Reported family aggregation of pancreatic cancer within a population-based case-control study in the Francophone community in Montreal, Canada

Citrus fruit intake and pancreatic cancer risk: a quantitative systematic review

OBJECTIVES

The purpose of this systematic review was to investigate the association between dietary intake of citrus fruits and pancreatic cancer risk.

METHODS

Authors searched electronic databases and the reference lists of publications of studies addressing diet and pancreatic cancer up to December 2007. All of the epidemiological studies that obtained individual data on dietary intake of citrus fruits and presented risk estimates of the association between intake of citrus fruits and risk of pancreatic cancer were identified and included. Using general variance-based methods, study-specific odds ratios (ORs)/relative risk and associated confidence interval (CI)/SE for highest versus lowest intake of citrus fruits level were extracted from each article.

RESULTS

Nine articles including 4 case-control studies and 5 cohort studies proved eligible. Overall summary OR using random effect model suggested an inverse association in risk of pancreatic cancer with intake of citrus fruits (summary OR, 0.83; 95% CI, 0.70-0.98) with large heterogeneity across studies (I = 49.9%).

CONCLUSIONS

Pooled results from observational studies showed an inverse association between intake of citrus fruits and the risk of pancreatic cancer, although results vary substantially across studies, and the apparent effect is restricted to the weaker study design (case-control studies).

Risk of other cancers in individuals with a family history of pancreas cancer

BACKGROUND

Inherited predisposition to pancreas cancer accounts for approximately 10% of cases. Familial aggregation may be influenced by shared environmental factors and shared genes. We evaluate whether a family history of pancreas cancer is a risk factor for ten specified cancers in first-degree relatives: bladder, breast, colon, head and neck, lung, lymphoma, melanoma, ovary, pancreas, and prostate.

METHODS

Risk factor data and cancer family history were obtained for 1,816 first-degree relatives of pancreas cancer case probands (n = 247) and 3,157 first-degree relatives of control probands (n = 420). Unconditional logistic regression models using generalized estimating equations were used to estimate odds ratios (ORs), and 95% confidence intervals of having a first-degree relative a specified cancer.

RESULTS

A family history of pancreas cancer was associated with a doubled risk of lymphoma (OR = 2.83, 95% CI = 1.02-7.86) and ovarian cancer (OR = 2.25, 95% CI = 0.77-6.60) among relatives after adjustment. Relatives with a family history of early-onset pancreas cancer in a proband had a sevenfold increased risk of lymphoma (OR = 7.31, 95% CI = 1.45 to 36.7). Relatives who ever smoked and had a family history of pancreas cancer had a fivefold increased risk of ovarian cancer (OR = 4.89, 95% CI = 1.16-20.6).

CONCLUSION

Family history assessment of cancer risk should include all cancers. Assessment of other known and suspected risk factors in relatives will improve risk evaluation. As screening and surveillance methods are developed, identifying those at highest risk is crucial for a successful screening program.

Stool testing for the early detection of pancreatic cancer: rationale and current evidence

The development of effective tools for the early detection of pancreatic cancer, or its precursors, in high-risk subjects could play a key role in reducing the burden of this disease, which is the most lethal among solid gastrointestinal tumors. Given the poor accessibility of the pancreas due to its anatomic site, and given the limitations of imaging modalities, biomarker screening might be a promising diagnostic option. This review focuses on the rationale of using stool markers for the early detection of pancreatic cancer, and systematically summarizes current evidence. Despite several potential advantages of stool testing for pancreatic cancer and its biological plausibility, only six studies investigating two genetic markers in stool (the K-ras and the p53 gene) could be identified. Even though these studies were limited in size and could hardly approximate the screening setting, both markers appear to lack sensitivity and, in particular, specificity. The investigation of further marker candidates (e.g., epigenetic markers) in adequately designed studies represents an important next step to explore the potential of stool testing for pancreatic cancer. Pertinent studies could greatly benefit from recent methodological advances gained in connection with stool testing for colorectal cancer.

