Small cell and non-small cell are the two main types of lung cancer. There are several key differences, including the outlook for those with each condition.

In a person with small cell lung cancer, the cancerous cells appear small and round under a microscope. The cells of non-small cell lung cancer are larger.

Smoking is a major risk factor for both types. Of those who receive a diagnosis of small cell lung cancer, 95% have a history of smoking.

There are several subtypes of both small and non-small cell lung cancer. Non-small cell lung cancers include adenocarcinoma, squamous cell, and large cell carcinoma.

Small cell lung cancers vary depending on the expression of specific genes.

Some types are more aggressive than others, but generally, small cell lung cancer is more aggressive than non-small cell lung cancer.

Lung cancer — including both small and non-small cell types — is the third most common form of cancer among adults in the United States. Lung cancers account for 13% of new cancer diagnoses.

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Small and non-small cell lung cancers cause similar symptoms. Sometimes, symptoms do not appear until the cancer reaches a later stage.

Symptoms include:

  • hoarse voice
  • persistent cough
  • fatigue
  • shortness of breath and wheezing
  • difficulty swallowing
  • loss of appetite
  • chest pain and discomfort
  • blood in the mucus brought up by coughing
  • swelling in the veins of the face and neck

The symptoms of small and non-small cell lung cancers are similar, but small cell lung cancer spreads more rapidly.

A person may be more likely to experience symptoms after lung cancer has reached a later stage.

Does lung cancer affect women differently? Learn more here.

Can shoulder pain be a sign of lung cancer? Find out more.

Causes and risk factors for small and non-small cell lung cancer tend to be similar.

Smoking is the main risk factor. Cigarette smoke and the chemicals it contains can damage the lungs. This can lead to cellular changes that may result in cancer.

Additional risk factors include:

  • exposure to secondhand smoke
  • living in an area with significant air pollution
  • older age
  • past exposure to radiation
  • exposure to arsenic and other chemicals
  • exposure to asbestos, nickel, chromium, soot, or tar
  • having a family history of lung cancer
  • having HIV

Smoking is a major risk factor for lung cancer. Find some ideas about how to quit here.

If a person sees a doctor about a persistent cough and other possible symptoms of lung cancer, the doctor will ask questions and take a medical history. They will also perform a physical examination.

If lung cancer may be present, the doctor will also request imaging scans, such as an X-ray or CT scan, and look for signs of a tumor, scarring, or a buildup of fluid.

They may also request samples of phlegm in order to perform a sputum test. This can help indicate whether cancer is present. The doctor will probably ask the person to provide a sample every morning for 3 days in a row.

Doctors may also perform a biopsy. This involves using a needle to take a sample of cells from the lungs for examination under a microscope. They may do this during surgery.

A biopsy can show:

  • whether cells are cancerous
  • what type of cancer is present, if any

Sometimes, the doctor requests a bronchoscopy. This procedure involves inserting a tool with a built-in camera through the mouth or nose and into the lungs. This helps them see the area and take tissue samples.

They may also carry out other tests to determine whether the cancer has spread beyond the lungs.

What does lung cancer look like? Find out here.

Staging

The stage of cancer describes how far it has spread within the body.

There are different ways to describe the stages. One simple way is:

  • In situ: This means abnormal cells have been detected but have not yet become cancerous or spread.
  • Localized: This means the cancer is only in one place.
  • Regional: The cancer has spread to nearby tissues or lymph nodes.
  • Distant: The cancer has spread to other parts of the body, such as the bones, brain, liver, or other lung.
  • Unknown: This means there is not enough information to determine the stage.

However, each type of lung cancer has its own specific method of staging.

Non-small cell lung cancer

For this type of cancer, doctors typically use a 5-stage system.

