What is Lung Cancer? Its Types, Stages, Symptoms & Diagnosis
Cancer that starts in the lungs is called lung cancer. Your lungs are two soft organs in your chest that take in oxygen when you breathe in and let out carbon dioxide when you breathe out.
Lung cancer is the most common type of cancer that kills people around the world. Lung cancer is most likely to happen to people who smoke, but it can also happen to people who have never smoked. The longer and more often you smoke, the more likely it is that you will get lung cancer. Even if you have smoked for a long time, quitting can make it much less likely that you will get lung cancer.
How many Types of lung cancer are there?
There are two main types of lung cancer: non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC). Non-small cell lung cancer is more common and tends to grow and spread more slowly than small cell lung cancer. Small-cell lung cancer is less common but tends to grow and spread more quickly.
Why does lung cancer happen?
Lung cancer can happen for many different reasons, but smoking is the most significant risk factor. Chemicals in tobacco smoke can damage the DNA in lung cells, which can lead to mutations and the development of cancer. Other things that can make you more likely to get lung cancer are being around people who smoke, being around chemicals and pollutants like radon, asbestos, and air pollution, having a family history of the disease, and having a history of lung diseases like COPD. Getting lung cancer is also more likely for people who have had radiation therapy to the chest.
How many stages are there of lung cancer?
The staging of lung cancer depends on the type of lung cancer.
For non-small cell lung cancer (NSCLC), there are four stages:
- Stage I: The cancer is confined to the lung and has not spread to nearby lymph nodes.
- Stage II: Cancer has spread to nearby lymph nodes but not to other parts of the body.
- Stage III: Cancer has spread to the lymph nodes in the middle of the chest and/or to the surrounding structures, such as the trachea or the main bronchus.
- Stage IV: Cancer has spread to other parts of the body, such as the bones, brain, or liver.
For small cell lung cancer (SCLC), there are two stages:
Limited stage: The cancer is confined to one lung and nearby lymph nodes.
Extensive stage: Cancer has spread beyond the lung and nearby lymph nodes to other parts of the body.
What are the symptoms of lung cancer?
Symptoms of lung cancer can vary depending on the type, location and stage of cancer. Some common symptoms of lung cancer include:
- A persistent cough that does not go away or gets worse over time
- Chest pain, especially when coughing or breathing deeply
- Shortness of breath
- Hoarseness or a change in the voice
- Coughing up blood or rust-coloured sputum
- Loss of appetite or weight loss
- Fatigue or weakness
- Recurrent lung infections such as bronchitis or pneumonia
- Swelling in the face or neck
It's important to note that these symptoms can also be caused by other conditions and do not necessarily mean that you have lung cancer. It's always best to consult a healthcare professional if you have any concerns about your health.
How is lung cancer diagnosed?
Lung cancer is typically diagnosed through a combination of methods, which may include:
- Physical exam: Your doctor will examine you for signs of lung cancer, such as lumps in the chest or swollen lymph nodes.
- Imaging tests: Imaging tests such as a chest X-ray, CT scan, or PET scan can help to create detailed images of the lungs and can detect any abnormalities.
- Biopsy: A biopsy is the removal of a small sample of tissue for examination under a microscope. A lung biopsy can be done in several ways, including bronchoscopy, in which a thin, flexible tube with a light and camera is passed through the nose or mouth into the lungs, or a needle biopsy, in which a needle is inserted through the chest wall to remove a small sample of tissue.
- Sputum cytology: Sputum cytology is the examination of cells from a sample of sputum (mucus that is coughed up from the lungs) under a microscope. This test can detect abnormal cells that may be cancerous.
- Blood tests: A blood test, such as a complete blood count (CBC) or a test for a protein called tumour marker (such as NSE or CEA) can also be done to help diagnose lung cancer.
Once a diagnosis of lung cancer is made, additional tests will be done to determine the stage of cancer, which can help to guide treatment decisions.
How is lung cancer treated?
Lung cancer is treated with a mix of surgery, radiation therapy, chemotherapy, and targeted therapy. The choice of treatment depends on many things, like the type and stage of cancer, the patient's overall health, and their own preferences. Surgery is the most common way to treat lung cancer in its early stages. Radiation and chemotherapy are used to treat lung cancer in its later stages. Targeted therapy uses drugs to target certain genes or proteins that help cancer cells grow and spread. In some cases, all of these treatments might be used together. The goal of treatment is to remove or kill cancer while keeping as much healthy lung tissue as possible.