Aimee L. Lucas

Pancreatic ductal adenocarcinoma: Risk factors, screening, and early detection

Pancreatic cancer is the fourth most common cause of cancer-related deaths in the United States, with over 38000 deaths in 2013. The opportunity to detect pancreatic cancer while it is still curable is dependent on our ability to identify and screen high-risk populations before their symptoms arise. Risk factors for developing pancreatic cancer include multiple genetic syndromes as well as modifiable risk factors. Genetic conditions include hereditary breast and ovarian cancer syndrome, Lynch Syndrome, familial adenomatous polyposis, Peutz-Jeghers Syndrome, familial atypical multiple mole melanoma syndrome, hereditary pancreatitis, cystic fibrosis, and ataxia-telangiectasia; having a genetic predisposition can raise the risk of developing pancreatic cancer up to 132-fold over the general population. Modifiable risk factors, which include tobacco exposure, alcohol use, chronic pancreatitis, diet, obesity, diabetes mellitus, as well as certain abdominal surgeries and infections, have also been shown to increase the risk of pancreatic cancer development. Several large-volume centers have initiated such screening protocols, and consensus-based guidelines for screening high-risk groups have recently been published. The focus of this review will be both the genetic and modifiable risk factors implicated in pancreatic cancer, as well as a review of screening strategies and their diagnostic yields.

High Prevalence of BRCA1 and BRCA2 Germline Mutations With Loss of Heterozygosity In a Series of Resected Pancreatic Adenocarcinoma and Other Neoplastic Lesions

PURPOSE Pancreatic ductal adenocarcinoma (PDAC) is associated with the breast ovarian cancer syndrome (BRCA1/BRCA2) mutations. It is unknown if this association is causal. EXPERIMENTAL DESIGN This is a single-site study of patients who underwent surgical pancreatic tumor resection and self-identified as Ashkenazi Jewish. DNA from normal pancreatic tissue was genotyped for the three Ashkenazi Jewish BRCA1/2 founder mutations BRCA1 185delAG, BRCA1 5382insC, and BRCA2 6174delT, and loss of heterozygosity (LOH) was determined by sequencing DNA from microdissected tumor. When additional tumor tissue was available, p53 immunohistochemistry (IHC) was conducted. RESULTS Thirty-seven patients underwent surgery for PDAC, seven for intraductal papillary mucinous neoplasm (IPMN), and 19 for other diseases. A high prevalence of BRCA1/2 mutations was found in the surgical cohort (12/63; 19.0%; P < 0.001), PDAC cohort (8/37; 21.6%; P < 0.001), and IPMN cohort (2/7; 28.6%; P = .01) compared with published control mutation frequency. A high prevalence of BRCA1 185delAG (8.1%; P < 0.001) and BRCA2 6174delT (10.8%; P < 0.001) in Ashkenazi Jewish patients with PDAC was shown. BRCA1/2 LOH was found in 2 of 4 BRCA1-associated PDACs and 3 of 4 BRCA2-associated PDACs. Positive p53 IHC was found in 5 of 8 BRCA1/2 PDACs. CONCLUSIONS We show a high prevalence of BRCA1/2 mutations with LOH in an Ashkenazi Jewish cohort of surgically resected PDAC and neoplastic lesions, suggesting that these germline mutations are causal in selected individuals.

MicroRNA in pancreatic ductal adenocarcinoma and its precursor lesions

Pancreatic ductal adenocarcinoma (PDAC) is the 4(th) deadliest cancer in the United States, due to its aggressive nature, late detection, and resistance to chemotherapy. The majority of PDAC develops from 3 precursor lesions, pancreatic intraepithelial lesions (PanIN), intraductual papillary mucinous neoplasm (IPMN), and mucinous cystic neoplasm. Early detection and surgical resection can increase PDAC 5-year survival rate from 6% for Stage IV to 50% for Stage I. To date, there are no reliable biomarkers that can detect PDAC. MicroRNAs (miRNA) are small noncoding RNAs (18-25 nucleotides) that regulate gene expression by affecting translation of messenger RNA (mRNA). A large body of evidence suggests that miRNAs are dysregulated in various types of cancers. MiRNA has been profiled as a potential biomarker in pancreatic tumor tissue, blood, cyst fluid, stool, and saliva. Four miRNA biomarkers (miR-21, miR-155, miR-196, and miR-210) have been consistently dysregulated in PDAC. MiR-21, miR-155, and miR-196 have also been dysregulated in IPMN and PanIN lesions suggesting their use as early biomarkers of this disease. In this review, we explore current knowledge of miRNA sampling, miRNA dysregulation in PDAC and its precursor lesions, and advances that have been made in using miRNA as a biomarker for PDAC and its precursor lesions.

