Genetic and non-genetic risk factors for early-onset pancreatic cancer

BACKGROUND

Early-onset pancreatic cancer (EOPC) represents 5-10% of all pancreatic ductal adenocarcinoma (PDAC) cases, and the etiology of this form is poorly understood. It is not clear if established PDAC risk factors have the same relevance for younger patients. This study aims to identify genetic and non-genetic risk factors specific to EOPC.

METHODS

A genome-wide association study was performed, analysing 912 EOPC cases and 10 222 controls, divided into discovery and replication phases. Furthermore, the associations between a polygenic risk score (PRS), smoking, alcohol consumption, type 2 diabetes and PDAC risk were also assessed.

RESULTS

Six novel SNPs were associated with EOPC risk in the discovery phase, but not in the replication phase. The PRS, smoking, and diabetes affected EOPC risk. The OR comparing current smokers to never-smokers was 2.92 (95% CI 1.69-5.04, P = 1.44 × 10-4). For diabetes, the corresponding OR was 14.95 (95% CI 3.41-65.50, P = 3.58 × 10-4).

CONCLUSION

In conclusion, we did not identify novel genetic variants associated specifically with EOPC, and we found that established PDAC risk variants do not have a strong age-dependent effect. Furthermore, we add to the evidence pointing to the role of smoking and diabetes in EOPC.

Abstract 2324: Characterizing the secretome of freshly dissociated gastroesophageal tumor biopsies to identify immune suppressive factors

Background: Treatment response to chemoradiotherapy and immune checkpoint blockade is limited in gastroesophageal adenocarcinoma (GEA). This is likely caused by the fact that the majority of GEAs, belonging to the chromosomally instable subgroup (70%), are often immune excluded. We hypothesize that the immune excluded state is caused by secretion of immune suppressive factors by the tumor cells, to protect themselves from immune attack. By identifying and targeting these factors we aim to increase immune infiltration and increase treatment response.

Method: To better understand the drivers of immune exclusion in GEA, we optimized methods to analyze the secretome of freshly dissociated GEA tumor biopsies (n=36) by plating single cells in a 96 well plate for 48 hours and performing targeted proteomics on the supernatant (50ul) using the Olink Target 96 ImmunoOncology panel. Using the same panel, we also analyzed the secretomes of patient-derived organoids (n=7). In parallel the immune infiltrate was characterized immediately in freshly dissociated biopsies with 14 color flow cytometry, and in FFPE material through 6 opal multicolor immunohistochemistry to determine the spatial organization of the immune infiltrate.

Results: We identified 62 factors in the panel that are secreted by at least 25% of the biposies. Pro- and anti-inflammatory factors were found to correlate frequently. Using ranked scores for the pro- and anti-inflammatory factors we were able to identify 7 patients with a predominantly inflamed secretome and 29 with a suppressive secretome. The inflamed secretomes are characterized by IFN-gamma, CXCL9-10-11, the presence of granzymes and higher CD8 T cell levels identified by flow cytometry, whereas tumors with dominant anti-inflammatory profile had lower CD8 higher CD4 T cell rates. Notably, the anti-inflammatory secretomes are characterized by an overall lack of pro-inflammatory factors. Among the factors that are most frequently detected (>85% of patients) are galectin-9, IL-8, VEGFA, HO-1 and CAIX, all factors with potential immune suppressive properties. These are also detected in the secretomes of the organoids, indicating direct tumor mediated suppressive effect in the GEA TME.

Conclusion: The analysis revealed that GEAs secrete immune suppressive factors and that the state of the TME as influenced by the secretome is reflected in the immune infiltrate composition. We found that tumors lacking a CD8 T cell infiltrate showed an absence of pro-inflammatory factors and had a secretome predominantly made up of anti-inflammatory factors that were also secreted by organoids. Moving forward we aim to further identify GEA associated suppressive factors by using a broader panel to analyze the secretome. Additionally, functional studies will determine whether targeting these immune suppressive factors will facilitate responses to immune checkpoint blockade

Citation Format: Jasper Sanders, Micaela H. Harrasser, Tessa S. van Schooten, Emma N. Bos, Benthe H. Doeve, Maarten F. Bijlsma, Hanneke W. van Laarhoven, Donald L. van der Peet, Sarah Derks. Characterizing the secretome of freshly dissociated gastroesophageal tumor biopsies to identify immune suppressive factors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2324.

Abstract 1727: CD8+ T cells in the invasive margin combined with FOXP3+ T cells in the tumor center significantly associate with survival in resectable gastric cancer, a post-hoc analysis of the Dutch D1/D2 trial

Introduction: In gastric cancer, studies of tumor infiltrating lymphocytes as a prognostic biomarker show contradictory results. These results may be caused by use of variable immunohistochemistry (IHC) quantification techniques, different marker selections and particularly inconsistency in the evaluated tumor regions. To overcome these issues, we performed a comprehensive digital image analysis of 5 immune cell markers for their prognostic value in a cohort of gastric cancer patients who were treated with surgery only in the Dutch D1/D2 trial.

Methods: All available surgical resection specimens of gastric cancer patients were included in this study (N=251). IHC for T-cell markers CD3, CD45RO, CD8, FOXP3 and Granzyme B was performed on serial slides. After manual annotation of the tumor area, an invasive margin was defined as 0.5 mm into the tumor still containing tumor cells (inner margin, IM) and 0.5 mm outside of the tumor not containing tumor cells (outer margin, OM). The density of positive immune cells (cells/mm2) was digitally quantified using QuPath for each 0.5x0.5 mm2 square across tumor center (TC), IM and OM, separately. A classification and regression tree (CART) model was employed to identify an optimal combination of prognostic markers from the continuous immune cell density variables with cancer specific survival (CSS) as outcome.

