nationwide and in the Washington, D.C., area. Locally, we have a prostate cancer incidence rate of 120.1 men per 100,000. That means more than 120 men out of every 100,000 in the area have prostate cancer—a rate that’s nearly 18 percent higher than the national average.

I recommend a prostate biopsy for men who repeatedly have test results that show high PSA levels. We traditionally use an ultrasound probe to first see if there are any abnormal areas in the prostate. If there are, we target the biopsy in those areas. If there aren’t, we sample 12 random areas to see if we can locate any cancerous cells. The challenge with this approach is that it’s possible to still miss cancerous cells.

As we’ve begun to use MRI scans more often, we’re able to find tumors within the prostate. MRI scans are especially helpful for detecting aggressive prostate tumors. Many times, I see patients who have high PSA scores but negative biopsies, and prostate tumors show up on an MRI scan.

MRI/ultrasound fusion biopsy combines the best parts of MRI and ultrasound for prostate biopsies. The fusion approach starts with an MRI scan of the prostate. We then use that to guide us as we perform an ultrasound and biopsy at the same time. Merging these images is almost like having a homing device in the prostate, telling us to change angles or move our probe slightly.

MRI/ultrasound fusion biopsy combines the best parts of MRI and ultrasound for prostate biopsies. via @MedStarWHC

Following the completion of the procedure, the distribution of the biopsy sites in relation to the targets can be easily visualized.

This technique increases the number of cases of prostate cancer we’re able to diagnose, especially higher-risk cases of the disease. One study found that targetedMRI/ultrasound fusion biopsy helped doctors diagnose 30 percent more high-risk cases of prostate cancer compared to standard biopsy.

During my training at Georgetown University, I had the opportunity to train at the National Institutes of Health (NIH) for four months. The NIH is where the MRI/ultrasound fusion biopsy system was developed. I use it frequently, and other centers are starting to use it more as well.

Related reading: Can an advanced MRI improve prostate cancer screening?

MRI/ultrasound fusion biopsy harnesses the strengths of both MRI and ultrasound to do more than either can do alone. The result: We can catch more cases of prostate cancer that might not otherwise be found. My hope is that MRI/ultrasound fusion biopsy becomes the standard method doctors everywhere use to detect prostate cancer.

Request an appointment with one of our urologists if you’ve had several high PSA scores but negative prostate biopsy results in the past.

Should men get a PSA test to screen for prostate cancer, and when?

Prostate cancer is the most common cancer in men, with one in seven men in the United States projected to get the disease in their lifetime. And the District of Columbia has the second highest prostate cancer incidence rate in the country behind only Louisiana, with 123 out of 100,000 men diagnosed with the disease in a given year.

One of the best screening tools we have for this disease is the prostate-specific antigen (PSA) test. While there’s no doubt this simple blood test has saved lives over the years, it’s not perfect. There’s been a lot of debate over who should be screened and when—and whether men should be screened at all. Even national health organizations differ slightly on their PSA testing guidelines.

PSA testing is not a one-size-fits-all approach to prostate cancer screening. The key is to have an honest conversation about the potential benefits and harms for each man based on his specific risk factors.

Tune in to this podcast to hear Dr. Krasnow further discuss PSA testing, including what men may expect from future prostate cancer screening.

Benefits and risks of PSA testing

Prostate-specific antigen is a protein made in the prostate gland and present in semen. A small amount of PSA enters the bloodstream, but high levels in a man’s blood can indicate prostate cancer. After the PSA test’s introduction in the late 1980s, deaths related to prostate cancer began to decrease. In fact, mortality rates fell nearly 40 percent between the early 1990s and 2008.  

This was a huge win in our fight against prostate cancer. However, there also have been some negatives associated with the test, the biggest being its 15 percent false-positive rate. A false positive is when the test detects cancer that is not present.

This means 15 in 100 men who get an elevated PSA test result do not actually have prostate cancer. Unfortunately, to confirm this, they’ve likely undergone an unnecessary biopsy. While generally safe, biopsies can cause complications, such as bleeding or infection and can induce unnecessary stress for the patient.  

