Screening for early pancreatic ductal adenocarcinoma in hereditary pancreatitis

Histopathology of SPINK-1 Hereditary Pancreatitis

Hereditary pancreatitis is a rare form of recurrent acute pancreatitis that typically has an onset in early adulthood. We report a rare case of hereditary pancreatitis in an individual with a serine protease inhibitor Kazal type 1 (SPINK1) mutation. Histologically the pancreas showed features of chronic pancreatitis with variable fibrosis, acinar destruction, and prominent inspissated secretions within the pancreatic ducts. Additionally, focal areas of low-grade pancreatic intraepithelial neoplasia (PanIN) were present. Although the histopathology of common gene mutations resulting in hereditary pancreatitis have been well described, the histopathology of pancreatitis secondary to SPINK1 mutation has been described in only one previous study.

A meta-analysis of the diagnostic value of detecting K-ras mutation in pancreatic juice as a molecular marker for pancreatic cancer

BACKGROUND

K-ras codon 12 mutation is one of the earliest genetic changes in the development of pancreatic cancer (PC) and accurate detection of K-ras mutations is gaining increasing attention in the field of molecular diagnosis.

METHODS

Original research articles which evaluated the diagnostic accuracy of K-ras mutation detection in PC were selected. Data were presented as forest plots and summary receiver operating characteristic curve analysis was used to summarize the overall test performance.

RESULTS

We assessed 16 studies from 15 published articles. The pooled sensitivity and specificity were 59% (95%CI: 54%-64%) and 87% (95%CI: 84%-89%), respectively. The pooled positive likelihood ratio and negative likelihood ratio were 4.13 (95%CI: 2.73-6.25) and 0.42 (95%CI: 0.32-0.56), respectively, and the pooled diagnostic odds ratio was 13.66 (95% CI: 7.25-25.74).

CONCLUSIONS

Our results indicate that the analysis of K-ras mutations in pancreatic juice has a considerable diagnostic value in PC. Further studies with rigorous design, large sample size, and multi-regional co-operation are needed.

Quality of life improves for pediatric patients after total pancreatectomy and islet autotransplant for chronic pancreatitis

BACKGROUND & AIMS

Total pancreatectomy (TP) and islet autotransplant (IAT) have been used to treat patients with painful chronic pancreatitis. Initial studies indicated that most patients experienced significant pain relief, but there were few validated measures of quality of life. We investigated whether health-related quality of life improved among pediatric patients undergoing TP/IAT.

METHODS

Nineteen consecutive children (aged 5-18 years) undergoing TP/IAT from December 2006 to December 2009 at the University of Minnesota completed the Medical Outcomes Study 36-item Short Form (SF-36) health questionnaire before and after surgery. Insulin requirements were recorded.

RESULTS

Before TP/IAT, patients had below average health-related quality of life, based on data from the Medical Outcomes Study SF-36; they had a mean physical component summary (PCS) score of 30 and mental component summary (MCS) score of 34 (2 and 1.5 standard deviations, respectively, below the mean for the US population). By 1 year after surgery, PCS and MCS scores improved to 50 and 46, respectively (global effect, PCS P < .001, MCS P = .06). Mean scores improved for all 8 component subscales. More than 60% of IAT recipients were insulin independent or required minimal insulin. Patients with prior surgical drainage procedures (Puestow) had lower yields of islets (P = .01) and greater incidence of insulin dependence (P = .04).

CONCLUSIONS

Quality of life (physical and emotional components) significantly improve after TP/IAT in subsets of pediatric patients with severe chronic pancreatitis. Minimal or no insulin was required for most patients, although islet yield was reduced in patients with previous surgical drainage operations.

Smoking as a cofactor for causation of chronic pancreatitis: a meta-analysis

OBJECTIVES

To assess the evidence for tobacco smoking as a risk factor for the causation of chronic pancreatitis.

