PD56-12: Utilization of MRI and Genomic Tests in Men with Low-Risk Prostate Cancer and a Limited Life Expectancy within a Multi-Institutional Regional Collaborative



Authors: Laura Kidd, Adrien Bernstein, Kevin Ginsburg, Elizabeth Handorf, Kaynaat Syed, Chintan Mehta, John Danella, Serge Ginzburg, Laurence Belkoff, Adam Reese, Jeffrey Tomaszewski, Eric Singer, Edouard Trabulsi, Bruce Jacobs, Jay Raman, Thomas Guzzo, Marc Smaldone

Introduction: Watchful waiting (WW) is the recommended management for men with low-risk prostate cancer (LRPC) and limited life expectancy (LLE). As such, the utility of ancillary testing (AT), MRI or genomics, in this population has not been well established. Herein we investigate the use of ancillary testing in a population of LRPC patients with LLE.

Methods: The Pennsylvania Urologic Regional Collaborative database was queried, identifying men with LRPC and LLE (age = 70 & Charlson Comorbidity Index = 5). Patients were stratified by receipt of post-diagnostic AT. The primary outcome was the proportion of men who underwent treatment with curative intent (radiation or surgery). AT results were deemed non-reassuring (non-RA; 2.7% probability of prostate cancer mortality for Prolaris, Risk group > low risk for OncotypeDx and Decipher, PIRADS 4 or 5 on mpMRI) or reassuring (RA). Categorical parameters were compared with the Chi-squared test and Fisher's exact test. Non-parametric continuous measures were assessed by the Wilcoxon rank sum test. Multivariable logistic regression models were fit to assess the association of obtaining an ancillary test and management strategy or obtaining additional biopsies.

Results: 299 men with LLE were newly diagnosed with LRPC. 155 (53%) underwent ancillary testing with their longitudinal experience plotted in Figure 1. Both groups had similar PSA at diagnosis and volume of disease on diagnostic biopsy. AT patients were more likely to have very low-risk prostate cancer (64.1% vs. 51.1%, p=0.03). There was also significant variability in testing by practice site (0-100% of LRPC patients, p<0.001). MRI was ordered in 80% of AT patients and was non-RA in 41%, while genomic testing was ordered in 35% and was non-RA for 73% of patients. Overall, 43% of men received definitive therapy, with the highest rate in RA patients (55%), and lower rates in non-RA (38%) or no ancillary studies (40%, p<0.001). On multivariable analysis, adjusting for age, disease volume and race, AT was not associated with odds of definitive treatment (OR=1.1, 95% CI 0.7-1.7, p=0.62). Paradoxically, men with RA tests were at increased risk of treatment (OR=3.1, 95% CI: 1.6-6.0 p=0.001). Additionally, men with AT were five-times more likely to receive additional biopsies (OR 5.2, 95% CI: 3.07-8.91 p<0.001).

Conclusions: Ancillary testing occurs frequently in older men with LRPC and does not appear to shape subsequent treatment decisions, potentially increasing the cost and invasiveness of care without adding value.

Source of Funding: None

Therapeutic Area
Oncology: Prostate