PSA testing also can increase the risk of overtreatment. Most diagnosed prostate cancers are low-grade, which means the abnormal cells are unlikely to impact a man’s life in any way. Prostate cancer is a slow-growing cancer, taking 10 to 15 years to progress and even longer to cause death. These tumors may only need close monitoring over the years, also known as active surveillance, and not treatment.

Do the potential benefits of PSA testing outweigh the potential harms? It depends on the person. Some of my patients who have received a false positive were relieved to know their cancer status for sure. Others, while relieved, continued to worry about their elevated PSA level as we monitored them over the following years. And still others were frustrated that they had to go through the biopsy process, which, while not painful, is awkward and uncomfortable.  

What studies and guidelines say about PSA testing

Actor Ben Stiller made waves in 2016 with a blog post titled “The Prostate Cancer Test That Saved My Life.” In the article, he attributed surviving prostate cancer to having a PSA test at age 46—earlier than most guidelines would recommend—despite having no indicators that he was at increased risk for the disease.  

He wrote: “If (my doctor) had waited (to get me a PSA test), as the American Cancer Society recommends, until I was 50, I would not have known I had a growing tumor until two years after I got treated. If he had followed the U.S. Preventive Services Task Force guidelines, I would have never gotten tested at all, and not have known I had cancer until it was way too late to treat successfully.”

If you’re looking to various health organizations for guidance on when you should have a PSA test, you may be confused by the differing recommendations. And these recommendations also may change over time. For example, the U.S. Preventive Services Task Force slightly revised its guidelines since Ben Stiller had his PSA test based on new evidence and studies.

Here is what some health organizations currently recommend:

  • American Cancer Society: The organization recommends that men at average risk for prostate cancer begin discussing screening with their doctors at age 50. Men at increased risk should consider screening at age 45.
  • American Urological Association: The organization recommends that doctors begin discussing screening at age 40 to 54 for men at high risk, 55 to 69 for men at average risk, and 70 and older for some men in excellent health with a 10- to 15-year life expectancy.
  • U.S. Preventive Services Task Force: The group in 2017 recommended that while the PSA test should not be used routinely, physicians should discuss the benefits and harms with men age 55 to 69. It recommends against PSA screening for men 70 and older. This is in contrast to its 2012 guidelines that recommended against PSA screening in men without prostate cancer symptoms.  

So what’s a man supposed to do? The answer lies in the common theme to these recommendations: a discussion between doctor and patient.  

How I advise men about screening for prostate cancer

I once treated a man in his 40s who was exhibiting signs of benign prostatic hyperplasia, a condition in which the prostate is enlarged. We decided to do a PSA test, despite most guidelines recommending against PSA testing for a man younger than 50 with no increased risk factors for prostate cancer. The test showed elevated PSA levels, but a traditional biopsy only found very low-grade cancer.  

This didn’t make sense considering his high PSA levels. We had a long conversation about how to proceed, and we decided to do advanced testing. An MRI-guided biopsy that is increasingly being used to detect prostate cancer revealed a high-grade prostate cancer that, left unchecked, would have been lethal.  

PSA test guidelines aren’t hard and fast rules—as my patient and Ben Stiller would attest to. The key is an open, honest conversation in which the patient and doctor come to a decision together.

Related reading: Shared decision-making: It’s no longer “doctor knows best”

For a man at average risk for prostate cancer, the discussion may center more on the potential benefits and harms of a PSA test. However, the conversation may take on a more urgent tone if the man has factors that put him at increased risk for prostate cancer. These can include:

  • Family history: Having a first-degree relative, such as a father or brother, who had the disease.
  • Genetic mutations: We’re continually learning more about how certain gene mutations can increase a man’s risk for prostate cancer. This includes mutations of the BRCA1 and BRCA2 genes, which are more commonly associated with breast and ovarian cancers.  
  • Race: African-Americans have double the incidence of prostate cancer compared with white men, and their risk of dying from the disease is two to three times higher.

A man’s age also should be taken into effect. Because prostate cancer grows so slowly, there’s little benefit to screening older men whose life expectancies are less than 10 to 15 years. When I see a patient who is 70 or older and has been referred to me for a PSA test, I usually advise against it unless they are extremely healthy for their age.  

I think as medical professionals, we’re doing a better job of screening smarter and being more selective in who gets a PSA test. But discussion is the key.

Request an appointment to talk to a doctor about your prostate cancer risk and screening options.