Lung cancer overview

Getting a lung cancer diagnosis may be daunting—with so much to learn and so many decisions to make. But knowledge is power, and equipping yourself with up-to-date information may help quell your anxiety and restore your hope.

Causes and risk factors for lung cancer

About one in 15 men and one in 17 women will get lung cancer, according to the American Cancer Society (ACS). Lung cancer is the third most common cancer, after skin cancer, prostate cancer (men) and breast cancer (women).

Despite a decrease in cases due to less smoking, lung cancer remains the most common cause of death from cancer in both men and women. Smoking is most often the cause.

  • About 236,000 cases of lung cancer are diagnosed every year—and smoking contributes to the cause in about 80 percent of these cases, according to ACS.
  • The risk increases with the number of years and the number of cigarettes you smoke. Cigar and pipe smoking poses only slightly less of a risk than cigarette smoking.
  • Secondhand smoke from tobacco is also a risk and may cause about 7,000 lung cancers each year.

Lung cancer typically develops in people older than 65. The average age of diagnosis for lung cancer is 70, with men at slightly higher risk than women.

Radon, a radioactive gas that leaks from soil and rock, is the second leading cause of lung cancer. It may be the leading cause for patients who never smoked tobacco. Radon is most dangerous in basements where it’s concentrated, not out in open air.

Other much-less common risk factors for lung cancer include:

  • Exposure to asbestos
  • Inhaled toxins from industrial chemicals or radioactive ores
  • Radiation therapy treatments of the chest, as in treatments for breast cancer or Hodgkin lymphoma
  • Air pollution
  • Family history of lung cancer, especially if diagnosed at a young age
  • Smoking marijuana or e-cigarettes may pose a risk, although more research is needed

Learn about risk factors for lung cancer

Signs and symptoms of lung cancer

Most people with lung cancer don’t have early signs or symptoms. However, when symptoms develop, they are most likely to include:

  • A cough that persists, worsens or produces blood
  • Chest pain
  • Shortness of breath
  • Wheezing
  • Fatigue
  • Unexplained weight loss

Lung cancer patients may experience chest pain that worsens with deep breathing or coughing, and have frequent lung infections such as bronchitis or pneumonia.

When lung cancer spreads to other areas of the body, a process referred to as metastasis, symptoms may include bone pain, headache, weakness, numbness, jaundice or enlarged lymph nodes.

Learn more about symptoms of lung cancer

How is lung cancer diagnosed

The diagnostic process may begin with or without symptoms.

A lung cancer screening, which is testing before the appearance of symptoms, involves a low-dose computed tomography (CT) scan. This type of imaging study is recommended only for people at high risk for lung cancer.

According to the American Lung Association, you may be screened if:

  • You are 55 to 80 years old.
  • You’ve smoked at least a pack of cigarettes per day for 30 years or an equivalent number, such as two packs per day for 15 years.
  • You are still smoking or you quit within the past 15 years.

Diagnosing lung cancer typically starts with a history and physical exam. The next step may be an imaging study—such as a chest X-ray, CT scan or PET (positron emission tomography) scan—to search for cancer in your lungs. Some patients may undergo a bone scan, an imaging study of the bones, to determine whether cancer has spread there.

Doctors use a biopsy to identify cancer cells, removing a piece of lung tissue or cells to study under a microscope. Common methods to obtain these samples include:

  • Removing cells through a tube placed into the lung or lung passages
  • Removing fluid or tissue from the lung using a needle
  • Collecting sputum from the lung

Learn about diagnostic procedures for lung cancer

Stages different types of lung cancer

Before starting treatment, your care team needs to identify the stage of your lung cancer. Staging tells your care team the extent of your cancer and helps decide the appropriate treatment.

The two main types of lung cancer are non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC). Knowing the type is important for staging and treatment.