Results: The CART decision tree identified CD8 OM (≥798 cells/mm2) as most dominant prognostic factor, followed by FOXP3 TC (≥20 cells/mm2) in the CD8 OM low subset. This resulted in 3 CART branches in the decision tree: CD8 OM high with best prognosis, CD8 OM low/FOXP3 TC high with intermediate prognosis, and CD8 OM low/FOXP3 TC low with worst prognosis (Log-rank P-value <0.0001). The CD8 OM high branch was enriched in EBV+ (38.2%) and MSI-high (17.6%) tumors, compared to the other two branches with poorer prognosis (4.2% and 3.4% for EBV+, 7.9% and 8.4% for MSI-high). The CART model was an independent predictor of CSS in a multivariable cox-regression (HR branch 2 vs 1: 4.87, 95% CI 1.96-12.07 and HR branch 3 vs 1: 7.97, 95% CI 3.20-19.86), which included T stage, N stage, Lauren subtype, EBV-status and MSI-status. The performance of the CART model was assessed by 5-fold cross-validation, where 4 out of 5 models reached a P-value < 0.05 (Likelihood-Ratio test).

Conclusions: The OM in gastric cancer contains previously overlooked important prognostic information valuable for immune biomarker studies. The combination of CD8 OM and FOXP3 TC is identified as strongest prognostic factor in the risk stratification of resectable gastric cancer, and is independent of T stage, N stage, EBV-status, MSI-status and Lauren subtype. Moreover, high T-cell densities found in a proportion of EBV-/MSS tumors support further investigation of response to immunotherapy in these subgroups.

Citation Format: Tanya T. Soeratram, Hedde D. Biesma, Jacqueline M. Egthuijsen, Elma Meershoek-Klein Kranenbarg, Henk H. Hartgrink, Cornelis J. van de Velde, Erik van Dijk, Yongsoo Kim, Bauke Ylstra, Hanneke W. van Laarhoven, Nicole C. van Grieken. CD8+ T cells in the invasive margin combined with FOXP3+ T cells in the tumor center significantly associate with survival in resectable gastric cancer, a post-hoc analysis of the Dutch D1/D2 trial [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1727.

Abstract 2616: Stemness factors nanog and oct4 contribute to epithelial-to-mesenchymal transition and are predictive for outcome in esophageal adenocarcinoma

Background and Aims: The incidence of esophageal adenocarcinoma (EAC) has increased six-fold in Western countries over the last decades, and 5-year survival rates remain low at 5-20%. While multimodality treatment strategies for curative treatment of esophageal cancer, including the CROSS regimen (chemoradiotherapy followed by surgery) have increased median overall survival, the majority of patients develop recurrences after several months. Epithelial to mesenchymal transition (EMT) has been recently shown by our group to be one of the major underlying mechanisms of resistance to therapy. Paradoxically, therapeutic pressure of effective therapies such as the CROSS regimen are found to instruct a mesenchymal, resistant phenotype in models for EAC. In this study, the aim was to delineate the heterogeneity for the propensity to undergo EMT after chemoradiation and which mechanisms underpin this propensity.

Methods: A panel of 8 EAC cell lines (5 primary and 3 ATCC cell lines) were treated with chemoradiotherapy and ranked by their propensity to undergo EMT, based on morphology when EMT occurred and protein marker expression. Next, the cell line panel as well as 44 pre-treated esophageal biopsies were RNA-sequenced. Expression data of the cell line panel were linked to their ranked in vitro EMT response. By means of Leave-one-out cross validation with Ridge Regression, EMT score prediction in pre-treated biopsies was validated. Gene expression profiles were related to clinical outcome data to identify markers that associated with propensity for EMT in patients.

Results: In the panel of in vitro EAC models, a strong heterogeneity was observed for the propensity to EMT after chemoradiation. For each marker, Ridge regression analysis identified the top 50 highly correlating genes. Combining all positively correlating genes of days to EMT, NCAD and ZEB1, known key transcription factors of pluripotency including NANOG and OCT4 emerged. Expression of NANOG and OCT4 in pre-treatment biopsies was highly predictive for response to neoadjuvant chemoradiation, occurrence of recurrences, and survival in patients. Genetic perturbation by knockout and inhibition of NANOG and OCT4 reduced the onset of EMT and sensitized cells for chemoradiation.

Conclusions: In conclusion, we were able to identify patients who are disproportionally prone to develop EMT in response to chemoradiation. Moreover, stemness factors NANOG and OCT4 are crucial regulators in plasticity of EAC and are promising predictive markers in pre-treatment biopsies of patients. By targeting NANOG and OCT4 in vitro, cells were sensitized to chemoradiation, holding promise for stemness inhibition to prevent therapy resistance in EAC.

Citation Format: Amber Perenna van der Zalm, Mark P. Dings, Reimer Janssen, Peter Bailey, Jan Koster, Danny Zwijnenburg, Richard Volckmann, Cynthia Waasdorp, Jeroen Blokhuis, César Oyarce, Gerrit Hooijer, Sybren L. Meijer, Jan Paul Medema, Hanneke W. van Laarhoven, Maarten F. Bijlsma. Stemness factors nanog and oct4 contribute to epithelial-to-mesenchymal transition and are predictive for outcome in esophageal adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2616.

The impact of cancer treatment on quality of life in patients with pancreatic and periampullary cancer: a propensity score matched analysis

BACKGROUND

The impact of pancreatic and periampullary cancer treatment on health-related quality of life (HRQoL) is unclear.

METHODS

This study merged data from the Netherlands Cancer Registry with EORTC QLQ-C30 and -PAN26 questionnaires at baseline and three-months follow-up of pancreatic and periampullary cancer patients (2015-2018). Propensity score matching (1:3) of group without to group with treatment was performed. Linear mixed model regression analyses were performed to investigate the association between cancer treatment and HRQoL at follow-up.

RESULTS

After matching, 247 of 629 available patients remained (68 (27.5%) no treatment, 179 (72.5%) treatment). Treatment consisted of resection (n = 68 (27.5%)), chemotherapy only (n = 111 (44.9%)), or both (n = 40 (16.2%)). At follow-up, cancer treatment was associated with better global health status (Beta-coefficient 4.8, 95% confidence-interval 0.0-9.5) and less constipation (Beta-coefficient -7.6, 95% confidence-interval -13.8-1.4) compared to no cancer treatment. Median overall survival was longer for the cancer treatment group compared to the no treatment group (15.4 vs. 6.2 months, p < 0.001).

CONCLUSION

Patients undergoing treatment for pancreatic and periampullary cancer reported slight improvement in global HRQoL and less constipation at three months-follow up compared to patients without cancer treatment, while overall survival was also improved.

