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 on the stage of your lung cancer 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:

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

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

Adenocarcinoma

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 was the most common type of NSCLC, but incidence has fallen over the last generation. This is attributed to changing smoking habits; smokers are at greatest risk for squamous carcinomas, and the number of smokers has decreased.

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.

Symptoms of Non-Small Cell Lung Cancer

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:

Causes

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.

Diagnosis

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 takes three or more visits to the doctor before their symptoms are correctly diagnosed as lung cancer.

A chest X-ray often offers the first evidence of lung cancer, though it is not entirely reliable for this purpose. This kind of imaging may be done for an unrelated problem or ordered because of suspicious symptoms.

Additional tests that can help determine if cancer is present include:

However, a lung biopsy is needed to confirm the diagnosis and determine what kind of lung cancer is present.

Staging

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 more 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).

Treatment

Doctors recommend treatments for lung cancer based on the stage your cancer is at. They include either:

  • Local treatments: These options are directed at the tumor and surrounding tissue.
  • Systemic treatments: These act on cancer throughout the body or wherever it has spread.

Many people with lung cancer have a treatment plan that includes both of these forms of therapy.

Possible treatments may include:

Treatment Purpose and Benefits Type
Surgery • Removal of cancer*
• Sometimes offers a chance for a cure in early stages
Local
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 Systemic
Radiation therapy • May be done with chemo or surgery to ensure all malignancy is completely destroyed
• Stereotactic body radiation therapy can be used alone to improve survival rates.
Local
Targeted drug therapies • Address specific genetic mutations in cancer cells to make them stop growing or causing more damage Systemic
Immunotherapy drugs • Offer new options for treatment
• Help your own immune system recognize and attack cancer cells
Systemic
Clinical trials • Studies that test new cancer treatments
• Access to experimental treatments that may offer new hope
​Local or systemic

*Note: May not be possible depending on tumor location or extent of metastasis

 

Prognosis

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 a 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.

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 eventually relapse. 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.

Coping

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 be around 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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