Lung cancer is a type of cancer that begins in the lungs. Your lungs are two spongy organs in your chest that take in oxygen when you inhale and release carbon dioxide when you exhale. Lung cancer is the leading cause of cancer deaths worldwide.

People who smoke have the greatest risk of lung cancer, though lung cancer can also occur in people who have never smoked. The risk of lung cancer increases with the length of time and number of cigarettes you've smoked. If you quit smoking, even after smoking for many years, you can significantly reduce your chances of developing lung cancer.

Lung cancer typically doesn't cause signs and symptoms in its earliest stages. Signs and symptoms of lung cancer typically occur when the disease is advanced.

Signs and symptoms of lung cancer may include:

• A new cough that doesn't go away
• Coughing up blood, even a small amount
• Shortness of breath
• Chest pain
• Hoarseness
• Losing weight without trying
• Bone pain
• Headache

Causes

Doctors believe smoking causes lung cancer by damaging the cells that line the lungs. When you inhale cigarette smoke, which is full of cancer-causing substances (carcinogens), changes in the lung tissue begin almost immediately.

At first your body may be able to repair this damage. But with each repeated exposure, normal cells that line your lungs are increasingly damaged. Over time, the damage causes cells to act abnormally and eventually cancer may develop.

Types of lung cancer

Doctors divide lung cancer into two major types based on the appearance of lung cancer cells under the microscope. Your doctor makes treatment decisions based on which major type of lung cancer you have.

• Small cell lung cancer:- Small cell lung cancer occurs almost exclusively in heavy smokers and is less common than non-small cell lung cancer.
• Non-small cell lung cancer:- Non-small cell lung cancer is an umbrella term for several types of lung cancers. Non-small cell lung cancers include squamous cell carcinoma, adenocarcinoma and large cell carcinoma.

Risk factors

A number of factors may increase your risk of lung cancer. Some risk factors can be controlled, for instance, by quitting smoking. And other factors can't be controlled, such as your family history.

• Smoking:- 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.
• Exposure to secondhand smoke:- Even if you don't smoke, your risk of lung cancer increases if you're exposed to secondhand smoke.
• Previous radiation therapy:- If you've undergone radiation therapy to the chest for another type of cancer, you may have an increased risk of developing lung cancer.
• Exposure to radon gas:- Radon is produced by the natural breakdown of uranium in soil, rock and water that eventually becomes part of the air you breathe. Unsafe levels of radon can accumulate in any building, including homes.
• Exposure to asbestos and other carcinogens:- Workplace exposure to asbestos and other substances known to cause cancer — such as arsenic, chromium and nickel — can increase your risk of developing lung cancer, especially if you're a smoker.
• Family history of lung cancer:- People with a parent, sibling or child with lung cancer have an increased risk of the disease.

Complications

Lung cancer can cause complications, such as:

• Shortness of breath.:- People with lung cancer can experience shortness of breath if cancer grows to block the major airways. Lung cancer can also cause fluid to accumulate around the lungs, making it harder for the affected lung to expand fully when you inhale.
• Coughing up blood:- Lung cancer can cause bleeding in the airway, which can cause you to cough up blood (hemoptysis). Sometimes bleeding can become severe. Treatments are available to control bleeding.
• Pain:- Advanced lung cancer that spreads to the lining of a lung or to another area of the body, such as a bone, can cause pain. Tell your doctor if you experience pain, as many treatments are available to control pain.
• Fluid in the chest (pleural effusion):- Lung cancer can cause fluid to accumulate in the space that surrounds the affected lung in the chest cavity (pleural space). Fluid accumulating in the chest can cause shortness of breath. Treatments are available to drain the fluid from your chest and reduce the risk that pleural effusion will occur again.
• Cancer that spreads to other parts of the body (metastasis):- Lung cancer often spreads (metastasizes) to other parts of the body, such as the brain and the bones. Cancer that spreads can cause pain, nausea, headaches, or other signs and symptoms depending on what organ is affected. Once lung cancer has spread beyond the lungs, it's generally not curable. Treatments are available to decrease signs and symptoms and to help you live longer.

Prevention

There's no sure way to prevent lung cancer, but you can reduce your risk if you:

• Don't smoke:- If you've never smoked, don't start. Talk to your children about not smoking so that they can understand how to avoid this major risk factor for lung cancer. Begin conversations about the dangers of smoking with your children early so that they know how to react to peer pressure.
• Stop smoking:- Stop smoking now. Quitting reduces your risk of lung cancer, even if you've smoked for years. Talk to your doctor about strategies and stop-smoking aids that can help you quit. Options include nicotine replacement products, medications and support groups.
• Avoid secondhand smoke:- If you live or work with a smoker, urge him or her to quit. At the very least, ask him or her to smoke outside. Avoid areas where people smoke, such as bars and restaurants, and seek out smoke-free options.
• Test your home for radon:- Have the radon levels in your home checked, especially if you live in an area where radon is known to be a problem. High radon levels can be remedied to make your home safer. For information on radon testing, contact your local department of public health or a local chapter of the American Lung Association.
• Avoid carcinogens at work:- Take precautions to protect yourself from exposure to toxic chemicals at work. Follow your employer's precautions. For instance, if you're given a face mask for protection, always wear it. Ask your doctor what more you can do to protect yourself at work. Your risk of lung damage from workplace carcinogens increases if you smoke.
• Eat a diet full of fruits and vegetables:- Choose a healthy diet with a variety of fruits and vegetables. Food sources of vitamins and nutrients are best. Avoid taking large doses of vitamins in pill form, as they may be harmful. For instance, researchers hoping to reduce the risk of lung cancer in heavy smokers gave them beta carotene supplements. Results showed the supplements actually increased the risk of cancer in smokers.
• Exercise most days of the week:- If you don't exercise regularly, start out slowly. Try to exercise most days of the week.