  • NSCLC, the most common type, comprises 80 to 85 percent of all lung cancers. Most of these cancers stem from gland tissues in the lungs and are called adenocarcinomas. They may occur in smokers or nonsmokers and are more common in women. The other main subtypes of NSCLC are squamous cell carcinoma and large cell carcinoma.
  • SCLC makes up 10 to 15 percent of lung cancers and is almost always caused by smoking. These cancers tend to grow and spread quickly, so they’re staged differently. Treatment may include chemotherapy or radiation.

To stage cancer, doctors use what’s called the TNM system. TNM stands for Tumor Node Metastasis, which are important factors in determining the severity of the cancer.

Depending on the TNM findings, lung cancer may be diagnosed from stage 0 to stage 4. The higher the stage, the more advanced the cancer.

For SCLC, doctors sometimes use a simplified system with just two stages. These two stages are limited and extensive.

  • Limited-stage SCLC is cancer in the lung, where it started, and may have spread to lymph nodes between the lungs or above the collarbone.
  • Extensive-stage SCLC is cancer that has spread anywhere beyond the limited stage.

Learn more about stages of lung cancer

Treatment for NSCLC and SCLC

As you learn more about your cancer and the available treatments, you’ll share in the decision-making process with your care team.

Treatments for NSCLC vary by stage and may include:

  • Stage 0: This cancer hasn’t spread into lung tissue, so surgery is typically the sole treatment. In most cases, doctors may remove a wedge of lung tissue.
  • Stage 1: Surgery may be the only treatment needed for this stage, although a larger section of lung may need to be removed. If there’s evidence of cancer near the edge of the removed lung or near a lymph node, surgery may be followed by chemotherapy (cancer drugs) or radiation therapy (ionizing radiation treatments).
  • Stage 2: You may need surgery to remove a whole lobe of lung or the entire lung. Chemotherapy often follows surgery. If tests certain DNA changes (mutations) in the cancer cells, a type of precision drug treatment called targeted therapy may be used to attack the tumor cells.
  • Stage 3: For this stage, doctors typically order some combination of surgery, chemotherapy, radiation therapy and targeted therapy. If cancer cells are found to contain certain types of proteins, your care team may add immunotherapy, which makes use of the body’s ability to fight cancer by helping the immune system recognize and attack cancer cells.
  • Stage 4: These cancers are difficult to treat, and treatment options may depend on your body’s response to the process.

For limited-stage SCLC, treatment may include:

  • Chemotherapy
  • Radiation therapy
  • Surgery (in some cases, this may be performed before chemotherapy and radiation therapy)

For extensive-stage SCLC, primary treatments include:

Patients with either limited- or extensive-stage disease may benefit from clinical trials for new treatments.

Life expectancy: Prognosis

Each cancer and each person is different. To determine a cancer prognosis, researchers calculate how many people with the same type of cancer and stage of cancer are alive five years after diagnosis (aka the five-year survival rate).

According to the ACS:

  • For NSCLC, the overall five-year survival rate is 25 percent. The survival rate ranges between 7 percent for advanced-stage disease and to 63 percent for early-stage disease.
  • For SCLC, the overall five-year survival is 7 percent. The survival rate ranges between 3 percent for extended-stage lung cancer and 27 percent for limited-stage.

Keep in mind that these rates are based on past years of statistics and may not reflect advances in treatment or new treatments that may be available in clinical trials.

Learn about treatment options for lung cancer

Preparing for lung cancer treatment

No one treatment is one-size-fits-all. You need to work with your care team to find the right option for you.

Below are tips to help you prepare for your treatment conversation:

  • Ask about the goal of treatment. Is it to kill the cancer, control the disease or make you more comfortable?
  • Ask whether your cancer has been tested for proteins or mutations that may expand your treatment options.
  • Ask about resources that provide specific information on your treatment, and learn as much as you can, including how the treatment works, how long it lasts and its possible side effects.
  • Find out what you can do to improve results before treatment starts. For example, your doctor may recommend you visit a dentist before undergoing chemotherapy.
  • Establish a support system. Ask how much help you may need at home. Ask about available support groups where you may share experiences with other lung cancer survivors.

Learn more about the questions to ask about lung cancer treatment