Citations

500 Background: The Memorial Sloan Kettering Cancer Center (MSKCC) prognostic score is based on clinical parameters and has several limitations. We analyzed whole blood mRNA expression in mCCRCC patients (pts) and compared it to MSKCC for predicting overall survival (OS). Methods: A prospective collection of whole blood in PAXgene RNA tubes from mCCRCC pts was performed between 2011 and 2015 with uniform processing. A discovery set (DS) of 19 randomly selected pt samples was used to generate whole transcriptome RNA sequencing and signatures describing differential gene expression patterns associated with OS. We calculated the fragment per kilobase of transcript per million (FPKM) of each transcript and gene to identify correlations between the differentially expressed genes and MSKCC score. Candidate genes were selected based on statistical significance (p<0.05) and associations with OS. In an independent validation set (VS) of 47 pts with mCCRCC, we used the nCounter Analysis System (NanoString Technologies, Seattle, WA, USA) to quantify gene transcript expression selected from the DS. Cox regression and Kaplan-Meier analysis were used for association of candidate mRNAs in the VS with OS (time of metastatic recurrence to death or last follow-up). We compared our gene signature to the MSKCC prognostic score for poor versus good survival. Results: In the DS, at a median follow-up of 4.13 years (yrs) (range: 1.3-4.5), 11 patients had died. We identified eighteen genes in the DS with statistically significant differential gene expression patterns and ability to discriminate patient OS. In the VS at a median follow-up of 4.9 yrs (range: 0.1-11.3), twenty-five patients had died. We confirmed two of the eighteen selected genes that had strong prognostic significance: BAG1 [hazard ratio (HR) 0.31, p=0.007] and NOP56 [HR 0.28, p=0.004]. Comparing OS between good and poor outcome groups for these 2 scores, our two-gene panel had higher prognostic ability (HR 20.07, p <0.0001) than the MSKCC prognostic score (HR 3.19, p 0.04). Conclusions: Prognostic value of using whole blood mRNA gene profiling in mCCRCC is feasible and should be prospectively confirmed in larger studies.

175 Background: Genome and transcriptome aberrations associated with primary resistance to abiraterone acetate/prednisone (AA/P) in mCRPC are not known. In a prospective trial (NCT#01953640) we assessed whole-exome and RNA-seq based aberrations in metastases of CRPC stage patients (pts) for identifying markers associated with primary resistance to AA/P. Methods: Whole-exome and RNA-seq of biopsies from metastases was performed followed by analyses for association between genomic aberrations & primary resistance. Primary resistance was defined by progression on AA/P after 12-weeks of therapy(non-responders) using PSA, RECIST, bone scan and symptom criteria (per PCWG2). Gene network analysis was performed in genes mutated more frequently in non-responders, and also in genes that were differentially expressed between non-responders and responders and a “risk ratio” (RR) was calculated thereof. Results: Between 6/2013 & 8/2015, 92 pts were enrolled of which 82 had complete whole-exome, RNA-seq and 12-week outcome data available for analysis. Median age was 72.5 yrs (IQR: 68.5-78); median PSA-18 ng/ml (IQR: 8.1- 46.6). At 12-weeks 33/82 had progressed. Using the RR of 2 as threshold, we identified 113 and 292 genes that were more frequently mutated in non-responders & responders respectively. Among the 113 genes, OBSCN, ADAM21, LPHN3, DOCK10 ( P = 0.08, RR= inf) & USP42 ( P = 0.16, RR = 5.71) were the top candidates.Gene network analysis revealed that in non-responders, genes involved in the Wnt/β-catenin pathway were frequently mutated and negative regulators of Wnt pathway ( DKK4, SFRP2 & LRP6) were also frequently deleted. Gene expression analyses revealed the expression levels of Wnt/β-catenin pathway inhibitors were significantly reduced while expression levels of cell cycle regulatory genes were significantly increased in non-responders. Conclusions: In this study we observed Wnt/β-catenin pathway activation to be associated with primary AA/P resistance. This finding offers a potential for the development of predictive biomarkers and modulation of targeted pathways to overcome AA/P resistance. Clinical trial information: NCT# 01953640.

