The MRI fusion guided prostate biopsy “fuses” MRI scans with real-time ultrasound images of the prostate. This cutting-edge biopsy system allows us here at the Dr. David Samadi Prostate Cancer Center to pinpoint specific tumors within the prostate gland. This information provides the patient with the most optimal treatment plan and best possible outcome in detecting and diagnosing prostate cancer.
Prostate cancer is the most common cancer in men. So far, the only tools available to detect and diagnose prostate cancer include: the PSA test (a blood marker for prostate cancer) and the transrectal ultrasound guided biopsy (TRUS biopsy). Every year, about 20 million PSA tests are performed and about 1.2 million men undergo a biopsy. Since the 1980’s, the technology to perform prostate biopsies on men has remained the same – ultrasound is used to guide a needle to collect twelve random samples within twelve cores of the prostate. Traditional techniques such as the TRUS biopsy only sample the lower portion of the prostate – yet almost 30% of cancers are found outside this area. For this reason, only 30-40% of the 1.2 million biopsies performed on men each year are positive for prostate cancer. While the majority of those biopsies are negative, a negative biopsy does not meant you don’t have prostate cancer – it just means that your biopsy was negative. There is still a possibility that you have undetected disease.
The TRUS biopsy samples less than 1% of the prostate tissue when searching for prostate cancer. Prostate cancer is the only type of cancer that is limited to detection by indirect sampling of tissue. Right now, many physicians rely on an elevated PSA to raise suspicion for prostate cancer. In most cases with elevated PSA, a TRUS biopsy is performed by the physician with no specific target towards any lesions.
There is no specific normal or abnormal level of PSA in the blood. However, most doctors consider a PSA greater than 4.0 ng/mL to be abnormal, or elevated. The sensitivity for a PSA greater than 4.0 ng/mL is only 20.5 percent in detecting prostate cancer. For the TRUS biopsy, the sensitivity is only 39 percent. Clearly, both tools are limited. For this reason, there are many men who continue to have elevated PSA results and repeat biopsies that turn up negative. For these men, a fusion biopsy may be the solution.
Researchers at North Shore LIJ Medical Center studied 105 men with an elevated PSA using the fusion guided prostate biopsy. Fusing a specialized MRI technique with transrectal ultrasound, researchers demonstrated that the prostate cancer detection rate was twice as high (62 percent) as the detection rate from previous studies using only transrectal ultrasound (30 percent.) The MRI fusion guided prostate biopsy method allowed them to make more precise identifications of suspicious lesions, which had not been previously found using traditional transrectal ultrasound.
With the TRUS biopsy, some patients are diagnosed with a Gleason score that is different (or less aggressive) than what the post-operative pathology identifies. The MRI fusion guided prostate biopsy plays a valuable role in evaluating low risk patients with active surveillance, as a way to follow up or monitor any change in their clinical status. The MRI fusion guided biopsy can also identify more aggressive cancers which need to be removed quickly in order to spare a patient’s quality of life and prevent metastasis.