A histopathological evaluation of STRUS-B materials based on suspicious DRE findings and high or increasing PSA levels is the gold standard in prostate cancer diagnosis. However, the fact that approximately one-third of malignant prostate lesions is isoechoic and cannot be detected using conventional grayscale transrectal ultrasonography (TRUS) decreases the sensitivity rates of STRUS-B. These restrictions on the use of TRUS have encouraged urologists to use new methods to diagnose prostate cancer. One of these methods is the biopsy of lesions defined using mpMR, which has been widely used for the past 10 years. An MR targeted biopsy can be performed cognitively under MR guidance or using ultrasound devices with fusion software that can combine MR images with sonographic images. mpMR targeted biopsies are recommended in the current clinical practice for re-biopsies of patients who had previous negative biopsy but clinically suspected of cancer, follow-up biopsies of active surveillance, and biopsies of patients who are suspected to have recurrence after local minimally invasive treatment, such as radiotherapy and high-intensity focused ultrasonography. Recent studies showed that the cancer detection rate of mpMRIguided prostate biopsy is between 33.7% and 79.5%, which is higher than that of standard 12-core transrectal biopsy. However, the number of studies evaluating the use of MR targeted prostate biopsy in biopsy naive patients is limited.

In this study it is aimed to compare cancer detection rates of STRUS-B and MR guided MR-US fusion transrectal prostate biopsy in the biopsy naive patient setting.

100 patients will be randomized to STRUS-B arm and another 100 to fusion arm. In the standard arm patients who have high PSA levels and/or suspicious DRE will be undertaken STRUS-B. In the study arm all patients will undergo a multiparametric prostate MR without endorectal coils. MRI will be performed by Siemens Magnetom(Trade mark) 1.5 T (Siemens Medical Solutions, Pennsylvania, USA) MRI system. The images wi,ll be reviewed by an experienced uro-radiologist who has no detailed clinical information about the patients. Suspected areas in T2, T1 contrast, and diffusion-weighted images of multiparametric MRI were reported according to Prostate Imaging Reporting and Data System Version-2 (PIRADS v2). In cases of multiple lesions with different PIRADS scores, the lesion with the highest PIRADS score will be accepted as dominant lesion. Biopsy procedures will be performed under local anesthesia or sedoanalgesia. However, sedoanalgesia will be preferred if the patient could not tolerate pain during the penetration of US probe due to low pain threshold or anal canal stricture due to previous rectal surgeries. The procedure will be performed in outpatient clinic conditions. Transrectal ultrasonography will be performed by using an ultrasonography system with rigid fusion software (LOGIQ E9; General Electric, Massachusetts, USA) when patients lie on the left decubitus position. Rectal lidocaine gel will be applied 5 min before rectal US probe is introduced. A sonographic examination of the prostate tissue will be performed to check the presence of prominent lesions. Total prostate volumes will be measured. Multiparametric prostate MRI images will be uploaded to the US system on the day of biopsy. After segmentation (matching) of MRI images with sonographic images, the lesions reported in mpMR will be marked. The periprostatic block will be then performed with 2% prilocaine hydrochloride (20 mg/mL) injected into the neurovascular bundle on both sides of the prostate, with 5 mL to the right and 5 mL to the left. Following the block, two to five core biopsies from the MRI-targeted lesions with PIRADS ≥3 will be obtained. All procedures in fusion biopsy will be performed by two urologists experienced and trained in transrectal prostate ultrasonography and biopsy. After the F-TRUS biopsy completed, a standard 12-core TRUS biopsy will performed on fusion group. STRUS_B arm only standard 12 core transrectal prostate biopsy will be performed. A histopathological evaluation of biopsy specimens will be performed by a uro-pathologist with \>10 years of experience. The percentage of cancer within the core, primary, and secondary Gleason score and grade according to the 2014 International Society of Urological Pathology (ISUP) grade will be specified in the final pathology report. Patients reported with high-grade prostatic intraepithelial neoplasm in three or more cores or atypical small acinar proliferation will be redirected to rebiopsy, but they will be included to the benign group in the evaluation of the present study.

As the secondary outcomes, pain level during MR fusion biopsy and STRUS biopsy evaluated by visual analogue scale score, cancer detection rates of different core numbers taken form MR targeted lesion, role of the peripheric blood parameters (such as, neutrophil to lymphocyte ratio and systemic immune inflammatuary index) in predicting prostate cancer in PRIADS 3,4 and 5lesions, and comparison of the tumor laterality and ISUP grade in MR US fuison biopsy and radical prostatectomy specimens will be evaluated.