Figure S1. hENT1 expression by modified Moffitt subtypes Figure S2. OS in GnP cohort stratified by hENT1 and modified Moffitt Classifier

697 Background: Locally advanced pancreatic cancer (LAPC) accounts for approximately 30% of pancreatic ductal adenocarcinomas (PDAC). Optimal management for LAPC is controversial and combination treatments are extrapolated from treatment guidelines for metastatic disease. The biological underpinnings of LAPC remain unclear, although the loss of tumor suppressor SMAD4 has been associated with metastatic disease. Here we characterize the genomic landscape of LAPC in a large series of prospectively sequenced PDAC. Methods: Clinical, genomic and survival data were obtained from the COMPASS trial (NCT02750657), a prospective multi-institutional study that included patients with treatment-naïve advanced PDAC, with predominantly metastatic cases due to ease of biopsy. Fresh tumor tissue was acquired by percutaneous core biopsy for real-time whole genome sequencing (WGS) and RNA sequencing (RNAseq). Laser capture micro-dissection was performed for all cases. Response to therapy was assessed every 8 weeks, and patients were followed prospectively. Results: Of 268 patients (268 with available WGS and 253 with RNAseq), 37 (14%) had LAPC. Baseline epidemiological variables were similar, with no differences between sex, age, smoking status, or history of diabetes. Patients with LAPC had a lower BMI (median 22 vs 24, p=0.005) and lower baseline CA19-9 (median 488 vs 2551, p=0.002) than metastatic cases. All patients with LAPC had a low (<2 points) Gustave Roussy Immune Score, previously shown to be prognostic in our dataset. Driver alternations were similar in LAPC and metastatic cases with no differences in SMAD4 loss between the two groups; however, major imbalances in mutant KRAS were absent in the LAPC group. The burden of SNVs, indels and SVs was significantly lower in LAPC (Table). All LAPC cases demonstrated a classical RNA subtype, compared to 23% in metastatic cases ( p=0.0008). Median OS measured 12.5 and 8.3 months for LAPC and metastatic cases, respectively (HR 0.65, 95% CI 0.48-0.89, p=0.003). In addition, when measuring CD8+ T cell infiltration by IHC using median cut-off values, primary site biopsies had a higher CD8+ T cell infiltrate compared to metastatic sites (77% vs 56% CD8-high, respectively, p=0.01). Conclusions: These integrated genomic, RNA subtyping and early immunophenotyping results suggest that LAPC demonstrate less genomic instability and classical programming. Further study will delineate how these genomic differences, along with better clinical features, may influence treatment decision-making and design of future clinical trials. Clinical trial information: NCT02750657 . [Table: see text]

4160 Background: Pancreatic adenocarcinoma (PDAC) has a poor prognosis. Only 10-15% of patients present with resectable tumors upfront, and most patients develop recurrence and die prematurely. The data are incongruous when considering R1 status, direct invasion is not consistently a significant prognostic factor. It is recommended that 7 margins be identified for surgery: the bile duct, pancreatic neck, proximal and distal duodenum, superior mesenteric vein (SMV), superior mesenteric artery (SMA), and posterior pancreas. By analyzing data from the PRODIGE 24-CCTG PA-6 trial that validated the mFOLFIRINOX regimen in adjuvant setting, our main objective was to analyze the prognostic value of margin involvement on disease-free survival (DFS). Methods: The protocol recommended that the surgeon inked the resection margins. R1 was defined as direct tumor margin infiltration within 1 mm of one or more resection margins. All patient data were re-evaluated centrally by an external review committee including pathologists, surgeons, and medical oncologists to verify key prognostic factors, including inking and filling of resection margins. Results: Among the 400 patients included in the study, the median number of documented margins was 6, IQR (5-7). In 214 patients (53.5%), fewer than 7 margins were reported. The most common margin involvement was on the SMV groove (28.3%), posterior margin (21%), SMA (14.5%), and pancreatic neck transection (5.3%). Margin inking was performed in 64.9% of cases. Misclassification of the R1 status concerned 24.1% of the files after centralized review. When positive, only 3 margins (SMV groove, median and posterior) were significant prognostic factors in unifactorial analysis (all p < 0.01). When combined, one R1 margin among these three had independent prognostic value in multivariable analysis. In multivariate analysis, DFS was significantly different by quality of resection margins in the gemcitabine arm (HR 95% CI 1.97 [1.23;3.16]; p = .005) but not in the mFOLFIRINOX arm (HR 95% CI 1.46 [0.91;2.35]; p = .114). Conclusions: Few studies have examined the prognostic implications of each margin. We consider that every effort should be made to evaluate the 3 best prognostic margins. One finding of this work is the likely effect of mFOLFIRINOX on local invasion in operated patients. It seems that this chemotherapy regimen (unlike gemcitabine) corrects the alteration related to margin involvement, probably explaining all or part of the improved survival. Therefore, the value of additional therapies, such as cloture radiotherapy, should be evaluated in patients with unknown marginal status or in those who did not benefit from mFOLFIRINOX chemotherapy. A patient who received mFOLFIRINOX as adjuvant therapy is more likely to recur with distant metastasis (80%) and with a better survival of 28 months. Clinical trial information: NCT01526135 .

