Characteristics of Anteriorly Located Prostate Cancer and the Usefulness of Multiparametric Magnetic Resonance Imaging for Diagnosis

Conventional diagnostic tools for prostate cancer are DRE (digital rectal examination) or transrectal ultrasound, as they rely on a posterior approach to diagnosis the prostate. However, the diagnosis of APC (anterior prostate cancer) can be missed because APC are frequently not amenable to DRE, which results in repeated biopsies. There has also been an increase in detection of low risk prostate cancer for active surveillance, but some cases of APC biopsies may yield false-negative or a shorter tumor length on the core, consequently underestimating the risk of prostate cancer. This study looks to draw more conclusions regarding APCs by investigating and distinguishing pathological and oncologic characteristics of APCs in a consecutive radical prostatectomy cohort, and assess the reliability of magnetic resonance imaging to detect anterior prostate cancer.

The investigators analyzed the records of 728 consecutive patients treated with radical prostatectomy between September 2007 and October 2012. APC was defined as a tumor predominantly located in the anterior portion of the urethra, while PPC was a tumor predominantly located in the posterior portion of the urethra. Patients were categorized with anterior or prostate cancer, or tumors involving the anterior and posterior prostate according to the dominant tumor location on the whole mount section.

The results of the study showed that APC was less commonly palpable (p<0.001) and needed more frequent repeat biopsy (p=0.012) than posterior prostate cancer. Anterior group also had fewer positive cores than the posterior group (p<0.001), despite comparable tumor volumes. The Gleason score upgrading was more frequently observed in anterior than in posterior prostate cancer (p=0.003). The estimated 5-year biochemical recurrence-free survival in patients with anterior prostate cancer was significantly higher than in patients with posterior prostate cancer (p<0.001).The multivariate analysis also showed that the anterior location was an independent prognostic factor for biochemical recurrence (HR 0.403, p=0.006) along with other well-known prognostic factors. The MRI’s sensitivity and specificity for anterior prostate tumors was 78.1% and 58.2%, respectively.

In conclusion, pathological features are similar in APC and PPC, but anterior prostate cancer has more favorable oncologic outcomes while also more frequent Gleason score upgrading. The use of multiparametric MRI has moderate diagnostic performances for anterior prostate cancers, and should be advised to identify tumor locations and extent for preoperative risk evaluations. The authors acknowledges limitations to the study, including retrospective study, pathological and oncologic characteristics bias, the examiners were not blinded to preoperative evaluations, and interobserver consistency assessment could not be performed.

Authors: Myong Kim, Seung-Kwon Choi, Myungchan Park, Myungsun Shim, Cheryn Song, In Gab Jeong, Jun Hyuk Hong, Choung-Soo Kim and Hanjong Ahn

Affiliations: Department of Urology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea

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