Pagliaro, Lance C.

672 Background: The optimal sequence of cytoreductive nephrectomy (CN) and targeted therapy (TT) for patients with metastatic renal cell carcinoma (mRCC) remains to be established. Herein, we compared overall survival (OS) between patients with mRCC receiving initial CN with or without subsequent TT versus initial TT with or without subsequent CN. Methods: The National Cancer Database (NCDB) was used to identify patients diagnosed between 2006-2013 with RCC that was metastatic at diagnosis who received CN, TT, or both. Those with other prior cancer history were excluded. The cumulative incidence of receiving TT after CN and CN after TT were evaluated, with death prior to second treatment as a competing risk. To account for treatment selection bias, inverse probability of treatment weighting (IPTW) was performed based on the propensity to receive initial CN or TT. OS from diagnosis was compared using Cox regression. Sensitivity analyses were performed. Results: The cohort included 15,068 patients, of whom 6,731 underwent initial CN and 8,337 underwent initial TT. At 6 months from diagnosis, the probability of receiving TT after CN was 46.2%, with 13.6% of patients having died after initial CN prior to receiving TT. Meanwhile, the probability at 6 months of undergoing CN after initial TT was 4.4%, with 38.3% of this group having died prior to undergoing CN. In the IPTW analysis, baseline characteristics were balanced (standardized difference < 0.1). Initial CN was associated with improved OS compared to initial TT (median 16.5 vs 9.2 months; HR 0.62; 95%CI 0.61-0.64; p < 0.001). Findings were similar in all sensitivity analyses (propensity score matching and adjustment; regression adjustment; 6-month landmark analysis; clear cell mRCC subset; exclusion of patients who had metastasectomy). Conclusions: Although initial CN was associated improved OS versus initial TT in this national dataset, initial CN was associated with delays in, and even death prior to, receipt of TT. As such, while the survival data here support initial CN in appropriate surgical candidates, continued efforts to develop the optimal multimodal approach to these patients are warranted.

259 Introduction: RA-223 prolongs OS in BM-CRPC pts but predictive markers are lacking. We hypothesized that molecular profiling of plasma-derived extracellular vesicles (EVs) from BM-CRPC pts treated with RA-223 would predict efficacy and inform development of combinations. Methods: Paired baseline (BL) and end of treatment (EoT) blood samples were collected from 25 pts treated with RA-223. Pts were stratified by median OS into 3 groups: 1) 6.3 months (range 3.3-8.5, n=5 pts, UnFav OS), 2) 18.2 months (range 12.6-19.4, n=7 pts, Middle OS) and 3) 27.6 months (range 23.1-33.8, n=13 pts, Fav OS). EVs were isolated from plasma and analyzed for specific proteins and RNA transcripts. Marker profiles by domain and analytic method were determined in pts from the stratified OS groups. Results: At EoT, there is enrichment of RNA transcripts and proteins involved in regulating immune responses, DNA Damage Response (DDR) and bone metabolism (Table). By benchmarking molecular signatures in pts with UnFav Os and Fav OS, we could analyze the molecular profiles of pts in the Middle OS group and stratify them to UnFav OS or Fav OS groups. Conclusion: Plasma-based molecular markers are predictive for RA-223 efficacy. An association between OS and immune and DDR profiles in men with BM-CRPC may indicate mechanism of action and identify subsets most likely to benefit. These preliminary results provide rationale for combination therapy with RA-223 and immune-checkpoint blockade or PARP inhibition. Clinical trial information: NCT02135484. [Table: see text]