Preoperative serum ADAM12 levels as a stromal marker for overall survival and benefit of adjuvant therapy in patients with resected pancreatic and periampullary cancer

BACKGROUND

We evaluated the stroma marker A Disintegrin And Metalloprotease 12 (ADAM12) as a preoperative prognostic and treatment-predictive marker for overall survival (OS) in pancreatic ductal adenocarcinoma (PDAC) and periampullary cancers.

METHODS

Materials were derived from the prospective nationwide Dutch Pancreas Biobank (2015-2017). We included patients who underwent resection because of PDAC/periampullary cancer or non-invasive IPMN (control group) and had a preoperative serum sample available. ADAM12 levels were dichotomized using a pre-defined cut-off (316 pg/mL). Univariable and multivariable Cox regression analyses (backward selection) were performed.

RESULTS

Median ADAM12 levels were 161 (IQR 79-352) pg/mL in 215 PDAC and periampullary adenocarcinomas. High ADAM12 levels (>316 pg/mL) predicted poor OS in the total group of pancreatic and periampullary adenocarcinomas (P = 0.04), but not after adjustment. In distal cholangiocarcinoma (n = 33), high ADAM12 levels predicted poor OS in univariable analysis (P = 0.02), but not in PDAC (P = 0.63). PDAC patients (n = 135) with high ADAM12 levels benefited from adjuvant treatment (median OS 27 vs 14 months, P = 0.02), whereas those with low levels did not (21 vs 21 months, P = 0.87).

CONCLUSION

High circulating ADAM12 levels, as a proxy for activated stroma, predict survival benefit from adjuvant chemotherapy in PDAC, requiring validation in future studies.

Readily available biomarkers predict poor survival in metastatic pancreatic cancer

BACKGROUND

Identification of metastatic pancreatic cancer (mPC) patients with the worst prognosis could help to tailor therapy. We evaluated readily available biomarkers for the prediction of 90-day mortality in a nationwide cohort of mPC patients.

METHODS

Patients with synchronous mPC were included from the Netherlands Cancer Registry (2015-2017). Baseline CA19-9, albumin, CRP, LDH, CRP/albumin ratio, and (modified) Glasgow Prognostic Score ((m)GPS composed of albumin and CRP) were evaluated. Multivariable logistic regression analyses were performed to identify predictors of 90-day mortality. Prognostic value per predictor was quantified by Nagelkerke's partial R².

RESULTS

Overall, 4248 patients were included. Median overall survival was 2.2 months and 90-day mortality was 59.4% (n = 1629). All biomarkers predicted 90-day mortality in univariable analysis, and remained statistically significant after adjustment for clinically relevant factors and all other biomarkers (all p < 0.001). The prognostic value of the biomarkers combined was similar to WHO performance status. Patients who received chemotherapy had better outcomes than those who did not, regardless of biomarker levels.

CONCLUSIONS

In mPC patients, albumin, CA19-9, CRP, LDH, CRP/albumin ratio, and (m)GPS are prognostic for poor survival. Biomarkers did not predict response to chemotherapy. These readily available biomarkers can be used to better inform patients and to stratify in clinical trials.

Nationwide compliance with a multidisciplinary guideline on pancreatic cancer during 6-year follow-up

BACKGROUND

Compliance with national guidelines on pancreatic cancer management could improve patient outcomes. Early compliance with the Dutch guideline was poor. The aim was to assess compliance with this guideline during six years after publication.

MATERIALS AND METHODS

Nationwide guideline compliance was investigated for three subsequent time periods (2012-2013 vs. 2014-2015 vs. 2016-2017) in patients with pancreatic cancer using five quality indicators in the Netherlands Cancer Registry: 1) discussion in multidisciplinary team meeting (MDT), 2) maximum 3-week interval from final MDT to start of treatment, 3) preoperative biliary drainage when bilirubin >250 μmol/L, 4) use of adjuvant chemotherapy, and 5) chemotherapy for inoperable disease (non-metastatic and metastatic).

RESULTS

In total, 14 491 patients were included of whom 2290 (15.8%) underwent resection and 4561 (31.5%) received chemotherapy. Most quality indicators did not change over time: overall, 88.8% of patients treated with curative intent were discussed in a MDT, 42.7% were treated with curative intent within the 3-week interval, 62.7% with a resectable head tumor and bilirubin >250 μmol/L underwent preoperative biliary drainage, 57.2% received chemotherapy after resection, and 36.6% with metastatic disease received chemotherapy. Only use of chemotherapy for non-metastatic, non-resected disease improved over time (23.4% vs. 25.6% vs. 29.7%).

CONCLUSION

Nationwide compliance to five quality indicators for the guideline on pancreatic cancer management showed little to no improvement during six years after publication. Besides critical review of the current quality indicators, these outcomes may suggest that a nationwide implementation program is required to increase compliance to guideline recommendations.

Patient Satisfaction and Quality of Life Before and After Treatment of Pancreatic and Periampullary Cancer: A Prospective Multicenter Study

BACKGROUND

This study sought to assess patient satisfaction and quality of life (QoL) before and after treatment of pancreatic and periampullary cancer.

METHODS

We conducted a prospective multicenter study of patients treated for pancreatic and periampullary cancer. General patient satisfaction was measured using the EORTC satisfaction with care questionnaire (IN-PATSAT32) at baseline and 3 months after treatment initiation, with a 10-point change on the Likert scale considered clinically meaningful. QoL was measured using the EORTC Core Quality of Life Questionnaire (QLQ-C30). The influence of treatment (curative and palliative) on patient satisfaction and QoL was determined.

RESULTS

Of 100 patients, 71 completed follow-up questionnaires. General satisfaction with care decreased from 74.3 before treatment to 61.9 after treatment (P<.001), whereas global QoL increased from 68.4 to 71.4 (P=.39). Clinically meaningful reductions were also observed for the reported interpersonal skills of doctors (from 73.4 to 63.3) and exchange of information within the care team (from 63.5 to 52.5). Satisfaction scores were lower for patients treated with curative intent than for those treated with palliative intent regarding interpersonal skills of doctors (P=.01), information provision by doctors (P=.004), information provision by nurses (P=.02), availability of nurses (P=.004), exchange of information within the care team (P=.01), and hospital access (P=.02). In multivariable analysis, clinicopathologic or QoL factors were not independently associated with general patient satisfaction.