  • Stage 0: Similar to “in situ,” this means that a doctor cannot detect cancerous cells from traditional imaging methods, but tests have revealed precancerous cells in the mucus or elsewhere in the body.
  • Stage 1: This signifies that the cancer is only in the lungs.
  • Stage 2: The cancer has reached nearby lymph nodes.
  • Stage 3: The cancer has spread to other lymph nodes in the chest, possibly to those in the middle or on the other side of the chest.
  • Stage 4: The cancer has spread to both lungs, other parts of the body, or both.

Stages of small cell lung cancer

Doctors generally categorize small cell lung cancer with one of two stages:

  • The limited stage: This means the cancer is on one side of the chest. It may be in one lung and, possibly, nearby lymph nodes.
  • The extensive stage: The cancer has spread to either the other lung or other organs outside of the original tumor.

Some doctors use further staging for small cell lung cancer.

Can a person have both types?

Around 5–28% of small cell lung cancer cases are “mixed.” This means that the person has small and non-small cell lung cancers. Research suggests that it may be easier to treat mixed cancer than small cell lung cancer alone.

After making a diagnosis, a doctor will describe the treatment options and develop a treatment plan.

Factors that affect the plan will include:

  • the type of cancer
  • how far it has spread
  • the individual’s age and overall health
  • the availability of therapies
  • personal preferences

As each person’s situation is different, treatment will vary accordingly.

Non-small cell lung cancer

Treatment options for non-small cell lung cancer include:

  • Surgery: A surgeon will remove cancerous cells and any nearby lymph nodes that may be affected. However, if cancer affects a large portion of the lungs, surgery may not be possible.
  • Radiation therapy: A radiologist will direct a beam of radiation toward malignant cells to destroy them.
  • Chemotherapy: A doctor will administer powerful drugs that can kill cancer cells.
  • Endoscopic stents: If a tumor has blocked part of the airway, a surgeon may insert a stent.
  • Targeted treatments: These drugs target specific genes or other factors that enhance cancer’s ability to grow. Blocking these factors can help stop or delay the growth of some types of cancer.
  • Immunotherapy: This treatment aims to boost the immune system’s ability to defend the body against cancer. It is an emerging treatment.

Small cell lung cancer

For small cell lung cancer, treatment mainly aims to manage the disease.

Options include:

  • chemotherapy, which is the main treatment
  • radiation therapy, which may help boost the effectiveness of chemotherapy or help prevent the cancer from spreading to the brain
  • surgery with chemotherapy, when the cancer has not yet reached the lymph nodes, which is rare

Doctors may use a combination of treatments for lung cancer, depending upon an individual’s needs, the stage of the cancer, and the location of the tumor.

Experts use past statistics to estimate the percentage of people who are likely to live for 5 or more years after a diagnosis of cancer. These estimations are called survival rates.

They represent averages and do not take into account factors such as a person’s age or overall health.

Non-small cell lung cancer

For non-small cell lung cancer, the American Cancer Society (ACS) reports the following relative 5-year survival rates:

  • for localized cancer: 64%
  • for regional cancer: 37%
  • for distant cancer: 8%

The overall average likelihood of living for at least another 5 years is 26%.

Small cell lung cancer

The ACS estimates the following 5-year survival rates for people with small cell lung cancer:

  • for localized cancer: 29%
  • for regional cancer: 18%
  • for distant cancer: 3%

The overall average likelihood of living for at least another 5 years after a diagnosis of small cell lung cancer is 7%.

Other factors that may affect survival rates include whether the cancer has come back after treatment and a person’s age. Recurring cancer and advanced age can have a negative effect on survival rates.

There are two main types of lung cancer: small cell and non-small cell. Small cell lung cancer is less common and more aggressive.

Quitting smoking — or never smoking — can significantly reduce the risk of developing any type of lung cancer.

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Q:

If a person has a diagnosis of small cell lung cancer, how long can they usually expect to live?

A:

It depends on the stage of the disease, but overall, the average survival rate is about 1–2 years.

Seunggu Han, MD Answers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.