249 Background: Serum CGA has been identified as a candidate prognostic biomarker for mCRPC. In a two cohort study, we compared the prognostic value of serum CGA with a validated CTC assay. Methods: In the discovery cohort (DC), blood samples were collected from 256 men with mCRPC. In an independent validation cohort (VC), 92 men with mCRPC were enrolled in a biospecimen collection study. In both cohorts, men receiving proton pump inhibitors and those with non-castrate levels of testosterone ( > 50ng/dl) were excluded. Serum CGA was measured in a homogeneous automated immunofluorescent assay using time-resolved amplified cryptate emission. In the VC, CTC enumeration was performed using the FDA cleared CELLSEARCH CTC test prior to treatment with abiraterone acetate/ prednisone. Cox proportional hazard regression and Kaplan-Meier analysis were performed for associations with elevated CGA (above reference range), unfavorable (≥ 5) CTCs, and overall survival (OS). Results: In the DC, 200 men were eligible for analysis. The median age was 72 years (yrs), 81/200 pts had a Gleason score (GS) ≥ 8, 34/200 had an elevated CGA. At a median follow up of 2.2 yrs, 156/200 were deceased. In the subset of men with GS ≥ 8, elevated CGA was associated with shorter OS [hazard ratio (HR) 2.19, p = 0.017]. In the VC, 71 men were eligible for analysis. The median age was 71 yrs, 36/71 tumors were GS ≥ 8, 31/71 pts had an elevated CGA, 26/66 had unfavorable CTCs (≥ 5). At a median follow up of 1.8 yrs, 31/71 were deceased. Elevated CGA (HR 1.91, p = 0.043) and unfavorable CTC counts (HR 2.97, p = 0.0012) were adversely associated with OS. In the high GS group, both CTCs and CGA had the same area under the curve (AUC) of 0.72. Pts with elevated CTC and CGA had the poorest OS (HR 3.76, p = 0.008). Conclusions: Elevated serum CGA was negatively associated with OS in men with mCRPC. Serum CGA represents a prognostic biomarker that may complement CTC enumeration. Clinical trial information: NCT#01953640.

129 Background: ADT is the first-line treatment for men experiencing recurrence after undergoing radical therapy for prostate cancer. However, timing of ADT initiation is controversial and there are limited data on prognostic factors in patients starting ADT. Methods: We identified consecutive men who underwent radical prostatectomy (RP) for localized prostate cancer at our institution between 1987 and 2007 and who subsequently received salvage ADT. Early progression on ADT was defined as development of metastatic disease within 2yrs of initiation. The primary outcomes of interest were cancer-specific (CSS) and overall survival (OS). Results: A total of 2418 men were included. Median age at RP was 64yrs and median follow-up was 13.9yrs. 48% and 20% of men had pathologic Gleason scores of 7 and 8-10 respectively. The median PSA was 2.6ng/ml, while 385 men (16%) had metastatic disease at receipt of ADT. Overall, 1060 men (44%) developed clinical metastases, with 625 (59%) of these doing so within 2yrs of starting ADT. On multivariable analysis, longer PSA DT before ADT was associated with lower odds of early progression on ADT (DT 3-9mths, OR = 0.19; DT ≥9mths, OR = 0.10, both p < 0.001). 10- and 20-year CSS were 89% and 70%, and 10- and 20-year OS were 82% and 40% respectively. Independent predictors of lower CSS included metastatic disease at time of ADT (HR = 2.60), PSA at ADT of 5-50ng/ml (HR = 2.68) and > 50ng/ml (HR = 4.33, all p < 0.001), while longer PSA DT was associated with higher CSS (DT 3-9mths, HR = 0.54; DT ≥9mths, HR = 0.45, both p < 0.001). PSA at ADT of 5-50ng/ml (HR = 3.10) and > 50ng/ml (HR = 5.20, both p < 0.001) were independent predictors of OS. Conclusions: PSA DT < 3mths and absolute PSA at ADT initiation of ≥ 5ng/ml are adverse prognostic indicators in men receiving salvage ADT for relapse after RP. For patients with these features, their risk of early progression and death should be part of a discussion about the timing of ADT and consideration given to more aggressive treatment strategies. Conversely, men with biochemical relapse who have longer DT and PSA < 5ng/ml are at lower risk and could make an informed decision to defer ADT initiation.

