Presentation Authors: David Johnson, Jason Yang*, Lorna Kwan, Danielle Barsa, Sohrab Mirak, Aydin Pooli, Taylor Sadun, Rajiv Jayadevan, Steve Zhou, Alan Priester, Shyam Natarajan, Anthony Sisk, Ely Felker, Steven Raman, Leonard Marks, Robert Reiter, Los Angeles, CA
Introduction: Hemiablation is a less morbid treatment alternative for select patients with unilateral prostate cancer. The accuracy of contemporary diagnostic techniques to identify appropriate candidates is currently unknown. The authors quantify the proportion of incorrectly identified hemiablation candidates and identify predictors of discordant laterality.
Methods: Retrospective analysis of patients undergoing multiparametric magnetic resonance imaging (MRI) with MRI-fusion prostate biopsy prior to radical prostatectomy at a single tertiary institution between June 2010-November 2017. The authors identified theoretical hemiablation candidates and a range of inclusion criteria in sensitivity analyses. Primary outcome was the proportion of hemiablation candidates with contralateral clinically significant prostate cancer on whole mount prostatectomy pathology and/or ipsilateral high-risk disease. The authors evaluate pre-operative predictors of undetected contralateral disease using multivariable analysis.
Results: Of 665 patients, 92 met primary hemiablation criteria. 44/92 (47.8%) had undetected contralateral Grade Group 2 and above prostate cancer on final pathology. Undetected contralateral disease ranged from 40.8%-47.8% depending on inclusion criteria. On multivariable analysis, men with anterior index tumors were 2.4 times more likely to harbor undetected significant contralateral prostate cancer than men with posterior lesions (p < 0.05). Limitations include unknown clinical significance of missed contralateral disease.
Conclusions: A substantial proportion of patients with presumed unilateral prostate cancer, based on contemporary imaging and biopsy techniques, harbor undetected clinically significant contralateral disease. The risk of inadequate treatment due to undetected contralateral disease must be weighed against the functional benefits of hemiablation. Further investigation to improve patient selection for focal therapy is necessary.
Source of Funding: Department of Radiology and Pathology Integrated Diagnostics (IDx) program and the specialized program of research excellence (SPORE) in prostate cancer