Supplementary Figure 2 shows the results of a pilot monotherapy trial to evaluate regimen-related toxicity

Supplementary Figure 6 shows the tumour ploidy analysis of xenografts evaluated in the preclinical trial that were not whole genome sequenced

Background Systemic inflammatory scores may aid prognostication and patient selection for trials. We compared five scores in advanced pancreatic adenocarcinoma (PDAC). Methods Unresectable/metastatic PDAC patients enrolled in the Comprehensive Molecular Characterisation of Advanced Pancreatic Ductal Adenocarcinoma for Better Treatment Selection trial (NCT02750657) were included. Patients had pre-treatment biopsies for whole genome and RNA sequencing. CD8 immunohistochemistry was available in a subset. The neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio, Prognostic Nutritional Index, Gustave Roussy Immune Score (GRIm-S), and Memorial Sloan Kettering Prognostic Score (MPS) were calculated. Overall survival (OS) was estimated using Kaplan–Meier methods. Associations between inflammatory scores, clinical/genomic characteristics, and OS were analysed. Results We analysed 263 patients. High-risk NLR, GRIm-S and MPS were poorly prognostic. The GRIm-S had the highest predictive ability: median OS 6.4 vs. 10 months for high risk vs. low-risk ( P < 0.001); HR 2.26 ( P < 0.001). ECOG ≥ 1, the basal-like subtype, and low-HRDetect were additional poor prognostic factors ( P < 0.01). Inflammatory scores did not associate with RNA-based classifiers or homologous recombination repair deficiency genotypes. High-risk MPS ( P = 0.04) and GRIm-S ( P = 0.02) patients had lower median CD8 + tumour-infiltrating lymphocytes. Conclusions Inflammatory scores incorporating NLR have prognostic value in advanced PDAC. Understanding immunophenotypes of poor-risk patients and using these scores in trials will advance the field.

PURPOSE: The Accelerated Diagnostic Assessment Program (ADAP) manages patients with imaging abnormalities, with or without concomitant symptoms, where cancer is suspected. The ADAP is offered to primary care practitioners and emergency departments with cases triaged by a medical oncologist. METHODS: We performed a retrospective patient chart review of electronic medical records from January 2019 until June 2021 to validate the program. We collected information on the referral pathways, patient demographics, wait-times, and diagnostic results. The control group consisted of outpatients who were referred for biopsy over a 1-year period outside the ADAP stream. Statistical analyses were performed using IBM SPSS software. RESULTS: Of the 97 patients included, 54% were female, with ages ranging from 18 to 96 years. Twenty-nine percent (n = 20) of the malignant cases were incidental findings. Most patients referred to the ADAP were diagnosed with a malignancy (71%; n = 69), comprising hematologic (45%; n = 31), GI (26%; n = 18), or other cancers (29%; n = 20). The ADAP had decreased wait-times from referral to biopsy collection (17.6 days ± 10.7 [standard deviation (SD)]; n = 43) when compared with the control group (41.2 days ± 40.0 [SD]; n = 67; P < .001). ADAP patients with malignancies saw a treating specialist 7.6 ± 7.6 days [SD] after their follow-up appointment at the ADAP. CONCLUSION: The ADAP accelerated time to biopsy in a statistically significant manner when compared with age-, referring physician–, and biopsy site–matched controls. It also outperformed national and provincial standards, suggesting that its model addresses a gap in care by providing an underserved population timely access to diagnosis and treatment.