Energy balance, physical activity, and cancer risk

This chapter posits that cancer is a complex and multifactorial process as demonstrated by the expression and production of key endocrine and steroid hormones that intermesh with lifestyle factors (physical activity, body size, and diet) in combination to heighten cancer risk. Excess weight has been associated with increased mortality from all cancers combined and for cancers of several specific sites. The prevalence of obesity has reached epidemic levels in many parts of the world; more than 1 billion adults are overweight with a body mass index (BMI) exceeding 25. Overweight and obesity are clinically defined indicators of a disease process characterized by the accumulation of body fat due to an excess of energy intake (nutritional intake) relative to energy expenditure (physical activity). When energy intake exceeds energy expenditure over a prolonged period of time, the result is a positive energy balance (PEB), which leads to the development of obesity. This physical state is ideal for intervention and can be modulated by changes in energy intake, expenditure, or both. Nutritional intake is a modifiable factor in the energy balance-cancer linkage primarily tested by caloric restriction studies in animals and the effect of energy availability. Restriction of calories by 10 to 40% has been shown to decrease cell proliferation, increasing apoptosis through anti-angiogenic processes. The potent anticancer effect of caloric restriction is clear, but caloric restriction alone is not generally considered to be a feasible strategy for cancer prevention in humans. Identification and development of preventive strategies that "mimic" the anticancer effects of low energy intake are desirable. The independent effect of energy intake on cancer risk has been difficult to estimate because body size and physical activity are strong determinants of total energy expenditure. The mechanisms that account for the inhibitory effects of physical activity on the carcinogenic process are reduction in fat stores, activity related changes in sex-hormone levels, altered immune function, effects in insulin and insulin-like growth factors, reduced free radical generation, and direct effect on the tumor. Epidemiologic evidence posits that the cascade of actions linking overweight and obesity to carcinogenesis are triggered by the endocrine and metabolic system. Perturbations to these systems result in the alterations in the levels of bioavailable growth factors, steroid hormones, and inflammatory markers. Elevated serum concentrations of insulin lead to a state of hyperinsulinemia. This physiological state causes a reduction in insulin-like growth factor-binding proteins and promotes the synthesis and biological activity of insulin-like growth factor (IGF)-I, which regulates cellular growth in response to available energy and nutrients from diet and body reserves. In vitro studies have clearly established that both insulin and IGF-I act as growth factors that promote cell proliferation and inhibit apoptosis. Insulin also affects on the synthesis and biological availability of the male and female sex steroids, including androgens, progesterone, and estrogens. Experimental and clinical evidence also indicates a central role of estrogens and progesterone in regulating cellular differentiation, proliferation, and apoptosis induction. Hyperinsulinemia is also associated with alterations in molecular systems such as endogenous hormones and adipokines that regulate inflammatory responses. Obesity-related dysregulation of adipokines has the ability to contribute to tumorigenesis and tumor invasion via metastatic potential. Given the substantial level of weight gain in industrialized countries in the last two decades, there is great interest in understanding all of the mechanisms by which obesity contributes to the carcinogenic process. Continued focus must be directed to understanding the various relationships between specific nutrients and dietary components and cancer cause and prevention. A reductionist approach is not sufficient for the basic biological mechanisms underlying the effect of diet and physical activity on cancer. The joint association between energy balance and cancer risk are hypothesized to share the same underlying mechanisms, the amplification of chemical mediators that modulate cancer risk depending on the responsiveness to those hormones to the target tissue of interest. Disentangling the connection between obesity, the insulin-IGF axis, endogenous hormones, inflammatory markers, and their molecular interaction is vital.

Early detection of pancreatic cancer: why, who, and how to screen

BACKGROUND

Pancreatic cancer represents the fourth-leading cause of cancer death in the United States, with a dismal 5-year survival rate of less than 5%. Despite advancements in screening and early detection of other cancers such as breast and colon cancer, no reliable screening test exists for pancreatic cancer. Subsequently, the majority of patients present with advanced-stage disease leading to a poor prognosis. Because of the relatively low incidence, current efforts are focused on early detection and screening only in patients at high risk for the development of the disease.

METHODS

We discuss the practical considerations encountered when determining if an individual should be screened for pancreatic cancer. The current literature was reviewed regarding risk factors, genetic syndromes, screening modalities, and screening studies of pancreatic cancer. The current high-risk pancreatic screening program at our institute is also summarized.

RESULTS

Current efforts to detect pancreatic cancer at a curative phase are focused on screening individuals at high risk for the development of this disease. They include kindreds with two or more first-degree relatives affected with this disease and those with known hereditary pancreatic cancer syndromes. Hereditary pancreatic cancer syndromes include Peutz-Jeghers syndrome, familial breast cancer syndrome, and familial atypical multiple mole melanoma syndrome. Of all the screening modalities available, endoscopic ultrasound is the most sensitive and specific screening tool to evaluate the pancreas and has been proven to detect early precancerous and cancerous changes in clinical studies.

CONCLUSIONS

Early detection and screening for pancreatic cancer in the current state should be limited to high-risk patients, although hereditary/familial factors account for only 10% of patients with pancreatic cancer. Continued efforts are needed to discover effective test to identify patients with nonhereditary risk factors who will benefit from screening and also to develop less invasive and more cost-effective screening modalities aimed at controlling pancreatic cancer.

Family history is a significant risk factor for pancreatic cancer: results from a systematic review and meta-analysis

Epidemiologic evidence suggests a family history of pancreatic cancer (PC) is a risk factor for the disease, yet the magnitude of risk varies between studies. We performed a systematic review of studies that quantified familial risks of PC, and through a meta-analysis, obtained more precise estimates of familial risk. A MEDLINE search identified published studies that reported relative risks (RR) of PC associated with a family history of the disease. A random effects model was used to summarize study-specific RRs and 95% confidence intervals (CI). Sensitivity and sub-group analyzes were performed. Seven case-control and two cohort studies involving 6,568 PC cases were identified. There was no evidence of statistical heterogeneity between studies (I(2) = 0%; P = 0.483). Results from case-control (RR = 2.82; 95% CI: 1.99-3.66) and cohort (RR = 1.62; 95% CI: 1.28-1.97) studies showed a significant increase in PC risk associated with having an affected relative, with an overall summary RR = 1.80 (95% CI: 1.48-2.12). Similar RR were observed for early (RR = 2.69; 95% CI: 0.56-4.82) and later (RR = 3.41; 95% CI: 0.79-6.03) onset disease in the index case. Data was too sparse to generate an overall summary RR based on the number or type of affected relatives. Individuals with a family history of PC have nearly a two-fold increased risk for developing PC compared to those without such a history. Families with two or more PC cases may benefit from comprehensive risk assessment that involves collection of detailed family history information and data regarding various risk factors for PC, especially smoking history. Those at highest risk may be referred to screening programs and studies; these are important steps toward early detection and greater odds of surviving this disease.