CONCLUSIONS

Satisfaction with care, but not QoL, decreased after pancreatic cancer treatment. Improvements in communication and interpersonal skills are needed to maintain patient satisfaction after treatment.

Comparison of short- and long-term outcomes between anatomical subtypes of resected biliary tract cancer in a Western high-volume center

BACKGROUND

Outcomes for the four anatomical subtypes of biliary tract carcinoma (BTC) - intrahepatic, perihilar and distal cholangiocarcinoma (ICC, PHCC, DCC) and gallbladder carcinoma (GBC) - are often combined. However, large cohorts comparing short- and long-term outcomes for the anatomical subtypes of BTC are lacking.

METHODS

All patients who underwent resection for pathology proven ICC, PHCC, DCC or GBC (2000-2016) from a single Western high-volume center were retrospectively selected. Clinicopathological characteristics, short- and long-term outcomes were compared between the four anatomical subtypes.

RESULTS

Overall, 361 patients with resected BTC were included (33 ICC, 135 PHCC, 148 DCC, 45 GBC). Clavien-Dindo grade III or higher complications were 48%, 51%, 36% and 8% (p < 0.001) and 90-day mortality was 9%, 15%, 3%, 4% (p < 0.001), for ICC, PHCC, DCC, GBC. Median overall survival was 37, 42, 29 and 41 months (p = 0.722), for ICC, PHCC, DCC, GBC. Five-year survival ranged between 29% and 37%. Anatomical subtype was not an independent predictor for overall survival.

CONCLUSION

In this large single-center cohort of resected BTC, major morbidity and 90-day mortality varied between the four anatomical subtypes of BTC, mainly due to differences in surgical approach However, a significant difference in overall survival was not detected.

Unsupervised class discovery in pancreatic ductal adenocarcinoma reveals cell-intrinsic mesenchymal features and high concordance between existing classification systems

Pancreatic ductal adenocarcinoma (PDAC) has the worst prognosis of all common cancers. However, divergent outcomes exist between patients, suggesting distinct underlying tumor biology. Here, we delineated this heterogeneity, compared interconnectivity between classification systems, and experimentally addressed the tumor biology that drives poor outcome. RNA-sequencing of 90 resected specimens and unsupervised classification revealed four subgroups associated with distinct outcomes. The worst-prognosis subtype was characterized by mesenchymal gene signatures. Comparative (network) analysis showed high interconnectivity with previously identified classification schemes and high robustness of the mesenchymal subtype. From species-specific transcript analysis of matching patient-derived xenografts we constructed dedicated classifiers for experimental models. Detailed assessments of tumor growth in subtyped experimental models revealed that a highly invasive growth pattern of mesenchymal subtype tumor cells is responsible for its poor outcome. Concluding, by developing a classification system tailored to experimental models, we have uncovered subtype-specific biology that should be further explored to improve treatment of a group of PDAC patients that currently has little therapeutic benefit from surgical treatment.

Added value of intra-operative ultrasound to determine the resectability of locally advanced pancreatic cancer following FOLFIRINOX chemotherapy (IMAGE): a prospective multicenter study

BACKGROUND

Determining the resectability of locally advanced pancreatic cancer (LAPC) after FOLFIRINOX chemotherapy is challenging because CT-scans cannot reliably assess vascular involvement. This study evaluates the added value of intra-operative ultrasound (IOUS) in LAPC following FOLFIRINOX induction chemotherapy.

METHODS

Prospective multicenter study in patients with LAPC who underwent explorative laparotomy with IOUS after FOLFIRINOX chemotherapy. Resectability was defined according to the National Comprehensive Cancer Network guidelines. IOUS findings were compared with preoperative CT-scans and pathology results.

RESULTS

CT-staging in 38 patients with LAPC after FOLFIRINOX chemotherapy defined 22 patients LAPC, 15 borderline resectable and one resectable. IOUS defined 19 patients LAPC, 13 borderline resectable and six resectable. In 12/38 patients, IOUS changed the resectability status including five patients from borderline resectable to resectable and five patients from LAPC to borderline resectable. Two patients were upstaged from borderline resectable to LAPC. Tumor diameters were significantly smaller upon IOUS (31.7 ± 9.5 mm versus 37.1 ± 10.0 mm, p = 0.001) and resectability varied significantly (p = 0.043). Ultimately, 20 patients underwent resection of whom 14 were evaluated as (borderline) resectable on CT-scan, and 17 on IOUS.

DISCUSSION

This prospective study demonstrates that IOUS may change the resectability status up to a third of patients with LAPC following FOLFIRINOX chemotherapy.

ITGA5 inhibition in pancreatic stellate cells attenuates desmoplasia and potentiates efficacy of chemotherapy in pancreatic cancer

Abundant desmoplastic stroma is the hallmark for pancreatic ductal adenocarcinoma (PDAC), which not only aggravates the tumor growth but also prevents tumor penetration of chemotherapy, leading to treatment failure. There is an unmet clinical need to develop therapeutic solutions to the tumor penetration problem. In this study, we investigated the therapeutic potential of integrin α5 (ITGA5) receptor in the PDAC stroma. ITGA5 was overexpressed in the tumor stroma from PDAC patient samples, and overexpression was inversely correlated with overall survival. In vitro, knockdown of ITGA5 inhibited differentiation of human pancreatic stellate cells (hPSCs) and reduced desmoplasia in vivo. Our novel peptidomimetic AV3 against ITGA5 inhibited hPSC activation and enhanced the antitumor effect of gemcitabine in a 3D heterospheroid model. In vivo, AV3 showed a strong reduction of desmoplasia, leading to decompression of blood vasculature, enhanced tumor perfusion, and thereby the efficacy of gemcitabine in co-injection and patient-derived xenograft tumor models.