Getting screening tests regularly may find breast, cervical, and colorectal (colon) cancers early, when treatment is likely to work best. Lung cancer screening is recommended for some people who are at high risk.

Screeningexternal icon means checking your body for cancer before you have symptoms. Getting screening tests regularly may find breast, cervical, and colorectal (colon) cancers early, when treatment is likely to work best. Lung cancer screening is recommended for some people who are at high risk.

Breast Cancer

Mammograms are the best way to find breast cancer early, when it is easier to treat and before it is big enough to feel or cause symptoms.

Cervical Cancer

The Pap test can find abnormal cells in the cervix which may turn into cancer. The HPV test looks for the virus (human papillomavirus) that can cause these cell changes. Pap tests also can find cervical cancer early, when the chance of being cured is very high.

Colorectal (Colon) Cancer

Colorectal cancer almost always develops from precancerous polyps (abnormal growths) in the colon or rectum. Screening tests can find precancerous polyps, so they can be removed before they turn into cancer. Screening tests also can find colorectal cancer early, when treatment works best.

Lung Cancer

The USPSTF recommends yearly lung cancer screening with low-dose computed tomography (LDCT) for people who have a history of heavy smoking, and smoke now or have quit within the past 15 years, and are between 50 and 80 years old.

Screening for Other Kinds of Cancer

Screening for ovarian,external icon pancreatic,external icon prostate,external icon testicular,external icon and thyroidexternal icon cancers has not been shown to reduce deaths from those cancers. The USPSTF found insufficient evidence to assess the balance of benefits and harms of screening for bladder cancerexternal icon and oral cancerexternal icon in adults without symptoms, and of visual skin examination by a doctor to screen for skin cancerexternal icon in adults.

Vaccines (Shots)

Vaccines (shots) also help lower cancer risk. The human papillomavirus (HPV) vaccine helps prevent most cervical cancers and several other kinds of cancer. The hepatitis B vaccine can help lower liver cancer risk.

The HPV vaccine can prevent several kinds of cancer, and the hepatitis B vaccine can help prevent liver cancer

Human Papillomavirus (HPV) Vaccine

Some cancers are caused by human papillomavirus (HPV), a very common sexually transmitted infection. The HPV vaccine protects against the types of HPV that most often cause these cancers.

• HPV vaccination is recommended for preteens aged 11 to 12 years, but can be given starting at age 9.
• HPV vaccine also is recommended for everyone through age 26 years, if they are not vaccinated already.
• HPV vaccination is not recommended for everyone older than age 26 years. However, some adults age 27 through 45 years who are not already vaccinated may decide to get the HPV vaccine after speaking with their doctor about their risk for new HPV infections and the possible benefits of vaccination. HPV vaccination in this age range provides less benefit, as more people have already been exposed to HPV.

HPV vaccination prevents new HPV infections, but does not treat existing infections or diseases. This is why the HPV vaccine works best when given before any exposure to HPV.

The HPV vaccine does not substitute for routine cervical cancer screening tests (Pap and HPV tests), according to recommended screening guidelines.Hepatitis B Vaccine

Hepatitis B Vaccine

Hepatitis B is a liver disease caused by the Hepatitis B virus (HBV). It ranges in severity from a mild illness, lasting a few weeks (acute), to a serious long-term (chronic) illness that can lead to liver disease or liver cancer. The hepatitis B vaccine is available for all age groups to prevent HBV infection.

Healthy Choices

You can reduce your risk of getting cancer by making healthy choices like keeping a healthy weight, avoiding tobacco, limiting the amount of alcohol you drink, and protecting your skin.You can lower your risk of getting cancer by making healthy choices like–

• Avoiding tobacco.
• Protecting your skin.
• Limiting the amount of alcohol you drink.
• Keeping a healthy weight.
• Getting tested for hepatitis C.

Avoiding Tobacco Cigarette Smoking

Lung cancer is the leading cause of cancer death, and cigarette smoking is the number one risk factor for lung cancer. In the United States, cigarette smoking is linked to about 80% to 90% of lung cancer deaths. Tobacco use can cause cancer almost anywhere in your body. Visit smokefree.govexternal icon to learn how you can quit smoking.

Secondhand Smoke

Smoke from other people’s cigarettes, pipes, or cigars (secondhand smoke) also causes lung cancer. When a person breathes in secondhand smoke, it is like he or she is smoking.

Protecting Your Skin

Skin cancer is the most common kind of cancer in the United States. Exposure to ultraviolet (UV) rays from the sun and tanning beds appears to be the most important environmental factor involved with developing skin cancer. To help prevent skin cancer while still having fun outdoors, protect yourself by staying in the shade, applying sunscreen, and wearing sun-protective clothing, a hat, and sunglasses.

Limiting Alcohol Intake

Drinking alcohol raises your risk of getting six kinds of cancer. The less alcohol you drink, the lower your risk for cancer.

Keeping a Healthy Weight

Being overweight or having obesity are linked with a higher risk of getting 13 types of cancer. These cancers make up 40% of all cancers diagnosed in the United States each year.

Getting Tested for Hepatitis C

Hepatitis is inflammation of the liver, which is most often caused by a virus. In the United States, the most common type of viral hepatitis is Hepatitis C. Over time, chronic Hepatitis C can lead to serious liver problems including liver damage, cirrhosis, liver failure, or liver cancer. CDC recommends that most adults get tested for Hepatitis C.