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.

BRCA2 mutations as a universal risk factor for pancreatic cancer has a limited role in Korean ethnic group

OBJECTIVES

BRCA2 mutations are the well-known cause of inherited susceptibility to pancreatic cancer. However, the true association of BRCA2 mutations with pancreatic cancer may vary among different ethnic groups. As such, we aimed to determine the role of BRCA2 mutations as a risk factor for sporadic and familial pancreatic cancer in Korean patients.

METHODS

Between January 1998 to October 2002, 110 patients with pancreatic ductal adenocarcinoma gave informed consent for pedigree cancer survey. Analysis of BRCA2 mutations was done in 60 of those patients, all of whom agreed to genetic test. BRCA 2 mutation was analyzed by denaturing high-performance liquid chromatography and direct sequencing.

RESULTS

Among the 110 patients, 8 cases (7.2%) were confirmed as familial pancreatic cancer. There were no pathogenic BRCA2 truncation mutations in 60 patients with BRCA2 mutation analysis. However, 2 single polymorphic amino acid changes, C1342A(H372N), A3199G(N991D), a silent polymorphism A7470G(S2414S), a splice site mutation intron 16:-14(T to C) polymorphism, and an intron 16:-12 (T to C) unclassified variant were detected in both 9 of 53 sporadic and 1 of 7 familial pancreatic cancer patients.

CONCLUSIONS

Our results suggest that the BRCA2 mutation may not contribute to increases in the risk for both sporadic and familial pancreatic cancer in Korea.

Genetic susceptibility in pancreatic ductal adenocarcinoma

BACKGROUND

The strongest risk factors for pancreatic adenocarcinoma are tobacco smoking and increasing age. However, only a few smokers or elderly individuals develop the disease and genetic factors are also likely to be important.

METHODS

The literature on genetic factors modifying susceptibility to cancer was reviewed, with particular regard to the interindividual variation that exists in the development of pancreatic adenocarcinoma.

RESULTS

Tobacco-derived carcinogen-metabolizing enzyme gene variants have been the main area of study in stratifying the risk of sporadic pancreatic cancer. Inconsistent results have emerged from the few molecular epidemiological studies performed.

CONCLUSION

There is great scope for further investigation of critical pathways and unidentified genetic influences may be revealed. This may eventually allow the identification of individuals at high risk who might be targeted for screening.

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.

Early prediction of severity in acute pancreatitis using infrared spectroscopy of serum

BACKGROUND

One of the main problems in the management of acute pancreatitis (AP) is the scarcity of accurate predictors of disease severity.

METHODS

In a prospective design, we compared APACHE II score, C-reactive protein (CRP) level, and infrared (IR) spectral absorption of serum (wavelength 940 nm) in 167 consecutive patients with AP, 34 with predicted severe and 133 with mild form.

RESULTS

The IR spectral absorption levels on admission and at 24 h after admission were significantly (p < 0.05) lower in patients with severe AP. On admission, the sensitivity was 74, 56, and 44%; the specificity was 82, 83, and 81%; the positive predictive value was 51, 45, and 37%, and the negative predictive value was 92, 88, and 85%, for IR spectroscopy, APACHE II, and CRP, respectively. At 24 h, the sensitivity, specificity, positive predictive value, and negative predictive value was 82, 74, 44, and 94%; 65, 72, 37, and 89%; 68, 73, 39, and 90%, for IR spectroscopy, CRP, and APACHE II, respectively.

CONCLUSIONS

IR spectroscopy seems to be useful for early detection of severe AP and, in turn, for identifying patients requiring treatment in the intensive care unit and who can benefit from novel therapies.

Familial pancreatic cancer: from genes to improved patient care

Pancreatic cancer is essentially a disease caused by inherited and acquired mutations in cancer-causing genes. A number of the genes responsible for the aggregation of pancreatic cancer in families have been discovered, including BRCA2, p16/CDKN2A, STK11 and PRSS1. Individuals can be tested for germline mutations in these genes; however, until recently, little could be done about the risk of pancreatic cancer if a patient was found to carry a mutation. Currently, new approaches are being developed to screen at-risk individuals for curable precancerous pancreatic lesions and laboratory studies have led to novel therapies that specifically target some of these genetic defects. This review focuses on the genetic basis for the familial aggregation of pancreatic cancer, with emphasis placed on the implications of the genetic alterations on clinical patient care.

Genetics and prevention of pancreatic cancer

BACKGROUND

Pancreatic cancer is an aggressive disease with a poor prognosis. Hereditary factors have been reported in up to 10% of cases of pancreatic cancer. The clinical characteristics and genetic abnormalities have been identified for a proportion of this high-risk group, and the development of preventive strategies for these individuals is now a primary goal of cancer clinicians.

METHODS

A review of the current literature regarding the genetics, screening, and prevention of pancreatic cancer and its precursor lesions was undertaken.