4161 Background: Validated biomarkers are urgently needed to provide a more precise approach in pancreatic cancer (PDAC). Homologous recombination deficiency (HRD) is a heterogenous cohort in PDAC and predicts platinum and PARP inhibitor sensitivity. The BRCA-1 genotype associates with distinct tandem duplications (TDs), however non-BRCA 1 TD phenotypes (TDP) have been observed across tumour types and may be associated with perturbations in CDK12, FBXW17, and CCNE1. Here, we characterize the prevalence and outcomes of TDP in a large series of prospectively sequenced PDAC. Methods: Whole-genome sequencing was performed in 191 early stage resected and 275 advanced PDAC cases in the PanCuRx initiative and the COMPASS trial at the Ontario Institute for Cancer Research and Princess Margaret Cancer Centre. Tumors underwent laser capture enrichment prior to sequencing. TD scores were calculated as previously described by Menghi et al, and HRDetect scores assigned. Samples were classified as classical or basal-like by Moffitt. Outcomes of patients with TDP tumors were evaluated. Tumors that are nonHRD and nonTDP are referred to as typicals. Results: Of 466 cases, 46 were identified as TDP (9.9%; 17 resected, 29 advanced). Subgroups of TDP by etiology included BRCA1 (n=8; 6 germline, 2 somatic), somatic CCNE1 (n=1), and unknown (n=37; no identified alterations in TDP-related genes). Pathogenic germline variants were not found in unique genes other than BRCA1. HRD TDP was associated with a significantly smaller TD size compared to nonHRD TDP (median 12 kb vs. 125 kb, p<0.0001) and median TD load of 114. NonHRD TDP genomes exhibited elevated TD load (median 70 vs. 13, p<0.0001) and HRDetect scores (p<0.0001) compared with typicals. NonHRD TDP was not prognostic in resected PDAC disease (p=0.6361) compared with typicals. We observed a trend towards improved response to 1st-line platinum therapy in nonHRD TDP vs. typicals (p=0.066) for patients with advanced disease. When stratified for only ‘classical’ RNA subtype cases as per Moffitt classification (HRD TDP:2 basal-like, 8 classical, 1 unknown; nonHRD TDP: 9 basal-like, 25 classical, 1 unknown), platinum therapy was correlated with better response in non-HRD TDP vs. typicals (n= 10, 70% ORR, p=0.0108) highlighting the chemoresistance of the basal-like subgroup. Superior survival was not observed in this small cohort. Conclusions: In PDAC, the etiology of nonHRD TDP is unclear but may represent a potential marker for platinum and DNA damage response agents. Further investigation is warranted with a larger sample size.

Supplementary Figure 10 shows multiplex IHC staining of the Q70P pancreatic resection specimen

Aims: First-line FOLFIRINOX (FOLinic acid, Fluorouracil, IRINotecan, and OXaliplatin) and gemcitabine plus nab-paclitaxel (GnP) have been publicly funded for patients with unresectable locally advanced pancreatic cancer (uLAPC) in Ontario, Canada. We examined the overall survival and surgical resection rate after first-line FOLFIRINOX or GnP and determined the association between resection and overall survival in patients with uLAPC. Materials and methods: We conducted a retrospective population-based study including patients with uLAPC who received first-line treatment FOLFIR-INOX or GnP from April 2015 to March 2019. The cohort was linked to administrative databases to ascertain demographic and clinical characteristics. Propensity score methods were used to balance differences between FOLFIRINOX and GnP. The Kaplan-Meier method was used to calculate overall survival. Cox regression was used to determine the association between receipt of treatment and overall survival, adjusting for time-dependent surgical resections. Results: We identified 723 patients with uLAPC (mean age 1/4 65.8, 43.5% female) who received FOLFIRINOX (55.2%) or GnP (4 4.8%). The median overall survival and 1-year overall survival probability were higher for FOLFIRINOX (13.7 months, 54.6%) than for GnP (8.7 months, 34.0%). Post-chemotherapy surgical resection occurred in 89 (12.3%) patients (FOLFIRINOX: 74 [18.5%] versus GnP: 15 [4.6%]), with no difference in survival since surgery between FOLFIRINOX and GnP (P 1/4 0.29). After adjusting time-dependent post-treatment surgical resection, FOLFIRINOX (inverse probability treatment weighting hazard ratio 0.72, 95% confi-dence interval 0.61, 0.84) was independently associated with improved overall survival. Conclusions: In this real-world population-based study of patients with uLAPC, FOLFIRINOX was associated with improved survival and higher resection rates. FOLFIRINOX was associated with improved survival in patients with uLAPC after accounting for the effect of post-chemotherapy surgical resection, suggesting the benefit of FOLFIRINOX was not solely due to improving resectability. (c) 2023 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

