Lung cancer occurs when cells divide uncontrollably in the lungs. This causes the growth of tumors. These can reduce the breathing ability of a person and spread to other parts of the body.
The third most common cancer is lung cancer and the leading cause of cancer death in the United States. It is more common in men and in the United States, black men are about 15% more likely to develop it than white men.
Smoking is a major risk factor, although not all people who develop lung cancer have a history of smoking.
Lung cancer can be fatal, but effective diagnosis and treatment improves the outlook.
This article explains lung cancer meaning, how to recognize the symptoms, and the treatment options available.
What is lung cancer?
Cancer causes changes in cells that are healthy. The cells grow too quickly, without dying.
Normal cells in the body usually die at some point in their life cycle, preventing too many cells from building up. In cancer, however, cells continue to grow and multiply. As a result, tumors develop.
The two main types of lung cancer are small cell lung cancer and non-small cell lung cancer, depending on how they look under a microscope. Non-small cell lung cancer is more common.
Anyone can develop lung cancer, but smoking and exposure to smoke, inhaled chemicals, or other toxins can increase the risk.
The main types of lung cancer include non-small cell lung cancer and small cell lung cancer. They differ in the size of the cell, as seen under a microscope.
Non-small cell lung cancer
About 84% of lung cancer cases in the United States are non-small cell. There are three subtypes:
- squamous cell cancer
- large cell carcinoma
Small cell lung cancer
About 13% of lung cancer cases in the United States are small cell. This type tends to grow faster than non-small cell lung cancer.
Symptoms and signs
Until a later stage, people with lung cancer may not have any symptoms. If symptoms do appear, they may resemble those of a respiratory infection.
Some possible symptoms include:
- changes in a person’s voice, such as hoarseness
- frequent lung infections, such as bronchitis or pneumonia
- swelling of the lymph nodes in the middle of the chest
- a persistent cough that may start to get worse
- chest pain
- shortness of breath and wheezing
Over time, a person may also experience more serious symptoms, such as:
- severe chest pain
- bone pain and bone fractures
- cough up blood
- blood clots
- loss of appetite and weight loss
The stage of cancer describes how far it has spread in the body and how severe it is. Staging helps healthcare professionals and individuals decide on an appropriate treatment.
The most basic form of staging is:
- localized, in which the cancer is in a limited area
- regional, in which the cancer has spread to nearby tissues or lymph nodes
- far away, where cancer has spread to other parts of the body
The TNM staging system is similar to this one. Healthcare professionals assess the size and spread of the tumor, whether or not it affects the lymph nodes and whether it has spread elsewhere.
There are also specific methods of staging non-small cell and small cell lung cancer.
Stages of non-small cell lung cancer
Healthcare professionals typically use the size and spread of the tumor to describe the stages of non-small cell lung cancer, as follows:
- Occult or hidden: Cancer does not show on imaging scans, but cancer cells may appear in phlegm or mucus.
- Stage 0: There are abnormal cells only in the upper layers of cells that line the airways.
- Stage 1: A tumor is present in the lung, but it is 4 cm or less and has not spread to other parts.
- Stage 2: The tumor is 7 cm or less and may have spread to nearby tissues and lymph nodes.
- Stage 3: The cancer has spread to the lymph nodes and has spread to other parts of the lung and the surrounding area.
- Stage 4: Cancer has spread to distant parts of the body, such as bones or the brain.
Stages of small cell lung cancer
Small cell lung cancer has its own categories. The stages are known to be limited and extensive, and they indicate whether the cancer has spread to the inside or outside of the lungs.
At the limited stage, the cancer affects only one side of the breast, although it may already be present in some surrounding lymph nodes.
About a third of people with this type find out they have limited-stage cancer. Healthcare professionals can treat it with radiation therapy as one area.
In the extensive stage, the cancer has spread beyond just one side of the breast. It can affect other lungs or other parts of the body.
About two-thirds of people with small cell lung cancer find it out when they are already in the extensive stage.
According to the American Cancer Society, the chances of surviving 5 years or more after being diagnosed with lung cancer are as follows.
The percentages reflect a person’s odds of surviving with lung cancer versus a person’s odds of surviving without lung cancer.
Non-small cell lung cancer
Localized – 63%
Regional – 35%
Distant – 7%
Overall – 25%
Small cell lung cancer
Localized – 27%
Regional – 16%
Distant – 3%
Overall – 7%
Regular screening can be a good idea for people at high risk of developing lung cancer. Screening is done by low dose computed tomography.
The American Lung Association recommends testing if a person meets all of the following criteria:
- is between 55 and 80 years old
- has a history of heavy smoking (30 packs of years, i.e. for 30 years, one pack per day or two packs per day for 15 years)
- currently smokes or has quit in the past 15 years
This screening will often be covered by insurance if a person is aged 55 to 80 and has private health insurance or is aged 55 to 77, has Medicare and meets all other criteria.
However, before signing up for lung cancer screening, people should check with their insurance company.
If a person has symptoms indicating lung cancer, or if the screening shows anything unusual, a healthcare professional will likely recommend diagnostic tests.
An x-ray, CT scan, MRI, or PET scan can reveal areas of cancerous lung tissue.
If the cancer has spread, imaging tests can also show changes in bones and other organs. Scans can also help monitor the progress of treatment.
A healthcare professional may want to take a biopsy to look for cancer cells. They will do this using a bronchoscope or a fine needle.
A bronchoscope is a thin, lighted telescope with a camera on the end that enters the lungs through the mouth or nose. A healthcare professional can use it to check for lesions and take samples.
For less accessible lesions, they may use a more invasive surgical procedure to remove the lung tissue, such as thoracoscopy or video-assisted thoracic surgery.
Laboratory tests can also reveal whether cancer is present or not in:
- pleural effusion, the fluid that collects around the lungs
- some blood
This information can help confirm the presence of cancer and, if so, determine its type and stage.
Treatment will depend on various factors, including:
- the type of cancer
- the place and the stage
- the general state of health of the person
- their individual preferences
All treatment options can have side effects. A person should discuss with their healthcare professional which choice is best for them, including the pros and cons of each option.
Some treatment options include:
- surgery to remove all of a lung or part of it
- chemotherapy, which is a drug treatment that can kill cancer cells and shrink tumors
- radiation therapy, uses high-energy rays to kill cancer cells
- radiofrequency ablation, in which a healthcare professional inserts a thin needle and uses an electric current to destroy cancer cells
- targeted therapy, which targets a specific behavior to prevent growth of tumor
- immunotherapy, which helps the body fight cancer cells
- palliative therapy, including pain relief, oxygen therapy, and any other help a person may need to manage their symptoms
A healthcare professional will work with the individual and adjust their treatment plan as per the needs change.
Lung cancer can be fatal, but emerging treatments mean many people are now surviving and recovering from lung cancer, especially if they are diagnosed early.
Some factors affecting the likelihood of a positive result include:
- the general state of health of a person
- their age
- the cancer stage at the time of diagnosis
- the type of cancer they have
It is not possible to predict exactly how cancer will affect a person, but a healthcare professional can help a person understand what to expect by looking at test results and other factors.