What is Non-Small Cell Lung Cancer (NSCLC)?
NSCLC usually begins as a small cluster of abnormal cells that grows in the lining of the bronchi-tubes that carry air–although it can also begin growing in other parts of the lungs. These cancer cells then divide without control, forming a growth or a primary tumor. As the primary tumor grows, cancer cells can break away and spread through the blood or lymph system to nearby organs. In addition, fluid usually containing cancer cells can build up in the space surrounding the lungs, causing a collection of fluid called a pleural effusion. This spreading of cancer cells and/or collection of fluid may sometimes be referred to by your health care team as stage IIIB NSCLC.
Cancer cells can also spread to distant sites, such as the liver, brain, or bones. This spreading of cancer is called metastasis and may sometimes be referred to by your health care team as advanced, metastatic, or stage IV NSCLC. Even though the cancer has spread to a new part of the body, the cells come from the original primary lung cancer, so it is still considered NSCLC.
What are the types of NSCLC?
Most lung cancers (about 85%) are classified as non-small cell lung cancers and tend to spread more slowly than small cell lung cancer. Non-small cell lung cancer is divided into 3 main subtypes based on the kind of cells found in the cancer. The tumor may differ in size, shape, and location depending on the subtype.
Squamous cell carcinoma: Affects approximately 25% of people with NSCLC. This cancer begins in squamous cells and tends to be found near the bronchus.
Non-squamous cell carcinoma: Affects approximately 75% of people with NSCLC.
- Adenocarcinoma: Cancer that is usually found in the tissues of the lung
- Large cell undifferentiated carcinoma: Cancer that can start in any part of the lung and often grows and spreads quickly; cells are large and look abnormal under a microscope
The type of NSCLC that you have may make a difference in the type of treatment your doctor recommends.
Tools
Chest X-ray
CT (computerized axial tomography) and MRI (magnetic resonance imaging) scans use computers to produce highly detailed pictures of the body. These images can show dimensions that help determine the size, shape, and location of the tumor. Both scans are helpful to see whether a tumor has spread from the lung to the lymph nodes or other parts of the body.
Bone scan
A small amount of harmless radioactive substance is injected into a vein. This is only done when there is pain in the bones, a sign that the cancer may have spread there.
Pet scans
PET (Positron Emission Tomography) scans are different from CT and MRI scans because they can distinguish between cells that are rapidly dividing-such as tumor cells. In addition to testing for lung cancer, PET scans can also be used as a follow-up to chest x-rays, CT scans, or MRI scans. This can determine if a tumor is cancerous as well as if and where it has spread.