Aims: To evaluate the safety and effectiveness of oxaliplatin-based combination chemotherapy for patients with metastatic colorectal cancer (mCRC) to extrahepatic sites. Materials and methods: We conducted a population-based retrospective study examining the safety and effectiveness of perioperative oxaliplatin for resectable or potentially resectable colorectal metastases in Ontario, Canada. Outcomes were also compared with patients with liver-only metastases. Patients received oxaliplatin for mCRC between 1 January 2013 and 30 June 2020. Results: In total, 192 patients had extrahepatic metastases. Seventy per cent had R0 metastasectomy. The 3-year disease-free survival and overall survival were 62% and 79%, respectively; <4% of patients died within 60 days of metastasectomy and 74-90% of patients received treatment according to recommendations from a multidisciplinary setting. Compared with liver-only controls (n 1/4 1306), patients had mCRC to the lung only (n 1/4 115), lung and liver (n 1/4 55) and liver with non-pulmonary site (n 1/4 22). Extrahepatic metastases were more likely to be found for patients whose primary colorectal resection had positive margins (14% versus 7%, P 1/4 0.005) and primary tumours located in the rectum [odds ratio 4.01 (2.31-6.97)]. After adjustment, there was no difference in overall survival between liver-only controls and patients with lung-only [hazard ratio 0.82 (0.59-1.15)] or liver and lung metastases [hazard ratio 1.26 (0.85-1.87)] (P 1/4 0.24). In total, 79/115 (69%) of patients with lung-only metastases had a metastasectomy compared with 645/1306 (49%) and 15/55 (27%) of patients with liver-only and liver and lung metastases, respectively. Hospital visits were similar between patients with liver-only and extrahepatic metastases. Conclusion: Oxaliplatin-based chemotherapy for patients with resectable or potentially resectable mCRC with extrahepatic metastases was safe and resulted in similar outcomes in appropriately selected patients when compared with patients with liver-only metastases. (c) 2022 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

Supplementary Table 1 shows the clinical characteristics of the patients from whom patient-derived xenografts were generated and evaluated in the preclinical trial

Supplementary Figure 7 shows the comparison of COSMIC SBS mutational signatures between untreated parent xenografts vs. xenografts treated with gemcitabine-cisplatin

Supplementary Figure 8 shows the principal component analysis followed by k-means clustering to group xenografts based on their sensitivity to cisplatin, talazoparib and cisplatin-talazoparib

Supplementary Figure 4 shows the Kaplan-Meier survival curves of mice evaluated in the preclinical trial

Supplementary Figure 5 shows the immunohistochemical analysis of apoptotic activity in xenografts treated with gemcitabine mono- and combination therapies

PURPOSE:GemPred, a transcriptomic signature predictive of the efficacy of adjuvant gemcitabine (GEM), was developed from cell lines and organoids and validated retrospectively. The phase III PRODIGE-24/CCTG PA6 trial has demonstrated the superiority of modified folinic acid, fluorouracil, irinotecan, and oxaliplatin (mFOLFIRINOX) over GEM as adjuvant therapy in patients with resected pancreatic ductal adenocarcinoma at the expense of higher toxicity. We evaluated the potential predictive value of GemPred in this population. PATIENTS AND METHODS:Routine formalin-fixed paraffin-embedded surgical specimens of 350 patients were retrieved for RNA sequencing and GemPred prediction (167 in the GEM arm and 183 in the mFOLFIRINOX [mFFX] arm). Survival analyses were stratified by resection margins, lymph node status, and cancer antigen 19-9 level. RESULTS:Eighty-nine patients' tumors (25.5%) were GemPred+ and were thus predicted to be gemcitabine-sensitive. In the GEM arm, GemPred+ patients (n = 50, 30%) had a significantly longer disease-free survival (DFS) than GemPred- patients (n = 117, 70%; median 27.3 v 10.2 months, hazard ratio [HR], 0.43 [95% CI, 0.29 to 0.65]; P < .001) and cancer-specific survival (CSS; median 68.4 v 28.6 months, HR, 0.42 [95% CI, 0.27 to 0.66]; P < .001). GemPred had no prognostic value in the mFFX arm. DFS and CSS were similar in GemPred+ patients who received adjuvant GEM and mFFX (median 27.3 v 24.0 months, and 68.4 v 51.4 months, respectively). The statistical interaction between GEM and GemPred+ status was significant for DFS (P = .008) and CSS (P = .004). GemPred+ patients had significantly more adverse events of grade ≥3 in the mFFX arm (76%) compared with those in the GEM arm (40%; P = .001). CONCLUSION:This ancillary study of a phase III randomized trial demonstrates that among the quarter of patients with a GemPred-positive transcriptomic signature, survival was comparable with that of mFOLFIRINOX, whereas those receiving adjuvant gemcitabine had fewer adverse events.

Supplementary Figure 3 shows the histological analysis of the xenografts evaluated in the preclinical trial

Supplementary Table 2 shows the clinical characteristics of 21 HRD PDAC patients whose tumours were whole genome and whole transcriptome sequenced