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Doctors looking at lung scan

Non-small cell lung cancer develops in the epithelial cells of the lungs. It is the most common form of lung cancer, representing about 85% of all diagnoses. Most lung cancer cases can be classified as either non-small cell or small cell.

What are the types of non-small cell lung cancer? 

Non-small cell lung cancer has three main subtypes, all of which look similar under a microscope. The main differentiator between these subtypes is what kind of epithelial cell they originate in. Each subtype responds differently to cancer therapies, so identifying what kind of non-small cell lung cancer is present is key to an effective treatment plan.


Adenocarcinoma is the most common subtype of non-small cell lung cancer. It usually develops around the outer part of the lungs in the cells that produce mucus. Adenocarcinomas are especially prevalent among women and individuals who do not have a history of smoking. Often diagnosed in an early stage, it usually has a more positive prognosis than other forms of lung cancer.

Squamous cell (epidermoid) carcinoma

As its name suggests, squamous cell carcinoma begins in the squamous cells that line the airways (bronchi). It is the second most common subtype of non-small cell cancer and is more frequently seen in men. Although this cancer tends to grow slowly, it can eventually create a cavity within the lung.

Large cell (undifferentiated) carcinoma

Large cell carcinoma can develop in various large cells in the lungs, other than the two described above. It is the least common subtype of non-small cell lung cancer and is usually more difficult to treat than adenocarcinoma and squamous cell carcinoma.

How is non-small cell lung cancer diagnosed?   

Only a biopsy can definitively diagnose non-small cell lung cancer, but there are several steps that must be taken before a biopsy is ordered. If a patient is exhibiting possible signs of lung cancer, a physician will likely begin by conducting a thorough physical examination and evaluating his or her medical history. If this exam indicates the need for further evaluation, one or more imaging tests may then be performed to obtain pictures of the lungs. Common imaging tools for lung cancer include:  

  • Chest X-ray
  • Computed tomography (CT) scan
  • Magnetic resonance imaging (MRI) scan
  • Positron emission tomography (PET) scan

These imaging tests can also provide valuable insight regarding if and how far lung cancer has spread (metastasized) to other areas of the body. 

If imaging tests indicate that lung cancer may be present, a biopsy procedure will be performed to remove a small sample of lung tissue or fluid. This sample will be examined for cancer cells under a microscope. There are several minimally invasive approaches to lung biopsy, such as fine needle aspiration (FNA), which uses a very thin, hollow needle to withdraw small pieces of lung tissue, and thoracentesis that also uses a hollow needle to draw out any fluid that has collected around the lungs. The most appropriate form of lung biopsy will vary according to the patient’s age, symptoms, overall health and other factors.

What causes non-small lung cancer to develop?  

What causes each case of non-small cell lung cancer – and cancer in general – is not fully understood. In a broad sense, cancer develops as a result of abnormal cellular changes in DNA. While what triggers these cancerous changes in lung cells isn’t always clear, researchers have found several factors that can increase an individual’s chance of developing non-small cell lung cancer. These include:


The link between tobacco smoke and lung cancer is well established. The American Cancer Society estimates that about 80% of all lung cancer cases are caused by smoking, while many others are related to inhaling secondhand smoke.

Environmental exposures

Frequent exposure to certain chemicals, including those found in air pollution, diesel exhaust and asbestos, may increase the risk of developing lung cancer.


Some people have a genetic predisposition for lung cancer. Individuals who have a family history of lung cancer should be particularly mindful of potential symptoms, even if they don’t smoke. 

Having one or more risk factors does not necessarily mean you will be diagnosed with lung cancer. It’s also possible to develop lung cancer without having any established risk factors. If you believe you have an increased likelihood of experiencing lung cancer, consider consulting with a physician about ways to help lower your risk.

What are the symptoms of non-small cell lung cancer?  

Non-small cell lung cancer typically does not cause noticeable symptoms in its early stages. When it does, however, symptoms may include:

  • A lingering cough, which may be dry or produce mucus or phlegm
  • Shortness of breath
  • Fatigue
  • Voice hoarseness
  • Coughing up blood
  • Chest pain that worsens with deep breathing
  • Unexplained weight loss

Noncancerous conditions are most often to blame for these symptoms, but it’s important to promptly speak with a physician should any of them occur. As with most other cancers, early diagnosis is key to a successful outcome and positive quality of life.

How is non-small cell lung cancer treated?   

Each patient’s ideal course of treatment will vary according to the cancer subtype, whether or not it has spread and other factors such as his or her age and overall health. The main treatment approaches for non-small cell lung cancer include surgery, chemotherapy, radiation therapy, targeted therapy and immunotherapy.

Non-small cell lung cancer treatment sometimes begins with surgery to remove tumors, a section of the lung or the entire lung, depending on the type and stage of the cancer. Chemotherapy and radiation therapy may also be given after or in place of surgery to destroy cancer cells in the lungs or throughout the body. Chemotherapy involves taking cancer-fighting medications that are administered orally or intravenously, whereas radiation therapy utilizes high-energy X-ray beams to attack cancer cells.

Targeted therapy and immunotherapy are two promising treatments for non-small cell lung cancer. Both are systemic therapies that use medication to disrupt cancer growth. Targeted therapy aims to impede the processes that contribute to the spread of cancer, such as blood vessel growth around tumors, and immunotherapy helps stimulate the patient’s immune system to more effectively identify and destroy cancer cells.

The outlook for patients with non-small cell lung cancer is usually more positive than those with small cell lung cancer, although multiple factors will influence each patient’s individual prognosis.

Moffitt’s approach to non-small cell lung cancer

The multispecialty team in Moffitt Cancer Center’s renowned Thoracic Oncology Program provides the very latest advances in treatment to patients with all forms of lung cancer. In a single location, our patients have access to medical oncologists, pulmonologists, thoracic surgeons, radiation oncologists, pathologists and multiple other specialists who focus exclusively on lung malignancies. Collaborating together, this team develops individualized treatment plans and refines them as necessary to help ensure the best possible outcome and quality of life for each of our patients.   

Moffitt also spearheads a groundbreaking clinical trial program and ambitious research initiatives to improve lung cancer treatment options, as well as a comprehensive and convenient Lung Cancer Screening and Surveillance Program. If you would like to speak with a Moffitt professional about lung cancer prevention, screening, treatment or clinical trials, call 1-888-663-3488 or fill out a new patient registration form online.