Objective: Image-guided targeted biopsy techniques have been proposed to address problems of systematic transrectal ultrasound guided prostate biopsies that lead to the suboptimal cancer detection rate as well as inaccurate grading of the disease. This study aims to provide local data on the diagnostic accuracy of multiparametric MRI (MP-MRI) and MP-MRI ultrasound cognitive fusion biopsy in identifying areas of clinically significant malignancy of the prostate.
Materials and Methods: This is a validity study involving patients who underwent MP-MRI and MPMRI ultrasound cognitive fusion biopsy, who eventually underwent robot-assisted laparoscopic radical prostatectomy (RALRP). Outcome measures included sensitivity, specificity, positive and negative predictive values of MP-MRI and MP-MRI ultrasound cognitive fusion biopsy. Reference standard used was the final histopathologic report obtained after RALRP.
Results: MP-MRI has a sensitivity of 35.5%, specificity of 95.2%, positive predictive value of 97.1%, and negative predictive value of 25%. MP-MRI ultrasound fusion biopsy had similar results, with sensitivity of 34.4%, specificity of 81.0%, positive predictive value of 88.9%, and negative predictive value of 21.8%.
Conclusion: The high specificity and positive predictive value of MP-MRI (95.2% and 97.1% respectively) indicates the necessity for a prostate biopsy and supports the utility of a targeted MPMRI guided ultrasound cognitive fusion biopsy. However, the low sensitivity and negative predictive value (25% and 35% respectively) of 35.5% indicates that MP-MRI guidance does not limit the number of biopsy samples only to visible MP-MRI lesions, since negative areas on MP-MRI still contains tumors in 75% of cases.