RESULTS

Risk factors for pancreatic cancer include smoking, chronic pancreatitis, and a genetic predisposition. The role of diabetes or a diet high in fat or meat remains unclear. The genetic mutations that accompany pancreatic cancer appear to occur in a temporal sequence, beginning in the earliest of precursor lesions. These mutations are detectable in pancreatic juice and, in conjunction with imaging, form the basis of screening programs for high-risk individuals. Not all precursor lesions will undergo malignant transformation, and testing is currently limited in its ability to determine which lesions will undergo transformation.

CONCLUSIONS

Avoiding tobacco smoking and minimizing risk factors associated with chronic pancreatitis are recommended to reduce the risk of pancreatic cancer. Individuals with a high-risk genetic background require counseling, genetic testing if appropriate (BRCA2 mutation or p16INK4A inactivity) and secondary screening for pancreatic cancer in specialist centers. Risk stratification will improve as more genetic abnormalities causing pancreatic cancer are defined.

Strategies for screening for pancreatic adenocarcinoma in high-risk patients

Identification of high-risk individuals, genetic counseling, and informed consent are important components of a screening program for familial pancreatic cancer. Screening high-risk individuals with imaging tests, such endoscopic ultrasound (EUS) and computed tomography (CT), can lead to the detection and treatment of predominantly asymptomatic early pancreatic neoplasms, as well as extra-pancreatic tumors. These pancreatic neoplasms consist of resectable, mostly branch-type non-invasive intraductal papillary mucinous neoplasms (IPMNs). EUS can visualize these very early IPMNs as focal duct ectasias or cysts. EUS features of chronic pancreatitis are highly prevalent in high-risk individuals and these directly correlate with multifocal lobulocentric parenchymal atrophy due to multifocal pancreatic intraepithelial neoplasia (PanIN). No one molecular marker is ready for "prime time" screening of high-risk individuals. Translational studies are underway to discover novel biomarkers for IPMNs, PanIN-3 lesions, or microinvasive adenocarcinoma, which are likely to be cured by timely intervention. Long-term, multi-prospective studies are needed to determine if screening for early pancreatic neoplasia and timely intervention results in decreased pancreatic cancer incidence and mortality in high-risk individuals.

Detecting early pancreatic cancer: problems and prospects

Pancreatic cancer has a poor prognosis. Improving survival will require diagnosis of early pancreatic cancer, which can be defined based on resectability, size, or curability. Pancreatic cancer progresses from noninvasive precursor lesions to invasive cancer over a variable time period. Retrospective review of computed tomography (CT) scans performed prior to diagnosis suggests that pancreatic cancer resectability may be significantly improved if detected as few as 6 months before clinical diagnosis. Since pancreatic cancer is relatively uncommon, to allow cost-effective screening the populations will have to be enriched for the disease using two "sieves." The first sieve would identify a population of subjects at higher than average risk of pancreatic cancer and the second sieve could be a characteristic phenotype among the members of the high-risk group, an abnormality seen on noninvasive imaging or a serologic marker of early pancreatic cancer. So far two high-risk groups have been targets of screening for pancreatic cancer: hereditary pancreatic cancer kindreds and new-onset diabetes. There is no serologic marker of early pancreatic cancer. Confirmation of diagnosis usually requires invasive procedures such as endoscopic ultrasonography (EUS). Although much work still needs to be done, the developments in the field provide us with hope that screening for early pancreatic cancer could become a reality in the not-so-distant future.

Pancreatic cancer and medical history in a population-based case-control study in the San Francisco Bay Area, California

OBJECTIVE

To determine the association between pancreatic cancer and medical conditions.

METHODS

A large population-based case-control study identified pancreatic cancer cases in the San Francisco Bay Area between 1995 and 1999. A total of 1,701 controls were randomly selected from the same population and were frequency-matched to 532 cases by sex and age. In-person interviews were conducted with no proxy interviews.

RESULTS

Prior history of gallbladder disease was associated with increased risk of pancreatic cancer (OR = 1.6, 95% CI = 1.2-2.2), with the highest risk occurring for gallbladder disease not caused by cholelithiasis (OR = 2.1, 95% CI = 1.1-3.7). Risk was associated with cholelithiasis only for participants diagnosed within the year before their pancreatic cancer (OR = 15, 95% CI = 6.2-34), and for those with cholelithiasis and cholecystectomy within the same time frame (OR = 28, 95% CI = 8.2-96). Gastric and/or duodenal ulcers were associated with increased risk of pancreatic cancer for individuals with ulcers of <or=two years duration (OR = 2.3, 95% CI = 1.1-4.6). Hyperthyroidism (OR = 2.1, 95% CI = 1.0-4.2) and "other" thyroid conditions (OR = 2.2, 95% CI = 1.1-4.2) were associated with increased risk. Participants with at least one first-degree relative with pancreatic cancer had an increased risk (OR = 1.6, 95% CI = 1.1-2.5).

CONCLUSION

History of recent gallbladder conditions, gastric and/or duodenal ulcers may represent an early manifestation of pancreatic cancer rather than an independent risk factor. These results warrant further investigation in pooled analyses.

