Lung Cancer: The Basics

OncoLink Team
Last Modified: April 14, 2016

Lung cancer is caused by lung cells growing out of control. As the number of cells grow, they form into a tumor. There are many types of lung cancers. They are described below.

  • Small Cell Lung Cancer (SCLC)
    • 15% of all lung cancers.
    • SCLC is more aggressive than non-small cell lung cancer.
    • Grows more quickly and is more likely to spread to other parts of the body.
  • Non-Small Cell Lung Cancer (NSCLC)  
    • 85% of all lung cancers.  
    • Generally slower growing than small cell lung cancer.
    • Divided into different types based on the cells that make up the tumor.
    • Include adenocarcinoma, squamous cell carcinoma, and poorly differentiated or large cell carcinoma.

Lung cancer that has spread to the lung from another part of the body is called metastatic cancer. Two other types of lung cancer are mesothelioma and carcinoid tumors. These cancers will not be discussed in here.

Risk Factors

Smoking cigarettes (now or in the past) is the leading cause of lung cancer. However, lung cancer in non-smokers has been rising in recent years. Other causes for lung cancer include radon, radiation, asbestos, and pollution.


Current or former heavy smokers, can have a special test (CT scan) to screen for lung cancer. This test can find lung cancer sooner and may help patients live longer. Speak to your healthcare provider to decide if this test is right for you.

Signs & Symptoms of Lung Cancer

The early stages of lung cancer may not have any symptoms. As the tumor grows in size, it can cause symptoms.

  • Cough (one that doesn't go away or gets worse). A cough is the most common      symptom. Many long-term smokers have a chronic cough. However, if there is a change in your cough, see your doctor.
  • Chest pain
  • Hard time breathing
  • Feeling winded with little activity
  • Wheezing
  • Coughing up blood or bloody phlegm
  • New hoarseness or change in speech
  • Having pneumonia or bronchitis that keeps coming back
  • Weight loss
  • Loss of appetite
  • Very tired

Diagnosis of Lung Cancer

When your healthcare providers think you may have lung cancer, they will order tests.  Here are some of the tests

  • Chest x-ray
  • CT scan (“Cat Scan”, a 3-D x-ray)
  • Sputum cytology (looking at your phlegm for cancer cells)
  • A PET scan and an MRI scan of the brain are often done to examine other areas of the body where lung cancer can spread.

These tests are important but a biopsy is the only way to know for sure if you have cancer. A biopsy

  • Looks at a sample of the lung for cancer cells
  • Is used to determine the cancer type, how abnormal it is [grade], and if it has spread
  • May look at samples from lymph nodes to check for cancer
  • The biopsy may be done using a brochoscopy (small camera passed down your throat into the lungs) or by surgery.

A pathology report summarizes these results and is sent to your healthcare provider, typically 5-10 days after the bronchoscopy. This report is an important part of planning your treatment. You can request a copy of your report for your records.

Staging Lung Cancer

To guide treatment, lung cancer is "staged." This stage is based on

  • Size and location of the tumor
  • Whether cancer cells are in the lymph nodes
  • Whether cancer cells are in other areas of the body

Stages range from stage I (smallest, most confined tumors) to stage IV (tumors that have spread to other areas of the body). The stage and type of lung cancer will guide your treatment plan,


In general, the following treatments are used:

  • Non Small Cell Lung Cancer:
    • In some cases, surgery is done to remove as much of the cancer as possible.
    • Most patients will also receive chemotherapy either given before surgery (called neoadjuvant) or after surgery (called adjuvant).
    • Radiation therapy can be used in addition to surgery, or when surgery is not possible.
    • Chemotherapy can be given before, during or after radiation therapy.
  • Small Cell Lung Cancer:
    • Surgery is not typically used for small cell lung cancers.
    • A combination of chemotherapy and radiation therapy is often given.
    • Most people with small cell cancers will also have radiation to the brain to prevent the cancer from spreading there.


This article is a basic guide to lung cancer. You can learn more about your type of lung cancer and treatment by using the links below.

All About Non-Small Cell Lung Cancer

All About Small Cell Lung Cancer

Lung Cancer Web-U-Cation Program: This video will help you learn about lung cancer. The topics include diagnosis, staging, and treatments. It also addresses coping with cancer and concerns surrounding work, insurance and disability.


Click on any of these terms for more related articles