FOLFIRINOX for advanced pancreatic cancer:The Princess Margaret Cancer Centre experience

BACKGROUND: FOLFIRINOX has been shown to significantly increase both overall survival (OS) and progression-free survival (PFS) in metastatic pancreas cancer. There is limited data regarding the treatment of locally advanced pancreatic cancer. We present a retrospective study of patients with both locally advanced and metastatic pancreas cancer using FOLFIRINOX as first-line therapy in our centre. METHODS: This is a retrospective review of patients treated with FOLFIRINOX for pancreatic cancer at Princess Margaret Cancer Centre, between December 2011 and July 2014. The primary objective was to evaluate the efficacy and safety of FOLFIRINOX when used with dose modifications. RESULTS: One hundred two patients were identified; 66 metastatic and 36 locally advanced. Sixty-eight per cent of patients initiated treatment with a dose reduction. The median (95% CI) OS in the metastatic group was 13.1 (6.3–16.1) months with full dose and 12.9 (10.3–30.1) months with modified dose. The median (95% CI) OS in the locally advanced group was 11.1 (6.1–not reached) months with full dose and 23 (not reached–not reached) months with modified dose. The median (95% CI) PFS in the metastatic group was 6.2 (4.9–15.2) months with full dose and 8.7 (5.7–12.9) months with modified dose. The median (95% CI) PFS in the locally advanced group was 11.1 (3.1–not reached) months with full dose and 10.4 (6.8–not reached) months with modified dose. Grade 3/4 haematologic adverse events were observed in 43% of patients. Grade 3/4 non-haematologic adverse events were observed in 28% of patients. Patient well-being significantly improved from baseline to cycle 4 (P=0.002). CONCLUSIONS: Efficacy was achievable with dose-modified FOLFIRINOX in daily setting. The safety of FOLFIRINOX remains a concern with a high rate of grades 3 and 4 neutropaenia despite dose reduction

Liver resection after chemotherapy and tumour downsizing in patients with initially unresectable colorectal cancer liver metastases

AbstractObjectivesAmong patients with initially unresectable colorectal cancer liver metastases (CLM), a subset are rendered resectable following the administration of systemic chemotherapy. This study reports the results achieved in liver resections performed at a single hepatobiliary referral centre after downsizing chemotherapy in patients with initially unresectable CLM.MethodsAll liver resections for CLM performed over a 10-year period at the Toronto General Hospital were considered. Data on initially non-resectable patients who received systemic therapy and later underwent surgery were included for analysis.ResultsBetween January 2002 and July 2012, 754 liver resections for CLM were performed. A total of 24 patients were found to meet the study inclusion criteria. Bilobar CLM were present in 23 of these 24 patients. The median number of tumours was seven (range: 2–15) and median tumour size was 7.0cm (range: 1.0–12.8cm) before systemic therapy. All patients received oxaliplatin- or irinotecan-based chemotherapy. Fourteen patients received combined treatment with bevacizumab. Negative margin (R0) resection was accomplished in 21 of 24 patients. There was no perioperative mortality. Ten patients suffered perioperative morbidity. Eighteen patients suffered recurrence of disease within 9 months. Rates of disease-free survival at 1, 2 and 3 years were 47.6% [95% confidence interval (CI) 30.4–74.6%], 23.8% (95% CI 11.1–51.2%) and 19.0% (95% CI 7.9–46.0%), respectively. Overall survival at 1, 2 and 3 years was 91.5% (95% CI 80.8–100%), 65.3% (95% CI 48.5–88.0%) and 55.2% (95% CI 37.7–80.7%), respectively.ConclusionsLiver resection in initially unresectable CLM can be performed with low rates of morbidity and mortality in patients who respond to systemic chemotherapy, although these patients do experience a high frequency of disease recurrence

Whole genomes define concordance of matched primary, xenograft, and organoid models of pancreas cancer

