Pancreatic cancer, linked to dietary habits, grows slowly - studies
A new study in the October 28, 2010 issue of the journal Nature suggests that the growth of pancreatic cancer is a slow process and it takes almost 20 years for the disease to develop from a pancreatic cancer cell to a tumor, which spreads to other organs (metastasis) and eventually kills a patient in a couple of years.
Christine Iacobuzio-Donahue, M.D., Ph.D., associate professor of pathology and oncology at Hopkins' Sol Goldman Pancreatic Cancer Research Center and colleagues studied genetic mutations using genetic material collected from pancreatic cancer patients who died from the disease and determined the timing of the carcinogenesis.
Based on sophisticated mathematical models, they found it takes an average of 11.7 years for the first cancer cell to develop within a high grade pancreatic lesion, and then another 6.8 years for the cancer to grow and for at least another cancer cell to potentially spread and finally an average of 2.7 years for the disease to kill a patient.
Pancreatic cancer is so dangerous that 95 percent of patients who are diagnosed with the disease die within five years of diagnosis because the cancer is hard to be found early enough to be treated.
Iacobuzio-Donahue's study was to find a screening method to help detect pancreatic cancer at a time the disease is still treatable.
Bert Vogelstein, M.D., at the Ludwig Center for Cancer Genetics & Therapeutics at the Johns Hopkins Kimmel Cancer Center said the study results show "many pancreatic cancer cases have a long lag time before they are detected through conventional tests. This leaves room to develop new early, diagnostic tools and intervene with potentially curative surgery."
Although pancreatic cancer is dangerous, the risk for a person to acquire the disease may be reduced by following a healthy lifestyle. Quite some research conducted suggests that dietary habits were linked to pancreatic cancer.
Fruit and vegetables cut the risk while meat, sugar and high GI diet boosts the risk
A study published in Nov 2009 in Cancer Causes and Control suggests eating meat may increase risk of pancreatic cancer while eating fruit and vegetables may reduce the risk.
The case-control study led by Jerry Polesel at Centro di Riferimento Oncologico, IRCCS in Aviano, Italy and colleagues showed those who frequently consumed meat were twice as likely to develop pancreatic cancer.
Polesel et al. analysed data on dietary habits of 326 patients with pancreatic cancer aged 63 on average and 652 controls at the same age and found the association.
They found meat cooked by boiling, stewing or broiling or roasting was also significantly associated with the risk.
Additionally, use of added table sugar and potatoes were also associated with about 100 percent increased risk of pancreatic cancer.
It is unknown why meat, sugar and potatoes were linked with increased risk of pancreatic cancer. One thing for sure is that cooked potatoes like fries and roasted or grilled meat, particularly red meat contain carcinogens. Sugar can boost the production of insulin-like growth hormone, which is known to promote cancer growth.
On the other hand, the authors of the study found non-citrus fruits, cooked vegetables and pulses may potentially reduce the risk of pancreatic cancer by 59 percent, 43 percent and 41 percent respectively.
Polesel et al concluded "The present study supports an inverse association between fruits and vegetables and pancreatic cancer risk, and it confirms a direct relation with meat. The increased risk for table sugar suggests that insulin resistance may play a role in pancreatic carcinogenesis."
Another study by researchers including Jerry Polesel at Istituto di Ricerche Farmacologiche “Mario Negri,” Milan, Italy also came to the same conclusion.
Marta Rossi SCD. and colleagues used the data set from the patients and controls and found glycemic index, but not glycemic load was associated with pancreatic cancer.
The researchers found a diet with highest glycemic index, which means the diet releases glucose at a fastest speed was linked with up to 78 percent increased risk of pancreatic cancer, compared to a diet with the lowest glycemic index.
Consumption of sugar, candy, honey, and jam was positively associated with the cancer while consumption of fruit was inversely associated.
The findings were reported in the June 2010 issue of Annals of Epidemiology.
Again based on data from the same study subjects and controls, Poelsel and colleagues found the highest quintile of intake of vitamin E, vitamin C and potassium were associated with 40 percent, 56 percent and 44 percent reduced risk of pancreatic cancer compared to the lowest quintle of intake.
The findings were published in April 2010 in Annals of Oncology.
It should be noted that the associations does not mean taking vitamin E, vitamin C and potassium supplements may definitely help reduce the risk even though the possibility can't be excluded either. These nutrients are present largely in plant foods.
By David Liu
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