SIU 2018: Atypical Anterior Localization of Prostate Cancer Foci in Patients Undergoing Initial and Repeat Biopsy: Results from 1,161 Patients Undergoing MRI Fusion Biopsies

Seoul, South-Korea (UroToday.com) In this work, Dr. Sami-Ramzi and colleagues described their experience with anterior prostate tumors in patients undergoing MRI-fusion biopsies.  It is known that a substantial proportion of prostate cancers are located in the anterior segment of the prostate, leading to a phenomenon called “evasive prostate cancer syndrome”. Diagnosing these anterior tumors during a transrectal ultrasound (TRUS) biopsy is quite challenging, with multiple repeat biopsies and extended number of cores needed. As a result, these lead to a delay in diagnosis. The authors hypothesized that using MRI fusion biopsies will help identify these tumors more easily. In this study the authors examined the distribution of PIRADS >=3 lesions in the anterior and posterior segment of the prostate and reported the histopathological characteristics of these lesions.

A total of 1161 patients underwent MRI/Ultrasound fusion guided targeted biopsies. Patients were stratified according to the number of prior systematic biopsies (SB) they underwent. Targeted biopsies were performed in 513 (44%) SB naïve patients, 396 (34%) patients with one prior negative SB, and 252 (22%) patients who had more than two prior negative SB. The proportion of patients with exclusively anterior located MRI PIRADS >=3 lesions increased from 3.5% to 9.1%, when patients were stratified according to number of prior SB sessions. Interestingly, clinically significant cancer (Gleason 3+4 and 4+3) were more often identified in exclusively anterior compared to exclusively posterior tumors (31% vs. 21%, p=0.016).

Multivariable logistic regression analysis revealed that exclusively anterior located MRI PIRADS >=3 lesions are a significant risk factor for detecting clinically significant prostate cancer (Gleason 3+4 or worse), with an odds ratio of 2.6 (1.3-5.2), p=0.007. Other significant factors predicting the detection of clinically significant prostate cancer disease in the anterior prostate included PIRADS >=4 lesions, previous history of two negative SB, clinical stage T2, and rising age.

The authors concluded that these results demonstrate an increasing proportion of anterior located MRI PIRADS>=3 lesions, when patients were stratified according to the number of prior SB. Interestingly, an increasing proportion of unfavorable prostate cancer within these anterior lesions was recorded, as compared to posterior prostate lesions. A practical recommendation that results from this interesting study, is consider an MRI of the prostate before planning a repeat biopsy after an initial negative transrectal ultrasound guided SB. This will help in the identification of elusive anterior located tumors.

The findings of this study are most interesting and show the real-world data on the importance of identifying and sampling anterior prostate tumors. The major limitations of this study include the fact that it is a retrospective single center study. 

Presented by: Sami-Ramzi Leyh-Bannurah, Martini-Klinic, Hamburg, Germany

Written By: Hanan Goldberg, MD, Urologic Oncology Fellow (SUO), University of Toronto, Princess Margaret Cancer Centre  Twitter: @GoldbergHanan at the 38th Congress of the Society of International Urology - October 4- 7, 2018 - Seoul, South Korea