Circulating tumor DNA quantity is related to tumor volume and both predict survival in metastatic pancreatic ductal adenocarcinoma

Circulating tumor DNA (ctDNA) is assumed to reflect tumor burden and has been suggested as a tool for prognostication and follow‐up in patients with metastatic pancreatic ductal adenocarcinoma (mPDAC). However, the prognostic value of ctDNA and its relation with tumor burden has yet to be substantiated, especially in mPDAC. In this retrospective analysis of prospectively collected samples, cell‐free DNA from plasma samples of 58 treatment‐naive mPDAC patients was isolated and sequenced using a custom‐made pancreatobiliary NGS panel. Pathogenic mutations were detected in 26/58 (44.8%) samples. Cross‐check with droplet digital PCR showed good agreement in Bland–Altman analysis (p = 0.217, nonsignificance indicating good agreement). In patients with liver metastases, ctDNA was more frequently detected (24/37, p < 0.001). Tumor volume (3D reconstructions from imaging) and ctDNA variant allele frequency (VAF) were correlated (Spearman's ρ = 0.544, p < 0.001). Median overall survival (OS) was 3.2 (95% confidence interval [CI] 1.6–4.9) versus 8.4 (95% CI 1.6–15.1) months in patients with detectable versus undetectable ctDNA (p = 0.005). Both ctDNA VAF and tumor volume independently predicted OS after adjustment for carbohydrate antigen 19.9 and treatment regimen (hazard ratio [HR] 1.05, 95% CI 1.01–1.09, p = 0.005; HR 1.00, 95% CI 1.01–1.05, p = 0.003). In conclusion, our study showed that ctDNA detection rates are higher in patients with larger tumor volume and liver metastases. Nevertheless, measurements may diverge and, thus, can provide complementary information. Both ctDNA VAF and tumor volume were strong predictors of OS.

What's new?

Circulating tumor DNA (ctDNA) attracts much interest as a possible prognostic tool for cancer. Here, the authors showed that the quantity of ctDNA correlated strongly with tumor volume in metastatic pancreatic ductal adenocarcinoma (mPDAC). They conducted a retrospective analysis using samples collected from 58 untreated mPDAC patients. For this study, the authors designed a pancreatobiliary NGS panel, which they used to test the patients’ cell‐free DNA, along with droplet digital PCR. Both ctDNA variant allele frequency and tumor volume predicted overall survival, they found.

Folic Acid and Vitamin B12 Supplementation and the Risk of Cancer: Long-term Follow-up of the B Vitamins for the Prevention of Osteoporotic Fractures (B-PROOF) Trial

BACKGROUND

Folic acid and vitamin B12 play key roles in one-carbon metabolism. Disruption of one-carbon metabolism may be involved in the risk of cancer. Our aim was to assess the long-term effect of supplementation with both folic acid and vitamin B12 on the incidence of overall cancer and on colorectal cancer in the B Vitamins for the Prevention of Osteoporotic Fractures (B-PROOF) trial.

METHODS

Long-term follow-up of B-PROOF trial participants (N = 2,524), a multicenter, double-blind randomized placebo-controlled trial designed to assess the effect of 2 to 3 years daily supplementation with folic acid (400 μg) and vitamin B12 (500 μg) versus placebo on fracture incidence. Information on cancer incidence was obtained from the Netherlands cancer registry (Integraal Kankercentrum Nederland), using the International Statistical Classification of Disease (ICD-10) codes C00-C97 for all cancers (except C44 for skin cancer), and C18-C20 for colorectal cancer.

RESULTS

Allocation to B vitamins was associated with a higher risk of overall cancer [171 (13.6%) vs. 143 (11.3%); HR 1.25; 95% confidence interval (CI), 1.00-1.53, P = 0.05]. B vitamins were significantly associated with a higher risk of colorectal cancer [43(3.4%) vs. 25(2.0%); HR 1.77; 95% CI, 1.08-2.90, P = 0.02].

CONCLUSIONS

Folic acid and vitamin B12 supplementation was associated with an increased risk of colorectal cancer.

IMPACT

Our findings suggest that folic acid and vitamin B12 supplementation may increase the risk of colorectal cancer. Further confirmation in larger studies and in meta-analyses combining both folic acid and vitamin B12 are needed to evaluate whether folic acid and vitamin B12 supplementation should be limited to patients with a known indication, such as a proven deficiency.

Abstract 872: IDH1-mutated cancer cells are sensitive to cisplatin and an IDH1-mutant inhibitor counteracts this sensitivity

Isocitrate dehydrogenase 1 (IDH1) is mutated in various types of human cancer and predicts improved response to treatment with irradiation or chemotherapy. Mutated IDH1 enzymes catalyze neomorphic conversion of α-ketoglutarate (α-KG) to the oncometabolite D-2-hydroxyglutarate (D-2HG) with concomitant consumption of NADPH, resulting in decreased reducing power needed for detoxification of e.g. reactive oxygen species (ROS). We report that a small-molecule inhibitor of IDH1-mutation (IDH1MUT) that is being investigated for cancer therapy may limit efficacy of treatment when co-administered with cisplatin.

In the present study, we investigated whether the efficacy of treatment with cisplatin, which is a widely-used chemotherapeutic agent, induces DNA strand breaks and oxidative damage in IDH1MUT cancer cells. We found that exposure to cisplatin induced higher levels of ROS, DNA double-strand breaks, and cell death in IDH1MUT cancer cells as compared to IDH1 wild-type (IDH1WT) cancer cells. Besides these cytotoxic effects, mechanistic investigations revealed that cisplatin treatment causes dose-dependent reduction of oxygen consumption and thus the oxidative respiration in lDH1MUT cells and not in lDH1WT cells, which was accompanied by disturbed mitochondrial proteostasis and impaired mitochondrial activity. These effects were abolished by the IDH1MUT inhibitor AGI-5198 and were recapitulated by treatment with D-2HG. Thus, our study shows that altered oxidative stress responses due to a vulnerable oxidative metabolism underlie the sensitivity of IDH1MUT cancer cells to cisplatin. Furthermore, our data offer an explanation for the relatively longer survival of patients with IDH1-mutated tumors, and imply that administration of IDH1MUT inhibitors in these patients limit efficacy of cisplatin treatment.

Citation Format: Mohammed Khurshed, Remco J. Molenaar, Johanna W. Wilmink, Hanneke W. van Laarhoven, Cornelis J. van Noorden. IDH1-mutated cancer cells are sensitive to cisplatin and an IDH1-mutant inhibitor counteracts this sensitivity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 872.