Pancreatic cancer genetic epidemiology consortium

We have organized the Pancreatic Cancer Genetic Epidemiology (PACGENE) Consortium to identify susceptibility genes in familial pancreatic cancer (FPC). The Consortium comprises seven data collection centers, a statistical genetics core, and a pathology/archival genotyping core. We recruit kindreds containing two or more affected blood relatives ascertained through incident pancreatic adenocarcinoma cases, physician referrals, and/or through Internet recruitment. Accrual to a database containing core clinical, demographic, lifestyle, and family history information from questionnaires is ongoing, along with biospecimen collection. To date, 13,147 patients have been screened for family history, of whom 476 (50% male) probands and 1,912 of their adult (99% unaffected) relatives have been enrolled. Of these, 379 kindreds meet criteria for FPC, having at least two first-degree relatives with pancreatic cancer. Cumulative incidence curves using available age of diagnosis (onset) among and affected relatives were compared with those for incident pancreatic cancer cases reported to 13 U.S. Surveillance Epidemiology and End Results (SEER) sites from 1973 to 2000 (N = 72,700). The mean age +/- SD at diagnosis among 466 PACGENE probands and 670 affected relatives was 64.1 +/- 11.8 and was 65.4 +/- 11.6 for the subset of 369 FPC probands and 429 relatives. Both samples were significantly younger than the mean age at diagnosis in the SEER population (70.0 +/- 12.1 years; differences in curves versus SEER, P < 0.001). Age at diagnosis (excluding probands) in FPC kindreds does not decrease with increasing number of affected individuals. In our sample, younger age at diagnosis was observed whether we grouped probands by recruitment sites that predominantly recruited through high-risk referrals, or through screening all pancreatic cancer patients for family history. Linkage studies are ongoing. The PACGENE Consortium will be a valuable family-based resource that will greatly enhance genetic epidemiology research in pancreatic cancer.

Dietary intake of lycopene is associated with reduced pancreatic cancer risk

Although fruits and vegetables have been implicated in the etiology of pancreatic cancer, the role of phytochemicals in these food groups has received little attention to date. In this study, we investigated the possible association between dietary carotenoids and pancreatic cancer risk. A case-control study of 462 histologically confirmed pancreatic cancer cases and 4721 population-based controls in 8 Canadian provinces took place between 1994 and 1997. Dietary intake was assessed by a self-administered FFQ. Unconditional logistic regression was used to assess associations between specific and total carotenoid intakes and the risk of pancreatic cancer. All tests of statistical significance were 2-sided. After adjustment for age, province, BMI, smoking, educational attainment, dietary folate, and total energy intake, lycopene, provided mainly by tomatoes, was associated with a 31% reduction in pancreatic cancer risk among men [odds ratio (OR) = 0.69; 95% CI: 0.46-0.96; P = 0.026 for trend] when comparing the highest and lowest quartiles of intake. Both beta-carotene (OR = 0.57; 95% CI: 0.32-0.99; P = 0.016 for trend) and total carotenoids (OR = 0.58; 95% CI: 0.34-1.00; P = 0.02 for trend) were associated with a significantly reduced risk among those who never smoked. The results of this study suggest that a diet rich in tomatoes and tomato-based products with high lycopene content may help reduce pancreatic cancer risk.

Advances in the Genetic Screening, Work-up, and Treatment of Pancreatic Cancer

Familiarity with the updated results in genetic screening and work-up presented here is essential to early diagnosis and possible cure. In the metastatic setting, we most frequently begin with the GTX regimen, consisting of Gemcitabine, Taxotere, and Xeloda. The regimen is based on our laboratory data demonstrating a synergistic increase in cell killing of pancreatic cancer cell lines. The combination takes advantage of the selective cell cycle effects of each of the three drugs. In our initial experience, we have seen a response rate of 40% at metastatic sites and 31% at the primary site after nine cycles of GTX. We are now conducting a formal phase II protocol to confirm these results. The median survival of this group of patients (at least 10.4 months) is as long as, or longer than other currently used regimens. In those patients who do not tolerate GTX or progress despite the regimen, we have found that a regimen of the same three drugs, administered on a different schedule, can produce responses. In the neoadjuvant (unresectable) setting, we treat with GTX initially and then follow with radiation; gemcitabine is used as a radiosensitizer during this treatment. An aggressive surgical approach with a team of surgeons were able to resect for cure 12 of the 16 patients who were initially unresectable; one year survival of these 12 was 100%; 2 year survival was 50%. Future work in this disease should focus on targeted agents such as bevacizumab.

Prospective risk of pancreatic cancer in familial pancreatic cancer kindreds

Individuals with a family history of pancreatic cancer have an increased risk of developing pancreatic cancer. Quantification of this risk provides a rational basis for cancer risk counseling and for screening for early pancreatic cancer. In a prospective registry-based study, we estimated the risk of pancreatic cancer in individuals with a family history of pancreatic cancer. Standardized incidence ratios were calculated by comparing the number of incident pancreatic cancers observed with those expected using Surveillance, Epidemiology and End Results (SEER) rates. Familial pancreatic cancer (FPC) kindreds were defined as kindreds having at least one pair of first-degree relatives with pancreatic cancer, and sporadic pancreatic cancer (SPC) kindreds as families without such an affected pair. Nineteen incident pancreatic cancers developed among 5,179 individuals from 838 kindreds (at baseline, 370 FPC kindreds and 468 SPC kindreds). Of these 5,179 individuals, 3,957 had at least one first-degree relative with pancreatic cancer and contributed 10,538 person-years of follow-up. In this group, the observed-to-expected rate of pancreatic cancer was significantly elevated in members of FPC kindreds [9.0; 95% confidence interval (CI), 4.5-16.1], but not in the SPC kindreds (1.8; 95% CI., 0.22-6.4). This risk in FPC kindreds was elevated in individuals with three (32.0; 95% CI, 10.2-74.7), two (6.4; CI, 1.8-16.4), or one (4.6; CI, 0.5-16.4) first-degree relative(s) with pancreatic cancer. Risk was not increased among 369 spouses and other genetically unrelated relatives. Risk was higher in smokers than in nonsmokers. Individuals with a strong family history of pancreatic cancer have a significantly increased risk of developing pancreatic cancer.

