Non-small cell lung cancer is an umbrella term that describes several lung cancers. Several treatment options are available, and early diagnosis can improve a person’s outlook.

Non-small cell lung cancer (NSCLC) is the most common type of lung cancer.

Understanding NSCLC can help people make treatment decisions that fit their goals and lifestyle, ask their doctor the right questions, and better advocate for quality care.

This article explains what NSCLC is. It will list the stages, possible causes, symptoms, and treatment options.

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The term NSCLC describes a group of cancers that includes the following:

  • Adenocarcinoma: This type of NSCLC is common in people who smoke. It is also the most prevalent form of lung cancer in people who do not smoke. It begins in mucus-secreting cells in the lungs. Doctors can often diagnose it before it spreads. A subtype of adenocarcinoma labeled in situ, a localized type of cancer that spreads more slowly, usually has a better prognosis.
  • Squamous cell carcinoma: This type of cancer begins in squamous cells, which are flat cells that line the airway, including the lungs. Doctors often find them near the main airway in the lungs.
  • Large cell (undifferentiated) carcinoma: This fast-growing cancer can appear anywhere in the lungs. A subtype called large-cell neuroendocrine carcinoma behaves similarly to small-cell lung cancer (SCLC).

Other types of cancer can also grow in the lungs.

Different cancers, such as pancreatic cancer, may also spread to the lungs.

Learn about lung cancer mutations here.

The main difference between small and non-small lung cancer is that SCLC usually starts in the bronchi, the airway passages into the lungs. NSCLC starts in different locations depending on the subtype a person has.

SCLC grows and spreads more quickly. Doctors usually identify NSCLC at a later stage, when it may have spread.

Learn more about the differences between SCLC and NSCLC here.

Doctors usually classify NSCLC into five stages based on how far the cancer has spread:

0Also called in situ cancer, this means that cancer is in the top cells of the lungs and has not spread outside the lungs
1This cancer remains in the lungs but has spread deeper into the lining of the lungs. Doctors may assign the letter A or B based on how deeply the cancer has penetrated the lungs.
2This cancer has spread either to lymph nodes near the lungs or to other structures in the lungs. It has not spread to other organs. The letter A or B further denotes how far the cancer has spread.
3This cancer has spread to the lymph nodes of the chest. The letters A, B, or C indicate how many lymph nodes it has penetrated and how far it has traveled.
4Stage 4 cancer has metastasized. This means it has spread to other organs, such as the liver or pancreas.

Treatment aims to cure or eliminate lung cancer in people with stages 1, 2, or 3A.

There is no cure for stage 3B or 3C cancer. Treatment aims to manage the disease, helping people to live as long and comfortably as possible.

Learn about how quickly lung cancer can spread here.

Lung cancer happens when cells divide out of control in the lungs, causing tumors or damaging healthy tissue. Doctors do not fully understand what causes cancer or why some people with risk factors develop it while others do not.


According to some estimates, smoking causes 90% of lung cancers. The risk increases the more a person smokes.

A person who smokes a pack a day for 40 years or an equivalent amount in a different period is about 20 times more likely to develop lung cancer.

Other risk factors

Some other risk factors include:

  • a family history of lung cancer, which may indicate a genetic predisposition to cancer, especially when environmental exposures, such as smoking, are involved
  • exposure to radon, asbestos, arsenic, and some other chemicals
  • frequent exposure to secondhand smoke
  • exposure to some pollutants, such as car exhaust
  • smoking while taking beta-carotene supplements

Learn about lung cancer in non-smokers here.

Some people with NSCLC have no symptoms, especially in the early stages of the disease.

However, the first noticeable symptom will likely be an unexplained chronic cough.

Some other symptoms include:

Doctors may suspect a person has lung cancer based on their medical history or symptoms. Sometimes, a doctor may recommend lung cancer screenings for a person with a long smoking history.

A doctor may recommend a series of tests, including:

Lung cancer treatment depends on its stage, whether it is curable, and a person’s treatment goals.

For example, some people choose not to have chemotherapy if they have terminal cancer because they do not want to experience the side effects. Other people choose to have aggressive treatment at all stages.

Some treatment options include:

  • Surgery: A surgeon may be able to remove the tumor or may recommend removing a portion of the lung.
  • Chemotherapy: Chemotherapy targets cancer cells but can also kill healthy cells. It is very effective at shrinking or eliminating certain types of NSCLC. It can also prevent cancer from returning after surgery.
  • Radiation: Like chemotherapy, radiation uses concentrated energy beams to target and kill cancer cells. A person may need radiation after chemotherapy.
  • Targeted therapies: Doctors sometimes recommend targeted therapy. This can help prevent a specific type of cancer cell from growing. A person may have targeted therapy along with or instead of chemotherapy.
  • Experimental therapies: If a person does not respond well to treatment or has a very aggressive cancer, a doctor may recommend they participate in a clinical trial. These trials can discover new treatments, though the treatments do not always work.

Sometimes, a doctor might recommend immunotherapy to treat NSCLC.

Learn about immunotherapy and NSCLC here.

A person should see a doctor if they have any symptoms of lung cancer, including a cough that does not go away or breathing difficulties.

People with cancer should regularly meet with their doctors after diagnosis.

Lung cancer can be aggressive and has often spread before a doctor diagnoses it. The outlook varies from person to person, and many stages of lung cancer are eventually fatal.

According to the American Cancer Society, the 5-year survival rate for NSCLC is 65% for cases detected when the disease is still localized (within the lungs).

For distant tumors (ones that have spread to other organs), the 5-year survival rate is 9%.

Learn more about metastatic lung cancer here.

Many people are understandably frightened when they receive a lung cancer diagnosis, but doctors constantly evaluate treatment options and explore potential new cures.

People with lung cancer should work with an oncologist they trust, ask lots of questions, and talk with their loved ones about end-of-life care.