BRCA1 and BRCA2 germline mutations are frequently demonstrated in both high‐risk pancreatic cancer screening and pancreatic cancer cohorts

Approximately 10% of pancreatic ductal adenocarcinoma (PDAC) is due to a genetic predisposition, including the breast and ovarian cancer syndrome germline mutations BRCA1 and BRCA2. Knowledge of specific genetic mutations predisposing to PDAC may enable risk stratification, early detection, and the development of effective screening and surveillance programs. In the current study, the authors attempted to determine the diagnostic yield of testing for BRCA1/2 germline mutations in a PDAC screening cohort and a PDAC cohort referred for genetic testing.

Metformin Improves Survival in Patients with Pancreatic Ductal Adenocarcinoma and Pre-Existing Diabetes: A Propensity Score Analysis

OBJECTIVES:Pancreatic ductal adenocarcinoma (PDAC) remains a highly lethal disease. Diabetes mellitus (DM) is both a risk factor for and a sequela of PDAC. Metformin is a commonly prescribed biguanide oral hypoglycemic used for the treatment of type II DM. We investigated whether metformin use before PDAC diagnosis affected survival of patients with DM, controlling confounders such as diabetic severity.METHODS:We used the Surveillance, Epidemiology, and End Results registry (SEER)-Medicare linked database to identify patients with PDAC diagnosed between 2007 and 2011. The diabetic TO comorbidity severity index (DCSI) controlled for DM severity. Inverse propensity weighted Cox Proportional-Hazard Models assessed the association between metformin use and overall survival adjusting for relevant confounders.RESULTS:We identified 1,916 patients with PDAC and pre-existing DM on hypoglycemic medications at least 1 year before cancer diagnosis. Of these, 1,098 (57.3%) were treated with metformin and 818 (42.7%) with other DM medications. Mean survival for those on metformin was 5.5 months compared with 4.2 months for those not on metformin (P<0.01). After adjusting for confounders including DCSI, Charlson score, and chronic kidney disease (CKD), patients on metformin had a 12% decreased risk of mortality compared with patients on other medications (hazard ratio (HR): 0.88, 95% confidence interval (CI): 0.81–0.96, P<0.01). In stratified analysis, differences persisted regardless of the Charlson score, the DCSI score, the presence of kidney disease, or the use of insulin/other hypoglycemic medications (P<0.01 for all).CONCLUSIONS:Metformin is associated with increased survival among diabetics with PDAC. If confirmed in a prospective study, then these results suggest a possible role for metformin as an adjunct to chemotherapy among diabetics with PDAC.

Evidence for treatment and survival disparities by age in pancreatic adenocarcinoma: a population-based analysis.

Objectives Studies demonstrate safety and survival benefits of surgical resection in older individuals with pancreatic adenocarcinoma. We investigated treatment disparities by age. Methods The Surveillance, Epidemiology, and End Results database for survival and treatment of pancreatic adenocarcinoma between 1983 and 2007 stratified by age: younger than 50 years, between 50 and 70 years, or older than 70 years. Kaplan-Meier curves and Cox proportional hazards models were used for survival differences, and logistic regression models were used for treatment disparities and the decision to refuse surgery. Results A total of 45,509 patients had microscopically confirmed pancreatic adenocarcinoma. Of these, 7374 (16%) received surgery and 9842 (22%) received radiation. Younger patients were more likely to receive both surgery and radiation. The prevalence of surgery decreased from 21% for those younger than 50 years to 19% for those between 50 and 70 years to 13% for those older than 70 years (P < 0.001). Radiation decreased from 28% to 25% to 17% (P < 0.001). Overall survival decreased with increasing age at diagnosis, 10.4 months (age <50 years) to 9.1 months (age 50–70 years) to 6.4 months (age >70 years) controlling for stage, sex, race, radiation, and surgery (P < 0.001). Increasing age negatively predicted the odds of receiving both surgery and radiation and increased the likelihood of refusing surgery. Conclusions Treatment disparities exist by age despite advances in radiation and surgical treatment. Increased treatment in the elderly will increase overall survival from pancreatic adenocarcinoma.

