Understanding and Reducing Your Risk
Smoking and secondhand smoke. More than 90 percent of lung cancers are unquestionably caused by tobacco and the 4000 cancer-causing substances in cigarette smoke (van Zandwijk N et al 2000). The risk of developing lung cancer increases 20- to 40-fold for lifelong smokers and 1.5-fold for people with long-term passive exposure to cigarette smoke. Population studies show that approximately 15 percent of heavy smokers will ultimately develop lung cancer but that, interestingly, 85 percent of heavy smokers will not develop lung cancer because of innate differences in cancer susceptibility, or in other words, genetics. If a family member has lung cancer, chances are your genes render you susceptible to cancer, and you should stop smoking.
The lung cancer death rate is related to the total number of cigarettes smoked, and the risk for a man smoking two packs daily for 20 years is 60- to 70-fold the risk run by a nonsmoker. Among individuals who smoke 15 or more cigarettes per day, reducing smoking by 50 percent significantly reduces the danger of lung cancer (Godtfredsen NS et al 2005). In addition, stopping smoking may prolong survival of cancer patients (Ozlu T et al 2005).
To reduce risk:
- Stop smoking. Use nicotine replacement therapy, Zyban®, counseling, and herbal tea made of cloves and milk vetch (Lee HJ et al 2005). A smoking cessation drug, Chantix™ (varenicline), is available by prescription.
- Increase intake of citrus fruits and tomatoes, which are high in beta-cryptoxanthin, lycopene, alpha-carotene, and lutein (Mannisto S et al 2004; Yuan JM et al 2001; Knekt P et al 1999; Le ML et al 1993).
- With the approval of your physician, take aspirin regularly (Moysich KB et al 2002).
- Take folate and vitamin B12, which improve abnormal bronchial cell growth in smokers (Heimburger DC et al 1988).
- Consume green tea, whose polyphenols prevent DNA damage in lung cells exposed to oxidants from cigarette smoke.
- Test your home for radon gas.
Dietary factors. A low intake of fruits and vegetables and consumption of red meat and preserved and fatty foods increase risk (Kubik A et al 2004; Wang J et al 2004). Therefore, your diet should consist mostly of vegetables, fruits, raw foods, and fresh fish (Takezaki T et al 2003; Gao CM et al 1993). However, the genes one inherits play an important role in individual susceptibility to lung cancer (Lam WK et al 2004).
- The overall risk of lung cancer decreases by one half among those with a high intake of lettuce and cabbage, even among current smokers (Gao CM et al 1993).
- Chinese leek (Allium tuberosum Rottler), also known as Chinese chives, reduced lung cancer metastasis (spread) in mice by 40 percent and prevented cancer cell growth in experimental conditions (Shao J et al 2001).
See the section below titled “Preventing Lung Cancer” for more recommendations.
Genetics. Especially among nonsmokers, a genetic predisposition increases an individual’s susceptibility to cancer-causing agents (carcinogens) in the environment. Nonsmokers with a close family member stricken by cancer might reduce their lung cancer risk by about 25 to 50 percent by taking the following steps:
- Increasing intake of darkly colored vegetables and fruits.
- Consuming carotene-containing fruits and vegetables—spinach, kale, carrots, cantaloupes, and sweet potatoes (Fabricius P et al 2003; Fontham ET 1990).
Lung disease. Lung diseases such as chronic obstructive pulmonary disease and infections such as tuberculosis, human papilloma virus, and Microsporum canis (skin fungus) are linked with a proinflammatory state and a high risk of lung cancer (Lam WK et al 2004; Biesalski HK et al 1998). Although most of these conditions are easily diagnosed and fairly well managed, smoking cessation is a must.
Environmental carcinogens. Certain elements in the environment further increase one’s risk of developing lung cancer. See the discussion under “Some lung cancer is caused by exposure to toxins and viruses” above.