Pancreatic ductal adenocarcinoma (PDAC) has the worst prognosis among solid malignancies and improved therapeutic strategies are needed to improve outcomes. Patient-derived xenografts (PDX) and patient-derived organoids (PDO) serve as promising tools to identify new drugs with therapeutic potential in PDAC. For these preclinical disease models to be effective, they should both recapitulate the molecular heterogeneity of PDAC and validate patient-specific therapeutic sensitivities. To date however, deep characterization of the molecular heterogeneity of PDAC PDX and PDO models and comparison with matched human tumour remains largely unaddressed at the whole genome level. We conducted a comprehensive assessment of the genetic landscape of 16 whole-genome pairs of tumours and matched PDX, from primary PDAC and liver metastasis, including a unique cohort of 5 'trios' of matched primary tumour, PDX, and PDO. We developed a pipeline to score concordance between PDAC models and their paired human tumours for genomic events, including mutations, structural variations, and copy number variations. Tumour-model comparisons of mutations displayed single-gene concordance across major PDAC driver genes, but relatively poor agreement across the greater mutational load. Genome-wide and chromosome-centric analysis of structural variation (SV) events highlights previously unrecognized concordance across chromosomes that demonstrate clustered SV events. We found that polyploidy presented a major challenge when assessing copy number changes; however, ploidy-corrected copy number states suggest good agreement between donor-model pairs. Collectively, our investigations highlight that while PDXs and PDOs may serve as tractable and transplantable systems for probing the molecular properties of PDAC, these models may best serve selective analyses across different levels of genomic complexity

Retrospective evaluation of whole exome and genome mutation calls in 746 cancer samples

Funder: NCI U24CA211006Abstract: The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) curated consensus somatic mutation calls using whole exome sequencing (WES) and whole genome sequencing (WGS), respectively. Here, as part of the ICGC/TCGA Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium, which aggregated whole genome sequencing data from 2,658 cancers across 38 tumour types, we compare WES and WGS side-by-side from 746 TCGA samples, finding that ~80% of mutations overlap in covered exonic regions. We estimate that low variant allele fraction (VAF < 15%) and clonal heterogeneity contribute up to 68% of private WGS mutations and 71% of private WES mutations. We observe that ~30% of private WGS mutations trace to mutations identified by a single variant caller in WES consensus efforts. WGS captures both ~50% more variation in exonic regions and un-observed mutations in loci with variable GC-content. Together, our analysis highlights technological divergences between two reproducible somatic variant detection efforts

Hypoxia, invasion and metastasis in pancreatic cancer

Hypoxia and tumour-stroma cross-talk are implicated in the aggressive pathophysiology of pancreatic ductal adenocarcinoma (PDAC). This thesis explores the heterogeneity in response of targeting hypoxia-related invasive and metastatic pathways in PDAC. The first focus is an exploration of focal adhesion kinase (FAK) targeting supported by prior observations of hypoxic-upregulation of FAK activity in PDAC. The second focus includes preliminary observations from PIMO-PANC, a trial characterizing hypoxia (using the hypoxia tracer PIMOnidazole) in patients with PANCreatic adenocarcinoma. To explore the phenotype of FAK inhibition, the dominant negative acting construct FRNK (FAK-related non-kinase) was stably overexpressed in human PANC1 and BxPC3 PDAC cell lines. Anti-cancer activity was observed in PANC1, a cell line demonstrating features of epithelial-to-mesenchymal transition (EMT), with impaired adhesion to collagen and serum-induced chemotaxis. Orthotopic Panc1-FRNK xenograft tumours were smaller, and tumour-bearing animals had reduced metastatic burden and prolonged survival. Similar effects were not apparent in the more epithelial BxPC3-FRNK tumors. In a patient-derived xenograft model OCIP5I, which demonstrates nuclear Snail expression with loss of cytokeratin, there was a trend to modest anti-invasive and anti-metastatic activity of the FAK/Pyk2 inhibitor PF-562271 (Pfizer). This differential activity in Panc1 and OCIP51 suggests that activity of FAK kinase inhibition might be most relevant to tumours with features of EMT. PIMO-PANC has a primary objective of evaluating the prognostic and biological relevance of severe hypoxia in PDAC through administration of the hypoxia marker pimonidazole to patients prior to resection. Bioactive reduction of pimonidazole yields immune-detectable adducts indicative of severe hypoxia. Although a well-established technique for studying tumour hypoxia, methods of analysis are not standardized. A semi-automated image analysis platform was used to differentiate epithelial and stromal tumour elements and quantify pimonidazole positivity in 10 patient tumours, analyzing multiple sections per individual tumour. This is the first analysis to describe tumoral hypoxia using quantitative immunohistochemistry while exploring the heterogeneity of hypoxia and related sampling error in surgical samples. These findings, including the minimal levels of nitroimidazole-detectable hypoxia observed in a subset of patients, have important implications for the development of hypoxia-targeting strategies in PDAC.Ph.D.2019-01-11 00:00:0

