Non-Small Cell Lung Cancer

January 24, 2025

This page was reviewed under our medical and editorial policy by Jyoti Malhotra, M.D., M.P.H., associate professor, Department of Medical Oncology & Therapeutics Research, City of Hope^® Orange County Lennar Foundation Cancer Center; and Jae Y. Kim, M.D., associate professor, Division of Thoracic Surgery, Department of Surgery, City of Hope Cancer Center Duarte

Non-small cell lung cancer, also known as NSCLC, is the most common type of lung cancer. About 226,650 lung cancer cases are diagnosed in the United States each year. NSCLC accounts for 80% to 85% of all lung cancer cases, according to the American Cancer Society.

This guide to non-small cell lung cancer is designed to help patients and their families learn more.

What Is Non-Small Cell Lung Cancer?

Non-small cell lung cancer is a type of cancer that originates within the lungs. The lungs are an important organ that facilitate breathing by bringing oxygen into the body and removing carbon dioxide.

Each lung is divided into sections called lobes. Each lung is slightly different in size. The right lung has three lobes and the left lung has two. Inside the lungs, there are small airway tubes (bronchioles) and air sacs (alveoli) that make breathing possible.

NSCLC can begin in several areas of the lungs.

Types of Non-Small Cell Lung Cancer

There are several types of non-small cell lung cancer. This includes three main subtypes, as well as less common subtypes. Each grows and develops in a slightly different way.

Adenocarcinoma

This is the most common type of NSCLC (and of all lung cancers). It accounts for about 40% of all lung cancers, according to the National Cancer Institute (NCI).

Adenocarcinoma starts in epithelial cells. These are cells that produce mucus in the lungs and line the interior surfaces of the lungs.

While it is most often seen in people who smoke, it is also the most common lung cancer type in nonsmokers.

Squamous Cell Carcinoma

Squamous cell carcinomas make up about 25% of all lung cancer cases, according to NCI. It begins in squamous cells, which are flat cells found in the lining of the lungs. Most often, this cancer type begins near a main airway within the central part of the lungs.

Large Cell Carcinoma

Accounting for about 10% of lung cancers, according to NCI, large cell carcinoma may begin anywhere in the lungs. Also known as undifferentiated carcinoma, this cancer type tends to grow quickly and spread to other areas of the body.

Other Subtypes of NSCLC

There are a few other subtypes of NSCLC, but they are rare.

Sarcomatoid carcinoma: This cancer type is a mix of carcinoma and sarcoma cells. Carcinoma cells begin in the internal lining of the lungs, and sarcoma cells begin in the bone, cartilage, fat, muscle or connective tissue.

Adenosquamous carcinoma: This cancer type is a mix of squamous cells and gland-like cells, which secrete substances.

What Causes Non-Small Cell Lung Cancer?

The most common cause of non-small cell lung cancer is smoking. It is linked to 80% of all non-small cell lung cancer cases, according to the U.S. National Library of Medicine.

The risk of developing NSCLC is linked to how many cigarettes are smoked daily, and for how long. Exposure to secondhand smoke from a relative or spouse may also increase a patient’s NSCLC risk.

Once someone quits smoking or is no longer exposed to secondhand smoke, their risk of developing NSCLC begins to decrease over time.

Other causes of non-small cell lung cancer may include:

• Long-term exposure to certain chemicals, including asbestos, arsenic, radon and others
• Previous radiation treatment of the lungs
• Certain types of pigments and paints
• Certain products that contain formaldehyde and/or chloride

Is Non-Small Cell Lung Cancer Hereditary?

Most lung cancer cases are not hereditary. However, recent research shows that there may be a link between certain inherited gene mutations (changes) and lung cancer. Inherited gene mutations are changes to a person’s DNA, passed down from their parents.

Inherited changes in the following genes may lead to lung cancer:

• CHEK2
• BRCA1
• TP53
• ATM
• PALB2
• EGFR
• APC

Symptoms

In the early stages, NSCLC may not cause noticeable symptoms. When symptoms do occur, the combination of symptoms may be different for each patient.

The most common symptoms of early-stage non-small cell lung cancer may include:

• Shortness of breath, wheezing or trouble breathing
• Pain in the chest
• Long-lasting cough
• Coughing up blood
• Unexplained weight loss or loss of appetite
• Fatigue
• Recurring chest infections, such as pneumonia
• A raspy or strained voice

Lung nodules may also be a sign of lung cancer, or they may develop into lung cancer later. These are small, abnormal areas seen in the lungs during computed tomography (CT) scans. If a nodule is found to grow over time, this may be a sign of cancer. However, most lung nodules are noncancerous, caused by things like scar tissue or infections. Patients should always speak with their doctor if they notice any unexpected changes to their health.

Diagnosis

If doctors suspect the patient may have NSCLC, they use a range of diagnostic tests to learn more. These may include the following.

Physical exam: The doctor reviews the patient’s medical history and conducts a physical examination to look for signs of lung cancer.

