Types of lung cancer

Lung cancer is cancer which begins in the lungs, from the lungs it may spread to the lymph nodes or other organs in the body. Cancer may also spread from another part of the body and metastasize to the lungs, causing secondary lung cancer.

There are two main types of lung cancer. Non-small cell lung cancer (NSCLC), which is most common and accounts for approximately 85% of lung cancers and Small cell lung cancer (SCLC). Both NSCLC and SCLC develop differently and are treated differently.

Non-small cell lung cancer

There are three types of NSCLC:

Adenocarcinoma: Starts in mucous-producing cells at the outer edges of the lungs. This is the most common form of lung cancer diagnosed in non-smokers.
Squamous cell carcinoma: Develops in cells that line the airways in central areas of the lung. Men are more likely to develop squamous cell carcinoma than women, and it is most common in smokers.
Large cell carcinoma: Can occur anywhere in the lungs but more often starts towards the edges, and can grow quite large before symptoms are detected.

Small cell lung cancer

SCLC usually develops in the cells of the large or small airways and is associated with smoking. SCLC cells divide quicker than NSCLC, SCLC is also more aggressive and more likely to spread before detection.

Symptoms of lung cancer

Lung cancer may display no symptoms until the disease has progressed, resulting in late stage diagnosis.

Where symptoms are displayed these may include:

Persistent cough	Chest, shoulder, or back pain
Changes in volume and colour of sputum	Shortness of breath
Hoarseness	Wheezing
Repeated bronchitis or pneumonia	Coughing up blood
Neck or facial swelling	Fatigue

If lung cancer has spread, other symptoms may also occur. It is crucial to consult with a doctor if any unusual or worrying symptoms are experienced.

How is lung cancer diagnosed?

To diagnose lung cancer, it may be necessary to carry out a range of tests. Once the presence of cancer is confirmed, further testing will identify the type and stage of the cancer.

Often the first step in lung cancer diagnosis will be a CT Scan. CT scans can detect tumours and determine if a tumour has spread beyond the lungs.

If screening identifies a problem area, a biopsy is required to determine if a tumour is cancerous.

Small pieces of suspicious tissue are removed and examined under a microscope by a pathologist. The biopsy confirms the presence of cancer and can also determine the kind of lung cancer.

When lung cancer has been diagnosed, the extent of the cancer and appropriate treatment options can be determined by staging.

Did you know?

More than 1.3 million cases in men and nearly 500 000 lung cancer cases in women are preventable, with the majority attributable to tobacco smoking (60–70%), followed by air pollution and occupational exposure.