Healthcare Professionals

Risk Factors

There is documented association between certain environmental exposures like smoking, environmental tobacco smoke (ETS), chemical exposure and the incidence of pancreatic cancer. Although the chain of causation is not exactly known, the following have been identified as risk factors for pancreatic cancer. All these factors possibly contribute to the development of pancreatic cancer at a later stage with other associated complications.

Risk factors for pancreatic cancer:

• Age

Age is the strongest risk factor for pancreatic cancer. The risk is almost 20 times higher for individuals older than 50 years as compared to younger persons.

• Smoking

Exposure to tobacco smoke has a predominant role in the development of pancreatic cancer. Established results confirmed that tobacco smoking contributes about 20-30% of all pancreatic cancers. Smoking cessation can reduce this risk.

• Environmental tobacco smoke (ETS)

Passive smoking is also a risk factor for pancreatic cancer. ETS contains the same toxins, irritant and carcinogens such as nicotine, carbon monoxide, ammonia, benzene, vinyl chlorides arsenic and other hydrocarbons similar to that of cigarette smoke.

• Diabetes mellitus

History of diabetes mellitus (DM) is associated with an increased risk of pancreatic cancer. The presence of DM, chronic cirrhosis, pancreatitis and fatty diet has a synergistic effect in development of pancreatic cancer. The association between pancreatic cancer and DM is complex because pancreatic cancer can itself damage the pancreatic parenchyma and lead to DM and pancreatitis.

Analysis of 20 epidemiologic studies have shown that relative risk of pancreatic cancer in patients with DM for 5 years is almost double compared to the risk of patients without DM. It also concluded that impaired glucose tolerance, insulin resistance, and hyperinsulinemia are involved in the etiology of pancreatic cancer.

• Obesity and physical activity

According to a cohort study of 160,000 healthcare professionals, it was concluded that high Body Mass Index, increased weight and less physical activity increased the risk of pancreatic cancer, while moderate physical activity resulted in decreased pancreatic cancer rates. Regular exercise, walking or hiking for 1.5 hours on weekly basis resulted in further reduction of pancreatic cancer by another 50%. These observations clearly suggest that weight loss and exercise can reduce the risk of developing pancreatic cancer but independent of smoking cessation.

• Occupational factors

An occupational study carried out during 1969-1998 observed that people who are often exposed to chlorinated hydrocarbon solvents, nickel and nickel compounds, chromium compounds, polycyclic aromatic hydrocarbons, organochlorine insecticides, silica dust and aliphatic solvents are at a much greater risk of developing pancreatic cancer. Some professions like petrochemical industry, hair dressing and rubber industry are associated with higher incidence of pancreatic cancer, possibly because of increased exposure to aromatic amines.

• Genetic predisposition

Pancreatic cancer is often characterised by inherited and genetic mutations. Genetic predisposition is regarded as one of the major risk factors in the development of cancer. It is considered that activation of the oncogene K-ras with simultaneous inactivation of the tumor suppressor genes (p53, DPC4, p16, and BRCA2) results in pancreatic cancer.

90% of all cases of pancreatic cancer have p16 mutations, 75% have p53 mutations, and 55% have DPC4 mutations. A small fraction may evolve due to the dysfunction of the various DNA mismatch repair genes [microsatellite instability (MSI)].

About 10-20% of all pancreatic cancers are considered to be hereditary in origin. Studies have shown an increased risk of developing pancreatic cancer is seen among individuals who report a family history of pancreatic cancer. The risk increases with the total number of affected members of the family. There was a 57-fold increased risk seen when three or more family members were affected with pancreatic cancer.

• Miscellaneous factors

Some of the other factors studied include moderate alcohol intake, nonhereditary and acute pancreatitis, and consumption of excess coffee. The effect of these parameters on incidence of pancreatic cancer is not clearly understood.

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