it is also best known as promensil
products containingÂ isoflavone:
it is also known as:
|trade name||generic name|
Mysteries Abound for Women and Lung Cancer
You may know that lung cancer is the leading cause of cancer-related deaths in women, including breast cancer, and that the number of new cases in women is increasing. But do you know why? If not, you're not alone - even researchers are puzzled by recent trends in lung cancer incidence in women.
A team of independent researchers presented highlights of recent studies at the International Conference of the American Thoracic Society in Toronto, Ontario, Canada on May 8.
Speaking about the incidence and epidemiolgy of lung cancer in the U.S., Dr. William Travis of the Armed Forces Institute of Pathology in Washington, D.C., pointed to recent statistics: the incidence for American men peaked between 1982 and 1984 and has declined since then. But rates for women have not declined, and more women than men are smokers. Some studies suggest that women today may be as much as two-to-three fold more likely to develop lung cancer.
There are regional and international disparities. Interestingly, the highest rates of the disease (in women) occur in the Maori tribe in New Zealand and in certain provinces in China. Within the U.S., the highest rates for women occur in the southeastern states and in California… due to smoking trends, said Dr. Travis.
The statistics suggest that women have an increased risk of developing lung cancer compared to men. Although not fully supported by scientific research, some researchers believe that the complex interaction of smoking, environmental exposure (partly due to occupation), family history, dietary factors and hormones, puts women at an increased risk for lung cancer.
But those same hormones may offer a protective effect too -- some research suggests that women survive the disease longer than men do. Estrogen receptors have been found in some types of lung cancers in women, suggesting that the hormone may help prevent cancerous cells from developing.
True - tobacco and hormones are pieces of the puzzle, but the role of genes can't be denied, said Dr. Charles Powell, assistant professor of clinical medicine, Columbia University. "A woman's history of smoking cannot fully explain the lung cancer story," he said. Having a family history or genetic predisposition for lung cancer can increase a woman's risk by 60 percent.
While studying the genes involved in the progression of lung cancer, Dr. Powell and colleagues found a possibly important gene called GSTMI, which is involved in the pathway from nicotine addiction to the development of cancer. People with normal copies of the gene either detoxify or excrete potentially dangerous by-products of nicotine but those with "null" GSTMI are unable to repair the DNA damage caused by the over 50 carcinogens present in the drug. Cells either die or mutate, leading to cancer.
The risk of lung cancer increases by 2.5 percent in women without the GSTMI gene while for men, the risk increases by 1.4 percent. "Women may be less likely to detoxify carcinogens, and there is a genetic propensity to develop DNA damage," said Dr. Powell.
While smoking is the leading cause of the DNA damage that leads to lung cancer, environmental and lifestyle factors have a role too, according to Dr. Steven Stellman, an epidemiologist with the American Health Foundation in New York City. He noted that factors such as air pollution and exposure to radon, asbestos, chromium, arsenic and certain beryllium compounds, increase the risk of cancer. Women in China, for example, who were exposed to specific cooking oils (possibly soybean or grapeseed oil) in unventilated kitchens have high rates of the disease as do women who have worked in mines and coal factories.
Studies surrounding diet are less conclusive, said Dr. Stellman. There are about 20 ongoing studies examining the link between lung cancer and intake of certain nutrients (including antioxidants such as beta carotene), cholesterol and alcohol. So far, studies of a diet rich in fruits and vegetables and the relative risk of lung cancer, are inconclusive. Other factors complicate matters -- women who smoke or consume excess alcohol may have poorer diets and therefore consume less protective dietary factors.
Dr. Stellman said that these other sources of lung cancer, and the gender differences within each, need further investigation.