Diagnosing lung cancer

Tests

Your doctors will arrange several tests to make a diagnosis and work out whether the cancer is in the lung only or has spread beyond the lung. The test results will help them recommend a treatment plan for you.

The first test is usually a chest x-ray, which is often followed by a CT scan. You may also have a breathing test to check how your lungs are working and blood tests to check your overall health.

Staging lung cancer

The tests described in this section help show what type of lung cancer you have and how far it has spread. Called staging, this helps your doctors recommend the best treatment for you.

Both non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC) are staged using the TNM (tumour-nodes-metastasis) system, which considers the size of the tumour, whether it has affected lymph nodes and whether it has spread. This information may be combined to give the lung cancer an overall stage of 0, 1, 2, 3 or 4 (often written in Roman numerals as I, II, III or IV).

Sometimes, SCLC is staged using a different system in which the cancer is classified as either limited stage or extensive stage. For more information about these 2 staging systems, see below.

Staging NSCLC

In the TNM system, each letter is given a number (and sometimes another letter) to show how advanced the cancer is. For example, T1 means the tumour is 1 cm or smaller, while T4 means the tumour is more than 7 cm, or has spread into nearby organs, or there are 2 or more separate tumours in the same lung.

• early (stage 1) - The cancer is no bigger than 4 cm and hasn't spread outside the lung or to any lymph nodes.
• locally advanced (stages 2-3) - The cancer can be any size and may have spread to nearby lymph nodes, other parts of the lung, the airway, or surrounding areas outside the lung.
• advanced (stage 4) - The cancer can be any size. It may have spread to lymph nodes and either to the other lung, to fluid in the pleura around the lungs or the heart, or to another part of the body such as the liver, bones or brain.

Staging SCLC

Sometimes, SCLC is staged using a 2-stage system in which the cancer is classified as either limited disease or extensive disease.

• limited disease (stages 1–3) – Cancer is only on one side of the chest and in one part of the lung; nearby lymph nodes may also be affected.
• extensive disease (stage 4) – Cancer has spread to the other lung, to lymph nodes on the other side of the chest or to other areas in the body.

Prognosis

Prognosis means the expected outcome of a disease. You may wish to discuss your prognosis and treatment options with your doctor, but it is not possible for anyone to predict exactly how the disease will respond to treatment. Instead, your doctor can give you a general idea of the outlook for people with the same type and stage of lung cancer.

To work out your prognosis, your doctor will consider:

• your test results
• the type and stage of lung cancer
• the rate and extent of tumour growth
• other factors such as your age, fitness and overall health, and whether you smoke or vape.

Discussing your prognosis and thinking about the future can be challenging and stressful. It is important to know that although some statistics for lung cancer can be frightening, they are an average and may not apply to your situation. Talk to your doctor about how to interpret any statistics that you come across, as well as the best and worst possible outcomes. This information can help you make treatment decisions.

As in most types of cancer, the outcomes of lung cancer treatment tend to be better when the cancer is found and treated early. Newer drug treatments such as immunotherapy and targeted therapy have given promising results in many people with advanced lung cancer and are bringing hope for a longer, healthier life to those who have lung cancer that has spread.

For certain circumstances, these therapies are now being used for earlier-stage lung cancer.