142 Background: Despite documented oncological benefit, postoperative adjuvant radiotherapy (aRT) utilization in prostate cancer (PCa) patients is still limited in the US. We aimed to develop and internally validate a risk stratification tool incorporating the Decipher score, along with routinely available clinicopathologic features, to identify patients who would benefit the most from aRT. Methods: Our cohort included a total of 512 PCa patients treated with RP at one of four US academic centers between 1990-2010. All patients had ≥ pT3a disease, positive margins, and/or pathologic lymph node invasion (LNI). Multivariable Cox regression analysis (MVA) tested the relationship between available predictors (including Decipher score) and clinical recurrence (CR), which were then used to develop a novel risk stratification tool. Our study adhered to the TRIPOD guidelines for development of prognostic models. Results: Overall, 21.9% patients received aRT. Median follow-up in censored patients was 8.3 years. The 10-year CR rate was 4.9% vs. 17.4% in patients treated with aRT vs. initial observation (p < 0.001). Pathological T3b/T4 stage, Gleason score 8-10, LNI and Decipher score > 0.6 were independent predictors of CR (all p < 0.01) Cumulative number of risk factors was 0, 1, 2, and 3-4 in respectively 46.5, 28.9, 17.2, and 7.4% of patients. Adjuvant RT was associated with decreased CR rate in patients with ≥ 2 risk factors (10-year CR rate 10.1% in aRT vs. 42.1% in initial observation, p = 0.008), but not in those with < 2 risk factors (p = 0.23). Conclusions: Utilizing the novel model to indicate aRT might reduce overtreatment, decrease unnecessary side effects, and reduce risk of CR in the subset of patients (~25% of all patients with aggressive pathological disease) who really benefit from this therapy.

Purpose Despite documented oncologic benefit, use of postoperative adjuvant radiotherapy (aRT) in patients with prostate cancer is still limited in the United States. We aimed to develop and internally validate a risk-stratification tool incorporating the Decipher score, along with routinely available clinicopathologic features, to identify patients who would benefit the most from aRT. Patient and Methods Our cohort included 512 patients with prostate cancer treated with radical prostatectomy at one of four US academic centers between 1990 and 2010. All patients had ≥ pT3a disease, positive surgical margins, and/or pathologic lymph node invasion. Multivariable Cox regression analysis tested the relationship between available predictors (including Decipher score) and clinical recurrence (CR), which were then used to develop a novel risk-stratification tool. Our study adhered to the Transparent Reporting of a Multivariable Prediction Model for Individual Prognosis or Diagnosis guidelines for development of prognostic models. Results Overall, 21.9% of patients received aRT. Median follow-up in censored patients was 8.3 years. The 10-year CR rate was 4.9% vs. 17.4% in patients treated with aRT versus initial observation ( P < .001). Pathologic T3b/T4 stage, Gleason score 8-10, lymph node invasion, and Decipher score > 0.6 were independent predictors of CR (all P < .01). The cumulative number of risk factors was 0, 1, 2, and 3 to 4 in 46.5%, 28.9%, 17.2%, and 7.4% of patients, respectively. aRT was associated with decreased CR rate in patients with two or more risk factors (10-year CR rate 10.1% in aRT v 42.1% in initial observation; P = .012), but not in those with fewer than two risk factors ( P = .18). Conclusion Using the new model to indicate aRT might reduce overtreatment, decrease unnecessary adverse effects, and reduce risk of CR in the subset of patients (approximately 25% of all patients with aggressive pathologic disease in our cohort) who benefit from this therapy.