Familial pancreatic carcinoma in Jews

Pancreatic cancer (PC) is the most fatal of all gastrointestinal cancers, wherein its mortality compares strikingly with its incidence. Unfortunately, 80-90% of PCs are diagnosed in the nonresectable stage. While the lifetime risk of PC in developed countries is approximately 1-3%, it is the fifth most common cause of cancer deaths among both males and females in Western countries. It occurs in excess in Jews. Approximately 5-10% of PC shows familial clustering. Examination of such familial clusters must take into consideration cancers of diverse anatomic sites, such as malignant melanoma in the familial atypical multiple melanoma (FAMMM) syndrome due to the CDKN2A (p16) germline mutation, and combinations of colorectal and endometrial carcinoma, ovarian carcinoma, and several other cancers in hereditary nonpolyposis colorectal cancer (HNPCC), which are due to mismatch repair germline mutations, the most common of which are MSH2 and MLH1 . Other hereditary disorders predisposing to PC include Peutz-Jeghers syndrome, due to the STK11 mutation, familial pancreatitis due to the cationic trypsinogen gene, site-specific familial pancreatic cancer which may be due to the 4q32-34 mutation, hereditary breast-ovarian cancer (HBOC) syndrome that is due to BRCA2 and possibly some families with HBOC that is due to BRCA1 , familial adenomatous polyposis due to the ATP gene, and ataxia telangiectasia due to the ATM germline mutation. This extant heterogeneity mandates that the physician be knowledgeable about these PC-prone syndromes which play such an important role when considering the differential diagnosis of hereditary PC. Unfortunately, there are no PC screening programs with acceptable sensitivity and specificity. However, the gold standard for screening at this time is endoscopic ultrasound. Clearly, there is a great need for the development of novel screening approaches with acceptable sensitivity and specificity. Further research is needed to elucidate those etiologic factors that contribute to the apparent excess of PC in Ashkenazi Jews. Attention should also be given to the search for mutations predisposing to PC in Jews so that opportunities to learn more about the disease's pathogenesis, as well as screening and control, may take place.

Molecular pathogenesis of pancreatic cancer

Pancreatic cancer is an almost universally fatal disease, with a five-year survival rate of 5%. Research into both sporadic and inherited forms of pancreatic cancer has yielded tremendous advances in the understanding of this disease at the molecular level. Elucidating genetic alterations in pancreatic cancer has identified various abnormalities ranging from gross chromosomal abnormalities to point mutations, many of which influence the development and progression of pancreatic cancer. Identifying precursor lesions within pancreatic ducts has led to the formulation of a progression model of pancreatic cancer and subsequent identification of early- and late-stage changes leading to invasive cancer. Ultimately, understanding the genetic events underlying the development of pancreatic cancer may serve as a useful adjunct in the screening and treatment of patients suffering from, or at risk for, pancreatic cancer.

Pancreatic cancer - a continuing challenge in oncology

Pancreatic cancer is still one of the major health problems because of its rising incidence and the modest therapeutic results. The paper surveys the statistical data, the risk factors, the preneoplastic ductal lesions, the hormonal sensitivity, the possible transdifferentiation in the endocrine and exocrine parts and the possibilities for chemoprevention. Hungary is peculiar among the European countries because during the last 50 years the incidence of pancreatic cancer has displayed a 15-fold increase. Apart from smoking, additional risk factors seem to be important, and recently a puzzling association between Helicobacter pylori seropositivity and pancreatic cancer was found. First-degree relatives of patients with pancreatic cancer are also at increased risk of this tumor. The term pancreatic intraepithelial neoplasia (PanIN) seems yet to be established, but the dynamics of these lesions needs to be further elucidated. Several lines of firmly established data indicate the hormonal sensitivity of this tumor, but still an unexplained discrepancy exists between the experimental and the clinical results. In addition to the somatostatin analogs, anti-gastrin vaccine is being tested. The mixed exocrine-endocrine tumors might suggest a real possibility of transdifferentiation between different compartments of the pancreas. Finally, the paper outlines the available data about the possibility of chemoprevention, including the role of cyclooxygenase inhibitors.

Update on familial pancreatic cancer

Approximately 5% to 10% of patients with pancreatic cancer have one or more first-degree relatives with this disease. A subset of these individuals have a hereditary form of pancreatic cancer designated by association with such hereditary disorders as familial adenomatous polyposis, hereditary nonpolyposis colorectal cancer, hereditary pancreatitis, or familial atypical multiple mole melanoma (FAMMM) syndrome. A subset of those FAMMM kindred with the CDKN2A (p16) germline mutation that expresses both pancreatic cancer and malignant melanoma may constitute a new hereditary pancreatic cancer-prone syndrome.

