Lung cancer is the leading cause of cancer deaths in the United States, among both men and women. It claims more lives than colon, prostate and breast cancer combined. In 1999, about 91,000 men and 68,000 women died of lung cancer.

Yet lung cancer is also among the most preventable of all cancers. Smoking alone accounts for about 85 percent to 90 percent of lung cancer cases. Other leading causes include exposure to radon, asbestos and secondhand smoke.

Although the mortality rate from lung cancer has been declining for men, the rate for women has increased. One reason may be that although smoking rates have decreased overall, the rate has decreased more rapidly for men. But new cases of lung cancer in women have been declining, which means that their mortality rate is likely to decline in the future.

Lung cancer may be divided into two groups: small cell and non-small cell. Small cell lung cancer spreads aggressively and occurs almost exclusively in smokers. In the United States it accounts for about 20 percent of lung cancers. Non-small cell lung cancer, which is more common, accounts for almost 80 percent of lung cancers. There are three major categories of non-small cell lung cancer:

• Squamous cell carcinoma. This cancer forms in cells lining your airways. It's the most common type of lung cancer in men.
• Adenocarcinoma. This type of cancer usually begins in the mucus-producing cells of the lung. It's the most common type of lung cancer in women and people who have never smoked.
• Large cell carcinoma. This type of cancer originates in the peripheral part of the lungs.

 Signs and Symptoms 

Unfortunately, lung cancer has no symptoms in its earliest stages. By the time most people with lung cancer see a doctor, the condition has reached an advanced stage. The most common symptom is a cough, which occurs when a tumor irritates the lining of the airways or blocks the passage of air. In addition to a new cough, be alert to the following:

• "Smoker's cough" that worsens
• Coughing up blood, even a small amount
• Chest pain
• Shortness of breath
• New onset of wheezing
• Repeated bouts of pneumonia or bronchitis
• Hoarseness that lasts more than 2 weeks

Lung cancer also may cause fatigue, loss of appetite and loss of weight. If it has spread to other parts of your body, you may have headaches or bone pain.

Although many of these symptoms might be attributed to other causes, inform your doctor if you experience such problems. The earlier you discover and treat lung cancer, the better chance you have of lengthening your life and reducing symptoms.

Causes 

Healthy cells grow and divide to keep your body functioning normally. But sometimes this growth gets out of control — cells continue reproducing even when new cells aren't needed.

In the lungs these abnormal cells primarily originate when the lungs are exposed to carcinogens (cancer-causing substances) — such as those found in cigarette smoke, radon and asbestos.

Although only a small number of abnormal cells might appear at first (precancerous lesions), these cells can progress with increased exposure to carcinogens. Ultimately, these abnormal cells become cancerous (malignant). All of this occurs over many years.

Once in the lungs, cancerous cells have easy access to a large number of blood and lymph vessels. Tumors can invade these vessels, which may carry cancerous cells to nearby sites and even to remote areas and organs within the body.

Cigarette smoking accounts for 85 percent to 90 percent of all lung cancers. Other risk factors for lung cancer include exposure to asbestos and other industrial carcinogens, secondhand smoke and high concentrations of radon.

Primary lung cancer is uncommon in nonsmokers, but cancer of the breast, colon, prostate, testicle, kidney, thyroid, bone, or other organs may spread (metastasize) to the lungs.

Risk Factors 

Smoking remains the greatest risk factor for lung cancer. Studies have shown that as many as 9 out of 10 cases of lung cancer are caused by smoking. Your risk increases with the number of cigarettes you smoke each day, the number of years you have smoked, and the earlier the age at which you started smoking.

In addition, several studies have reported that women smokers (current or former) are at greater risk of developing lung cancer than men who've smoked an equal amount. The studies indicate that women who smoke may be at a 1.5 to 2-fold greater risk than men who smoke. This increased risk may indicate that women have a greater susceptibility to the cancer-causing substances found in tobacco.

The good news is, it's never too late to quit smoking. Research has shown that quitting — at any age — can significantly lower your risk of developing lung cancer. A study presented in the August 5, 2000, British Medical Journal reported that smokers who quit for less than 10 years lowered their risk of lung cancer by one-third. And those who quit for more than 30 years lowered their risk to 10 percent.