Extracellular Influences: Molecular Subclasses and the Microenvironment in Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) is the most prevalent form of pancreatic cancer and carries the worst prognosis of all common cancers. Five-year survival rates have not surpassed 6% for some decades and this lack of improvement in outcome urges a better understanding of the PDAC-specific features which contribute to this poor result. One of the most defining features of PDAC known to contribute to its progression is the abundance of non-tumor cells and material collectively known as the stroma. It is now well recognized that the different non-cancer cell types, signalling molecules, and mechanical properties within a tumor can have both tumor-promoting as well as –inhibitory effects. However, the net effect of this intratumour heterogeneity is not well understood. Heterogeneity in the stromal makeup between patients is even less well established. Such intertumour heterogeneity is likely to be affected by the relative contributions of individual stromal constituents, but how these contributions exactly relate to existing classifications that demarcate intertumour heterogeneity in PDAC is not fully known. In this review, we give an overview of the available evidence by delineating the elements of the PDAC stroma and their contribution to tumour growth. We do so by interpreting the heterogeneity at the gene expression level in PDAC, and how stromal elements contribute to, or interconnect, with this.

Abstract 4141: Phosphoproteome networks display consistent hyperactive kinase activity in pancreatic cancer: evidence for new therapeutic options

Introduction Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal disease due to its aggressive nature. Patients typically present with distant metastases, at which point cytotoxic agents can extend life expectancy by several months at most. Large-scale phosphoproteomics complements our knowledge obtained from genomics and transcriptomics as it provides information on which proteins and kinases are phosphorylated, thereby implicating pathways that are activated. This approach in cancer research may lead to improved patient selection for treatment with tyrosine kinase inhibitors (TKI). This study is the first to employ phosphotyrosine-based phosphoproteomics on three different preclinical PDAC models as well as patient tumor tissues to understand the aggressive nature of this disease and identify new drug targets.

Approach We performed phosphoproteomics on a panel of 11 PDAC cell lines, 7 primary cell cultures, 10 patient-derived xenografts (PDX) and 16 fresh frozen human tumor tissues. Tyrosine phosphopeptides were enriched via immunoprecipitation and phosphopeptides were analyzed by high-resolution nano-LC mass spectrometry.

Results Using phosphotyrosine-based phosphoproteomics, we identified a total of 1723 tyrosine phosphorylated proteins and 138 phosphorylated kinases, representing 27% of the kinome. The reproducibility of our workflow was very high, with Pearson correlation coefficients of r = 0.937 for technical replicates of cell lines and r = 0.876 for biological replicates of tumors. In our cell line panels, multiple kinases were commonly highly phosphorylated (e.g. PTK2, EPHA2, EGFR and MET). Functional testing of PTK2 by using TKI defactinib in primary cell lines with high phosphorylation resulted in inhibition of proliferation and migration in vitro. Inhibition of EPHA2 by shRNAs resulted in reduced proliferation in vitro. To validate the relevance of these candidate target proteins in vivo, the tyrosine phosphoproteome of PDXs and human tumors was analyzed. In these tumors, kinase activity analysis based on kinase phosphorylation levels and kinase-substrate networks validated these common active nodes in the majority of these tumors.

Conclusion Our extensive tyrosine phosphoproteome analysis spanning a wide range of PDAC models revealed high phosphorylation levels of multiple kinases. Interestingly, the phosphorylated kinase profiles of tumors and cell lines did not show as much heterogeneity as expected, taken into account the existence of biological subtypes in PDAC identified by others via transcriptomics. The aggressive biology of this disease may be correlated with the consistent activation of multiple pathways, some of which we have shown to be targetable in vitro. This study prompts further validation and prognostic evaluation of the identified active kinases to improve treatment of PDAC.

Citation Format: Tessa Y. Le Large, Maarten F. Bijlsma, Btissame El Hassouni, Nicolla Funel, Nicole C. van Grieken, Helene Damhofer, Jaco C. Knol, Sander R. Piersma, Thang V. Pham, Henk M. Verheul, Hanneke W. van Laarhoven, Geert Kazemier, Elisa Giovannetti, Connie R. Jimenez. Phosphoproteome networks display consistent hyperactive kinase activity in pancreatic cancer: evidence for new therapeutic options [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 4141. doi:10.1158/1538-7445.AM2017-4141

Stromal SPOCK1 supports invasive pancreatic cancer growth

Pancreatic ductal adenocarcinoma (PDAC) is marked by an abundant stromal deposition. This stroma is suspected to harbor both tumor‐promoting and tumor‐suppressing properties. This is underscored by the disappointing results of stroma targeting in clinical studies. Given the complexity of tumor–stroma interaction in PDAC, there is a need to identify the stromal proteins that are predominantly tumor‐promoting. One possible candidate is SPOCK1 that we previously identified in a screening effort in PDAC. We extensively mined PDAC gene expression datasets, and used species‐specific transcript analysis in mixed‐species models for PDAC to study the patterns and driver mechanisms of SPOCK1 expression in PDAC. Advanced organotypic coculture models with primary patient‐derived tumor cells were used to further characterize the function of this protein. We found SPOCK1 expression to be predominantly stromal. Expression of SPOCK1 was associated with poor disease outcome. Coculture and ligand stimulation experiments revealed that SPOCK1 is expressed in response to tumor cell‐derived transforming growth factor‐beta. Functional assessment in cocultures demonstrated that SPOCK1 strongly affects the composition of the extracellular collagen matrix and by doing so, enables invasive tumor cell growth in PDAC. By defining the expression pattern and functional properties of SPOCK1 in pancreatic cancer, we have identified a stromal mediator of extracellular matrix remodeling that indirectly affects the aggressive behavior of PDAC cells. The recognition that stromal proteins actively contribute to the protumorigenic remodeling of the tumor microenvironment should aid the design of future clinical studies to target specific stromal targets.

Induction Chemotherapy Followed by Resection or Irreversible Electroporation in Locally Advanced Pancreatic Cancer (IMPALA): A Prospective Cohort Study

BACKGROUND

Following induction chemotherapy, both resection or irreversible electroporation (IRE) may further improve survival in patients with locally advanced pancreatic cancer (LAPC). However, prospective studies combining these strategies are currently lacking, and available studies only report on subgroups that completed treatment. This study aimed to determine the applicability and outcomes of resection and IRE in patients with nonprogressive LAPC after induction chemotherapy.