479 Background: We and others have previously shown that the ccRCC epigenome is characterized by widespread DNA hypermethylation (CCR 2014, Nature 2014). Various important tumor suppressor genes (TSGs), such as SMAD7 (inhibitor of oncogenic TGF-β signaling), are under-expressed due to aberrantly methylated promoters or enhancers. We hypothesized that the hypermethylation in ccRCC could be due to low activity of the TET enzymes, which convert methylcytosine (5-mc) to hydroxymethylcytosine (5-hmc). Loss of function of TET enzymes can occur with an inactivating mutation (TET-2 is mutated in about 6% of ccRCC (Science Signaling 2013) or hypoactivity of normal TET enzymes, through inhibition by metabolic intermediates. AA is an essential co-factor for TET enzymes (JACS 2015). We hypothesized that high dose AA treatment of ccRCC could potentially increase the functional activity of TET enzymes leading to demethylation of the RCC genome, and enhance expression of TSGs. Methods: In vitro TET activity was performed on ccRCC cell line 769P with increasing doses of AA (L-AA). Genome wide quantitative 5-mc and 5-hmc was evaluated using mass spectrometry. SMAD7 expression was determined using qRT-PCR. Proliferation assay (MTT) was performed with AA in combination with pazopanib. Cell cycle and apoptosis assays were performed. Results: AA, at doses achieved only by the intravenous route (1-10mM), increased TET activity in ccRCC cell line 769P. Genome wide 5-mc was significantly reduced and 5-hmc was increased, correlating with increase in TET activity. SMAD7 expression was increased with AA treatment. High dose AA led to proliferation inhibition with a cell cycle arrest in the G1 phase, and had a synergistic effect with pazopanib. Since AA leads to the generation of H2O2 in-vitro, catalase was used as control. This did not reverse the effect of AA on epigenetic changes; and proliferation inhibition was seen despite catalase control. Conclusions: High dose AA causes TET mediated DNA demethylation of the hypermethylated RCC genome, resulting in the re-expression of TSGs, and proliferation inhibition. Sequencing and xenograft studies are underway.

456 Background: Renal medullary carcinoma (RMC) is a rare, aggressive malignancy for which relatively limited characterization exists to date. We evaluated clinicopathologic features, treatment patterns, and variables associated with outcomes for patients with RMC. Methods: We reviewed the National Cancer Database to identify patients diagnosed with RMC between 1998-2012. Overall survival (OS) was estimated using the Kaplan-Meier method. Clinicopathologic features associated with all-cause mortality (ACM) were assessed using Cox regression analysis. Results: We identified 153 patients with RMC, comprising approximately 0.04% of renal malignancies during this time period. Median age at diagnosis for RMC was 24 years (IQR 20, 31). The majority of RMC patients were black (135; 88%), male (108; 71%), and presented with unilateral, right-sided tumors (101; 66%). Notably, nearly half (72; 48.9%) presented with metastatic disease. A total of 92 (64.3%) patients underwent radical nephrectomy (RN), and 2 (1.3%) were treated with partial nephrectomy. Pathologic stage at nephrectomy was ≤pT2 in 30 patients (32.6%), pT3 in 43 (46.7%), pT4 in 7 (7.6%), and N+ in 50 (55.6%). Of the patients who underwent RN, 60 (65.2%) received multimodal therapy (MMT), including radiation (3; 3.3%), systemic therapy (49; 53.3%), and radiation + systemic therapy (8; 8.7%). Of the 59 patients who did not undergo surgical resection, the majority (46; 77.8%) presented with M1 disease. Median OS was 7.8 months for the entire RMC cohort, with 1- and 3-year OS of 34% and 11%, respectively. Notably, median OS for patients presenting with M1 and M0 disease was 5.2 months versus 11.2 months, respectively (p< 0.01). On multivariable analysis, treatment with RN (HR 0.40; p=0.003) or RN+MMT (HR 0.44; p<0.001) were associated with decreased ACM, whereas the presence of metastatic disease at diagnosis remained associated with an increased risk of ACM (HR 1.74; p=0.02). Conclusions: The prognosis for patients with RMC is dismal, with a median OS under 8 months. Further studies, including the development of novel therapies, are needed to establish the optimal multimodal management approach for these patients.