METHODS

We performed a meta-analysis with random-effects models to estimate pooled relative risks (RRs) of chronic pancreatitis for current, former, and ever smokers, in comparison to never smokers. We also performed dose-response, heterogeneity, publication bias, and sensitivity analyses.

RESULTS

Ten case-control studies and 2 cohort studies that evaluated, overall, 1705 patients with chronic pancreatitis satisfied the inclusion criteria. When contrasted to never smokers, the pooled risk estimates for current smokers was 2.8 (95% confidence interval [CI], 1.8-4.2) overall and 2.5 (95% CI, 1.3-4.6) when data were adjusted for alcohol consumption. A dose-response effect of tobacco use on the risk was ascertained: the RR for subjects smoking less than 1 pack per day was 2.4 (95% CI, 0.9-6.6) and increased to 3.3 (95% CI, 1.4-7.9) in those smoking 1 or more packs per day. The risk diminished significantly after smoking cessation, as the RR estimate for former smokers dropped to a value of 1.4 (95% CI, 1.1-1.9).

CONCLUSIONS

Tobacco smoking may enhance the risk of developing chronic pancreatitis. Recommendation for smoking cessation, besides alcohol abstinence, should be incorporated in the management of patients with chronic pancreatitis.

Genomic instability at both the base pair level and the chromosomal level is detectable in earliest PanIN lesions in tissues of chronic pancreatitis

OBJECTIVE

Chronic pancreatitis (CP) is a predisposing disease for pancreatic carcinoma (PC), however, precise molecular mechanisms of cancer development in the background of CP are ill defined.

METHODS

A total of 443 laser-microdissected pancreatic intraepithelial neoplasias (PanINs), acinar-ductal metaplasia (ADM), and normal ducts from 21 patients with CP were analyzed for loss of heterozygosity (LOH) and immunohistochemical protein expression of p53, p16, and DPC4. Pancreatic intraepithelial neoplasias were analyzed for mutations in p53, p16, and Ki-ras genes by ABI sequencing. Aneuploidy was determined by fluorescence in situ hybridization with probes for chromosomes 3, 7, 8, and 17.

RESULTS

Loss of heterozygosity rate in PanIN-1 and ADM was between 1.7% (p53) and 5.8% (p16). In PanIN-3, p53 protein overexpression and loss of expression for p16 and DPC4 protein were seen. Heterozygous mutations of p53 and p16 without LOH were found in PanIN-1A and ADM, whereas homozygous mutations were found in PanIN-3. Aneuploidy increased from PanIN-1A to PanIN-3. Ki-ras mutations were discovered first in PanIN-1.

CONCLUSIONS

Heterozygous mutations of p53- and p16 genes together with chromosomal instability occur early in CP and are clonally expanded, but final inactivation mostly by LOH happens later in pancreatic carcinogenesis. Determination of aneuploidy in pancreatic juice may be of value for early detection and risk assessment in patients with long-standing CP.

Early detection of pancreatic cancer: the Japanese approach

Pancreatic cancer is the fifth leading cause of cancer-related deaths in Japan. Small pancreatic cancers have some abnormal findings on ultrasonography, and diagnosis with endosonography is useful. Positron emission tomography and contrast-enhanced ultrasonography are expected to serve as new modalities for the early detection of pancreatic cancer. The identification of high-risk individuals is necessary to perform efficient screening. Intraductal papillary mucinous neoplasms and chronic pancreatitis are important risk factors for pancreatic cancer.

Peutz-Jeghers syndrome and screening for pancreatic cancer

BACKGROUND

Cancer risk, including pancreatic, is high in those with Peutz-Jeghers syndrome (PJS). It has been suggested that such patients should undergo screening for pancreatic cancer.

METHODS

The risk of pancreatic cancer in PJS, pancreatic screening and potential screening strategies were reviewed. Cost-effectiveness was assessed according to American Gastroenterology Association guidelines and a risk stratification model proposed by the European Registry of Hereditary Pancreatitis and Familial Pancreatic Cancer.

