Tests for lung cancer

At the hospital Back to top

The chest specialist will ask you about your general health and any previous medical problems before examining you.

A chest x-ray| will be taken to check for any abnormalities in your lungs. Lung cancer will often show up on a chest x-ray.

You may also be asked to give samples of phlegm (sputum) to the hospital, so that they can be examined under a microscope for cancer cells – this is known as sputum cytology|.

In addition, a bronchoscopy| and a CT scan| (or occasionally a spiral CT scan|) may be used to confirm a diagnosis of cancer of the lung. In the bronchoscopy, a thin, flexible is passed down your throat and into your lungs to examine them. The CT scan uses x-rays to build up a three-dimensional picture of the inside of your body. Your doctor may arrange for you to have one or more of these tests at the hospital.

Further tests you may have Back to top

If the first tests suggest that you may have lung cancer, your specialist may want to do some of the further tests described below, to confirm the diagnosis and to see if the cancer has spread to any other part of the body. The results will help your doctor to decide the best type of treatment for you.

• MRI scan - uses magnetic fields to build up a series of cross-sectional pictures of the body
• Mediastinoscopy - a procedure done under a general anaesthetic, where the doctor can look inside your chest at the area behind the breast bone
• Lung biopsy - some cells are removed from the abnormal area and examined under a microscope
• PET scan - a scan that shows how tissues inside your body are working
• Ultrasound scan - uses sound waves to look at internal organs
• Isotope bone scan - a scan to check for abnormalities in the bones
• Lung function tests - breathing tests to check how well your lungs are working

What the tests involve Back to top

Chest x-ray 

This uses a low dose of radiation to take a picture of the inside of the chest. It is painless and needs no special preparation. The test is carried out by a radiographer, usually as an outpatient appointment in the hospital’s x-ray department. Women should always tell their radiographer if there is any possibility they may be pregnant.

Sputum cytology

In this test, samples of your phlegm (sputum) are examined under a microscope for cancer cells – this is called sputum cytology.

The moist linings of the airways leading into our lungs produce small amounts of fluid, or secretions, which can be coughed up as sputum. Lung cancers usually develop in these lining tissues of the airways, so sputum which forms near the growth may contain cancer cells.

If sputum is collected, it can be examined under the microscope to see if there are cancer cells.  It’s not a very specific or sensitive test so even if there aren’t any cancer cells it doesn’t mean there isn't a cancer. So it’s not used on its own as a way of diagnosing lung cancer.

The test simply involves coughing up sputum into a container that your doctor will provide. It is then sent to the laboratory for examination. Often two or three separate samples taken on different occasions will be needed to give the best chance of accurate results.

Bronchoscopy 

A doctor, or a specially trained nurse, passes a thin, flexible tube, called a bronchoscope, down your throat and into the main airways (bronchi) of the lungs.

With the bronchoscope the doctor or nurse is able to:

• look at the lining of the air passages leading into the lungs
• take photographs of what they see
• take 'brushings' or 'washings' of the surface of any suspicious looking area so that the cells can be looked at under the microscope (this is called a cytological test)
• take a small piece of tissue from any suspicious area so that it can be examined under the microscope (this is called a biopsy).

A CT scan will tell the doctors whether a bronchoscopy will be helpful. It will also guide the doctor or nurse to the abnormal area in the lung.

Before your bronchoscopy, you will be asked not to eat or drink anything for a few hours. Just before the test you may be given a mild sedative, to help you relax and to relieve any discomfort. You will be given another medicine which reduces the production of natural fluids in the mouth and throat. This medicine can make your mouth feel dry.

A local anaesthetic will be sprayed onto the back of your throat, making it numb. The bronchoscope is then gently passed into your nose or mouth and down into the lung airways. The doctor or nurse can look through the bronchoscope to check for any abnormalities. Photographs and biopsies can be taken at the same time. The test may be slightly uncomfortable, but it only takes a few minutes.

You shouldn’t eat or drink for at least an hour afterwards, because your throat will be numb and you won’t know if food and drink is going down the wrong way. As soon as the sedation has worn off you will be able to go home. You shouldn’t drive for 24 hours after the test as you may feel sleepy, so you'll need to arrange for someone to collect you from hospital. You may have a sore throat for a couple of days after your test, but this will soon disappear.

Lung cancers most often arise from the surface of the lining of the bronchi and so the bronchoscopy often confirms the diagnosis of lung cancer. Sometimes if a growth is deep inside the lung then a bronchoscopy may fail to detect it.

Occasionally it may be necessary to use a rigid bronchoscope rather than the flexible bronchoscope. If this happens, a general anaesthetic is given, and you may have to stay in hospital overnight.

CT scan

A CT (computerised tomography) scan takes a series of x-rays which build up a three-dimensional picture of the inside of the body. The scan is painless but takes from 10 to 30 minutes. CT scans use a small amount of radiation, which is unlikely to harm you and will not harm anyone you come into contact with. You will be asked not to eat or drink for at least four hours before the scan.

You may be given a drink or injection of a dye called contrast which allows particular areas to be seen more clearly. For a few minutes, this may make you feel hot all over. If you are allergic to iodine or have asthma you could have a more serious reaction to the injection, so it is important to let your doctor know beforehand.

