Age is likely the most important overall factor associated with breast cancer risk.  Breast cancer risk increases in the older post-menopausal population.  For this reason, all breast cancer screening recommendations are based primarily on age.  Obesity, however, may be the single most preventable risk factor associated with breast cancer.  With the dramatic increase in obesity in the U.S., this may be the number one reason for a persistently high incidence in breast cancer.  Other physical factors also play some roles in breast cancer risk.  These include height, body shape, breast size, and mammographic density.  These physical factors are summarized below.

Body Weight and Breast Cancer:  A woman’s body weight does affect her risk of breast cancer but the effect is different for premenopausal and postmenopausal breast cancer.  Most studies have found that heavier women (weighing more than 175 pounds) have a lower risk of breast cancer before menopause and higher risk of breast cancer after menopause, compared to thinner women (weighing less than 130 pounds).  Since 80% of breast cancers occur after menopause, the negative effects of obesity far outweigh the beneficial effects.  The results are the same whether body weight is examined directly or if body mass index is used to adjust for the effects of height on body weight.

Body Shape and Breast Cancer:  Several human studies have found that women who carry more of their body fat on their stomach (apple shaped) have higher rates of postmenopausal breast cancer compared to women with more of their body fat around their hips (pear shaped).  This seems to be true regardless of women’s body weight.  The relationship of the location of fat on the body and premenopausal breast cancer risk has not been clearly determined

Height and Breast Cancer:  A woman’s height has been associated with breast cancer risk in many studies.  Taller women (5′ 9″ or taller) have a small increase in risk of both premenopausal and postmenopausal breast cancer compared to shorter women (5′ 3″ or shorter).  A person’s height is determined by the interaction of genetics and nutrition.  How height might affect breast cancer risk is unclear.  

Breast Size and Breast Cancer:  There is a popular belief that small breasts are at lower risk of breast cancer.  This theory has been used to explain why women with breast implants have a smaller risk of breast cancer.  However, most studies have found no association between breast size and breast cancer risk.  One study, however, did find an increase in the risk of breast cancer among lean women with larger breasts.  In this study, more than 4,000 women were grouped according to their bra size before childbirth.  Women who were lean (chest size less than 34 inches) and had larger breasts (size B, C or larger cups) were at higher risk of post menopausal breast cancer relative to women of the same chest size with an A or smaller cup size.  Women with other chest sizes had no association between breast cup size and breast cancer risk.  More studies are needed to confirm these results

Mammographic density:  Numerous epidemiological studies have shown that breast density as measured on mammograms is a significant risk factor for breast cancer.  The risk of breast cancer associated with the highest category of density has been estimated to be much greater than in the lowest density category.  Mammographic density appears to be predictive for developing invasive cancer after DCIS (ductal carcinoma in situ).  Increasing density is associated with increasing breast cancer risk in both premenopausal and postmenopausal women, with the effect persisting for ten years after mammography.  Mammographic density has also been shown to be a risk factor for breast cancer in women with a family history of the disease.  Mammographic density is probably important even in patients who are BRCA gene positive.  In fact, mammographic density may actually have a substantial heritable component.

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.