Choosing the Best Method for Prostate Cancer Detection
Photo Courtesy of Invivo Corporation/Philips Healthcare
Your physician may inform you that you need an ultrasound-guided biopsy because (1) your PSA reading is elevated or rapidly rising, (2) a digital rectal exam indicates an enlargement or other abnormality in your prostate, or (3) prostate cancer is prevalent in your family. If the recommendation of a biopsy is made, you may wish to steer the conversation in another direction.
While transrectal ultrasound core biopsy of the prostate (TRUS) has been the “gold standard” for many years, a more recent alternative is the multiparametric MRI (mpMRI). A better understanding of each procedure will help to guide your discussion with your physician and, ultimately, your decision of which to choose.
TRUS Prostate Cancer Biopsy
TRUS is performed by a urologist or radiologist on an outpatient basis in a hospital or clinic setting. During the procedure, samples of tissue from the prostate are removed and sent to the pathology lab for analysis. TRUS involves insertion of a special biopsy needle through the wall of the rectum and into the prostate gland to capture the core samples. The greater number of core samples taken, the better the detection rate of early prostate cancer. Six to 14 core samples are generally taken during an initial biopsy. Even with this number of biopsies, it is possible to extract only healthy tissue and completely miss unhealthy, cancerous tissue.
Some patients who have had an initial TRUS that resulted in no detection of cancer may need a repeat biopsy if their PSA continues to rise and, in these cases, the number of cores taken may be as high as 60. The patient experiences slight to significant pain with each core sample taken, so pain management must be addressed by the physician to minimize the patient’s discomfort during the procedure. This may be in the form of a local anesthetic or sedative, a light general anesthetic, or a periprostatic nerve block. The anxiety of pain from the procedure is a common reason that many patients actually refuse TRUS.
Other factors to consider when contemplating TRUS include:
- Risk of infection—Patients usually take antibiotics for a day or two prior to the procedure, and additional antibiotics may be injected just before the procedure.
- Bowel cleansing—This is important to maximize clarity of the ultrasound and reduce risk of infection.
- Blood thinning medications—These may need to be stopped for days prior to the procedure, so it is important to report all such medications and follow the advice of your physician regarding these medications before and after the procedure.
mpMRI for Tumor Detection
At SIR-Florida, Dr. Grubbs is an advocate of the mpMRI to detect the presence or absence of a tumor and, using the most current post-processing software, has read and interpreted over 10,000 of these exams. With this level of experience, it is understandable that physicians across the U.S. come to Dr. Grubbs for his expertise in diagnosing prostate cancer.
The mpMRI is advanced technology that does not require tissue samples to determine the presence or absence of prostate cancer. It shows the exact shape and location of an enlarged area or mass and also distinguishes between healthy and unhealthy tissue by using two or more special imaging sequences, thus the term multiparametric. This important information then leads to the determination of whether or not a biopsy is needed. The mpMRI is painless, but claustrophobic patients may need relaxation methods or medication for anxiety.
MR/US Fusion Biopsy
If a tumor is not detected, the mpMRI has established a baseline for future monitoring of the patient. If cancer is detected, Dr. Grubbs develops a roadmap for an MR/US fusion biopsy to pinpoint the suspicious lesion. The MR/US fusion biopsy is performed instead of the more invasive multiple core sample biopsies of the TRUS.
The MR/US fusion biopsy is a precision method that directs a minimum number of needles into the center of the visible tumor to retrieve the largest quantity of cells. The cancerous tissue samples are then further analyzed to determine the best course of treatment for the patient. High Intensity Focused Ultrasound (HIFU), a revolutionary treatment for prostate cancer, is a minimally invasive technique that will be discussed in a future article.