RESULTS

The risk of pancreatic cancer is increased in PJS but screening would cost over US 35,000 dollars per life saved. Risk stratification reduces cost by 100,000 dollars and costs fall to 50,000 dollars per life saved if deaths from other forms of cancer are avoided.

CONCLUSION

Screening should be performed only on a research basis to evaluate the benefit and cost-effectiveness in high-risk groups.

The inherited genetics of pancreatic cancer and prospects for secondary screening

It is estimated that pancreatic cancer has a familial component in approximately 5-10% of cases. Some of these cases are part of a defined cancer syndrome with a known gene mutation but in the remaining the causative gene remains unknown. In recent years, a better understanding of the molecular events that occur in the progression model of pancreatic cancer has lead to the development of secondary screening programmes with the aim of identifying early precursor lesions or pre-invasive cancer at a stage amenable to curative resection. High-risk groups who have an inherited predisposition for pancreatic cancer form the ideal group to study in developing a robust screening programme. Multimodality screening using computed tomography and endoluminal ultrasound in combination with molecular analysis of pancreatic juice are proving promising as diagnostics tools or at least serving as predictors of risk over a defined period.

Molecular analysis to detect pancreatic ductal adenocarcinoma in high-risk groups

BACKGROUND & AIMS

Screening of high-risk groups for pancreatic cancer has not been adopted because of concerns regarding specificity and sensitivity. Suitability of a combination of 3 novel molecular screening techniques was investigated.

METHODS

Pancreatic juice was extracted from 146 patients with pancreatic ductal adenocarcinoma, chronic pancreatitis, or biliary tract stones. p53 mutations were analyzed by using a modified yeast functional assay, K-ras status was analyzed using mutation-specific real-time PCR and the proportion of p16(INK4a) promoter methylation was estimated using comparative methylation-specific real-time PCR.

RESULTS

p53 mutations were detected in 20 of 48 (42%) cancer cases, none of 49 controls, and 2 of 49 (4%) patients with pancreatitis. K-ras mutations were detected in 31 of 57 (54%) cancer patients, 13 of 61 (21%) controls, and 23 of 67 (34%) patients with pancreatitis. Twenty-six of 42 (62%) cancer patients had promoter methylation levels > 12%, compared with 3 of 24 (13%) controls, and 2 of 26 (8%) with pancreatitis. Mutations in p53 or high-level p16(INK4a) promoter methylation occurred in 29 of 36 (80%) patients with cancer, 3 of 24 (13%) controls, and 3 of 22 (13%) with pancreatitis. Three patients (8%) of 36 with cancer; 14 of 24 (58%) controls, and 13 of 22 (59%) patients with pancreatitis had no marker. The gallstone disease patients had a high rate of positive K-ras mutations, possibly reflecting the fact that they were not disease free.

CONCLUSIONS

Combination molecular analysis increased the discrimination between patients with malignant and benign disease. This level of discrimination would allow patients in high-risk groups to be stratified from negligible risk to over 50% probability of an early cancer.

Management of Patients at High Risk for Pancreatic Cancer

Because pancreatic cancer patients seldom exhibit disease-specific symptoms until the cancer is at an advanced stage, its diagnosis is a virtual death sentence. Therefore, to make a significant impact on long-term survival for subjects with pancreatic cancer, asymptomatic individuals would have to be screened for premalignant precursors of pancreatic cancer or for asymptomatic pancreatic cancer. A number of formidable obstacles limit the ability of healthcare providers to screen for early neoplastic changes and to make a very early and specific diagnosis of pancreatic cancer. These include lack of a high-risk population for sporadic pancreatic cancer and lack of a simple, noninvasive test sensitive enough to detect small cancers. However, progress is being made in defining various high-risk groups for pancreatic cancer, and improvements in imaging modalities make detection of premalignant lesions and small cancers possible in such individuals. The protocols currently being studied, including use of endoscopic ultrasound and endoscopic retrograde cholangiopancreatography to detect precancerous lesions and small pancreatic cancer in high-risk patients, are still in the research arena and not yet ready for clinical practice.

