The leading risk factor for lung cancer is smoking. More than 80% of lung cancers are due to cigarette smoking. The longer a person has been smoking and also the more cigarettes a person smokes a day, the greater the risk is for developing lung cancer. Not only are smokers vulnerable to lung cancer, but the people around them are at a greater risk as well due to breathing second-hand smoke. Non-smokers who are married to smokers are at a 30% greater risk than non-smokers who are married to non-smokers. Marijuana cigarettes may also increase the risk of lung cancer since they contain many of the same cancer-causing agents that tobacco cigarettes have and are inhaled more deeply.

Lung cancer most commonly begins in the cells that line your lungs. Smoking causes the majority of lung cancers â?? both in smokers and in people exposed to secondhand smoke. But lung cancer also occurs in people who never smoked. In these cases, there may be no clear cause of lung cancer. Doctors have identified factors that may increase the risk.

Lung cancer is one of the most common cancers in the world. It is a leading cause of cancer death in men and women in the United States. Cigarette smoking causes most lung cancers. The more cigarettes you smoke per day and the earlier you started smoking, the greater your risk of lung cancer. High levels of pollution, radiation and asbestos exposure may also increase risk.

Causes of Lung Cancer

Smoking: smoking remains the greatest risk factor for lung cancer. Your risk of lung cancer increases with the number of cigarettes you smoke each day and the number of years you have smoked. Quitting at any age can significantly lower your risk of developing lung cancer.

Diet: Scientists are studying many different foods to see how they may change the risk of getting lung cancer. However, any effect diet may have on lung cancer risk is small compared with the risk from smoking. Eating a lot of fat and cholesterol might increase risk of lung cancer. Drinking a lot of alcohol may raise risk as well.

Family History: Studies have found a chromosome that may be resposible for lung cancer. The chromosome can be inherited. If you have had lung cancer before, there is a chance you may develop another type of lung cancer.

Air pollution from vehicles, industry, and power plants can raise the likelihood of developing lung cancer in exposed individuals. Up to 1% of lung cancer deaths are attributable to breathing polluted air, and experts believe that prolonged exposure to highly polluted air can carry a risk similar to that of passive smoking for the development of lung cancer.

Symptoms of Lung Cancer

People often decide to visit the doctor only after they have been bothered by certain complaints over a period of time. Individuals who have lung cancer frequently experience symptoms such as the following:

Metastasis to the bones is most common with small cell type cancers but also occurs with other lung cancer types. Lung cancer that has metastasized to the bone causes bone pain, usually in the backbone (vertebrae), the thighbones, and the ribs.

Shortness of breath usually results from a blockage to the flow of air in part of the lung, collection of fluid around the lung (pleural effusion), or the spread of tumor throughout the lungs.

A cough that does not go away or gets worse over time should be evaluated by a health-care provider.

Chest pain is a symptom in about one-fourth of people with lung cancer. The pain is dull, aching, and persistent and may involve other structures surrounding the lung.

Wheezing or hoarseness may signal blockage or inflammation in the lungs that may go along with cancer.

The breasts sit on the chest muscles that cover the ribs. Each breast is made of 15 to 20 lobes. Lobes contain many smaller lobules. Lobules contain groups of tiny glands that can produce milk. Milk flows from the lobules through thin tubes called ducts to the nipple. The nipple is in the center of a dark area of skin called the areola. Fat fills the spaces between the lobules and ducts.

Breast cancer incidence is much higher in industrialised Western countries, whether in Europe or North America, than in developing countries. North American women have the highest incidence of breast cancer in the world. Among women in the U.S., breast cancer is the most common cancer and the second-most common cause of cancer death (after lung cancer). Women in the U.S. have a 1 in 8 (12.5%) lifetime chance of developing invasive breast cancer and a 1 in 35 (3%) chance of breast cancer causing their death. In 2007, breast cancer was expected to cause 40,910 deaths in the U.S. (7% of cancer deaths; almost 2% of all deaths)

Breast cancer is the most common cause of cancer in women and the second most common cause of cancer death in women in the U.S. While the majority of new breast cancers are diagnosed as a result of an abnormality seen on a mammogram, a lump or change in consistency of the breast tissue can also be a warning sign of the disease. Heightened awareness of breast cancer risk in the past decades has led to an increase in the number of women undergoing mammography for screening, leading to detection of cancers in earlier stages and a resultant improvement in survival rates.

Breast cancer is the number one disease that women in the United States fear the most, and for compelling reasons. It is the leading cause of death among women between 40 and 55 years of age and is the second overall cause of death among women (exceeded only by lung cancer). Unfortunately, it is also on the rise worldwide. According to the American Cancer Society, this year about 175,000 new cases of invasive breast cancer and about 43,300 deaths from breast cancer will occur among women in the USA.

Breast cancer is the most common malignancy affecting women in North America and Europe. Close to 200,000 cases of breast cancer were diagnosed in the United States in 2001. Breast cancer is the second leading cause of cancer death in American women behind lung cancer. The lifetime risk of any particular woman getting breast cancer is about 1 in 8 although the lifetime risk of dying from breast cancer is much lower at 1 in 28. Men are also at risk for development of breast cancer, although this risk is much lower than it is for women.

Breast cancer is more easily treated and often curable if it is found early. Monthly breast self-examinations should begin at age 20. Recommended screening methods include breast self-examination and mammography.

The most serious cancers are metastatic cancers. Metastasis means that the cancer has spread from the place where it started into other tissues distant from the original tumor site. The most common place for breast cancer to metastasize is into the lymph nodes under the arm or above the collarbone on the same side as the cancer. Other common sites of breast cancer metastasis are the brain, the bones, and the liver.

Death rates from breast cancer have been gradually declining and continue to decline. These decreases are likely due both to increased awareness and screening and improved treatment methods.