While elevated blood cholesterol has been associated with an increased risk of colorectal cancer (CRC) in observational studies, causality is uncertain. Here we apply a Mendelian randomisation (MR) analysis to examine the potential causal relationship between lipid traits and CRC risk. We used single nucleotide polymorphisms (SNPs) associated with blood levels of total cholesterol (TC), triglyceride (TG), low‐density lipoprotein (LDL), and high‐density lipoprotein (HDL) as instrumental variables (IV). We calculated MR estimates for each risk factor with CRC using SNP‐CRC associations from 9,254 cases and 18,386 controls. Genetically predicted higher TC was associated with an elevated risk of CRC (odds ratios (OR) per unit SD increase = 1.46, 95% confidence interval [CI]: 1.20–1.79, p = 1.68 × 10−4). The pooled ORs for LDL, HDL, and TG were 1.05 (95% CI: 0.92–1.18, p = 0.49), 0.94 (95% CI: 0.84–1.05, p = 0.27), and 0.98 (95% CI: 0.85–1.12, p = 0.75) respectively. A genetic risk score for 3‐hydoxy‐3‐methylglutaryl‐coenzyme A reductase (HMGCR) to mimic the effects of statin therapy was associated with a reduced CRC risk (OR = 0.69, 95% CI: 0.49–0.99, p = 0.046). This study supports a causal relationship between higher levels of TC with CRC risk, and a further rationale for implementing public health strategies to reduce the prevalence of hyperlipidaemia.

Coronary artery aneurysm is defined as a coronary dilation that exceeds the diameter of adjacent segments or the diameter of the patient's largest normal coronary vessel by 1.5×. It is an uncommon disease that has been diagnosed with increasing frequency since the widespread appearance of coronary angiography. The published incidence varies from 1.5% to 5%, suggesting male dominance and a predilection for the right coronary artery. Although several causes have been described, atherosclerosis accounts for ≥50% of coronary aneurysms in adults. Reported complications include thrombosis and distal embolization, rupture, and vasospasm, causing ischemia, heart failure, or arrhythmias. The natural history and prognosis remain unknown, as definitive data are scarce. Controversies persist regarding the use of medical management (antithrombotic therapy) or interventional/surgical procedures. Only some case reports or small case series are available about this condition. The Coronary Artery Aneurysm Registry (CAAR; http://www.ClinicalTrials.gov NCT02563626) is a multicenter international ambispective registry that aims to provide insights on anatomic, epidemiologic, and clinical aspects of this substantially unknown entity. In addition, the registry will assess management strategies (conservative, interventional, or surgical) and their short‐ and long‐term results in a large cohort of patients.Clinical Trial registration: ClinicalTrials.gov. Unique identifier: NCT02563626.

757 Background: Progression free survival (PFS) and overall survival (OS) appear to differ across trials, even when pts receive the same regimen (REG). This analysis aimed to benchmark the clinical outcomes in the 2nd line treatment of metastatic colorectal cancer (mCRC). Methods: Individual patient (pt) data was available on 6,462 pts with mCRC enrolled in 7 2ndline clinical trials (8 REGs) in the ARCAD database. Regimens used in at least two trials included FOLFIRI +/- an EGFR inhibitor (EGFRi), FOLFOX +/- a VEGF inhibitor (VEGFi), and irinotecan (IRI). Descriptive statistics were used to describe pt demographics. Multivariable Cox models were used to assess differences (DIFFs) in PFS and OS, while p-value <0.05 were considered statistically significant (SS). Results: 500-1400 pts received each REG (see Table). Median OS and PFS differed by 0.2 to 4.6 months (mo) and 0.8 to 2.5 mo across trials within the same REG. These DIFFs were SS except for PFS in REGs containing FOLFIRI +/- EGFRi. After multivariable adjustment, all DIFFs in OS were attenuated and non-significant. DIFFs in PFS attenuated for most REGs but remained SS for FOLFOX and IRI. Conclusions: After multivariable adjustment, there were no SS DIFFs in outcomes across trials within the same REG, with the exception of PFS in FOLFOX and IRI. The initial observed DIFFs in outcomes could be due to confounding factors and the remaining SS DIFFs in PFS in FOLFOX and IRI may be due to variation in definition of progression across trials. Therefore, caution is warranted when using historical data to design future trials.[Table: see text]

