Let’s say you never had a problem with ants in your kitchen. Then, one day you spy a single ant zigzagging its way around the floor. You don’t jump to the conclusion that your home is infested, and you can live with a random ant or two. But what if that first ant is a sign that a colony has established itself at the base of your home, and an invasion is about to take over your cupboards and counters?

Trying to determine if there’s a hidden horde of six-legged creatures determined to pillage your pantry is not easy. You look for tiny cracks where the floor meets walls, you examine pipe portals under the sink, etc. Even if you find how those pesky ants are getting in, it tells you little about the actual location and extent of the colony—or even if there is one. Wouldn’t it be nice if there were some kind of ant infestation imaging detector? You could quickly screen your residence for the presence of a nest, and a single picture would tell you if next steps were needed, and what they would be.

Screening for prostate cancer

Relatively speaking, an ant infestation is small potatoes compared to having a colony of cancer cells growing in your body. However, they have something in common: the earlier you detect them, the more time you have to research options, consider solutions, and have the greatest chance for success.

This is why screening for prostate cancer (PCa) matters. Screening saves lives through early detection. However, the problem with the conventional PSA blood test is not what it tells you, it’s what it doesn’t tell you. A higher-than-expected number, or a rising number, is not specific for prostate cancer. Many conditions can bump up a man’s PSA. It’s like taking someone’s temperature: you may detect a fever, but the number on the thermometer does not tell you what’s causing the fever.

But doctors don’t want to take a chance on ignoring a high PSA that might be a red flag for PCa. Therefore, nearly a million needle biopsies are conducted annually in the U.S., and countless men are rushed into treatment even if their PCa is indolent (insignificant), leaving them with short- or long-term urinary or sexual side effects.

Greater screening accuracy with MRI

In hopes of avoiding unnecessary biopsies, researchers are hard at work to come up with a way to gain screening accuracy. One path involves analysis for specific biomarkers that could only mean PCa. There are already several tests using blood, urine or tissue samples. However, in their current form, they don’t lend themselves to broad population screening; they are primarily used for better definition of a patient’s risk level once he’s been diagnosed with PCa.

Another path is noninvasive imaging. In fact, a growing number of clinicians are turning to multiparametric MRI (mpMRI) following a suspicious PSA. Studies have repeatedly shown that this approach cuts way down on the number of prostate biopsies, and greatly increases the accurate diagnosis of significant PCa that needs immediate treatment.

The question is, can mpMRI be used for screening purposes, and how would it stack up against the limitations of PSA blood draws?^[i] To find out, a multicenter British team conducted the first study ever to compare the screening performance of a 15-minute “fast” MRI (T2-weighted and diffusion parameters only, no contrast administered) vs. PSA blood draws. The study, called IP1-PROSTAGRAM, was a prospective, blinded, paired screen-positive comparison with 408 men enrolled (406 were screened with both PSA and fast MRI. The authors note, “MRI was scored using PIRADS version 2.0 without knowledge of PSA; screen-positive MRI (defined as either PIRADS score 3-5 or 4-5) were compared against a screen-positive PSA defined as ≥3ng/ml.”

Among the noteworthy results of this study were the following:

• 17.7% of men were screen-positive on MRI (PIRADS 3-5 or 4-5) vs. 9.9% on PSA at ≥3ng/ml
• Compared to PSA alone, MRI detected a total of 32 significant PCa cases
• There were no serious adverse events
• The results suggest that screening with fast MRI could lead to more men diagnosed with clinically significant cancer without increasing the number of men biopsied or diagnosed with clinically insignificant cancer.

What this study shows is that a 15-minute scan provides far more specific information about what’s happening in a man’s prostate than the PSA blood draw, with instant results, and superior screening for significant PCa. While the world still lacks a technology that could provide a “snapshot” of a suspected ant colony lurking to take over your kitchen, we already have the technology to quickly obtain a hi-resolution, 3D portrait of suspicious cancer colonies in the prostate.

Since the IP1-PROSTAGRAM research is the first of its kind, more studies are needed to support these results. Also, more logistics are needed if such MRI screenings were to be widely implemented, given that the technology is not portable. Nonetheless, I congratulate the research team on demonstrating the potential for broad MRI screening to transcend the limitations of PSA.

NOTE: This content is solely for purposes of information and does not substitute for diagnostic or medical advice. Talk to your doctor if you are experiencing pelvic pain, or have any other health concerns or questions of a personal medical nature.

References

[i] Eldred-Evans E, Burak P, Connor MJ, Day E et al. Population-based prostate cancer screening using a prospective, blinded, paired screen-positive comparison of PSA and fast MRI: The IP1-PROSTAGRAM study. J Clin Onc. 2020 May; 38:15 suppl. 5513-5513.