Hackert, Thilo

Abstract Background Some centres advocate preoperative radiotherapy in patients with pancreatic cancer and arterial involvement despite a lack of Level 1 evidence on survival benefit. Although it has been suggested that preoperative radiotherapy may increase the risk of postpancreatectomy haemorrhage (PPH) and morbidity, evidence is again lacking. This study investigated the association between preoperative radiotherapy and both PPH and major morbidity following arterial divestment/resection during pancreatic adenocarcinoma resection after chemotherapy. Methods Consecutive patients diagnosed with pancreatic adenocarcinoma and > 180° arterial involvement who were treated with preoperative chemotherapy with or without radiotherapy followed by pancreatic resection with arterial divestment/resection were included in the study. Logistic regression analyses including propensity score-based overlap weighting were performed to investigate associations between radiotherapy and in-hospital PPH grade B/C and major morbidity, expressed as adjusted risk differences (aRDs). Results Overall, 246 patients undergoing pancreatic resection with arterial resection (169, 69%) or divestment (77, 31%) were included. Radiotherapy was not associated with PPH (aRD 6%; 95% confidence interval (c.i.) −3 to 14), regardless of arterial divestment (aRD 3%; 95% c.i. −5 to 11) or arterial resection (aRD 12%; 95% c.i. 1 to 23; Pinteraction = 0.189). Radiotherapy was associated with a 14% (95% c.i. 2 to 25) higher risk of major morbidity, especially after arterial resection (aRD 27%; 95% c.i. 11 to 43) compared with arterial divestment (aRD −12%; 95% c.i. −35 to 11; Pinteraction = 0.006) and after external beam radiotherapy (aRD 21%; 95% c.i. 8 to 32) compared with stereotactic body radiotherapy (aRD −12%; 95% c.i. −27 to 6; Pinteraction = 0.0001). Ninety-day mortality was increased, albeit not significantly, after preoperative radiotherapy (10 (8%) versus 3 (3%) deaths with versus without preoperative radiotherapy, respectively; P = 0.067). Conclusions Radiotherapy before resection of pancreatic cancer with > 180° arterial involvement was associated with an increased risk of postoperative major morbidity when arterial resection, but not arterial divestment, was performed. This risk should be taken into account when considering preoperative radiotherapy in patients who may require arterial resection.

Abstract Background: There are conflicting data on whether nonalcoholic fatty liver disease (NAFLD) is associated with susceptibility to pancreatic cancer. Using Mendelian randomization (MR), we investigated the relationship between genetic predisposition to NAFLD and risk for pancreatic cancer. Methods: Data from genome-wide association studies (GWAS) within the Pancreatic Cancer Cohort Consortium (PanScan; cases n = 5,090, controls n = 8,733) and the Pancreatic Cancer Case Control Consortium (PanC4; cases n = 4,163, controls n = 3,792) were analyzed. We used data on 68 genetic variants with four different MR methods [inverse variance weighting (IVW), MR-Egger, simple median, and penalized weighted median] separately to predict genetic heritability of NAFLD. We then assessed the relationship between each of the four MR methods and pancreatic cancer risk, using logistic regression to calculate ORs and 95% confidence intervals (CI), adjusting for PC risk factors, including obesity and diabetes. Results: No association was found between genetically predicted NAFLD and pancreatic cancer risk in the PanScan or PanC4 samples [e.g., PanScan, IVW OR, 1.04; 95% confidence interval (CI), 0.88–1.22; MR-Egger OR, 0.89; 95% CI, 0.65–1.21; PanC4, IVW OR, 1.07; 95% CI, 0.90–1.27; MR-Egger OR, 0.93; 95% CI, 0.67–1.28]. None of the four MR methods indicated an association between genetically predicted NAFLD and pancreatic cancer risk in either sample. Conclusions: Genetic predisposition to NAFLD is not associated with pancreatic cancer risk. Impact: Given the close relationship between NAFLD and metabolic conditions, it is plausible that any association between NAFLD and pancreatic cancer might reflect host metabolic perturbations (e.g., obesity, diabetes, or metabolic syndrome) and does not necessarily reflect a causal relationship between NAFLD and pancreatic cancer.

Abstract Background: Whether circulating polyunsaturated fatty acid (PUFA) levels are associated with pancreatic cancer risk is uncertain. Mendelian randomization (MR) represents a study design using genetic instruments to better characterize the relationship between exposure and outcome. Methods: We utilized data from genome-wide association studies within the Pancreatic Cancer Cohort Consortium and Pancreatic Cancer Case–Control Consortium, involving approximately 9,269 cases and 12,530 controls of European descent, to evaluate associations between pancreatic cancer risk and genetically predicted plasma n-6 PUFA levels. Conventional MR analyses were performed using individual-level and summary-level data. Results: Using genetic instruments, we did not find evidence of associations between genetically predicted plasma n-6 PUFA levels and pancreatic cancer risk [estimates per one SD increase in each PUFA-specific weighted genetic score using summary statistics: linoleic acid odds ratio (OR) = 1.00, 95% confidence interval (CI) = 0.98–1.02; arachidonic acid OR = 1.00, 95% CI = 0.99–1.01; and dihomo-gamma-linolenic acid OR = 0.95, 95% CI = 0.87–1.02]. The OR estimates remained virtually unchanged after adjustment for covariates, using individual-level data or summary statistics, or stratification by age and sex. Conclusions: Our results suggest that variations of genetically determined plasma n-6 PUFA levels are not associated with pancreatic cancer risk. Impact: These results suggest that modifying n-6 PUFA levels through food sources or supplementation may not influence risk of pancreatic cancer.

Abstract Registry-based epidemiologic studies suggest associations between chronic inflammatory intestinal diseases and pancreatic ductal adenocarcinoma (PDAC). As genetic susceptibility contributes to a large proportion of chronic inflammatory intestinal diseases, we hypothesize that the genomic regions surrounding established genome-wide associated variants for these chronic inflammatory diseases are associated with PDAC. We examined the association between PDAC and genomic regions (±500 kb) surrounding established common susceptibility variants for ulcerative colitis, Crohn's disease, inflammatory bowel disease, celiac disease, chronic pancreatitis, and primary sclerosing cholangitis. We analyzed summary statistics from genome-wide association studies data for 8,384 cases and 11,955 controls of European descent from two large consortium studies using the summary data-based adaptive rank truncated product method to examine the overall association of combined genomic regions for each inflammatory disease group. Combined genomic susceptibility regions for ulcerative colitis, Crohn disease, inflammatory bowel disease, and chronic pancreatitis were associated with PDAC at P values < 0.05 (0.0040, 0.0057, 0.011, and 3.4 × 10−6, respectively). After excluding the 20 PDAC susceptibility regions (±500 kb) previously identified by GWAS, the genomic regions for ulcerative colitis, Crohn disease, and inflammatory bowel disease remained associated with PDAC (P = 0.0029, 0.0057, and 0.0098, respectively). Genomic regions for celiac disease (P = 0.22) and primary sclerosing cholangitis (P = 0.078) were not associated with PDAC. Our results support the hypothesis that genomic regions surrounding variants associated with inflammatory intestinal diseases, particularly, ulcerative colitis, Crohn disease, inflammatory bowel disease, and chronic pancreatitis are associated with PDAC. Significance: The joint effects of common variants in genomic regions containing susceptibility loci for inflammatory bowel disease and chronic pancreatitis are associated with PDAC and may provide insights to understanding pancreatic cancer etiology.