Abstract 3803: Characterization of fluid biopsy using the HD-SCA platform to re-stratify intermediate-risk organ-confined prostate cancer patients

Abstract

Abstract Recent studies have demonstrated that even with current risk stratification of intermediate-risk organ-confined prostate cancer patients, 30-50% of patients are incorrectly categorized and overtreated. As the second leading cause of cancer in men, 90% of prostate cancer patients are diagnosed at organ-confined stages, where radical prostatectomy (RP) is the “golden standard” of treatment. However, deferring intervention is becoming a more popular option for low-risk patients, with a 15-year progression-free survival of 95%. High-risk patients greatly benefit from RP, with a 5-year progression-free survival of 85%, while the decision to proceed with RP is not so candid for intermediate-risk patients. Using the high-definition single cell assay (HD-SCA) platform, circulating tumor cells (CTCs) from peripheral blood (PB) and disseminating tumor cells (DTCs) from bone marrow aspirate (BMA) will be analyzed for morphological, genomic, and proteomic profiling. We hypothesize that by using morpho-proteo-genomic parameters we may develop predictive markers for a more accurate stratification of intermediate-risk patients, offering a more personalized treatment for each individual. Preliminary data shows 86% (n=43) of PB samples and 5% (n=40) of BMA are positive for Cytokeratin (CK) expressing rare circulating cells, as defined by ≥5 cells/mL. The incidence of CK+ cells in PB did not correlate with PSA, Gleason score, or clinical parameters. However, incidence of CK+ cells in PB was higher in high-risk group, though not statistically significant (p=0.784) when compared to intermediate-risk groups. Additionally, higher levels of CK expression (p<0.0001), as measured by relative intensity of fluorescent staining, were detected in cells detected in PB of high-risk patients relative to intermediate- and low-risk groups as measured by an analysis of variance (ANOVA) statistical model. Low levels of genomic aberrations are observed in all CK+ rare circulating cells (5%, n=118), which may speak to the fact that these patients are in early stages of their disease. The use of the HD-SCA platform to characterize the fluid biopsy may result in the identification of predictive markers of treatment response for intermediate-risk patients, resulting in reduction of overtreatment. Citation Format: Paymaneh D. Malihi, Kenneth Pienta, James Hicks, Michael Gorin, Carmen Ruiz Velasco, Anders Carlsson, Anand Kolatkar, Mariam Rodriguez Lee, Michael Morikado, Peter Kuhn. Characterization of fluid biopsy using the HD-SCA platform to re-stratify intermediate-risk organ-confined prostate cancer patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3803. doi:10.1158/1538-7445.AM2017-3803