Smoking may be an environmental trigger that activates pancreatic cancer in people with a family history of this usually fatal disease, a new study suggests.

The finding underscores the importance of not smoking if your family members have had pancreatic cancer. In addition, you should consider being screened for the disease beginning at around 40. About 10 percent to 15 percent of those with pancreatic cancer have a family history of the disease.

"We found that patients with a hereditary predisposition to pancreatic cancer tend to present at an earlier age, compared with the general population of patients who have pancreatic cancer," said lead researcher Dr. Ted James, a clinical fellow at Roswell Park Cancer Institute. In addition, "The majority of patients with familial pancreatic cancer were smokers."

In their study, James and his colleagues collected data on 826 patients with pancreatic cancer. Among these, 30 had a family history of pancreatic cancer, according to the report in the November online edition of Cancer.

The data revealed the average age at diagnosis of those with a family history of pancreatic cancer was 57.1 years, compared with 61 years for those without a family history. Moreover, 36.7 percent of those with hereditary pancreatic cancer were diagnosed before age 50, compared with 18.3 percent of those who had no family history of this cancer.

James� team also found that 87 percent of those with hereditary pancreatic cancer smoked, compared with 66 percent of others with the disease.

There may be a different expression of genes among people with a family history of pancreatic cancer, and smoking may put them at a higher risk, James said.

"Unfortunately, survival from this disease is pretty poor," James said. "Survival tends to be the lowest, compared with other cancers. Anything we can do in terms of prevention or early detection is going to have a great impact. Even with its dismal prognoses, it is much better if you find it early, when you have a better chance of survival, than if you find it in the later stages."

James said that many are coming to the conclusion that early screening with ultrasound is important for those with a family history of pancreatic cancer.

"There may be a benefit in some sort of screening program for these patients. Screening should begin around 40. If you have a family history of pancreatic cancer, you may want to look for screening programs," James said. "And obviously, if you smoke, you should stop smoking, and if you are a nonsmoker, then stay so."

"It�s not just lung cancer," said Dr. Herman Kattlove, a medical oncologist and spokesman for the American Cancer Society. "Smoking is a cause of many cancers, and is a risk factor for all pancreatic cancer."

Kattlove believes that those with a family history of pancreatic cancer should be evaluated. "There is evidence that if you catch them early you can cure them," he said.