[MOL] Pamcreas Camcer Risks - Series [02088] Medicine On Line


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[MOL] Pamcreas Camcer Risks - Series



Pancreas


Roni Falk, M.S.*

The pancreas, an organ about six inches long located behind the stomach, has two functions: to send insulin into the bloodstream to control the amount of sugar in the blood and to send pancreatic juice into the intestine to help digest food. Cancer usually occurs in the small tubes or ducts in the organ which transport the pancreatic juice.

Cancer of the pancreas is a Òsilent" disease that occurs in an inaccessible part of the body, remaining asymptomatic until well advanced. Characteristically, pancreatic cancer presents with pain, biliary obstruction, clinical wasting (10 percent or more of normal body weight by the time of diagnosis), and early subclinical metastases. To date, only a biopsy will yield a certain diagnosis. Survival is poor; only about 3 percent of patients are alive five years after diagnosis (Ries et al., 1994).

Pancreatic cancer ranks 11th in incidence of all cancers in the United States, but is the fifth most common cause of cancer death (Falk et al., 1988). From the early 1950s through the mid-1970s, incidence rates for pancreatic cancer in the United States rose nearly 30 percent, quite possibly the result of improved diagnostic techniques. Thereafter, rates decreased slightly for males and remained unchanged for females. Mortality rates showed similar trends, reaching 9.7 deaths per 100,000 men and 6.9 per 100,000 women by 1987-91 (Ries et al., 1994). During this time, both underdiagnosis and overdiagnosis of pancreatic cancer was suspected; in the late 1940s, only 53 percent of cases were microscopically confirmed compared to 71 percent of cases by the mid-1970s (Devesa et al., 1987). In the United States, pancreatic cancer incidence is lower among Seventh Day Adventists and Mormons and higher among blacks and Jews (Mack, 1982; Gordis et al., 1980; MacMahon, 1982; Gordis and Gold, 1984). The median age at diagnosis is 70 years; it rarely occurs before age 40. Worldwide, pancreatic cancer occurs slightly more frequently in males than in females and in urban areas more than in rural regions. The highest incidence rates in the world were observed among blacks in the United States and New Zealand Maoris; the lowest rates were reported for India and Thailand (Parkin et al., 1992).

Little is known about the etiology of pancreatic cancer, but studies of ethnic and religious groups suggest that environmental factors play a dominant role. Cigarette smoking is the only established risk factor, with a two-fold risk for smokers relative to nonsmokers. In analytic studies, associations between pancreatic cancer and consumption of alcohol, coffee and tea, and previous medical conditions such as diabetes mellitus, pancreatitis, and allergies have been inconsistent (Velema et al., 1986; Falk et al., 1988; Mack et al., 1986; Mills et al., 1988). Excess pancreatic cancer deaths have been observed in some occupational cohorts exposed to chemicals or petroleum, including manufacturers of photographic film (Hearne et al., 1987), chemists (Li et al., 1969; Hoar and Pell, 1981), leather tanners (Constantini et al., 1989), and auto mechanics (Hansen, 1989), but case-control studies have not consistently confirmed these associations (Mack et al., 1985; Falk et al., 1990). Ecologic studies correlate high pancreatic cancer rates with dietary fat (Maruchi et al., 1977), and recent analytical studies show high-fat foods such as meats and butter are associated with increased pancreatic cancer risk (Gold et al., 1985; Mack et al., 1986; Falk et al., 1988; Norell et al., 1986; Olsen et al., 1989; Farrow and Davis, 1990), while diets with high fruit and vegetable intake are associated with a reduced risk (Falk et al., 1988; Olsen et al., 1989; Norell et al., 1986; Gold et al., 1985; Bueno De Mesquita et al., 1991; Mack et al., 1986). High levels of dietary protease inhibitors found in beans, lentils, and peas have been associated with low rates of pancreatic cancer in Seventh Day Adventists (Mills et al., 1988). However, the specific dietary determinants of pancreatic cancer, if any, have not been identified.

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