Laser microdissection of small tissue samples--application to chronic pancreatitis tissues

Laser microdissection is considered to be the gold standard of tissue sampling, especially if a defined small tissue area consisting of single or few cells within a heterogeneous tissue compartment is of interest. This sophisticated technique offers the opportunity of rapid and contamination-free tissue sampling for RNA- or DNA-based molecular genetic studies. We have applied laser microdissection to a molecular genetic study of pancreatic intraductal lesions (PanINs) in tissues of chronic pancreatitis, where an exact microdissection of small ducts within a dense fibrous tissue is of paramount importance for following analysis. From nine patients suffering from chronic pancreatitis, formalin-fixed, paraffin-embedded tissue specimens were laser microdissected, and a total of 202 normal ducts and PanINs of grade PanIN-1A to grade PanIN-2 were harvested. After whole genome amplification by improved primer extension and preamplification PCR (I-PEP-PCR), microsatellite-PCR based loss of heterozygosity analysis (LOH) of the tumor suppressor gene loci TP53, p16INK4, and DPC4 was performed. One of 85 informative duct lesions (1.2%) had LOH of TP53, 1 of 76 duct lesions (1.3%) had LOH of DPC4, and 2/29 duct lesions (6.9%) showed LOH of p16INK4. Microsatellite instability (MSI) was seen in 2 of 178 duct lesions (1.1%). Immunohistochemical staining of p53 protein and DPC4 protein revealed no aberrant expression. These preliminary data indicate that LOH of tumor suppressor genes, important in pancreatic cancer genesis or MSI, can be found in chronic pancreatitis tissues, but their incidence is low.

Hereditary pancreatitis

Hereditary pancreatitis is an autosomal dominant condition, which results in recurrent attacks of acute pancreatitis, progressing to chronic pancreatitis often at a young age. The majority of patients with hereditary pancreatitis express one of two mutations (R122H or N29I) in the cationic trypsinogen gene (PRSS1 gene). It has been hypothesised that one of these mutations, the R122H mutation causes pancreatitis by altering a trypsin recognition site so preventing deactivation of trypsin within the pancreas and prolonging its action, resulting in autodigestion. Families with these two mutations have been identified in many countries and there are also other rarer mutations, which have also been linked to hereditary pancreatitis.

Patients with hereditary pancreatitis present in the same way as those with sporadic pancreatitis but at an earlier age. It is common for patients to remain undiagnosed for many years, particularly if they present with non-specific symptoms. Hereditary pancreatitis should always be considered in patients who present with recurrent pancreatitis with a family history of pancreatic disease. If patients with the 2 common mutations are compared, those with the R122H mutation are more likely to present at a younger age and are more likely to require surgical intervention than those with N29I. Hereditary pancreatitis carries a 40% lifetime risk of pancreatic cancer with those patients aged between 50 to 70 being most at risk in whom screening tests may become important.

Molecular diagnosis of early pancreatic ductal adenocarcinoma in high-risk patients

