Pancreatic cancer surveillance in a high-risk cohort. Is it worth the cost?

Heterodimeric RGD-NGR PET Tracer for the Early Detection of Pancreatic Cancer

PURPOSE

Pancreatic ductal adenocarcinoma (PDAC) is the most lethal gastrointestinal cancer, and its poor prognosis is highly associated with the lack of an efficient early detection technology. Here, we report that RGD-NGR heterodimer labeled with PET isotope could be applied in PDAC early detection.

PROCEDURES

The RGD-NGR tracer was first compared with its corresponding monomeric counterparts via PET imaging studies using mice bearing a subcutaneous BxPC3 tumor. Subsequently, the RGD-NGR tracer was evaluated in autochthonous mouse models with spontaneously developed late stage PanIN lesions (KCER mice) or PDAC (KPC mice) via both PET imaging studies and ex vivo biodistribution studies. Furthermore, a comparison between 2-deoxy-2[18F]fluoro-D-glucose ([18F]F-FDG) and the RGD-NGR tracer was conducted via PET imaging of the same KCH mouse bearing spontaneously developed PDAC. H&E staining was performed to confirm the malignant pancreatic tissue in the KCH mouse. Immunofluorescence staining was performed to confirm the expression of integrin αVβ3 and CD13.

RESULTS

The RGD-NGR tracer exhibited improved in vivo performance as compared with its corresponding monomeric counterparts on the subcutaneous BxPC3 tumor mouse model. Subsequent evaluation in autochthonous mouse models demonstrated its capability to detect both pre-malignant and malignant pancreases. Further comparison with [18F]F-FDG revealed the superiority of the proposed heterodimer in imaging spontaneously developed PDAC. H&E staining confirmed the malignant pancreatic tissue in the KCH mouse, while the expression of both integrin αVβ3 and CD13 receptors was demonstrated with immunofluorescence staining.

CONCLUSION

The proposed RGD-NGR heterodimer possesses the potential to be applied in the PDAC early detection for high-risk populations.

Current status of molecular markers for early detection of sporadic pancreatic cancer

Pancreatic cancer (PC) is a highly lethal malignancy with near 100% mortality. This is in part due to the fact that most patients present with metastatic or locally advanced disease at the time of diagnosis. Significantly, in nearly 95% of PC patients there is neither an associated family history of PC nor of diseases known to be associated with an increased risk of PC. These groups of patients who comprise the bulk of PC cases are termed as "sporadic PC" in contrast to the familial PC cases that comprise only about 5% of all PCs. Given the insidious onset of the malignancy and its extreme resistance to chemo and radiotherapy, an abundance of research in recent years has focused on identifying biomarkers for the early detection of PC, specifically aiming at the sporadic PC cohort. However, while several studies have established that asymptomatic individuals with a positive family history of PC and those with certain heritable syndromes are candidates for PC screening, the role of screening in identifying sporadic PC is still an unsettled question. The present review attempts to assess this critical question by investigating the recent advances made in molecular markers with potential use in the early diagnosis of sporadic PC - the largest cohort of PC cases worldwide. It also outlines a novel yet simple risk factor based stratification system that could be potentially employed by clinicians to identify those individuals who are at an elevated risk for the development of sporadic PC and therefore candidates for screening.

[Risk factors and early diagnosis of pancreatic cancer]

Pancreatic cancer (PC) is usually incurable. Identifying people at risk for developing PC may improve the prognosis of this entity. The main risk factors for PC are Peutz-Jeghers syndrome, hereditary pancreatitis and a history family of PC. Other factors, such as advanced age and smoking, should also be taken into account. PC screening is only useful in very high risk individuals. Tools that allow tumors to be identified in the early stages are required in order to apply appropriate curative treatments. In this scenario, only endoscopic ultrasound with cytological analysis of suspicious pancreatic lesions has proved to be useful.

Screening and surveillance approaches in familial pancreatic cancer

Screening and surveillance for pancreatic cancer and its precursors is a relatively new indication for endoscopic ultrasound. It provides an alternative approach to the ineffective treatment of mostly incurable symptomatic pancreatic cancer. It is currently reserved for individuals with an increased risk for pancreatic ductal adenocarcinoma, such as those who have inherited genetic syndromes (eg, patients who have Peutz-Jeghers syndrome or hereditary pancreatitis, germline mutation carriers of p16 and BRCA2) and at-risk relatives of patients who have familial pancreatic cancer. This article discusses the rationale for performing screening and surveillance, the types of patients who are eligible for screening, the diagnostic modalities and technique for screening, the diagnostic yield of screening, and the ongoing research.