The rate of the 6174delT founder Jewish mutation in BRCA2 in patients with non-colonic gastrointestinal tract tumours in Israel

Inherited predisposition occurs in 5-10% of all gastrointestinal (GI) cancer patients, but with the exception of colorectal cancer (CRC), the genes involved in conferring genetic susceptibility remain largely unknown. Indirect evidence indicates that germline mutations in BRCA2 might be associated with an increased risk for various GI malignancies. A single mutation (6174delT) occurs in the BRCA2 gene in high-risk breast ovarian cancer families of Jewish Ashkenazi origin, in about 1% of the general Ashkenazi population, and rarely in non-Ashkenazi Jews. In order to assess the contribution of this germline mutation to non-CRC GI cancer in Jewish Israeli patients, we tested 70 unselected, consecutive Jewish Ashkenazi patients with gastrointestinal malignancies for this mutation by PCR amplification and modified restriction enzyme digests. Patients' age range was 38-90 years (mean 65.8+/-11.8 years). The most common malignancies were gastric cancer (n = 35) and exocrine pancreatic cancer (n = 23). Overall, 6 mutation carriers were detected: 3/23 (13%) of the patients with pancreatic cancer, 2/35 (5.7%) of patients with gastric cancer and 1/4 (25%) of patients with bile duct cancer. The 8.6% mutation carrier rate among patients is a rate significantly higher than that of the general Ashkenazi population (1.16%, P = 0.0002). We conclude that the rate of the predominant Jewish BRCA2 mutation in patients with gastric and pancreatic cancer significantly differ from that of the general population of the same ethnic origin. Thus, BRCA2 mutations probably contribute to gastrointestinal tumorigenesis other then colon cancer, and the surveillance scheme for mutation carriers should incorporate this information.

Familial pancreatic cancer

BACKGROUND

For many years anecdotal case reports have suggested that pancreatic cancer aggregates in some families.

METHODS

Two recent advances have established that this is in fact the case. First, large registries, such as the National Familial Pancreas Tumor Registry (NFPTR) at Johns Hopkins, have identified a number of families in which multiple family members have been diagnosed with pancreatic cancer. As a result, the patterns of inheritance of pancreatic cancer can now be studied on a scale not possible before. Second, advances in molecular genetic techniques make it possible to test members of these families for germline mutations in known candidate cancer causing genes. As a result, some of the genetic alterations responsible for the familial aggregation of pancreatic cancer have been identified in some families.

RESULTS

The NFPTR has enrolled 362 families in which at least one family member has been diagnosed with pancreatic cancer. These include 151 families in which at least two first-degree relatives have been diagnosed with pancreatic cancer. Analysis of these families has revealed that even second-degree relatives of patients from these families are at increased risk of developing pancreatic cancer. In addition, a number of kindreds which exhibit aggregation of cancer have been tested for germline mutations in known cancer causing genes. Germline mutations in BRCA2 have been shown to predispose to both breast and pancreatic cancer, germline mutations in p16 to melanoma and pancreatic cancer (the FAMMM syndrome), and genetic mutations in STK11/LKB1 to pancreatic cancer in patients with the Peutz-Jeghers Syndrome (PJS).

CONCLUSIONS

Pancreatic cancer aggregates in some families, and relatives of patients with pancreatic cancer have an increased risk of developing pancreatic cancer themselves. The genetic basis for the familial aggregation of pancreatic cancer has been shown to be germline mutations in known cancer causing genes in some of these families.

Diabetes mellitus, other medical conditions and familial history of cancer as risk factors for pancreatic cancer

In a population-based case-control study of pancreatic cancer conducted in three areas of the USA, 484 cases and 2099 controls were interviewed to evaluate the aetiologic role of several medical conditions/interventions, including diabetes mellitus, cholecystectomy, ulcer/gastrectomy and allergic states. We also evaluated risk associated with family history of cancer. Our findings support previous studies indicating that diabetes is a risk factor for pancreatic cancer, as well as a possible complication of the tumour. A significant positive trend in risk with increasing years prior to diagnosis of pancreatic cancer was apparent (P-value for test of trend = 0.016), with diabetics diagnosed at least 10 years prior to diagnosis having a significant 50% increased risk. Those treated with insulin had risks similar to those not treated with insulin (odds ratio (OR) = 1.6 and 1.5 respectively), and no trend in risk was associated with increasing duration of insulin treatment. Cholecystectomy also appeared to be a risk factor, as well as a consequence of the malignancy. Subjects with a cholecystectomy at least 20 years prior to the diagnosis of pancreatic cancer experienced a 70% increased risk, which was marginally significant. In contrast, subjects with a history of duodenal or gastric ulcer had little or no elevated risk (OR = 1.2; confidence interval = 0.9-1.6). Those treated by gastrectomy had the same risk as those not receiving surgery, providing little support for the hypothesis that gastrectomy is a risk factor for pancreatic cancer. A significant 40% reduced risk was associated with hay fever, a non-significant 50% decreased risk with allergies to animals, and a non-significant 40% reduced risk with allergies to dust/moulds. These associations, however, may be due to chance since no risk reductions were apparent for asthma or several other types of allergies. In addition, we observed significantly increased risks for subjects reporting a first-degree relative with cancers of the pancreas (OR = 3.2), colon (OR = 1.7) or ovary (OR = 5.3) and non-significantly increased risks for cancers of the endometrium (OR = 1.5) or breast (OR = 1.3). The pattern is consistent with the familial predisposition reported for pancreatic cancer and with the array of tumours associated with hereditary non-polyposis colon cancer.

