Receiving a prostate cancer diagnosis used to be a painful ordeal involving guesswork and, often, false results. A newer approach involving magnetic resonance imaging (MRI) has improved accuracy, but men still have needles inserted into sensitive areas for biopsy. Researchers at GE HealthCare are working to advance MRI technology so that men can eventually be diagnosed with prostate cancer with fewer biopsies, only used when absolutely necessary.
“We see multiparametric MRI in the care pathway as a gatekeeper,” says Professor Dr. Mathias Goyen, GE HealthCare’s chief medical officer for Europe, the Middle East and Africa, a practicing radiologist with a specialty in prostate imaging. “Something for biopsy for diagnosis, but also active surveillance, meaning doing nothing, watchful waiting.”
How prostate cancer has been diagnosed
Prostate cancer is the second-most common cancer in men and the fourth most common cancer overall. More than 1.4 million men worldwide were diagnosed in 2020.
Physicians typically screen patients for prostate cancer, beginning at age 50, with a digital rectal exam and a blood test looking for elevated levels of prostate specific antigen (PSA). Patients need a biopsy when PSA levels are higher than 4 ng/ml, which may indicate the presence of cancer. However, PSA levels sometimes are elevated when no cancer is present, leading to unnecessary biopsies. Stimulation of the prostate — riding a bike or having sex with men — may increase PSA levels.
Historically, urologists used a 12-core needle to take multiple samples of prostate tissue during a biopsy. Urologists aimed systematically at the prostate, rather than directly at sites of possible tumors.
“Without guidance for the biopsy, you are going to get false negatives due to incomplete sampling, meaning that you are missing cancer,” says Jason Polzin, general manager of MR Applications Platform and Research Technologies at GE HealthCare. “Guiding the biopsy helps significantly reduce these missed cancers.”
Each biopsied tissue sample is examined by a pathologist and given a Gleason score. A higher Gleason score means that biopsied cells appear abnormal and are expected to grow quickly, indicating aggressive prostate cancer that warrants treatment. However, if the biopsy misses aggressive tumor cells, the Gleason score isn’t accurate and can be underestimated.
“Every man, if old enough, will eventually get prostate cancer,” Polzin says. “What you’re trying to do is distinguish between the indolent — meaning very slow growing — [and] the very-fast-growing, aggressive prostate cancers. Because the more aggressive ones … tend to metastasize — meaning spread — into the lymph nodes and other parts of the body, and that’s ultimately what you could die from.”
When physicians began using MRI to view the prostate, in approximately the 1990s, patients needed an endorectal coil. The endorectal coil is a probe placed in the rectum, close to the prostate. It helped to create clearer, improved images. “This can be very uncomfortable; also, a little bit humiliating, especially for an older gentleman,” Polzin says. Today, MRI prostate exams can be completed using surface coils placed on the pelvis. Additional innovations, including GE HealthCare’s AIR™ Coils, are lighter and more flexible than traditional surface coils.
MRI provides high-quality images of the prostate that can highlight potential areas of concern, including the presence of suspicious lesions that could be cancerous.
How prostate cancer is diagnosed today
In many urban centers across the U.S. and Europe, the standard of care is now ultrasound-guided biopsy with MRI fusion. Patients with high PSA levels receive an MRI with unobtrusive surface coils, not endorectal coils. Prostate cancer imaging benefits from technologies like GE HealthCare’s AIR™ Coils, which are very lightweight and conform to the patient better than traditional surface coils. Physicians overlay the outputs of these MR images onto ultrasound, providing real-time guidance for biopsy, enabling physicians to target suspicious regions with a single needle. As part of its prostate reporting package, PROView, GE HealthCare has recently introduced software that allows these high-quality MRIs to be segmented, measured and exported to ultrasound-based fusion systems.
“You can be pretty sure that the Gleason score really is almost the truth because you have caught the most aggressive part of that heterogeneous tumor,” Goyen says.
How prostate cancer may be diagnosed without biopsy
A partnership with the University of California, San Diego may enable GE HealthCare to offer fewer biopsies to future patients with elevated PSA scores, thereby eliminating unnecessary biopsies, especially in men who do not have clinically significant prostate cancer.
UCSD researchers have developed a method called Restriction Spectrum Imaging (RSI) using MRI, which improves detection of clinically significant prostate cancer and can be used to better target biopsies and treatments, helping to avoid unnecessary biopsies.
“RSI provides similar information to the biopsy, [and] can provide something similar to a Gleason score noninvasively,” Polzin says. “It’s consistent with the actual microscopic biopsy, even though you’re not able to image directly at the cellular level.”
GE HealthCare researchers are also developing artificial intelligence technology methods to detect prostate lesions via MRI. They already have AIR Recon DL, which allows sharper and higher quality MRI to be scanned in shorter time periods.
“We could get to a point where a man with an elevated PSA could go in for an annual 15-minute MRI scan that uses AI to assist the physician in detecting and quantitatively assessing potentially cancerous areas on the MRI that could be tracked over time,” Polzin says.
Men with elevated PSA scores could get MRI screenings regularly instead of repeated biopsies, which may cause bleeding, infection or urination difficulty. Some men who need repeated biopsies opt to have their prostates removed, which may cause incontinence or impotence.
If MRI screenings help change the standard of care for prostate cancer assessments, men may be monitored, diagnosed and treated, without an unnecessary biopsy, before the cancer spreads.
“We can turn this into a chronic disease,” Goyen says. “When they die, they die with prostate cancer and not because of prostate cancer.”
