Lung Cancer


Lung cancer occurs mainly in older people. Two out of three people diagnosed with lung cancer are age 65 years or older; the average age at the time of diagnosis is 70. Most people who are diagnosed with lung cancer are current or former smokers; however, people who have never smoked also can be diagnosed with lung cancer.

Cancer is an abnormal growth of cells (the building blocks that make up the tissue and organs in the body). Old or damaged cells usually die, and new cells take their place. But sometimes, the process goes wrong or a single cell starts to grow uncontrollably until it becomes a mass of tissue called a tumor.

Sometimes, tumors are benign and are not life threatening; other times, the tumors are cancerous (malignant) and can invade surrounding tissues or spread to other areas of the body. 

The American Cancer Society (ACS) estimates that more than 234,000 new cases of lung cancer will be diagnosed and more than 154,000 patients will die from lung cancer in 2018. Lung cancer accounts for 27% of all cancer deaths and is, by far, the leading cause of cancer deaths among men and women. Each year, more people die of lung cancer than colon, breast, and prostate cancers combined.



See an interactive, 3D simulation of the lungs.*


For viewing the 3D model, please use a supported browser: Chrome, Firefox, and Microsoft Edge (for Windows 10). **Internet Explorer is not supported.** The model may take up to 40 seconds to load with a fast Internet connection.
Types of Lung Cancer

Types of Lung Cancer

There are three main types of lung cancer: Non-small-cell lung cancer (NSCLC), small cell lung cancer (SCLC), and lung carcinoid tumors. 

Non-small-cell lung cancer (NSCLC)
The most common type of lung cancer is NSCLC, which accounts for about 83% of lung cancers. It is named non-small-cell lung cancer because, under a microscope, the cells are larger than small-cell lung cancer. While there are many types of NSCLC, the two most common types are adenocarcinoma and squamous cell carcinoma. 

Small-cell lung cancer (SCLC)
About 13% of lung cancers are SCLC, named for the size of the cancer cells when seen under a microscope. This type of cancer is less common than non-small-cell lung cancer and is diagnosed almost exclusively in heavy smokers. It is usually treated with chemotherapy and radiation; however, surgery may be an option for small tumors that have not spread to the lymph nodes. 

SCLC often starts in the bronchus (the airways of the lung), near the center of the chest. It tends to spread quickly to the lymph nodes and other areas of the body. 

Lung carcinoid tumor 
Carcinoid tumors of the lung account for fewer than 5% of lung tumors. They are made up of special kinds of cells, called neuroendocrine cells, that help regulate your body’s breathing. Most are slow-growing tumors and usually can be cured by surgery. 

Cancers that spread to the lungs
Cancers that start in other organs of your body (like the colon or kidney) can sometimes spread (metastasize) to the lungs, but these are not lung cancers. For example, cancer that starts in the colon and spreads to the lungs is still colon cancer; it has just spread to your lungs. Treatment for metastatic cancer to the lungs is based on where it started (the primary cancer site), the involvement of other areas of the body (such as the liver or brain), and the size, number, and location of the nodules. Metastatic tumors from certain cancers, like colon and kidney cancers, can be limited to the lung and removal can improve outcomes, whereas other cancers tend to spread widely throughout the body and should be treated with chemotherapy rather than surgery.

Causes and Symptoms

Causes and Symptoms of Lung Cancer

Smoking, present or past, is the leading risk factor for lung cancer. Cigar and pipe smoking are almost as likely to cause lung cancer as cigarette smoking.

At least 8 out of 10 lung cancer deaths are believed to result from smoking, according to the American Cancer Society.

Smokers are 25 times more likely than non-smokers to have lung cancer, and the longer you smoke and the more packs a day you smoke, the greater your risk. Even if you smoke low-tar or “light” cigarettes, you are still at risk. 

Exposure to secondhand smoke increases your risk for developing lung cancer, as do environmental toxins such as arsenic, diesel exhaust, asbestos, beryllium, silica, and radon.

Some people may have a predisposition to cancer, and a family history of lung cancer can increase your risk but specifics are not well known. Be sure to let your doctor know if you have a parent, sibling, or child with lung cancer, as you may be at an increased risk of developing the disease. 

If you have ever been diagnosed with chronic obstructive pulmonary disease or emphysema, you also are at increased risk of developing lung cancer.

Common symptoms of lung cancer include persistent coughing, chest pain, coughing up mucus or sputum streaked with blood, voice changes, worsening shortness of breath, and recurrent pneumonia or bronchitis; however, most patients with lung cancer have no symptoms at all. 

If you think you have any of the signs or symptoms listed above or any other symptoms that cause you to worry, make an appointment to see your family doctor or general practitioner. If your doctor suspects you have lung cancer, you will be referred to a specialist who can run additional tests to find out the cause of your symptoms.

