Many people will experience a nagging cough at some point in their life, and it is usually possible to identify the likely cause. In most cases, over-the-counter medications can help soothe the irritation until it passes.
Coughing serves a useful purpose. It helps the lungs clear potential germs and harmful objects out of the airway.
However, a cough that lingers for weeks or even months could indicate something more serious. Sometimes, it is due to lung cancer.
This article looks at the link between coughing and lung cancer, including when to see a doctor.
There are many reasons for a cough. Having a cough does not usually mean that lung cancer is present.
However, a persistent cough is a common symptom of lung cancer at the time of diagnosis.
Anyone who has a cough with the following symptoms should see a doctor as soon as possible:
- blood or rust colored mucus or phlegm
- shortness of breath
- chest pain
- infections such as bronchitis or pneumonia that recur or do not go away
A cough that occurs with lung cancer can be either dry or wet. It can occur at any time, and it can interfere with sleep at night.
Most people who develop lung cancer have a history of smoking. Smoking can also irritate the lungs and cause a short term cough.
Avoiding or quitting smoking can reduce the risk of many conditions that involve a cough, including lung cancer.
A persistent or worsening cough is not the only symptom of lung cancer. Other symptoms of this condition include:
- wheezing and difficulty breathing
- voice hoarseness
- problems swallowing or speaking
- loss of appetite
- weight loss
- swelling in the face or neck
Chronic obstructive pulmonary disease (COPD) is another serious condition that often affects people who smoke. Is there a link with lung cancer? Learn more here.
There are many reasons for a cough. For example, a short term cough could be a result of:
- an infection, such as a cold, pneumonia, or bronchitis
- an allergy, such as hay fever
- inhaled dust, smoke, or debris
- a long term respiratory condition, such as asthma or COPD
Sometimes, a short term cough can develop into a chronic or persistent cough.
The following can also lead to a persistent cough:
- a long term respiratory infection, such as chronic bronchitis or pneumonia
- asthma, which causes shortness of breath, tightening of the chest, and wheezing
- allergies, such as hay fever
- smoking, as smoke and other debris can irritate the airways
- bronchiectasis, which is a widening of the airways in the lungs
- postnasal drip, which occurs when mucus triggers a cough by dripping down the throat, usually due to a cold or allergy
- gastroesophageal reflux disease, wherein stomach acid flows back into the esophagus, causing irritation
- medications such as ACE inhibitors, which treat high blood pressure and heart disease
What causes a dry cough? Find out here.
Most coughs will subside or disappear within a few days to a few weeks.
However, if a cough lasts for a long time or occurs alongside other symptoms — such as coughing up blood or chest pain — it is important to see a doctor.
The doctor can determine the cause of the cough and provide appropriate treatment, if necessary.
Not everyone with lung cancer will have a cough. Pancoast tumors develop at the top of the lung and do not cause a cough. Find out more.
If a person visits the doctor with a cough, they will ask the person about:
- their family and personal medical history
- how long the cough has lasted
- what type of cough it is
- when it is most likely to occur
- any other symptoms
They will also carry out a physical examination. They will listen to the person's heart and lungs and look for other possible causes of the cough, such as signs of an infection or postnasal drip.
Depending on the findings, the doctor may order additional tests, such as:
Imaging tests: These include a chest X-ray and a CT or MRI scan.
Sputum test: The person may have to provide sputum samples, which a health professional will check for cancer cells.
Biopsy: One way to conduct a biopsy is to pass a needle into the lung tissue through the skin.
Another option is a bronchoscopy, wherein a health professional inserts a small tube down the nose and into the lungs. The same tool can take a small sample of tissue for analysis.
A specialist called a pathologist will look at the cell samples under the microscope to see if cancer is present, and, if so, what type of cancer it is.
Some types are more aggressive than others. This will affect the outlook and the treatment.
If the diagnosis is lung cancer, a specialist team will carry out further tests to see how far it has spread.
Sometimes, a doctor may also suggest genetic testing.
Genetic features can vary between cancer types. Some newer drugs target specific features that encourage cancer to grow. Knowing what features are present may enable a doctor to suggest a treatment that will target that type of cancer more effectively than conventional treatments can.
The main types of lung cancer are small cell and non-small cell. Find out more about the features of each type here.
If a person receives a diagnosis of lung cancer, the doctor will talk to them about a treatment plan.
These plans vary from person to person. They will take into account the type of cancer and the age and overall health of the person, among other factors.
Surgery: If the cancer is limited, a surgeon can remove part of the lung. They may also remove nearby lymph nodes.
Radiation therapy: A machine targets the malignant cells with a beam. This can kill cancer cells, either to shrink a tumor before surgery, or to remove any remaining cells after surgery.
Chemotherapy: This can kill cancer cells, but it can also have severe adverse effects on healthy cells.
Targeted therapy: These drugs target specific genes, proteins, and other factors that contribute to cancer development. They aim to stop or delay cancer growth.
Some lifestyle changes may also help improve the outlook, even after a diagnosis. These include:
- quitting smoking, according to one 2015 study
- following a healthful diet
- getting regular exercise
If the cancer has spread significantly, it may no longer be possible to remove or cure it. The doctor may recommend palliative care, including radiation therapy, to prevent further complications and treat any symptoms.
The outlook for lung cancer depends on various factors, including:
- the person's age and overall health
- the stage of the cancer at diagnosis
- the type of cancer
Early stage cancer is easier to treat and likelier to have a positive outcome than later stage cancer.
For people with non-small cell lung cancer, the chance of living for at least another 5 years after diagnosis is:
- 60% when the cancer is localized, which means that it is still in the original location
- 33% if it is regional, having spread to nearby tissues
- 6% if it has spread to more distant parts of the body
- 23% overall
For small cell lung cancer, the average chances of living for another 5 years or more are:
- 29% for localized cancer
- 15% if it has spread to nearby lymph nodes
- 3% if it has reached distant parts of the body
- 6% overall
Anyone with a persistent cough that occurs alongside chest pain, shortness of breath, or bloody sputum should see a doctor. If lung cancer is present, the outlook will be better if a person seeks help at once, rather than waiting.
The best way to prevent lung cancer is to avoid smoking and exposure to secondhand cigarette smoke. A doctor can help an individual make a plan to quit smoking.
Products that can help are also available for purchase online.
In this article, we provide some tips for giving up smoking.
I used to smoke, and now I have a persistent cough. I see the doctor sometimes when it gets worse, but they never talk about lung cancer. Should I undergo screening?
Depending on a person’s age and how much they previously smoked, they may need screening.
According to the United States Preventive Services Task Force, anyone between the ages of 55 and 80 years with a 30 pack year history of smoking and who currently smokes should have a low dose CT scan for lung cancer screening.
If a person has quit within the past 15 years and has a previous 30 pack year history, they should also undergo lung cancer screening.Alana Biggers, MD, MPH Answers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.