593 Background: Cancer stem cells or stemness-high cancer cells are considered to be fundamentally important for resistance to therapy, recurrence and metastasis. Napabucasin, a first-in-class cancer stemness inhibitor in clinical development, suppresses cancer stemness by targeting Stat3-driven gene transcription. Preclinical studies suggest that napabucasin sensitizes heterogeneous cancer cells to chemotherapeutics and targeted agents. Methods: This study was performed to assess signs of anti-tumor activity of napabucasin in combination with FOLFIRI +/- Bev in CRC pts. Napabucasin was administered at 240 mg BID. FOLFIRI (5-FU 400 mg/m2 bolus with 2400 mg/m2, irinotecan 180 mg/m2, and leucovorin 400 mg/m2 infusion) +/- Bev 5 mg/kg was administered biweekly until disease progression or other discontinuation criterion. pSTAT3 status of archival tumor tissue was assayed by immunohistochemistry using the H-score with pSTAT3highdefined as ≥ 5% pSTAT3+ cancer cells and tumor stroma staining at ≥ 2+ intensity. Results: 63 CRC pts with an average of >2 prior therapy lines were enrolled. No pharmacokinetic interactions or dose-limiting toxicity was observed. Most common adverse events (AEs) included grade 1/2 diarrhea, nausea, vomiting and fatigue. 25 pts had grade 3 AEs, including diarrhea (14), fatigue (4), dehydration (2), electrolyte imbalance (4), nausea (1) and weight loss (1) resolved with dose reduction and supportive care. Among 63 pts enrolled who received RECIST evaluation, disease control (CR+PR+SD) was observed in 49 pts (86%) with an overall response (CR+PR) of 28% with 1 pt achieving CR. Clinical trial information: NCT02024607. Conclusions: This phase Ib/II study suggests napabucasin may sensitize chemorefractory CRC to FOLFIRI +/- Bev. Encouraging signs of synergistic activity between napabucasin and FOLFIRI was observed in CRC pts regardless of pSTAT3 status.[Table: see text]

389 Background: The liver is one of the most radiosensitive organs, making radiation therapy (RT) for liver tumors extremely challenging. RT is appropriate only for a minority of liver patients with limited tumor burden; a reduction in the prescribed radiation dose may be needed to lower the probability of radiation-induced liver disease especially in the presence of cirrhosis. Proton beam therapy (PBT) delivers less dose to the liver than photon therapy and is expected to reduce toxicity while also permitting safe dose escalation for some patients with liver tumors. Methods: The Proton Collaborative Group REG001-09 trial (NCT01255748) prospectively collects data for PBT patients with a variety of cancer types. To better understand treatment details and outcomes associated with liver PBT, patients enrolled on the PCG registry trial from 5 institutions who received liver PBT for any cancer between 2012 and 2016 were analyzed. Results: A total of 43 liver cancer patients were included, most with hepatocellular carcinoma (48.8%) or cholangiocarcinoma (25.6%). The vast majority did not have surgery at any time (86%). Most were treatment naive prior to PBT; 2 previously had RT and 8 had prior chemotherapy (mostly cholangiocarcinoma patients). The median total prescribed PBT dose was 58.05 Gy(RBE) (range 21.7-67.5). The median number of prescribed fractions was 15 (range 12-37). PBT was delivered to only the liver in 90.7% of patients; inclusion of lymph nodes was rare. Uniform scanning was used in 26 (72.1%) and pencil beam scanning in 2 patients (4.7%); the delivery technique used for the remaining patients was unknown (23.2%). With median follow up of 4.4 months (range 1.3-17.9), 3 patients (7%) had an intrahepatic recurrence, 2 patients (4.6%) developed distant metastasis, and 10 patients (23.3%) died. No grade 3 or higher toxicity was reported although 17 patients (39.5%) had grade 2 toxicity predominantly fatigue, anorexia, nausea, or vomiting. Conclusions: Although longer follow up is needed to assess late toxicities as well as disease control, early outcomes from the PCG registry trial for liver cancer patients shows that predominantly hypofractionated PBT has a very favorable acute toxicity profile.