The second highest risk factor for lung cancer is exposure to radon gas. Radon comes from the natural (radioactive) breakdown of uranium in soil, rock and water and can become part of the air you breathe. It can get into homes, offices and schools. Radon levels are generally highest in the basement. The greatest exposure risk most people face is at home, so it's important to test for unsafe levels of the gas. The best tests for radon are longer-term tests that take 3 to 6 months to determine radon levels. The Environmental Protection Agency publishes a free guide to radon .

Workplace exposure to asbestos and other cancer-causing agents — such as vinyl chloride, nickel chromates and coal products — also can put you at a higher risk for developing lung cancer.

Finally, your chances of developing lung cancer may be increased as much as 30 percent by daily exposure to secondhand smoke. And according to the National Cancer Institute, if both parents smoke, a teenager is more than twice as likely to smoke than a young person whose parents are both nonsmokers.

 Complications 

Your lungs are abundantly supplied by blood and lymph, a fluid that helps to return water and proteins from your tissues to your blood. Lung cancer spreads easily to other parts of your body through your bloodstream and lymph system.

Small cell cancer is a fast-growing tumor that quickly spreads to other organs. At the time of diagnosis, this type of cancer will have already spread (metastasized) in over two-thirds of people with the condition. Without treatment the tumor will grow, leading to death within several months. Even with treatment and apparent response, relapses usually occur within 2 years, and then the cancer usually isn't responsive to further chemotherapy or radiation therapy.

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Treatment 

After diagnosis, treatment of lung cancer depends on the size, location (stage) and type of cancer, as well as on your overall health The average length of survival after treatment and the chance of a cure also depend on the stage of the cancer, the cell type and your response to treatment.

Small cell lung cancer

Surgery generally isn't a treatment option for small cell lung cancer. The most effective treatment is chemotherapy, either alone or in combination with radiation therapy. The exact treatment depends on the extent of the cancer (limited or extensive stage).

The standard chemotherapy for small cell lung cancer is etoposide (VePesid) and cisplatin (Platinol) or carboplatin (Paraplatin), and patients generally receive four to six treatment cycles. Additionally, there are some promising newer chemotherapeutic agents, such as paclitaxel (Taxol) and topotecan (Hycamtin) that are currently being evaluated to determine their optimal role.

Non-small cell lung cancer

For non-small cell lung cancers confined to a limited area, surgery is usually the initial treatment of choice. Three types of surgery involve removal of lung tissue:

• Wedge resection is removal of only a small section of one lung.
• Lobectomy entails removal of an entire lobe of one lung. Your right lung has three lobes, and your left lung has two. Lobectomy is the most common type of lung cancer surgery.
• Pneumonectomy involves removal of an entire lung.

At the time of these surgeries, surgeons also sample lymph nodes from the center of the chest (mediastinum), even if an earlier biopsy of the chest (mediastinoscopy) was negative for cancer in the lymph nodes. If surgeons find that the extent of the nodal involvement is greater than anticipated from preoperative testing, they might not remove any lung tissue. Unless the lymph node involvement is very limited to the base of the lobe containing the cancer, it's almost impossible to remove all the other cancerous lymph nodes. Also, if there is fairly extensive lymph node involvement, it's almost certain that the cancer has spread to other parts of the body (micrometastasis), even though they have yet to be detected.

After having surgery to remove lung tissue, you can expect, on average, a 1 week hospital stay and a month or more of avoiding strenuous activity. In addition, because surgeons have to cut between your ribs to get to your lungs, you may experience pain in your ribs until they fully heal.

If you have other chronic lung conditions, such as emphysema or bronchitis, it is possible that you also might encounter more prolonged hospitalization from complications as well as long-term shortness of breath.

More advanced non-small cell lung cancers are generally treated with chemotherapy alone, or a combination of chemotherapy and radiation therapy. Using combination therapy depends on your physical condition and the stage of the disease.

