Prostate Magnetic Resonance Imaging (MRI) holds the promise of avoiding unnecessary prostate biopsies in men with elevated Prostate Specific Antigen (PSA) blood levels. The PSA blood test has been used for over 25 years to screen men for early stage Prostate Cancer. Elevated PSA blood levels can signal the presence of prostate cancer, even when the Digital Rectal Exam (DRE) is normal. In fact, over 80 percent of prostate cancers are diagnosed because of an elevated PSA blood test. However, when the PSA is between 4 and 10, approximately 30 percent of men will have a positive biopsy for prostate cancer and 70 percent will have a negative biopsy after a standard Ultrasound Guided biopsy is performed.
A standard Ultrasound Guided Biopsy consists of an ultrasound probe, shaped like a finger, which is placed in the rectum, local anesthetic is injected into the prostate to anesthetize the prostate. Typically 12 biopsies are obtained with a biopsy needle. A “standard pattern” of 12 biopsies are taken in locations where prostate cancer is likely to be found. However, with the standard pattern, prostate cancer can be missed, and 70 percent of the biopsies are negative for prostate cancer.
This can lead to continued worry about the presence of missed cancer, repeat biopsies, delay in diagnosis, etc. Every time a biopsy is performed, there is a small chance of infection, as well as increased costs and discomfort.
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Recently, Multi-parametric MRI has been shown to hold promise to reduce the number of un-necessary biopsies, and be more accurate when biopsies are obtained. Prostate MRI uses no X-Rays and is very safe. The MRI exam takes approximately one hour. Once the images are obtained, several parameters are analyzed to determine if prostate cancer is present. If the Multi-parametric MRI is normal, we are at the 90 percent confidence level that no cancer is present, (which is more accurate than a prostate biopsy) and a prostate biopsy can be avoided. If the MRI is highly suggestive of prostate cancer, than a biopsy is indicated. Moreover, we now know where the cancer is “hiding” in the prostate. We can fuse the MRI images onto the “real time” Ultrasound images, and target our biopsies directly into the suspicious area. This greatly improves the accuracy of the Prostate Biopsies, with biopsies positive in 90 percent of men without previous biopsies and in 60 percent of men with previous negative biopsies. In addition, MRI detected biopsies tend to be the higher grade, more aggressive types – i.e., the ones that will require active treatment. The slower growing, more indolent types, are usually not seen on MRI, so we avoid “over diagnosing” those which do not require treatment.
Pacific Urology, a division of Diablo Valley Oncology Hematology Medical Group, is the first to offer the MRI-Ultrasound Fusion Guided Biopsies in the San Francisco EAST BAY. Dr. Stephen Taylor have undergone specific training for this procedure, and are available to perform this procedure in their Walnut Creek office.