Pancreatic adenocarcinoma: epidemiology and genetics

Pancreatic adenocarcinoma is an important cause of death from cancer throughout the developed world. There are few established environmental risk factors, but a previous history of pancreatitis and exposure to tobacco and salted food appear to be the most important. A family history of pancreatic adenocarcinoma is not common in patients with this disease, but recent research has shown that pancreatic adenocarcinoma can be a feature of cancer susceptibility syndromes associated with germline mutations in p16, BRCA1, BRCA2, and APC. This highlights the need for a full family history in apparently sporadic cases. Somatic mutations in p16, BRCA2, and APC have also been reported in pancreatic cancer; however, K-RAS mutations appear to be the commonest oncogenic alteration. Recent advances in our understanding of the basis of hereditary cancer syndromes may be applicable to the diagnosis, treatment, and possibly prevention of pancreatic adenocarcinoma in the future.

Clinical relevance of serological markers in the detection and follow-up of pancreatic adenocarcinoma

Pancreatic adenocarcinoma is a relatively common malignancy and its incidence is increasing. Prognosis in these patients is poor, and surgery, the only effective treatment, saves only a minority of patients. The number in this small group of patients might be increased by early detection of pancreatic tumours. This review examines the current status of pancreatic tumour associated proteins in the detection of pancreatic cancer. As well as existing markers, the review also reports on newer markers that may offer advantages over existing ones in the detection of pancreatic adenocarcinoma. This is particularly important because recent studies have identified high-risk groups susceptible to pancreatic cancer. Future research in pancreatic cancer should be directed at earlier detection, and tumour markers may play an important role in this process.

Epidemiology of and risk factors for pancreatic cancer

In the United States, incidence of and mortality from pancreatic cancer increased for several decades earlier in this century but have tended to level off in recent years. Rates increase with age and are higher in blacks than in whites and higher in males than in females. No consistent differences by socioeconomic status or by geographic location in the United States have been identified, although international variation and differences in migrants have been observed. Thus, both genetic and environmental factors may be playing significant roles in the development of pancreatic cancer. Cigarette smoking increases the risk of pancreatic cancer, but the strength of this association is much less than for lung cancer or other smoking-related cancers. Epidemiologic studies of the effect of alcohol consumption on pancreatic cancer largely show no relationship, and the results for coffee consumption indicate little, if any, association. Human studies have suggested positive associations with meat consumption and carbohydrate intake and a protective effect of dietary fiber and consumption of fruits and vegetables. Results of a number of occupational studies are suggestive of increased risk associated with some exposures but are not fully consistent. Thus, much progress has been made in the last two decades in identifying risk factors, but much epidemiologic work is needed to identify and reduce putative exposures.

Tobacco-specific N-nitrosamines and Areca-derived N-nitrosamines: chemistry, biochemistry, carcinogenicity, and relevance to humans

Nicotine and the minor tobacco alkaloids give rise to tobacco-specific N-nitrosamines (TSNA) during tobacco processing and during smoking. Chemical-analytical studies led to the identification of seven TSNA in smokeless tobacco (< or = 25 micrograms/g) and in mainstream smoke of cigarettes (1.3 micrograms TSNA/cigarette). Indoor air polluted by tobacco smoke may contain up to 24 pg/L of TSNA. In mice, rats, and hamsters, three TSNA, N'-nitrosonornicotine (NNN), 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), are powerful carcinogens; two TSNA are moderately active as carcinogens; and two TSNA appear not to be carcinogenic. The TSNA are procarcinogens, agents that require metabolic activation. The active forms of the carcinogenic TSNA react with cellular components, including DNA, and with hemoglobin (Hb). The Hb adducts in chewers and smokers serve as biomarkers for the uptake and metabolic activation of carcinogenic TSNA and the urinary excretion of NNAL as free alcohol and as glucuronide for the uptake of TSNA. The review presents evidence that strongly supports the concept that TSNA contribute to the increased risk for cancer of the upper digestive tract in tobacco chewers and for the increased risk of lung cancer, especially pulmonary adenocarcinoma, in smokers. The high incidence of cancer of the upper digestive tract especially among men on the Indian subcontinent has been causally associated with chewing of betel quid mixed with tobacco. In addition to the TSNA, the betel quid chewers are exposed to four N-nitrosamines that are formed during chewing from the Areca alkaloids, two of these N-nitrosamines are carcinogens. The article also reviews approaches toward the reduction of the carcinogenic potency of smokeless tobacco, betel quid-tobacco mixtures, and cigarette smoke. Although the safest way to reduce the risk for tobacco-related cancers is to refrain from chewing and smoking, modifications of smokeless tobacco and of cigarettes are indicated to lead to less toxic products. Another more recent approach for reducing the carcinogenic effect of tobacco products is the application of chemopreventive agents, primarily of micronutrients. Future aspects in tobacco carcinogenesis, especially as it relates to TSNA, are expected in the field of molecular biochemistry and in biomarker studies, with the goal of identifying those tobacco and betel quid chewers and tobacco smokers who are at especially high risk for cancer.