There is no standard chemotherapy for non-small cell lung cancer. Typical chemotherapy drugs used to treat non-small cell lung cancer include a cisplatin- (Platinol) or carboplatin- (Paraplatin) based regimen. The most commonly used combination therapies include paclitaxel (Taxol) and carboplatin (Paraplatin), gemcitabine hydrochloride(Gemzar) and cisplatin (Platinol) and vinorelbine (Navelbine) and cisplatin (Platinol). Other treatments may be equally effective. Active research to discover new and more effective therapy is ongoing.

Advances in computed tomography (CT) imaging techniques have provided radiation oncologists with a more precise means of locating tumors. This helps them to administer radiation treatments from multiple angles with a maximum dose to the tumor while minimizing damage to surrounding tissue. Radiation treatments may be administered before, with or after chemotherapy treatments.

In patients with stage IIIA or IIIB disease, chest radiation is generally combined with systemic chemotherapy. Recent studies have suggested that concurrent treatment is more effective than sequential treatment.

Early detection and treatment make a difference. Nearly half of all people with lung cancer whose tumors are detected early — before spreading beyond the lungs — live 5 or more years after diagnosis and treatment. Among all people with lung cancer, only about 14 percent of people live 5 years after diagnosis and are cured of the disease.

Self-Care 

One of the best things you can to do to care for yourself if you've got lung cancer is also one of the most obvious — don't smoke. You should also try to avoid being around people who are smoking. Although it may be too late to prevent developing lung cancer, this will help optimize your lung function while you are being treated and improve your tolerance to treatment that may have some effects on your lungs.

Your doctor also may prescribe the use of supplemental oxygen at home. Supplemental oxygen may ease shortness of breath and improve your sense of well-being, as well as decrease the strain on your heart. Whenever supplemental oxygen is prescribed, it should be used only as directed to achieve maximum benefits.

Regular exercise, such as walking, exercise bicycling or swimming, will help you to maintain your general strength and stamina. Twenty to 30 minutes of exercise at least four to five times a week will provide the most benefit.

In addition, eating well and managing stress are both ways to promote your overall health and cope with any form of cancer. Eating well during cancer treatment can help you maintain your stamina and better cope with chemotherapy or radiation. Good nutrition also may help you prevent infections and remain more active.

Coping Strategies

A diagnosis of cancer can be extremely challenging. It's important to remember that no matter what your concerns or prognosis, you're not alone. Here are some strategies and resources that may make dealing with cancer easier:

• Know what to expect. Find out everything you can about your cancer — the type, stage, your treatment options and their side effects. The more you know, the more active you can be in your own care. In addition to talking with your doctor, look for information in your local library and on the Internet. The National Cancer Institute will answer questions from the public. You can reach them at 800-4-cancer. Or contact the American Cancer Society (ACS) at 800-227-2345.
• Be proactive. Although you may feel tired and discouraged, don't let others — including your family or your doctor — make important decisions for you. It's vital that you take an active role in your treatment.
• Maintain a strong support system. Having a support system can help you cope with any issues, pain and anxieties that might occur. Although friends and family can be your best allies, they sometimes may have trouble dealing with your illness. If so, the concern and understanding of a formal support group or others coping with cancer can be especially helpful. Although support groups aren't for everyone, they can be a good source for practical information. You may also find you develop deep and lasting bonds with people who are going through the same things you are.
• Set reasonable goals. Having goals helps you feel in control and can give you a sense of purpose. But don't choose goals you can't possibly reach. You may not be able work a 40-hour week, for example, but you may be able work at least half-time. In fact, many people find that continuing to work can be helpful.
• Take time for yourself. Eating well, relaxing and getting enough rest can help combat the stress and fatigue of cancer. Also, plan ahead for the down times when you may need to rest more or limit what you do.
• Stay active. Being diagnosed with cancer doesn't mean you have to stop doing the things you enjoy or normally do. For the most part, if you feel well enough to do something, go ahead and do it. It's important to stay involved as much as you can.
• Look for a connection to something beyond yourself. Having a strong faith or a sense of something greater than yourself seems to be a key factor in successfully coping with cancer.