A clinical and economic evaluation of endoscopic ultrasound for patients at risk for familial pancreatic adenocarcinoma

BACKGROUND AND AIMS

Approximately 10% of pancreatic adenocarcinoma is familial. Approximately 50% of 1st-degree relatives (FDRs) have endoscopic ultrasound (EUS) findings of chronic pancreatitis. We modeled the natural history of these patients to compare 4 management strategies.

METHODS

We performed a systematic review, and created a Markov model for 45-year-old male FDRs, with findings of chronic pancreatitis on screening EUS. We compared 4 strategies: doing nothing, prophylactic total pancreatectomy (PTP), annual surveillance by EUS, and annual surveillance with EUS and fine needle aspiration (EUS/FNA). Outcomes incorporated mortality, quality of life, procedural complications, and costs.

RESULTS

In the Do Nothing strategy, the lifetime risk of cancer was 20%. Doing nothing provided the greatest remaining years of life, the lowest cost, and the greatest remaining quality-adjusted life years (QALYs). PTP provided the fewest remaining years of life, and the fewest remaining QALYs. Screening with EUS provided nearly identical results to PTP, and screening with EUS/FNA provided intermediate results between PTP and doing nothing. PTP provided the longest life expectancy if the lifetime risk of pancreatic cancer was at least 46%, and provided the most QALYs if the risk was at least 68%.

CONCLUSIONS

FDRs from familial pancreatic cancer kindreds, who have EUS findings of chronic pancreatitis, have increased risk for cancer, but their precise risk is unknown. Without the ability to further quantify that risk, the most effective strategy is to do nothing.

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.

Genetic counseling for hereditary pancreatitis--the role of molecular genetics testing for the cationic trypsinogen gene, cystic fibrosis and serine protease inhibitor Kazal type 1

The importance of pretest information, using an accredited DNA laboratory and interpreting the genotype on behalf of the patient and their physicians is emphasized. Care with predictive testing and the strong encouragement to involve a specialist genetic counseling service is made. A similar approach to genetic testing should be used when children are involved. Because of the incomplete pickup of PRSS1 mutations, particularly of a limited mutation panel of R122H and N291 (perhaps with A16V), a diagnosis of HP cannot be ruled out by molecular genetic testing alone. The A16V mutation has a reduced penetrance, and its contribution to pancreatitis remains unclear. The advice to patients with genetic forms of pancreatitis is a strong encouragement to avoid smoking, to avoid alcohol, and to remain in contact with clinical and research groups for their follow-up and screening trials for early pancreatic cancer. The remaining issues are of how wide to cast the net of investigation in patients with unexplained pancreatitis, particularly looking for mutations in the CFTR and lower penetrance genes such as PSTI/SPINK1.

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.

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.

Cost-effectiveness of pancreatic cancer screening in familial pancreatic cancer kindreds

BACKGROUND

Endoscopic screening of families predisposed to pancreatic cancer is increasingly used, but the cost-effectiveness of screening is unknown.

METHODS

A decision analysis was used to compare one-time screening for pancreatic dysplasia with EUS to no screening in a hypothetical cohort of 100 members of familial pancreatic cancer kindreds. Abnormal EUS findings are confirmed with ERCP and patients with abnormal findings are candidates for total pancreatectomy. Lifetime medical care costs and life expectancy were modeled, and the main analysis was conducted from the third-party payer perspective. The base-case analysis assumed a 20% prevalence of pancreatic dysplasia and 90% sensitivity of EUS and ERCP.

RESULTS

Endoscopic screening was cost-effective, with an incremental cost-effectiveness ratio of $16,885/life-year saved. Screening was more cost-effective as the probability of dysplasia increased and as the sensitivity of EUS and ERCP increased. Screening remained cost-effective if the prevalence of dysplasia was greater than 16% or if the sensitivity of EUS was greater than 84%. Procedure costs had a limited impact on cost-effectiveness.

CONCLUSIONS

Endoscopic screening of carefully selected members of familial pancreatic cancer kindreds appears to increase patient life expectancy in a cost-effective manner. Screening should be performed in centers that have experience with endoscopic screening for pancreatic dysplasia. The cost-effectiveness of repeated screening remains to be determined.