Chest X-ray: This is a commonly used imaging test for lung cancer. This procedure uses X-rays to take internal pictures of the lungs.

Imaging tests: Other imaging tests may be used to diagnose lung cancer, including CT, magnetic resonance imaging (MRI), bone and positron emission tomography (PET) scans.

Lung biopsy: A tissue sample is removed from the lungs using a needle or during surgery. It is then examined under a microscope to look for lung cancer cells.

Bronchoscopy: Using a small tube with a camera on the end, doctors look inside the lungs for tumors or signs of lung cancer. It is inserted through the mouth or nose.

Ultrasound: Several types of ultrasounds may be used, with the most common being an endobronchial ultrasound. These allow doctors to take internal pictures of areas like the lungs, lymph nodes and esophagus to look for lung cancer cells. 

Mediastinoscopy: During this surgical procedure, a rigid tube is inserted behind the breast bone and used to take tissue samples from the lymph nodes near the esophagus and lungs. 

If cancer is diagnosed, additional testing may be performed to determine the cancer’s type and stage.

Stages of NSCLC

After diagnosis, non-small cell lung cancer is given a stage, which determines the cancer’s size and if it has spread into other areas of the body. There are five stages of NSCLC.

Stage 0: The cancer is only found in the inner lining of the lungs.

Stage 1: The cancer is smaller than 4 centimeters and has not spread elsewhere.

Stage 2: The cancer may have spread into lymph nodes on the same side of the chest as where the cancer began. Or, the cancer has grown to 7 centimeters or less.

Stage 3: The cancer may be more than 7 centimeters and may have grown into the chest wall, its lining or other nearby structures, including lymph nodes.

Stage 4: The cancer has spread into distant areas of the body, such as the bones or liver.

Non-Small Cell Lung Cancer Treatment

Each patient receives a personalized lung cancer treatment plan, depending on its stage, type and their overall health and preferences.

Treatment options for NSCLC may include the following.

Surgery: Either part or all of one lung is surgically removed in a procedure called lung resection. Surgery is an option only for early-stage cancers and for patients otherwise in good health.

Radiation therapy for lung cancer: This treatment uses high-energy X-rays to destroy cancer cells. It may be used before surgery to shrink the tumor or after surgery to help destroy any remaining cancer cells.

Chemotherapy for lung cancer: Using medication to destroy cancer cells, chemotherapy is given orally or intravenously. It may also be used before or after surgery, or as a standalone treatment.

Immunotherapy for lung cancer: This treatment uses medication to boost the patient’s immune system, allowing it to better destroy cancer cells.

Targeted therapy: These are types of medications that help the body better identify cancer cells and stop their growth.

Additional treatments may also be used, depending on the cancer’s type. Some patients may also qualify for clinical trials, which assist research and allow access to leading-edge medical treatments.

Who Treats NSCLC?

The patient’s NSCLC care team will work together to pinpoint the least invasive, most targeted treatment option for each patient. The non-small cell lung cancer care team may include these doctors:

• Thoracic surgeons, who operate on conditions affecting the lungs and chest cavity
• Pulmonologists, who are experts trained to diagnose and treat lung diseases
• Medical oncologists, who work with patients to pinpoint the most effective, least invasive treatment option for each NSCLC patient
• Radiation oncologists, who are experts in radiation therapy, which may be used to treat cancer

What Is the Survival Rate of Non-Small Cell Lung Cancer?

The survival rate for NSCLC varies based on a number of factors, including the cancer subtype and stage; the patient’s age and overall health when diagnosed; his or her response to treatment; and whether certain mutations are present in the cancer cells.

The National Cancer Institute’s Surveillance, Epidemiology, and End Results (SEER) Program Database is often used to measure the five-year relative survival rate for NSCLC. This reflects the percentage of people with this type of cancer who survived for five years or more after diagnosis, compared to those who don’t have that cancer type.

The American Cancer Society reports that the overall five-year relative survival rate for all NSCLC stages was 32% for people diagnosed between 2015 and 2021, based on SEER data.

This survival rate estimate varies based on whether the disease was diagnosed before it spread outside the lung tissue (localized stage), after it spread to area lymph nodes and structures (regional stage) or after it spread to distant parts of the body (distant stage):

• Localized: 67%
• Regional: 40%
• Distant: 12%

Patients should always speak with their NSCLC care teams to get a personalized prognosis.

Non-Small Cell Lung Cancer Versus Small Cell

There are key differences between non-small cell lung cancer and small cell lung cancer. These differences affect both treatment and outcomes.

Non-small cell lung cancer accounts for 80% to 85% of all lung cancers, making it far more common than small cell lung cancer.

NSCLC is typically not as aggressive as SCLC, and grows slower than SCLC.

Surgery is a common and appropriate treatment for NSCLC and not commonly an option for SCLC.

The estimated five-year relative survival rate for all stages combined of NSCLC is higher (28%) than that for SCLC (7%). Survival rates are based on previous patients and past treatments, and may have improved.