NORTH SIOUX CITY -- A new approach to diagnosing prostate cancer in Siouxland could help local men avoid unnecessary prostate biopsies.
After years of trying, Dr. Tim Kneib, who practices with Siouxland Urology, said he was finally able to bring MRI-ultrasound guided fusion biopsy to the area 1 1/2 years ago, after Mercy Medical Center obtained a 3 Telsa MRI and radiologists who can read MRIs of the prostate gland became available.
So far, Kneib said he has performed around 140 MRI-ultrasound guided fusion biopsies, which are often ordered when a patient's Prostate-Specific Antigen (PSA), a protein produced by the prostate gland, is elevated to an abnormal level. The higher a man's PSA level, the more likely it is that he has prostate cancer.
"Biopsies are no fun for the men. It's painful and uncomfortable," said Kneib, who said bleeding, infection and pain are possible side effects of prostate biopsy. "I think if we can do fewer, but better biopsies, I think that would be wise."
Before the pieces were in place to offer MRI-ultrasound guided fusion biopsy, also referred to as MRI-targeted biopsy, Kneib said men suspected of having prostate cancer were subjected to routine ultrasound guided biopsy, during which a total of 12 tissue sample -- six from each side of the prostate -- are collected with a small needle under the guidance of a grid. MRI provides more detailed images of the prostate than ultrasound can.
"We often missed a lot of the lesions that were way anterior in the gland, because we just couldn't reach them with that platform or didn't know where they were," Kneib explained. "Now, when we can say the MRI is negative, that's probably greater than 90 percent accurate that we're not going to miss a clinically significant prostate cancer lesion."
A study published in the New England Journal of Medicine in March that was funded by the National Institute for Health Research and the European Association of Urology Research Foundation, found that men who had MRI-targeted biopsies experienced fewer side effects following the biopsies than men who received a standard biopsy. The study also revealed that MRI-targeted biopsies were better at detecting prostate cancer. Clinically significant cancer was detected in 38 percent of men in the MRI-targeted biopsy group versus 26 percent in the standard biopsy group, even though fewer tissue samples were taken from the MRI-targeted group.
Kneib said the first step in MRI-ultrasound guided fusion biopsy in Siouxland is obtaining an MRI at Mercy Medical Center. If a suspicious prostate lesion is detected after the scan and that lesion has a PI-RAD score ranging from 3-5, he said a biopsy with ultrasound guidance follows at Siouxland Urology in Dakota Dunes.
Before the biopsy, the MRI images are examined and special software is used to target specific areas of the prostate. The images are then fused with real-time ultrasound images during the biopsy, which take about 15 minutes. The patient is awake during the biopsy and numbing medication is injected around the prostate. Instead of collecting 12 random prostate tissue samples, Kneib said he only takes 6-10 from abnormal areas identified by the MRI images. Each time a needle passes through a probe inserted into the patient's rectum, Kneib said the patient feels a sensation similar to a rubber band snapping.
The tissue samples are sent to a pathologist who examines them under a microscope for cancer. Depending on the aggressiveness of the cancer, treatment could range from an operation to remove the prostate gland to radiation therapy to active surveillance.
Patients with low-grade cancers may be placed on active surveillance, which Kneib said involves watching a patient's PSA level and, now, often rechecking their MRI 12 to 18 months later in lieu of another prostate biopsy.
Kneib said MRI-ultrasound guided fusion biopsy, which around 80 percent of health insurers cover, is a stepping stone to focal therapy, the targeted destruction of cancer within a specific area of the prostate gland.
"As we get better with these MRIs and our imaging modalities get better, we're going to get to where we can do some focal therapy for some of these men with maybe one biopsy in just one area of the prostate and it's low-grade cancer instead of destroying the whole gland or taking out the whole gland and causing them erectile dysfunction or incontinence," he said.