Inflammation and the development of pancreatic cancer

OBJECTIVE

Pancreatic cancer has an extremely poor prognosis and the cellular mechanisms contributing to pancreatic cancer are relatively unknown. The goals of this review are to present the epidemiological and experimental data that supports inflammation as a key mediator of pancreatic cancer development, to explain how inflammatory pathways may create an environment that supports tumor formation, and to discuss how the use of novel agents directed at these pathways may be used for the treatment of pancreatic malignancy.

SUMMARY BACKGROUND DATA

Inflammation has been identified as a significant factor in the development of other solid tumor malignancies. Both hereditary and sporadic forms of chronic pancreatitis are associated with an increased risk of developing pancreatic cancer. The combined increase in genomic damage and cellular proliferation, both of which are seen with inflammation, strongly favors malignant transformation of pancreatic cells. Cytokines, reactive oxygen species, and mediators of the inflammatory pathway (e.g., NF-kappaB and COX-2) have been shown to increase cell cycling, cause loss of tumor suppressor function, and stimulate oncogene expression; all of which may lead to pancreatic malignancy. Anti-cytokine vaccines, inhibitors of pro-inflammatory NF-kappaB and COX-2 pathways, thiazolidinediones, and anti-oxidants are potentially useful for the prevention or treatment of pancreatic cancer. Redirection of experimental interests toward pancreatic inflammation and mechanisms of carcinogenesis may identify other novel anti-inflammatory agents or other ways to screen for or prevent pancreatic cancer.

CONCLUSION

Pancreatic inflammation, mediated by cytokines, reactive oxygen species, and upregulated pro-inflammatory pathways, may play a key role in the early development of pancreatic malignancy.

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.

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.

Chronic pancreatitis: diagnosis, classification, and new genetic developments

The utilization of recent advances in molecular and genomic technologies and progress in pancreatic imaging techniques provided remarkable insight into genetic, environmental, immunologic, and pathobiological factors leading to chronic pancreatitis. Translation of these advances into clinical practice demands a reassessment of current approaches to diagnosis, classification, and staging. We conclude that an adequate pancreatic biopsy must be the gold standard against which all diagnostic approaches are judged. Although computed tomography remains the initial test of choice for the diagnosis of chronic pancreatitis, the roles of endoscopic retrograde pancreatography, endoscopic ultrasonography, and magnetic resonance imaging are considered. Once chronic pancreatitis is diagnosed, proper classification becomes important. Major predisposing risk factors to chronic pancreatitis may be categorized as either (1) toxic-metabolic, (2) idiopathic, (3) genetic, (4) autoimmune, (5) recurrent and severe acute pancreatitis, or (6) obstructive (TIGAR-O system). After classification, staging of pancreatic function, injury, and fibrosis becomes the next major concern. Further research is needed to determine the clinical and natural history of chronic pancreatitis developing in the context of various risk factors. New methods are needed for early diagnosis of chronic pancreatitis, and new therapies are needed to determine whether interventions will delay or prevent the progression of the irreversible damage characterizing end-stage chronic pancreatitis.

Growth factors, receptors, and molecular alterations in pancreatic cancer. Putting it all together

Because of the dismal prognosis of advanced ductal pancreatic adenocarcinoma, recent investigational strategies have focused on improved detection and therapeutic intervention in early-stage pancreatic cancer. The obvious cost constraints of screening populations at risk but with a low tumor yield will restrict screening protocols to only the highest risk groups (hereditary pancreatitis = age 50, certain hereditary pancreatic cancer kindreds). The vast majority of patients, either lacking or exhibiting an inherited predisposition to pancreatic cancer, will continue to present with disease not resectable for cure. The authors believe that the best hope for these patients lies in the further delineation of the integrative pathophysiology driving tumor growth; this would facilitate the future development of a computer program or other modality that would predict the dominant pathways driving the growth and spread of each tumor based on its "molecular profile." This article reviews the authors' current knowledge regarding the growth factors, receptors, and molecular alterations driving uncontrolled proliferation, local invasion, and metastatic spread of these tumors. The current and potential contributions of studies in cohorts with an inherited predisposition to pancreatic cancer to this pathophysiologic model are also discussed. The future strategy for incorporating this information into a working pathophysiologic road map with clinical relevance is subsequently outlined.