Incidence of subsequent pancreatic adenocarcinoma in patients with a history of nonpancreatic primary cancers.

Several environmental risk factors are known to predispose individuals to pancreatic cancer, and up to 15% of pancreatic cancers have an inherited component. Understanding metachronous cancer associations can modify pancreas cancer risk. The objective of this study was to investigate the association of nonpancreatic cancers with subsequent pancreatic adenocarcinoma.

Adherence to World Cancer Research Fund/American Institute for Cancer Research recommendations and pancreatic cancer risk

BACKGROUND Pancreatic cancer is a leading cause of cancer death. A role of dietary factors in pancreatic carcinogenesis has been suggested. The World Cancer Research Fund (WCRF) and the American Institute for Cancer Research (AICR) published 8 recommendations for cancer prevention. We evaluated the effect of adherence to the WCRF/AICR recommendations on pancreatic cancer risk. METHODS We operationalized 7 of the 8 WCRF/AICR recommendations to generate a WCRF/AICR score. We examined the association of WCRF/AICR score with pancreatic cancer in data from an Italian case-control study of 326 incident cases and 652 controls. RESULTS Adherence to WCRF/AICR recommendations was associated with a significantly decreased risk of pancreatic cancer. Using a WCRF/AICR score <3.5 as a reference, the adjusted odds ratio (OR) for a score 3.5-<4 was 0.80 (95% CI 0.49, 1.28), for a score 4-<5 0.54 (95% CI 0.35, 0.82), and for score 5 or more 0.41 (95% CI 0.24, 0.68; p-value for trend 0.0002). The OR for a continuous increment of one unit of the WCRF/AICR score was 0.72 (95% CI 0.60, 0.87). CONCLUSION Adherence to the WCRF/AICR recommendations may reduce pancreatic cancer risk.

The Role of Common Pharmaceutical Agents on the Prevention and Treatment of Pancreatic Cancer

Survival from pancreatic cancer remains poor. Conventional treatment has resulted in only marginal improvements in survival compared with survival in the previous several decades. Thus, considerable interest has emerged regarding the potential use of common pharmaceutical agents as chemopreventative and chemotherapeutic options. Aspirin, metformin, statins, β-blockers, and bisphosphonates have biologically plausible mechanisms to inhibit pancreatic neoplasia, whereas dipeptidyl-peptidase 4 inhibitors may promote it. Regardless, real-world epidemiological data remain inconclusive. This review examines the hypotheses, evidence, and current state of the literature for each of these medications and their potential roles in the prevention and treatment of pancreatic cancer.

Absence of pancreatic intraepithelial neoplasia predicts poor survival after resection of pancreatic cancer.

Objectives Pancreatic intraepithelial neoplasia (PanIN), thought to represent the dominant precursor of pancreatic adenocarcinoma (PDAC), is often found synchronously adjacent to resected PDAC tumors. However, its prognostic significance on outcome after PDAC resection is unknown. Methods A total of 342 patients who underwent resection for PDAC between 2005 and 2010 at a single institution were identified and stratified according to highest grade of PanIN demonstrated surrounding the tumor. Clinical and pathologic characteristics of each patient and tissue were recorded and analyzed. The primary outcome was length of survival after resection. Results An absence of PanIN lesions was identified in 32 patients (9%), low grade PanIN without synchronous high grade lesions was identified in 52 patients (15%), and high grade PanIN was found in 258 patients (75%). Median survival were 12.8 months for the non-PanIN group, 26.3 months for the low-grade PanIN group, and 23.8 months for the high-grade PanIN groups (P = 0.043). In multivariable analysis, absence of PanIN was independently associated with poor survival (P = 0.002). Conclusions The patients who demonstrate an absence of PanIN in the pancreatic tissue adjacent to the resected PDAC tumor have shorter postresection survival compared with those who demonstrate a PanIN lesion.