A rapidly evolving landscape: immune checkpoint inhibitors in pretreated metastatic endometrial cancer

Background and objectives: Endometrial cancer is a common malignancy and recurrences can be fatal. Although platinum-pretreated endometrial tumors are commonly treated with anthracyclines and taxanes, there is no current standard of care. Both immune checkpoint inhibitors (ICIs) and tyrosine kinase inhibitors (TKIs) have been extensively assessed in this setting, including tumors selected for DNA mismatch repair (MMR)/microsatellite instability (MSI) and programmed death-ligand 1 expression status. This review will provide evidence-based guidance on use of ICIs alone or in combination with TKIs in patients with pretreated advanced, persistent, or recurrent metastatic endometrial cancer. Data sources and methods: Randomized phase II–III trials in unselected populations pretreated, recurrent, or metastatic endometrial cancer and phase I–II trials in biomarker selected populations were identified from PubMed as well as conference proceedings using the key search terms ‘immune checkpoint inhibitors’, ‘endometrial cancer’, and ‘advanced’. Results: A total of nine eligible studies were identified assessing ICI monotherapy for biomarker-selected or ICI plus TKI combinations and a dual ICI regimen for biomarker-unselected patients with pretreated recurrent or metastatic endometrial cancer. In MMR/MSI-selected tumors, five phase I/II studies evaluated ICI monotherapy indicating benefit in these patients. Only the phase III KEYNOTE-775 trial reported a statistically significant overall survival improvement for the combination of pembrolizumab plus lenvatinib compared with docetaxel or paclitaxel regardless of MMR/MSI status. Conclusions: Pembrolizumab plus lenvatinib is indicated for patients with unselected pretreated metastatic endometrial cancer and pembrolizumab monotherapy is a preferred option for patients with MMRd/MSI-H tumors

Impact of tissue transport on PET hypoxia quantification in pancreatic tumours

Abstract Background The clinical impact of hypoxia in solid tumours is indisputable and yet questions about the sensitivity of hypoxia-PET imaging have impeded its uptake into routine clinical practice. Notably, the binding rate of hypoxia-sensitive PET tracers is slow, comparable to the rate of diffusive equilibration in some tissue types, including mucinous and necrotic tissue. This means that tracer uptake on the scale of a PET imaging voxel—large enough to include such tissue and hypoxic cells—can be as much determined by tissue transport properties as it is by hypoxia. Dynamic PET imaging of 20 patients with pancreatic ductal adenocarcinoma was used to assess the impact of transport on surrogate metrics of hypoxia: the tumour-to-blood ratio [TBR(t)] at time t post-tracer injection and the trapping rate k 3 inferred from a two-tissue compartment model. Transport quantities obtained from this model included the vascular influx and efflux rate coefficients, k 1 and k 2, and the distribution volume v d ≡k 1/(k 2+k 3). Results Correlations between voxel- and whole tumour-scale k 3 and TBR values were weak to modest: the population average of the Pearson correlation coefficients (r) between voxel-scale k 3 and TBR (1 h) [TBR(2 h)] values was 0.10 [0.01] in the 20 patients, while the correlation between tumour-scale k 3 and TBR(2 h) values was 0.58. Using Patlak’s formula to correct uptake for the distribution volume, correlations became strong (r=0.80[0.52] and r=0.93, respectively). The distribution volume was substantially below unity for a large fraction of tumours studied, with v d ranging from 0.68 to 1 (population average, 0.85). Surprisingly, k 3 values were strongly correlated with v d in all patients. A model was proposed to explain this in which k 3 is a combination of the hypoxia-sensitive tracer binding rate k b and the rate k eq of equilibration in slow-equilibrating regions occupying a volume fraction 1−v d of the imaged tissue. This model was used to calculate the proposed hypoxia surrogate marker k b. Conclusions Hypoxia-sensitive PET tracers are slow to reach diffusive equilibrium in a substantial fraction of pancreatic tumours, confounding quantification of hypoxia using both static (TBR) and dynamic (k 3) PET imaging. TBR is reduced by distribution volume effects and k 3 is enhanced by slow equilibration. We proposed a novel model to quantify tissue transport properties and hypoxia-sensitive tracer binding in order to improve the sensitivity of hypoxia-PET imaging