The prevalence of pancreatic cancer in the general population is too low--even in high-prevalence areas such as Northern Europe and North America (8-12 per 10(5) population)--relative to the diagnostic accuracy of present detection methods to permit primary screening in the asymptomatic adult population. The recognition that the lifetime risk of developing pancreatic cancer for patients with hereditary pancreatitis (HP) is extremely high (20% by the age of 60 years and 40% by the age of 70 years) poses considerable challenges and opportunities for secondary screening in those patients without any clinical features of pancreatic cancer. Even for secondary screening, the detection of cancer at a biological stage that would be amenable to cure by surgery (total pancreatectomy) still requires diagnostic modalities with a very high sensitivity and specificity. Conventional radiological imaging methods such as endoluminal ultrasound and endoscopic retrograde pancreatography, which have proved to be valuable in the early detection of early neoplastic lesions in patients with familial pancreatic cancer, may well be applicable to patients with HP but only in those without gross morphological features of chronic pancreatitis (other than parenchymal atrophy). Unfortunately, most cases of HP also have associated gross features of chronic pancreatitis that are likely to seriously undermine the diagnostic value of these conventional imaging modalities. Pre-malignant molecular changes can be detected in the pancreatic juice of patients. Thus, the application of molecular screening in patients with HP is potentially the most powerful method of detection of early pancreatic cancer. Although mutant (mt) K-ras can be detected in the pancreatic juice of most patients with pancreatic cancer, it is also present in patients with non-inherited chronic pancreatitis who do not progress to pancreatic cancer (at least in the short to medium term), as well as increasingly in the older population without pancreatic disease. Nevertheless, the presence of mt-K-ras may identify a genuinely higher-risk group, enabling additional diagnostic imaging and molecular resources to be focussed on such a group. What is clear is that prospective multi-centre studies, such as that being pursued by the European Registry of Hereditary Pancreatitis and Familial Pancreatic Cancer (EUROPAC), are essential for the development of an effective secondary screening programme for these patients.

Inherited pancreatic cancer: surveillance and treatment strategies for affected families

BACKGROUND

Nearly 10% of pancreatic cancers are hereditary in origin, and in some individuals, the risk of pancreatic cancer approaches 50%. A number of defined syndromes can predispose families to pancreatic cancer, although many of the mechanisms that result in familial pancreatic cancers are unknown. This article reviews current knowledge regarding familial pancreatic cancers and highlights the rationale for screening and surveillance. Methods for screening and surveillance of these high-risk individuals are described that allow the detection of pancreatic dysplasia, the precursor to pancreatic cancer. We also describe a single-center experience with the management and surveillance of familial pancreatic cancer kindreds.

METHODS

Thirty-five patients from 13 familial pancreatic cancer kindreds underwent screening and/or surveillance. Endoscopic ultrasound (EUS) is the initial test of choice. Endoscopic retrograde cholangiopancreatography (ERCP) is reserved for symptomatic individuals or to investigate abnormal findings on EUS. In the proper clinical setting, patients with abnormal findings on both EUS and ERCP are candidates for total pancreatectomy.

RESULTS

Twelve of 35 patients were noted to have abnormal findings on EUS and ERCP. All of these individuals underwent pancreatectomy, 10 total and 2 partial. The patients who underwent partial pancreatectomy are currently awaiting resection of the pancreatic remnant. Histopathologic examination of all 12 specimens demonstrated pancreatic dysplasia (the precursor lesion to pancreatic cancer). These specimens had no evidence of pancreatic cancer; nor were any of the resected pancreata normal. Follow-up of the 35 high-risk patients at present varies from 1 to 48 months, and none of the patients under surveillance have developed pancreatic cancer.

CONCLUSION

The screening and surveillance of high-risk members of familial pancreatic cancer kindreds using EUS and ERCP is an effective method for identifying individuals with pancreatic dysplasia prior to the onset of invasive pancreatic cancer. The surveillance needs to be performed by a team of specialists who have experience in dealing with pancreatic cancer and its precursors.

Recurrent Acute Pancreatitis

Patients with recurrent acute pancreatitis should be treated with the same supportive and symptom-oriented measures as those with acute pancreatitis. The need for specific treatment depends on the cause of the pancreatitis. Patients should discontinue alcohol use, putative causative medications, and exposure to toxins or helminths in endemic areas. Metabolic abnormalities need to be corrected, and appropriate treatment should be initiated for associated infections, autoimmune diseases, vasculitis, and hypercoagulable states. For patients with gallstone pancreatitis, endoscopic retrograde cholangiopancreatography is indicated if biliary obstruction persists or if cholangitis is present. Elective cholecystectomy may be performed in appropriate patients; otherwise, consider biliary sphincterotomy and ursodeoxycholic acid for prevention of recurrent attacks. Transpapillary stenting or sphincterotomy of the minor papilla benefits some patients with pancreas divisum and no other explanation for recurrent pancreatitis. Surgical sphincteroplasty is reserved for those failing endoscopic treatment. Biliary sphincterotomy benefits more than 50% of patients with sphincter of Oddi dysfunction and recurrent acute pancreatitis. Some authors advocate pancreatic sphincter manometry and sphincterotomy for persistent pancreatic segment hypertension in patients who have recurrent pancreatitis after biliary sphincterotomy. In patients with pancreatic duct strictures, transpapillary stent placement serves as a short-term measure; most patients ultimately require surgery.