367 Background: While neoadjuvant chemotherapy (NAC) for muscle−invasive bladder cancer (MIBC) is recognized as the standard of care, the management of patients with locally advanced and/or nodal disease after NAC and radical cystectomy (RC) is not well defined. We sought to evaluate the association of adjuvant chemotherapy (AC) and overall survival (OS) among patients with adverse pathology after NAC and RC. Methods: The National Cancer Database was reviewed to identify patients with adverse pathology (pT3N0, pT4N0, or pTanyN1−3) at RC following NAC from 2006−2012. Patients were stratified by receipt of AC. Clinical and pathologic variables were abstracted. OS was the primary end−point and differences on the basis of AC were assessed by the Kaplan−Meier method and log−rank test. Multivariable Cox proportional hazards regression was used to assess the association of AC with OS controlling for age, sex, race, Charlson score, year of diagnosis, pathologic stage, and receipt of adjuvant radiotherapy. Results: Adverse pathology following NAC and RC was identified in 1,361 patients from 2006−2012, of whom 328 (24.1%) received AC. Staging was pT3N0 in 444 (32.6%), pT4N0 in 162 (11.9%), and pTanyN1−3 in 755 (55.5%). Median OS for the entire cohort was 22.9 months, which differed by pathologic stage: 34.6 months (pT3N0), 21.4 months (pT4N0), and 19.3 months (pTanyN1-3)(p < 0.01). No difference in OS was noted by receipt of AC in the overall cohort (median OS 24.6 months with AC vs 22.0 months without AC; p = 0.18), or when stratified by pathologic stage. On multivariable analysis, receipt of AC was not significantly associated with overall mortality (HR 0.86; 95%CI 0.74−1.01; p = 0.06) for all patients. When stratified by stage, AC was associated with a significantly decreased risk of mortality among patients with pT4N0 disease (HR 0.56; 95%CI 0.33−0.97; p = 0.04), but not pT3N0 or pTanyN1−3 (p > 0.05). Conclusions: Patients with adverse pathology at RC after NAC have a median OS of approximately 2 years. AC was not associated with improved survival, except in the subgroup with pT4N0 disease. Clinical trials with newer systemic therapies are warranted for patients in this setting.

355 Background: While neoadjuvant chemotherapy (NAC) prior to radical cystectomy (RC) improves survival compared to RC alone for urothelial carcinoma of the bladder (UCB), the bulk of this survival benefit has been attributed to patients who achieve ypT0 status at RC. The implications of having residual UCB (rUCB) at RC after NAC are less clear. As such, we evaluated whether the outcomes for patients with rUCB after NAC differ from stage-matched RC patients who did not receive NAC. Methods: Patients undergoing RC for UCB between 1981-2010 at Mayo Clinic were identified. All RC pathology was re-reviewed by a single genitourinary pathologist. Patients who received NAC were matched 1:2 to patients not exposed to NAC based on pT and pN-stage, margin status, and year of RC. Kaplan Meier and Cox regression analyses were used to evaluate the associations between NAC and cancer-specific (CSS) and overall survival (OS), stratified by presence of rUCB (i.e. (y)pT0N0 and non-(y)pT0N0). Results: We matched 111 patients who underwent NAC + RC to 222 RC-alone patients. Median age was 68 years (IQR 60,74); 59 (18%) were female. Median follow-up among survivors was 7.2 years (IQR 6,16). A total of 248 patients died; 148 died from UCB. In patients without rUCB at RC, there were no differences in 5-yr CSS (86% vs. 90%, p=0.85) or OS (82% vs. 84%, p=0.46) between patients who did and did not receive NAC. Moreover, on multivariable analysis, NAC exposure was not associated with CSS (HR=1.0; 95%CI 0.3-3.1; p=0.9) or OS (HR=0.9; 95%CI 0.4-1.9; p=0.8) in this subgroup. Among patients with rUCB, receipt of NAC was associated with significantly worse 5-yr CSS (32% vs. 56%, p<0.001) and OS (25% vs. 48%, p<0.001). NAC exposure remained independently associated with worse CSS (HR=2.2; 95%CI 1.6-3.1; p<0.001) and OS (HR=2.0; 95%CI 1.5-2.7; p<0.001) among these patients. Conclusions: While patients who achieve a complete response to NAC have excellent survival outcomes, patients with residual UCB at RC after NAC have a worse prognosis compared to stage-matched RC patients not exposed to NAC. Such patients should be considered for enrolment in novel adjuvant therapy trials.