Diagnosis and Treatment Options

Diagnosis and Treatment Options

Most lung cancers are now found during radiology scans performed for other reasons. Several imaging tests are available to help confirm or rule out the diagnosis. These tests include chest x-ray, computed tomography (CT) scan, magnetic resonance imaging (MRI), or positron emission tomography (PET scan).

Chest x-ray showing lung cancer Chest x-ray shows signs of lung cancer

PET scan showing mass in left upper lobe

PET scan showing mass in left upper lobe

If you are at high risk for lung cancer, talk with your doctor about undergoing a screening test using low-dose CT scan.  People at the highest risk for lung cancer include current and former smokers, people who have been exposed to high levels of radon, and those who have a family history of lung cancer.

For more information on these tests, visit our common diagnostic tests page.

Stages of Lung Cancer 
Once you have been diagnosed with cancer, imaging studies such as a CT scan or a PET scan will be performed to determine the extent, or stage, of the tumor. The stage of your lung cancer will help you understand how advanced the disease is, whether the cancer has spread to other parts of your body, and what treatments to consider.

A higher stage tumor means that the cancer is more advanced and has a worse prognosis.

The stages of SCLC differ from those for non-small cell lung cancer. SCLC stages include: 

  1. Limited – Cancer is limited to one lung
  2. Extensive – Cancer has spread beyond the one lung

If you and your cardiothoracic surgeon decide to move forward with surgery, you likely would undergo one of the following: 

  • Lobectomy 
  • Segmentectomy/wedge resection 
  • Pneumonectomy 

For all three operations, cardiothoracic surgeons can use either an incision between two ribs in your back that requires a rib spreader (posterolateral thoracotomy) or a muscle-sparing incision (a thoracotomy that avoids dividing some of the chest wall muscles).

If you are about to undergo surgery for lung cancer, it is important to ask your surgeon about these approaches to determine what is best for you.

To determine whether you are a good candidate for surgery, you will need to undergo pulmonary function testing. Depending on your symptoms and risk factors, cardiac testing to evaluate your heart also may be performed.

In early stage cancer, surgery generally is the standard treatment, removing the primary tumor as well as surrounding lymph nodes to accurately stage the lung cancer. For patients with inadequate pulmonary function or significant shortness of breath, resection of smaller portions of the lung (segmentectomy) or stereotactic radiation are considered as second line treatments.

You can print these sample questions to use as a basis for discussion with your doctor. 


Procedure to remove the portion of the lung (lobe) that contains the cancer and is the standard treatment for early stage lung cancers.

  • Blue section shows right middle lobe to be removed
  • Blue section shows left upper lobe to be removed
  • Access points for a video-assisted lobectomy
  • Scarring from a video-assisted lobectomy

Segmentectomy/ Wedge Resection

Procedure to remove only the cancerous part of the lobe, rather than the entire lobe; may be recommended for carcinoid tumors, metastatic nodules that have spread from other cancers, certain subtypes of slow-growing NSCLC, or if your lung function is not adequate for resection of the entire lobe.

Both segmentectomy, and wedge resections can be performed using minimally invasive techniques by surgeons with expertise in video-assisted thoracoscopic surgery (VATS) or robotic surgery. 

  • Thoracoscopic wedge resection of the left upper lobe
  • After wedge resection, the remaining lung is stapled


Procedure to remove the entire lung and is performed for tumors that are located centrally in the lung, involving the main airway or blood vessels. When possible, lung-sparing procedures resecting only the involved portion of the airway or blood vessels and reattaching the normal structures (sleeve resection) should be considered by surgeons experienced in these techniques and can preserve a lobe or sometimes even the entire lung depending on the tumor’s location.

  • Patient image after pneumonectomy


As with any surgery or operation, risks are involved. Possible complications depend on the extent of the surgery and your overall health. Serious complications can include excess bleeding, infections, and pneumonia. 

After most surgical procedures, you will have one or two tubes inserted into your chest to help air and fluid drain out of the area. Once the drainage has decreased and any air leak has stopped, the chest tubes will be removed. 

You can expect to go home from the hospital 2-5 days after surgery. While in the hospital, it is important that you work on deep breathing and coughing to keep your lungs functioning.

Following surgery, if your lungs are in good condition, you can usually return to normal activities after a period of recovery, even if a lobe or an entire lung has been removed. Total time for recovery will be different for every patient and depends on the condition of your lungs prior to surgery and any complications experienced following surgery.  

If you previously have been diagnosed with a non-cancerous lung disease such as emphysema or chronic bronchitis (which are common among heavy smokers), you likely will still experience shortness of breath with certain levels of activity, even after surgery. 


Reviewed by: Robbin G. Cohen, MD, with assistance from John Hallsten and Travis Schwartz
July 2016 

Previously reviewed by: Rishindra Reddy, MD and Jules Lin, MD