METHODS

This was a prospective, single-center cohort study in consecutive patients with LAPC (September 2013 to March 2015). All patients were offered 3 months of induction chemotherapy (FOLFIRINOX or gemcitabine depending on performance status), followed by exploratory laparotomy for resection or IRE in patients with Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 nonprogressive, IRE-eligible tumors.

RESULTS

Of 132 patients with LAPC, 70% (n = 93) started with chemotherapy (46% [n = 61] FOLFIRINOX). After 3 months, 59 patients (64%) had nonprogressive disease, of whom 36 (27% of the entire cohort) underwent explorative laparotomy, resulting in 14 resections (11% of the entire cohort, 39% of the explored patients) and 15 IREs (11% of the entire cohort, 42% of the explored patients). After laparotomy, 44% (n = 16) of patients had Clavien-Dindo grade 3 or higher complications, and 90-day all-cause mortality was 11% (n = 4). With a median follow-up of 24 months, median overall survival after resection, IRE, and for all patients with nonprogressive disease without resection/IRE (n = 30) was 34, 16, and 15 months, respectively. The resection rate in 61 patients receiving FOLFIRINOX treatment was 20%.

CONCLUSION

Induction chemotherapy followed by IRE or resection in nonprogressive LAPC led to resection or IRE in 22% of all-comers, with promising survival rates after resection but no apparent benefit of IRE, despite considerable morbidity. Registered at Netherlands Trial Register (NTR4230).

The use of adjuvant chemotherapy for pancreatic cancer varies widely between hospitals: a nationwide population-based analysis

Adjuvant chemotherapy after pancreatoduodenectomy for pancreatic cancer is currently considered standard of care. In this nationwide study, we investigated which characteristics determine the likelihood of receiving adjuvant chemotherapy and its effect on overall survival. The data were obtained from the Netherlands Cancer Registry. All patients alive 90 days after pancreatoduodenectomy for M₀‐pancreatic cancer between 2008 and 2013 in the Netherlands were included in this study. The likelihood to receive adjuvant chemotherapy was analyzed by multilevel logistic regression analysis and differences in time‐to‐first‐chemotherapy were tested for significance by Mann–Whitney U test. Overall survival was assessed by Kaplan–Meier method and Cox regression analysis. Of the 1195 patients undergoing a pancreatoduodenectomy for pancreatic cancer, 642 (54%) patients received adjuvant chemotherapy. Proportions differed significantly between the 19 pancreatic centers, ranging from 26% to 74% (P < 0.001). Median time‐to‐first‐chemotherapy was 6.7 weeks and did not differ between centers. Patients with a higher tumor stage, younger age, and diagnosed more recently were more likely to receive adjuvant treatment. The 5‐year overall survival was significantly prolonged in patients treated with adjuvant chemotherapy—23% versus 17%, log‐rank = 0.01. In Cox regression analysis, treatment with adjuvant chemotherapy significantly prolonged survival compared with treatment without adjuvant chemotherapy. The finding that elderly patients and patients with a low tumor stage are less likely to undergo treatment needs further attention, especially since adjuvant treatment is known to prolong survival in most of these patients.

Developing a core set of patient-reported outcomes in pancreatic cancer: A Delphi survey

BACKGROUND

Patient-reported outcomes (PROs) are amongst the most relevant outcome measures in pancreatic cancer care and research. However, it is unknown which out of the numerous PROs are most important to patients and health care professionals (HCPs) in this setting. The aim of this study was to identify a core set of PROs to be incorporated in a nationwide prospective multidisciplinary pancreatic cancer registry.

PATIENTS AND METHODS

We performed a two-round Delphi survey among 150 patients diagnosed with pancreatic or periampullary cancer (treated either with curative intent or in palliative setting) and 78 HCPs (surgeons, medical oncologists, gastroenterologists, radiotherapists, nurses, and dietitians) in The Netherlands. In round 1, participants were invited to rate the importance of 53 PROs, which were extracted from 17 different PRO measures and grouped into global domains, on a 1-9 Likert scale. PROs rated as very important (score 7-9) by the majority (≥ 80%) of curative and/or palliative patients as well as HCPs were considered sufficiently important to be incorporated in the core set. PROs not fulfilling these criteria in round 1 were presented again to the participants in round 2 along with individual and group feedback.

RESULTS

A total of 97 patients (94%) in curative-intent setting, 38 patients (81%) in palliative setting and 73 HCPs (94%) completed both rounds 1 and 2. After the first round, 7 PROs were included in the core set: general quality of life, general health, physical ability, satisfaction with caregivers, satisfaction with services and care organisation, coping and defecation. After the second round, 10 additional PROs were added: appetite, ability to work/do usual activities, medication use, weight changes, fatigue, negative feelings, positive feelings, fear of recurrence, relationship with partner/family, and pancreatic enzyme replacement therapy use.

CONCLUSION

This study provides a core set of PROs selected by patients and HCPs, which may be incorporated in pancreatic cancer care and research. Validation outside the Dutch context is recommended for generalisation and use in international studies.

Establishment of patient-derived xenograft models and cell lines for malignancies of the upper gastrointestinal tract

Background

The upper gastrointestinal tract is home to some of most notorious cancers like esophagogastric and pancreatic cancer. Several factors contribute to the lethality of these tumors, but one that stands out for both tumor types is the strong inter- as well as intratumor heterogeneity. Unfortunately, genetic tumor models do not match this heterogeneity, and for esophageal cancer no adequate genetic models exist. To allow for an improved understanding of these diseases, tissue banks with sufficient amount of samples to cover the extent of diversity of human cancers are required. Additionally, xenograft models that faithfully mimic and span the breadth of human disease are essential to perform meaningful functional experiments.

Methods

We describe here the establishment of a tissue biobank, patient derived xenografts (PDXs) and cell line models of esophagogastric and pancreatic cancer patients. Biopsy material was grafted into immunocompromised mice and PDXs were used to establish primary cell cultures to perform functional studies. Expression of Hedgehog ligands in patient tumor and matching PDX was assessed by immunohistochemical staining, and quantitative real-time PCR as well as flow cytometry was used for cultured cells. Cocultures with Hedgehog reporter cells were performed to study paracrine signaling potency. Furthermore, SHH expression was modulated in primary cultures using lentiviral mediated knockdown.

