Risk of malignancy in first-degree relatives of patients with pancreatic carcinoma

The inherited genetic component of sporadic pancreatic adenocarcinoma

Pancreatic cancer, like many other complex diseases, has genetic and environmental components to its etiology. It is likely that relatively common genetic variants with modest effects on pancreatic cancer risk play an important role in both familial and sporadic forms of the disease, either individually or in interaction with environmental factors. The relatively high frequency of such variants means that they could potentially explain a substantial portion of disease risk. Here we summarize the findings published to date from genetic association studies. In general, very few low-penetrance variants have been identified and those that have require replication in independent studies. Possible gene-environment interactions arising from these studies also require replication. More comprehensive approaches are needed to make progress, including global analyses of biologically sound pathways and genome-wide association studies. Large sample sizes are required to do this appropriately and multi-study consortia make this possible. A number of consortia of pre-existing studies have already been formed, and these will facilitate the identification of further low-penetrance variants and gene-environment interaction. However, these approaches do not substitute for the design of novel, sufficiently powered studies that apply uniform criteria to case selection, the acquisition of environmental exposure information, and to biological sample collection.

Pancreatic cancer: translating lessons from mouse models and hereditary syndromes

Pancreatic ductal adenocarcinoma is the overwhelmingly predominant form of pancreatic cancer and the second most common type of gastrointestinal cancer (behind colorectal cancer) in the United States. Recent exciting advances in two areas of pancreatic ductal adenocarcinoma (i.e., the development and characterization of genetically engineered mouse models and the dissection of the genetic basis of hereditary forms in families) have been illuminating. These preclinical models and clinical syndromes provide the first tangible basis for progress in screening and prevention in high-risk populations and in the development of molecular diagnostics and experimental therapeutics.

ABO blood group and the risk of pancreatic cancer

BACKGROUND

Other than several rare, highly penetrant familial syndromes, genetic risk factors for sporadic pancreatic cancer are largely unknown. ABO blood type is an inherited characteristic that in previous small studies has been associated with the risk of gastrointestinal malignancies.

METHODS

We separately examined the relationship between ABO blood type and the risk of incident pancreatic cancer in two large, independent, prospective cohort studies (the Nurses' Health Study and Health Professionals Follow-up Study) that collected blood group data on 107 503 US health professionals. Hazard ratios for pancreatic cancer by ABO blood type were calculated using Cox proportional hazards models with adjustment for other known risk factors, including age, tobacco use, body mass index, physical activity, and history of diabetes mellitus. All statistical tests were two-sided.

RESULTS

During 927 995 person-years of follow-up, 316 participants developed pancreatic cancer. ABO blood type was associated with the risk of developing pancreatic cancer (P = .004; log-rank test). Compared with participants with blood group O, those with blood groups A, AB, or B were more likely to develop pancreatic cancer (adjusted hazard ratios for incident pancreatic cancer were 1.32 [95% confidence interval {CI} = 1.02 to 1.72], 1.51 [95% CI = 1.02 to 2.23], and 1.72 [95% CI = 1.25 to 2.38], respectively). The association between blood type and pancreatic cancer risk was nearly identical in the two cohorts (P(interaction) = .97). Overall, 17% of the pancreatic cancer cases were attributable to inheriting a non-O blood group (blood group A, B, or AB). The age-adjusted incidence rates for pancreatic cancer per 100 000 person-years were 27 (95% CI = 23 to 33) for participants with blood type O, 36 (95% CI = 26 to 50) for those with blood type A, 41 (95% CI = 31 to 56) for those with blood type AB, and 46 (95% CI = 32 to 68) for those with blood type B.

CONCLUSIONS

In two large, independent populations, ABO blood type was statistically significantly associated with the risk of pancreatic cancer. Further studies are necessary to define the mechanisms by which ABO blood type or closely linked genetic variants may influence pancreatic cancer risk.

ABO blood group and the risk of pancreatic cancer

BACKGROUND

Other than several rare, highly penetrant familial syndromes, genetic risk factors for sporadic pancreatic cancer are largely unknown. ABO blood type is an inherited characteristic that in previous small studies has been associated with the risk of gastrointestinal malignancies.

METHODS

We separately examined the relationship between ABO blood type and the risk of incident pancreatic cancer in two large, independent, prospective cohort studies (the Nurses' Health Study and Health Professionals Follow-up Study) that collected blood group data on 107 503 US health professionals. Hazard ratios for pancreatic cancer by ABO blood type were calculated using Cox proportional hazards models with adjustment for other known risk factors, including age, tobacco use, body mass index, physical activity, and history of diabetes mellitus. All statistical tests were two-sided.

