What Is Non-Small Cell Lung Cancer?

In This Article

Non-small cell lung cancer (NSCLC) is the most common type of lung cancer, accounting for about 80% to 85% of all cases of lung cancer. 

There are different stages of NSCLC—higher-numbered stages indicate that the cancer has spread further and tumors are larger. Your symptoms and your options for treatment will depend upon what stage you're at along with what type of NSCLC you're diagnosed with.

Lung cancer remains a difficult disease to completely overcome. However, improvements in screening are enabling doctors to catch lung cancer earlier than previous generations and advancements in treatments have been improving survival rates for all stages of NSLC.

Types of Non-Small Cell Lung Cancer

There are three primary types of non-small cell lung cancer. These include adenocarcinoma, squamous cell carcinoma, and large cell carcinoma.

Types of Non-Small Cell Lung Cancer
Verywell / Emily Roberts


Adenocarcinoma is the most common form of non-small cell lung cancer, comprising approximately 40% of NSCLC cases. It's common in current and former smokers, but it is also found in young adults, women, and people who have never smoked.

Lung adenocarcinoma usually begins in the outer regions of the lungs and can grow quite large before it's detected.

Squamous Cell Carcinoma

Squamous cell carcinoma accounts for roughly 30% of non-small cell lung cancers. These tumors usually develop in the center of the lung next to an air tube (bronchus).

Historically, squamous cell carcinoma had been the most common type of NSCLC, but incidents have fallen over the last generation. This change is attributed to changing smoking habits since smokers are at greatest risk for squamous carcinomas.

Large Cell Carcinoma

Large cell lung cancers are considerably less common, accounting for less than 2% of non-small cell lung cancers. These tumors can occur in any part of the lung and tend to grow and spread more rapidly than adenocarcinoma or squamous cell carcinoma.

There are other subtypes of NSCLC that occur less frequently. These include adenosquamous carcinoma and sarcomatoid carcinoma.


Different types of NSCLC tumors present in different ways. With adenocarcinoma, tumors are usually located away from the airways. This means that breathing-related problems associated with lung cancer may not be present until much later. Instead, early symptoms are often subtle and may include a general sense of ill health. Squamous cell carcinoma usually interferes with the bronchial tubes, which can cause unusual coughing or recurrent respiratory illness. Meanwhile, large cell lung cancers progress so quickly that symptoms may come on all of a sudden.

Unless you recognize that you're at great risk for lung cancer due to smoking habits or a family history of NSCLC, you may miss the early signs of lung disease. Being aware of common lung cancer symptoms can help you recognize when you might need to get screened.

As the cancer grows and spreads, you may begin to notice these types of problems:


Smoking continues to be the leading cause of non-small cell lung cancer. Secondhand smoke is also a risk factor. Smoke exhaled by smokers and smoke emitted from the lit end of a cigarette, pipe, or cigar, or from tobacco burning in a hookah is responsible for an estimated 7,330 lung cancer deaths each year.

Other risk factors can raise your chances of developing NSCLC. The leading cause of lung cancer in non-smokers is radon exposure. Radon, a radioactive gas, can be present in your home without you knowing it, so you may want to test your home for the carcinogen.

Air pollution is also increasingly recognized as contributing to lung cancer diagnoses. Researchers have estimated that air pollution is responsible for 15% of worldwide lung cancer deaths.


The diagnosis of non-small cell lung cancer can be challenging. It's not uncommon for people to be misdiagnosed. For more than 30% of NSCLC patients, it took three or more visits to the doctor before their symptoms were correctly diagnosed as lung cancer.

A chest X-ray often offers the first evidence of lung cancer. This may be a test that is conducted for an unrelated problem, or that was ordered because of suspicious symptoms. Additional tests that can help determine if cancer is present include a computed tomography (CT) scan, which provides an image of the chest, or sputum cytology, which examines mucus from your lungs under a microscope to check for cancer cells. However, a lung biopsy is usually needed to confirm the diagnosis and to determine what kind of lung cancer is present.


Non-small cell lung cancer is generally broken down into four stages, depending on the size of the tumor and how far it has spread.

  • Stage 1: Small growths have not spread beyond the site of the primary tumor.
  • Stage 2: Slightly larger tumors may or may not have spread to local lymph nodes.
  • Stage 3A: Tumors are between 3 and 7 centimeters (cm) and have usually spread to local lymph nodes.
  • Stage 3B: Tumors may measure larger than 7 cm and have spread into surrounding tissue and lymph nodes.
  • Stage 4: Tumors can be any size; cancer has spread beyond the site of the primary tumor to the other lung or other parts of the body.

Each stage is divided into more specific designations based on the TNM system of staging lung cancer, where T stands for tumor size, N stands for lymph nodes, and M stands for metastasis (the spread of cancer).


Doctors recommend treatments for lung cancer based on the stage your cancer is at. They include either local treatments, in which cancer treatments are directed at tissue around where cancer originated, and systemic treatments, which act on cancer throughout the body or wherever it has spread. Local treatments include surgery and radiation therapy. Systemic treatments are broader treatments and include chemotherapy, targeted therapies, and immunotherapy. Many people with lung cancer receive treatments with both of these forms of therapy.

Possible treatments may include:

  • Surgery: Surgery for lung cancer can sometimes offer the chance for a cure in the early stages of the disease. Not all tumors can be removed via surgery either due to their location or the extent of the metastasis.
  • Chemotherapy: Chemotherapy may be used with surgery to ensure all the cancer is destroyed or as palliative care to manage symptoms when the cancer is advanced.
  • Radiation Therapy: Radiation therapy may be done with chemotherapy or along with surgery to ensure all malignancy is completely destroyed. One type of radiation therapy, stereotactic body radiation therapy, can be used alone to improve survival rates.
  • Targeted Therapies: Targeted therapies are drugs that address specific genetic mutations in cancer cells, working to make these cells stop growing or stop causing more damage.
  • Immunotherapy: These drugs offer new options for treatments. Immunotherapies help your own immune systems recognize and attack cancer cells.
  • Clinical Trials: These are studies that test new cancer treatments; you can enroll in these trials if you want to be involved in trying out experimental treatments that may be able to offer new hope.


The five-year survival rate for non-small cell lung cancer is 24% across all stages. If tumors are diagnosed early, before there has been any spread, the five-year survival rate increases to 61%.

It's important to realize that these estimates are based on numbers collected over more than one decade, so they don't fully reflect advances that have been made in recent years. Keep in mind, too, that everyone responds to treatment differently. Statistics can only tell us what the average might be, not what your particular changes are.

To improve your chances of a long-term remission, be sure you understand your specific diagnosis and all of your treatment options. This will help you make the best decision about your care.

Because there is a high risk of recurrence with lung cancer, doctors do not like to use the word "cured" even when there are no signs of lung cancer for years after treatment. However, you may hear doctors use terms like durable response or stable disease, which describe situations in which your cancer is not progressing and you should be able to fully enjoy life.

While surgery offers the best chance for remission, even that treatment comes with a high risk that you will relapse eventually. Rates of recurrence following lung cancer surgery range from 30% to 75%. In most cases, the tumors appear somewhere other than where the primary tumor first appeared, which makes for a poor prognosis.


If you're newly diagnosed with lung cancer, you're probably feeling frightened and overwhelmed. Stress is only going to make it harder for you to keep up your strength and fight cancer. So, in addition to researching your condition and options, be sure you are taking time to care for yourself and surround yourself with positive influences. Having a good attitude will make you more resilient and better able to stand up to the physical and emotional strain that lung cancer can place upon you.

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