Results

We have established a panel of 29 PDXs from esophagogastric and pancreatic cancers, and demonstrate that these PDXs mirror several of the (immuno)histological and biochemical characteristics of the original tumors. Derived cell lines can be genetically manipulated and used to further study tumor biology and signaling capacity. In addition, we demonstrate an active (paracrine) Hedgehog signaling mode by both tumor types, the magnitude of which has not been compared directly in previous studies.

Conclusions

Our established PDXs and their matching primary cell lines retain important characteristics seen in the original tumors, and this should enable future studies to address the responses of these tumors to different treatment modalities, but also help in gaining mechanistic insight in how some tumors respond to certain regimens and others do not.

Electronic supplementary material

The online version of this article (doi:10.1186/s12967-015-0469-1) contains supplementary material, which is available to authorized users.

Cost effectiveness of primary pegfilgrastim prophylaxis in patients with breast cancer at risk of febrile neutropenia

PURPOSE

Guidelines advise primary granulocyte colony-stimulating factor (G-CSF) prophylaxis during chemotherapy if risk of febrile neutropenia (FN) is more than 20%, but this comes with considerable costs. We investigated the incremental costs and effects between two treatment strategies of primary pegfilgrastim prophylaxis.

METHODS

Our economic evaluation used a health care perspective and was based on a randomized study in patients with breast cancer with increased risk of FN, comparing primary G-CSF prophylaxis throughout all chemotherapy cycles (G-CSF 1-6 cycles) with prophylaxis during the first two cycles only (G-CSF 1-2 cycles). Primary outcome was cost effectiveness expressed as costs per patient with episodes of FN prevented.

RESULTS

The incidence of FN increased from 10% in the G-CSF 1 to 6 cycles study arm (eight of 84 patients) to 36% in the G-CSF 1 to 2 cycles study arm (30 of 83 patients), whereas the mean total costs decreased from € 20,658 (95% CI, € 20,049 to € 21,247) to € 17,168 (95% CI € 16,239 to € 18,029) per patient, respectively. Chemotherapy and G-CSF determined 80% of the total costs. As expected, FN-related costs were higher in the G-CSF 1 to 2 cycles arm. The incremental cost effectiveness ratio for the G-CSF 1 to 6 cycles arm compared with the G-CSF 1 to 2 cycles arm was € 13,112 per patient with episodes of FN prevented.

CONCLUSION

We conclude that G-CSF prophylaxis throughout all chemotherapy cycles is more effective, but more costly, compared with prophylaxis limited to the first two cycles. Whether G-CSF prophylaxis throughout all chemotherapy cycles is considered cost effective depends on the willingness to pay per patient with episodes of FN prevented.

Primary granulocyte colony-stimulating factor prophylaxis during the first two cycles only or throughout all chemotherapy cycles in patients with breast cancer at risk for febrile neutropenia

PURPOSE

Early breast cancer is commonly treated with anthracyclines and taxanes. However, combining these drugs increases the risk of myelotoxicity and may require granulocyte colony-stimulating factor (G-CSF) support. The highest incidence of febrile neutropenia (FN) and largest benefit of G-CSF during the first cycles of chemotherapy lead to questions about the effectiveness of continued use of G-CSF throughout later cycles of chemotherapy.

PATIENTS AND METHODS

In a multicenter study, patients with breast cancer who were considered fit enough to receive 3-weekly polychemotherapy, but also had > 20% risk for FN, were randomly assigned to primary G-CSF prophylaxis during the first two chemotherapy cycles only (experimental arm) or to primary G-CSF prophylaxis throughout all chemotherapy cycles (standard arm). The noninferiority hypothesis was that the incidence of FN would be maximally 7.5% higher in the experimental compared with the standard arm.

RESULTS

After inclusion of 167 eligible patients, the independent data monitoring committee advised premature study closure. Of 84 patients randomly assigned to G-CSF throughout all chemotherapy cycles, eight (10%) experienced an episode of FN. In contrast, of 83 patients randomly assigned to G-CSF during the first two cycles only, 30 (36%) had an FN episode (95% CI, 0.13 to 0.54), with a peak incidence of 24% in the third cycle (ie, first cycle without G-CSF prophylaxis).

CONCLUSION

In patients with early breast cancer at high risk for FN, continued use of primary G-CSF prophylaxis during all chemotherapy cycles is of clinical relevance and thus cannot be abandoned.

Survival after recurrent esophageal carcinoma has not improved over the past 18 years

BACKGROUND

Numerous patients will develop recurrent disease after esophagectomy for esophageal carcinoma (EC). In literature, survival after recurrent EC is poor with 6-8 months. In these studies, diagnostic imaging during follow-up (FU) is routinely performed. In the Netherlands, routine imaging is not part of FU and only performed on indication. The aim of this study was to determine survival after diagnosis of recurrent disease in patients after esophagectomy without routine imaging during FU.

METHODS

All EC patients who underwent esophagectomy between 1993 and 2010 were included and followed for clinical evidence of recurrent EC. Location, symptoms, diagnosis, and treatment of recurrent disease were registered. Pattern of recurrence was compared between patients who underwent neoadjuvant therapy and patients who underwent surgery alone. Survival after detection of recurrence was determined in all patients and related to the year of surgery.

RESULTS

A total of 493 of 1,088 patients (45 %) who underwent esophagectomy between 1993 and 2010 developed recurrent disease. Median interval between esophagectomy and recurrence was 10.5 months. Within the first 2 years after surgery, 33 % of patients developed recurrent EC. The majority of patients (51 %) were diagnosed with distant metastases. Locoregional recurrence occurred significantly less often among patients who underwent neoadjuvant therapy (6 vs 16 %, p = .017). Median survival after diagnosis of recurrent disease was 3 months. No relation was observed between the year of surgery and survival after recurrent disease (p = .931).

CONCLUSIONS

Survival after recurrent EC in patients who undergo FU without routine imaging after esophagectomy is approximately 3 months and has not improved over the past 18 years.