RESULTS

During 927 995 person-years of follow-up, 316 participants developed pancreatic cancer. ABO blood type was associated with the risk of developing pancreatic cancer (P = .004; log-rank test). Compared with participants with blood group O, those with blood groups A, AB, or B were more likely to develop pancreatic cancer (adjusted hazard ratios for incident pancreatic cancer were 1.32 [95% confidence interval {CI} = 1.02 to 1.72], 1.51 [95% CI = 1.02 to 2.23], and 1.72 [95% CI = 1.25 to 2.38], respectively). The association between blood type and pancreatic cancer risk was nearly identical in the two cohorts (P(interaction) = .97). Overall, 17% of the pancreatic cancer cases were attributable to inheriting a non-O blood group (blood group A, B, or AB). The age-adjusted incidence rates for pancreatic cancer per 100 000 person-years were 27 (95% CI = 23 to 33) for participants with blood type O, 36 (95% CI = 26 to 50) for those with blood type A, 41 (95% CI = 31 to 56) for those with blood type AB, and 46 (95% CI = 32 to 68) for those with blood type B.

CONCLUSIONS

In two large, independent populations, ABO blood type was statistically significantly associated with the risk of pancreatic cancer. Further studies are necessary to define the mechanisms by which ABO blood type or closely linked genetic variants may influence pancreatic cancer risk.

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.

Genetic predisposition and environmental risk factors to pancreatic cancer: A review of the literature

Some cases of pancreatic cancer (PC) are described to cluster within families. With the exception of PALLD gene mutations, which explain only a very modest fraction of familial cases, the genetic basis of familial PC is still obscure. Here the literature was reviewed in order to list the known genes, environmental factors, and health conditions associated with PC or involved in the carcinogenesis of the pancreas. Most of the genes listed are responsible for various well-defined cancer syndromes, such as CDKN2A (familial atypical mole-multiple melanoma, FAMMM), the mismatch repair genes (Lynch Syndrome), TP53 (Li-Fraumeni syndrome), APC (familial adenomatous polyposis), and BRCA2 (breast-ovarian familial cancer), where PC is part of the cancer spectrum of the disease. In addition, in this review I ranked known/possible risk factors extending the analysis to the hereditary pancreatitis (HP), diabetes, or to specific environmental exposures such as smoking. It appears that these factors contribute strongly to only a small proportion of PC cases. Recent work has revealed new genes somatically mutated in PC, including alterations within the pathways of Wnt/Notch and DNA mismatch repair. These new insights will help to reveal new candidate genes for the susceptibility to this disease and to better ascertain the actual contribution of the familial forms.

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.

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.

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.

Association of family history of specific cancers with a younger age of onset of pancreatic adenocarcinoma

BACKGROUND & AIMS

Pancreatic adenocarcinoma has been associated with several familial cancer syndromes that also predispose to other malignancies. Younger ages of onset of pancreatic cancer (PC) have been reported in families with these syndromes.

METHODS

Six hundred twenty-four consecutive patients (probands) from the Mayo Clinic Pancreatic Cancer Patient Registry who completed questionnaires were analyzed for family history of cancer and cigarette smoking. The ages at diagnosis of those probands who reported a family history (first- or second-degree relative) of PC, breast, ovarian, colorectal cancer, or melanoma were compared with those probands who did not. Multivariable regression analyses were performed with age at diagnosis as the primary outcome variable.

RESULTS

As expected, smokers had a younger median age of onset of PC than nonsmokers in dose-dependent fashion (P = .0003). After controlling for tobacco exposure and gender, those probands with a family history of breast (-3.23 years, P = .001), ovarian (-5.63 years, P = .005), colorectal (-3.19 years, P = .002) cancers, and melanoma (-5.75 years, P = .017) had a younger age of onset of PC than those who did not. Those with a family history of PC (-.61 years, P = .65) exhibited no difference. Probands reporting other cancers in relatives showed no difference (+.78 years, P = .49) in age of onset of PC.

CONCLUSION

A family history of cancers (breast, ovarian, colorectal, melanoma) associated with specific cancer syndromes that are known to contribute also to PC risk is associated with a younger onset of PC. A family history of PC does not appear to affect age of onset of PC.