You will probably be able to go home as soon as the scan is over.

Spiral CT scan 

Some hospitals use low-dose spiral CT scans (helical CT scans). A CT scanning machine rotates rapidly around the body, taking more than one hundred pictures in sequence. The scan can detect smaller lung tumours than a conventional CT scan and takes only a few minutes. Spiral CT scans are quite new and you may have to travel to a specialist hospital to have one. They are not always necessary, but you can discuss with your doctor whether one would be useful in your case.

MRI scan 

This test is similar to a CT scan but uses magnetism instead of x-rays to build up a detailed picture of areas of your body. Before the scan you may be asked to complete and sign a checklist. This is to make sure that it’s safe for you to have an MRI scan (because the scanner is a powerful magnet). The checklist asks about any metal implants you may have, for example a pacemaker, surgical clips, bone pins etc. You should also tell your doctor if you have ever worked with metal or in the metal industry (as very tiny fragments of metal can sometimes lodge in the body). If you do have any metal in your body it’s likely that you won’t be able to have an MRI scan. In this situation another type of scan can be used.

Before having the scan, you’ll be asked to remove any metal belongings including jewellery. Some people are given an injection of dye into a vein in the arm, which doesn’t usually cause discomfort. This is called a contrast medium and can help the images from the scan to show up more clearly. During the test you will be asked to lie very still on a couch inside a long cylinder (tube) for about 30 minutes. It is painless but can be slightly uncomfortable, and some people feel a bit claustrophobic during the scan. It’s also noisy, but you’ll be given earplugs or headphones. You will be able to hear, and speak to, the person operating the scanner.

Mediastinoscopy 

In this test, the doctor examines the area at the centre of your chest (mediastinum), and the lymph nodes closest to the lungs. These are often the first places that lung cancer spreads to, and so are usually checked for signs of cancer. It’s important to know whether these nodes contain cancer cells as this will affect the likelihood of an operation being able to remove all the cancer.

The test is done under a general anaesthetic and will mean a short stay in hospital. A small cut is made in the skin at the base of your neck, and a tube is passed into the chest. The tube has a light and camera at the end, and can magnify the areas it looks at. The doctor can see any abnormal areas, and may also take samples of the cells and lymph nodes to examine under a microscope.

A similar test, known as a thoracoscopy, involves making a small cut in the skin and inserting a similar tube into another part of your chest, to look directly at the cancer and take samples from it.

Lung biopsy 

This test is usually done in the x-ray department, most commonly during a CT scan. A local anaesthetic is used to numb the area. You will then be asked to hold your breath while a thin needle is passed through the skin and into the lung. An x-ray is used to make sure that the needle is in the right place. The doctors will then take a sample of cells to be examined under a microscope. The biopsy is sometimes slightly uncomfortable, but it only takes a few minutes.

After a lung biopsy, a small number of people may develop air between the layers that cover the lungs. This is known as a pneumothorax. Symptoms of a pneumothorax include sharp chest pain, breathlessness and a tight chest. You may be asked to remain in hospital for a few hours after your biopsy, to make sure that you have not got a pneumothorax. Let your doctor or nurse know if you develop any symptoms.

PET scan 

A PET (positron emission tomography) scan uses low-dose radioactive glucose (a type of sugar) to measure the activity of cells in different parts of the body. A very small amount of this mildly radioactive substance is injected into a vein, usually in your arm. A scan is then taken a couple of hours later. Areas of cancer usually absorb more of the sugar than surrounding tissue and so show up on the scan.

PET scans may be used before surgery as they can give accurate information about the size of the cancer in the lung and whether a cancer has spread beyond the lungs. They can also be used to examine any lumps that remain after treatment to see whether they are scar tissue or whether cancer cells are still present. PET scans are a new type of scan and you may have to travel to a specialist centre to have one. They are not always necessary but you can discuss with your doctor whether one would be useful in your case.

Ultrasound scan 

An ultrasound may be used if the doctors think the cancer may have spread to the liver or other parts of the abdomen (tummy). Ultrasound uses sound waves to look at the liver and the other organs in the upper part of the abdomen. It is the same sort of scan that pregnant women have.

Once you are lying comfortably on your back, a gel is spread on to the area to be scanned.

A small device that produces sound waves is passed over the area and the sound waves are converted into a picture by computer. The test only takes a few minutes.

Isotope bone scan 

This is more sensitive than an x-ray, and shows up any abnormal areas of bone more clearly. However, it is not always clear whether an abnormality is caused by cancer or other conditions such as arthritis.

A small amount of a mildly radioactive substance is injected into a vein, usually in your arm. Abnormal bone absorbs more radioactivity than normal bone, so these areas are highlighted and picked up by the scanner as ‘hot spots’. There is generally a wait of 2–3 hours between having the injection and the scan taking place, so you may like to take a magazine or book to pass the time. The level of radioactivity used in the scan is very small and doesn’t cause any harm.

Lung function tests 

If your doctor wants to remove the lung cancer using surgery, or is planning for you to have a course of radiotherapy, they may first ask you to have breathing tests to see how well your lungs are working.