TransRectal UltraSound (TRUS) guided biopsy has been the standard of care for diagnosing prostate cancer in men with a clinical suspicion of prostate cancer. TRUS guided biopsy is a blind biopsy of the lateral and posterior peripheral zone of the prostate using a template, and 10 to 12 cores of prostate tissue is obtained. Even though this may result in a higher rate of prostate cancer detection, many detected are low grade tumors that do not benefit from treatment. The major limitation of this biopsy procedure is the risk of under-sampling a more significant tumor that is located in a region of the prostate not usually targeted with a template.
Multiparametric MRI (mp-MRI) combines anatomic imaging in the form of T2-weighted imaging, with functional imaging, and is being used to detect or rule out cancer in men who have persistent concern for prostate cancer. It can be used as a triage test to avoid a biopsy if the results were negative, and if positive could be used for targeting abnormal areas in the prostate during biopsy. In the PRECISION study, mp-MRI was superior to standard TRUS guided biopsy, and was able to identify a high proportion of men who would benefit from treatment, and minimizes the identification of men with clinically insignificant cancer, thereby preventing overtreatment. Utilizing mp-MRI, more than 25% of the participants in this study were able to avoid a biopsy.

SUMMARY: Prostate cancer is the most common cancer in American men with the exclusion of skin cancer, and 1 in 9 men will be diagnosed with prostate cancer during their lifetime. It is estimated that in the United States, about 164,690 new cases of prostate cancer will be diagnosed in 2018 and 29,430 men will die of the disease. TransRectal UltraSound (TRUS) guided biopsy has been the standard of care for diagnosing prostate cancer in men with a clinical suspicion of prostate cancer, based on an abnormal Digital Rectal Examination and/or an elevated Prostate Specific Antigen (PSA) level. TransRectal UltraSound (TRUS) guided biopsy is a blind biopsy of the lateral and posterior peripheral zone of the prostate using a template, and 10 to 12 cores of prostate tissue is obtained. Even though this may result in a higher rate of prostate cancer detection, many detected are low grade tumors that do not benefit from treatment, and these patients are on active surveillance for their low risk disease. The major limitation of this biopsy procedure is the risk of under-sampling a more significant tumor that is located in a region of the prostate not usually targeted with a template. Further, in patients with a rising PSA with a prior negative biopsy, patients are often subjected to a repeat blind biopsy with the same limitations as the original biopsy. Since biopsy access is through the rectum and only specific zones of the prostate are sampled, large areas of the prostate, especially the anterior and central prostate, are not routinely sampled and clinically significant higher-grade cancers are sometimes missed.

Multiparametric MRI (mp-MRI) combines anatomic imaging in the form of T2-weighted imaging, with functional imaging and is being used to detect or rule out cancer in men who have persistent concern for prostate cancer. Previously published studies have shown that MRI-targeted biopsies alone have shown similar or higher rates of detection of clinically significant cancer in the prostate gland and lower rates of detection of clinically insignificant cancer, when compared to standard TRUS guided biopsy. This interesting advantage allows the use of mp-MRI as a triage test to avoid a biopsy if the results were negative, and if positive could be used for targeting abnormal areas in the prostate during biopsy.

The PRECISION (Prostate Evaluation for Clinically Important Disease: Sampling Using Image Guidance or Not?) trial is a multicenter, randomized, noninferiority study, which prospectively evaluated whether mp-MRI with targeted biopsy in the presence of an abnormal lesion, was noninferior to standard TRUS guided biopsy, in the detection of clinically significant prostate cancer in men, with a clinical suspicion of prostate cancer, who had not undergone biopsy previously. A total of 500 men were randomly assigned in a 1:1 of whom 252 participants were assigned to the MRI-targeted biopsy group (N=252) and 248 to the standard 10-12 core TRUS guided biopsy group (N=248). The baseline characteristics of the participants were similar in the two groups. Eligible participants were required to have a PSA level of 20ng/ml or less, no evidence of extracapsular disease on Digital Rectal Examination and be suitable candidates for an MRI and biopsy of the prostate. Clinically significant prostate cancer was defined as the presence of disease of Gleason sum 7 or higher. Men who had a positive mp-MRI test underwent MRI-targeted biopsy of only these qualifying lesions (up to three areas). The Primary outcome was the proportion of men who received a diagnosis of clinically significant cancer. Secondary outcomes included the proportion of men who received a diagnosis of clinically insignificant cancer.

It was noted that multiparametric MRI was superior to standard TRUS guided biopsy, with a significantly higher percentage of men receiving a diagnosis of clinically significant prostate cancer in the MRI-targeted biopsy group, as compared with the standard TRUS guided biopsy group (38% versus 26%, P=0.005). Further, fewer men in the MRI-targeted biopsy group than in the standard biopsy group received a diagnosis of clinically insignificant cancer (9% versus. 22%, P<0.001). In the MRI-targeted biopsy group, 28% of the men had mp-MRI results that were not suggestive of prostate cancer, and therefore did not undergo biopsy.

It was concluded that in men with a clinical suspicion of prostate cancer and had not undergone biopsy previously, the use of risk assessment with MRI before biopsy and MRI-targeted biopsy, was superior to standard TRUS guided biopsy. MRI-targeted biopsy is able to identify a high proportion of men who would benefit from treatment, and minimizes the identification of men with clinically insignificant cancer, thereby preventing overtreatment. Utilizing mp-MRI, more than 25% of the participants in this study were able to avoid a biopsy. MRI-Targeted or Standard Biopsy for Prostate-Cancer Diagnosis. Kasivisvanathan V, Rannikko AS, Borghi M, et al. N Engl J Med 2018; 378:1767-1777