More Power to Population Studies in Pancreas Cancer Research
UCSF clinicians and researchers are joining with counterparts far and wide to conduct large studies that will yield the statistical power necessary to clearly identify factors associated with risk for pancreas cancer.
So far, the only undisputed factors known to increase one's chances of getting pancreas cancer are cigarette smoking - which doubles risk - and a strong family history of the disease.
Because pancreas cancer is rare, it takes a long time to conduct studies with enough patients to yield statistically meaningful results. The Pancreas Cancer Program at UCSF has joined with Seattle researchers at Group Health Cooperative and Fred Hutchinson Cancer Research Center, as well as UC Irvine researchers, to form the Western Pancreatic Cancer Consortium. As patients are enrolled in new studies, data will be collected similarly, so that they may be pooled for analysis.
UCSF Population Scientist Is a Pioneer
Much of the consortium's research will build on earlier studies by UCSF's Elizabeth Holly. Before the UCSF Pancreas Cancer Program was established, Holly had nearly finished collecting data for the largest-ever population study of pancreas cancer: a comparison of 600 diagnosed cases of pancreas cancer and 1,700 controls - people who were demographically similar, but did not have pancreas cancer.
Cases for the National Cancer Institute (NCI)-sponsored study were identified through the Bay Area SEER cancer registry. Holly's research team contacted patients and controls, and asked individuals to participate in a survey. In many cases, the researchers also were able to study blood or tissue.
From an earlier analysis of the results, Holly concluded that allergies are likely to be somewhat protective against the disease. In addition, Holly and UCSF molecular epidemiologist John Wiencke identified genetic variations that can amplify a smoker's risk for the disease.
More recent analysis of the data from this study now indicates that one's diet may, in some cases, affect the likelihood of developing pancreas cancer.
Holly has found that individuals who ate five or more servings of vegetables daily had about 50 percent less risk of pancreas cancer than people who ate fewer servings. Whole grains, fruits and fiber also appear to have a protective effect, Holly says. Sweets containing trans fats appear to increase risk.
Holly also investigated in more detail the previous observation that pancreatitis and diabetes are sometimes associated with pancreas cancer. Holly found that pancreas cancer is most often diagnosed within just a few years of these other diseases, as opposed to many years later. This suggests to Holly that undetected pancreas cancers may, in some cases, cause diabetes and pancreatitis - not the other way around. But she plans to further investigate these associations in her next study.
"Gastroenterologists may want to carefully follow smokers under age 60 who develop pancreatitis to see whether they have or develop pancreas cancer," Holly says.
Holly and colleagues recently were funded by the NCI to collect data on 600 more cases and 600 controls. This time, patients will be enrolled very close to the time when they are first diagnosed and seen in the clinic. A strong emphasis will be placed on molecular epidemiology and on the detection of interactions between genetic makeup and environmental exposures that influence pancreas cancer risk or survival.
Worldwide Collaboration
As part of another, worldwide collaboration - funded in part by the NCI - Holly's research results will be analyzed together with data obtained in 14 other studies on populations from Baltimore, Houston, Seattle, Connecticut, Florida, Louisiana, Michigan, Minnesota, Australia, Canada, the European Union, China and Egypt.
Nearly 5,000 cases will be included in this meta-analysis, as well as 7,000 controls. With so many more cases to study, there will be a greater opportunity to identify gene-environment interactions, and to conduct an open-ended search for genes that may play a role in pancreas cancer, Holly says.
This story first appeared in Pancreas Cancer News.
Related Links:
Elizabeth A. Holly, PhD, MPH
UCSF Comprehensive Cancer Center
High-Vegetable Diet Linked to Protection Against Pancreatic Cancer
UCSF News Release, September 15, 2005
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Elizabeth Holly |
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Vegetable and Fruit Intake and Pancreatic Cancer in a Population-Based Case-Control Study in the San Francisco Bay Area
June M. Chan, Furong Wang and Elizabeth A. Holly
Cancer Epidemiology Biomarkers and Prevention 2005; 14:2093-2097
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Reproductive and Menstrual Risk Factors for Pancreatic Cancer: A Population-Based Study of San Francisco Bay Area Women
Eric J. Duell and Elizabeth A. Holly
American Journal of Epidemiology 2005; 161(8):741-747
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Signs and Symptoms of Pancreatic Cancer: A Population-Based Case-Control Study in the San Francisco Bay Area
Elizabeth A. Holly, Indranushi Chaliha, Paige M. Bracci and
Manjushree Gautam
Clincal Gastroenterology and Hepatology 2004; 2:510-517
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Prior History of Allergies and Pancreatic Cancer in the
San Francisco Bay Area
Elizabeth A. Holly, Carey A. Eberle and Paige M. Bracci
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A Population-Based, Case-Control Study of Polymorphisms in Carcinogen-Metabolizing Genes, Smoking, and Pancreatic Adenocarcinoma Risk Eric J. Duell, Elizabeth A. Holly, Paige M. Bracci, Mei Liu, John K. Wiencke and Karl T. Kelsey Journal of the National Cancer Institute 2002; 94(4):297-306 Abstract | Full Text | Full Text (PDF) |
Related Links
- Elizabeth A. Holly, PhD, MPH
- UCSF Comprehensive Cancer Center
- High-Vegetable Diet Linked to Protection Against Pancreatic Cancer
- UCSF News Release, September 15, 2005