807 Characteristics of anterior predominant prostate cancer and the usefulness of multiparametric MRI in diagnosis

Abstract

INTRODUCTION AND OBJECTIVES: In prostate-specific antigen(PSA) era, late detection of prostate cancer still exists when the tumor arised from anterior portion of prostate. We analyzed the characteristics of anterior predominant prostate cancer, and assess the usefulness of MRI to detect the tumor preoperatively. METHODS: We evaluated clinicopathological data and radiologic findings of 660 patients treated with radical prostatectomy between July, 2007 and June, 2012. All patients underwent MRI with diffusion-weighted imaging, and ADC mapping. When the lesion was larger than 8mm in diameter, showed low signal intensity on T2weighted image, restricted diffusion on diffusion-weighted images and ADC maps, it was considered presence of tumor. RESULTS: Anterior predominant prostate cancer constituted 26.8% of total patients. Index tumor in anterior peripheral zone, anterior fibromuscular stroma, and transition zone were 27.7%, 3.4%, and 69.0% respectively. Age, BMI, PSA, prostate volume, and PSA density in anterior predominant prostate cancer were not different from posterior prostate cancer. Diagnosis with repeated biopsy was more frequent in anterior predominant cancer, and clinical T stage (p 0.001), pathologic T stage (p 0.001), pathologic GS (p 0.040) were lower. In D’Amico low-risk patients, anterior predominant cancer presented in 40.1%, and upgrading was more frequently observed than posterior predominant cancer (65.1% vs 49.5%, p 0.027). In anterior predominant cancer, sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of MRI were 64.2%, 83.0%, 63.8%, 83.2%, and 77.0%, respectively. CONCLUSIONS: Anterior predominant cancer had favorable pathologic features compared with posterior dominant cancer. However, more frequent upgrading was noted. MRI was useful to detect the hidden anterior predominant cancer.