Presentation Authors: David Johnson*, Steven Raman, Sohrab Mirak, Lorna Kwan, Amirhossein Bajgiran, Izak Faeina, Aydin Pooli, Los Angeles, CA, Amirali Salmasi, San Diego, CA, Anthony Sisk, Ely Felker, David Lu, Robert Reiter, Los Angeles, CA
Introduction: Multiparametric magnetic resonance imaging (mpMRI) undoubtedly affects the diagnosis and treatment of localized prostate cancer (CaP). However, clinicians need a better understanding of its accuracy and limitations detecting individual CaP foci to optimize management. We determined the per-lesion detection rate of CaP foci by mpMRI and identify predictors of tumor detection.
Methods: Retrospective analysis of 588 consecutive patients with biopsy-proven CaP and mpMRI prior to radical prostatectomy at a single tertiary institution from June 2010 to February 2018. We correlated co-registered mpMRI lesions with whole mount prostatectomy specimens. We calculated mpMRI sensitivity detecting individual CaP and clinically significant CaP foci (any Gleason Grade greater than 1) and predictors of tumor detection using multivariate analysis.
Results: Final analysis included 1213 pathologically-confirmed tumor foci in 588 patients with primarily intermediate (75%) or high risk (12%) CaP. mpMRI detected 45% (95% CI; 42-47%) of all lesions, including 65% (95% CI; 61-69%) of clinically significant lesions. 74% and 31% of missed solitary and multifocal tumors were clinically significant, respectively. While the majority of missed lesions were small (61.1% â‰¤ 1 cm), 28.3% were between 1-2 cm, and 10.4% > 2cm. mpMRI missed at least one clinically significant foci in 34% of patients, including in 45% with multifocal lesions. On multivariate analysis, smaller, low-grade, multi-focal, non-index tumors in men with lower PSA-density were more likely to be missed. Limitations include imperfect co-registration process and uncertain clinical significance of undetected lesions.
Conclusions: mpMRI detects less than half of all and less than two-thirds of clinically significant CaP foci. The moderate per-lesion sensitivity and significant proportion with undetected tumor foci demonstrate the current limitations of mpMRI.
Source of Funding: Department of Radiology and Pathology Integrated Diagnostics (IDx) program and the specialized program of research excellence (SPORE) in prostate cancer.