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Lung cancer

Dr Karen Martin
Reviewed by Dr Karen MartinReviewed on 19.10.2023 | 4 minutes read

Lung cancer is one of the most common cancers in the US, and sadly, it often has a poor outlook. Cancer occurs when there is an uncontrolled growth of abnormal cells in the lung tissue. This can cause a blockage in the airways or fluid on the lungs, making breathing difficult, and ultimately it can spread to other organs and cause widespread damage and threat to life. Smoking is the cause of most lung cancers – because smoking is so common, this makes lung cancer very common. Older people are more likely to be affected, and men more often than women.

When cancer starts in the lungs, it is called primary lung cancer. Cancer spreading from another organ via the blood to the lungs is known as secondary lung cancer or metastatic cancer. Breast and bowel cancer often metastasize to the lungs unless they are diagnosed and treated early.

What are the symptoms?

In the early stages, lung cancer may not cause symptoms, and it may be diagnosed while you have a chest X-ray for another reason. Symptoms develop at a later stage, commonly with a persistent cough lasting more than three weeks, difficulty breathing, coughing up blood, unintentional weight loss, fatigue, and lethargy. People may also experience a change in their voice or chest or shoulder pains. You should speak to your doctor urgently if you have any of these symptoms.

Established lung cancer can cause other symptoms such as repeated chest infections, fluids in the lung causing worsening shortness of breath, numbness and weakness in the arms due to the lung tumor squeezing a nerve, or facial swelling due to the lung tumor compressing a vein.

What causes lung cancer?

Smoking is a major cause of lung cancer, making up about 9 in 10 cases and is due to the toxic chemicals found within tobacco smoke. Compared with non-smokers, if you smoke between 1-14 cigarettes a day you have eight times the risk of dying from lung cancer. If you smoke 25 or more cigarettes a day you have 25 times the risk and the risk of lung cancer increases the greater the length of time a person has smoked.

A family history of lung cancer in a sibling or parent increases the risk of developing lung cancer, (although most cases do not run in families), as does living with a smoker because of passive smoking. There is an increased risk from people with a history of chest diseases such as emphysema or people who are regularly exposed to chemicals or pollution due to their job or where they live.

How is lung cancer diagnosed?

Your doctor will ask about your symptoms, including your smoking history, they will examine your heart and lungs, and they may feel for any enlarged lymph nodes in your armpits. They may weigh you. They will refer you for an urgent chest X-ray to look at the lungs.

They will refer you urgently to the hospital’s respiratory team, who will order more tests to confirm the diagnosis. This will likely include a CT scan of the chest as well as other areas of the body. They may perform a bronchoscopy to take a look at the airways and take some tissue samples. If cancer is identified, it is important for them to understand the type of cancer and whether it has spread to lymph nodes or other organs.

There are two main types of primary lung cancer: non-small cell lung cancer is the most common, where a tissue sample of the lung will show the sub-type, such as squamous cell carcinoma, adenocarcinoma, or large cell carcinoma. Small cell lung cancer is less common but more aggressive, which means it grows and spreads faster than non-small cell lung cancer.

How is it treated?

Treatment depends on the type of cancer you have, whether it has spread to involve other organs, and your overall health.

Early detection of cancer puts you at the best chance of more prolonged survival. Surgery may be the best option if the cancer is confined to a small area. Otherwise, radiotherapy (use of targeted radiation) and chemotherapy (use of anticancer drugs) can be used instead or even alongside. Different types of medicines called targeted therapies can help slow the spread of cancer.

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This article has been written by UK-based doctors and pharmacists, so some advice may not apply to US users and some suggested treatments may not be available. For more information, please see our T&Cs.
Dr Karen Martin
Reviewed by Dr Karen Martin
Reviewed on 19.10.2023
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