Molecular pathogenesis of pancreatic ductal adenocarcinoma and clinical implications

Pancreatic ductal adenocarcinoma (PDAC) is a significant cause of cancer death worldwide. PDAC is also one of the best-studied cancers with regard to molecular pathogenesis. The chief risk factors associated with PDAC are smoking and pancreatitis, in addition genetic predisposition seems to play a major role. This genetic predisposition may in some cases be indirect, for example via the elevated risk of pancreatitis seen in patients with hereditary pancreatitis (HP). The elucidation of the molecular causes of PDAC has enabled the provision of secondary screening for PDAC in conditions such as HP. This review is concerned with the molecular pathogenesis of PDAC and the application of this basic scientific understanding into state-of-the-art clinical practice.

Surveillance of pre-malignant disease of the pancreatico-biliary system

Technical advancements in ultrasonography, contrast-enhanced computed tomography and magnetic resonance imaging, as well as the wider availability of these ultramodern imaging techniques, have resulted in the early detection and a better classification of various asymptomatic and symptomatic pancreatico-biliary lesions. Pre-malignant biliary and pancreatic lesions are rare disorders, and no clear data are available to define their malignant potential. Because of the lack of controlled epidemiological data, the time span for malignant transformation and its frequency cannot be defined in the majority of these lesions. Adenomyomatosis of the gallbladder and gallbladder polyps larger than 10 mm should be treated by cholecystectomy even in asymptomatic patients because of an increased risk of malignant transformation. Chronic cholangitis, primary sclerosing cholangitis and choledochal cysts are also pre-malignant conditions. The timing of surgery, once it is advised for a pre-malignant condition that is still benign, should, however, be individualized to the particular patient situation. In patients with chronic pancreatitis, surgery may be indicated for disease-related complications. In as much as chronic pancreatitis predisposes to a higher risk of pancreatic cancer, any suspicion of malignancy should warrant a surgical exploration. Intraductal papillary tumours and mucin-producing pancreatic tumours are other pre-malignant pancreatic lesions whose malignant potential cannot be precisely determined pre-operatively. They should be resected in situations where there is a high degree of suspicion even without a clear objective diagnosis. In conclusion, pre-malignant hepato-biliary and pancreatic lesions of uncertain pathology should undergo early resection in view of treatment limitations and the dismal prognosis of established cancers. While hepato-biliary and pancreatic surgery is nowadays performed in specialized centres, with a low post-operative morbidity and mortality, it is equally important to understand that observation alone with regular computed tomography or magnetic resonance imaging control can no longer be recommended in the management of these lesions.

Recurrent acute pancreatitis: an algorithmic approach to identification and elimination of inciting factors

Recurrent acute pancreatitis represents a challenging clinical problem associated with significant morbidity, impairment in quality of life, and expense. If unchecked, recurrent episodes of acute pancreatitis may lead to chronic pancreatitis. In this work we have combined the opinion of experts in pancreatology and an extensive review of the literature to develop a logical algorithm that facilitates the stepwise identification and elimination of inciting factors using current technology. The approach taken in recurrent acute pancreatitis is clearly dependent on adequate and appropriate evaluation and treatment of the patient with an initial episode of acute pancreatitis. Future advances in the treatment of these patients will almost certainly depend on improved imaging modalities, prospective clinical trials assessing the efficacy of endoscopic and surgical intervention, a better understanding of mutations and pathophysiologic mechanisms responsible for recurrent acute pancreatitis, and the development of novel, effective preventive and therapeutic strategies.