Diagnostic tests for head and neck cancer

The doctor will examine your mouth, throat, nose, neck, ears and eyes depending on your symptoms. A spatula may be used to see inside the mouth more clearly. The doctor may also insert a gloved finger into your mouth to feel areas that are difficult to see, and check your lymph nodes by gently feeling both sides of your neck.

To see some areas of the head and neck, such as the nasopharynx, tongue base and pharynx, the doctor may use viewing equipment and take a tissue sample.

A nasendoscopy examines the nose and throat area using a thin flexible tube with a light and camera on the end. This device is called a nasendoscope. Before the nasendoscope is inserted, a local anaesthetic is sprayed into the nostril to numb the nose and throat.

You may find that the spray tastes bitter. The doctor will gently pass the nasendoscope into one of your nostrils and down your throat to look at your nasal cavity, nasopharynx, oropharynx, hypopharynx and larynx. Images from the nasendoscope may be projected onto a screen. This test may feel uncomfortable, but should not hurt.

You will be asked to breathe lightly through your nose and mouth, and to swallow and make sounds. The doctor may also take tissue samples (biopsy). A nasendoscopy usually takes a few minutes. If you need a biopsy, the test may take longer, and you will be advised to not have any hot drinks for about 30 minutes after the procedure, but you can go home straight away.

A laryngoscopy is a procedure that allows a doctor to look at your larynx and pharynx, and take a tissue sample (biopsy). A tube= with a light and camera on it (laryngoscope) is inserted into your mouth and throat and shows the area on a screen. The procedure is done under a general anaesthetic and takes 10–40 minutes. You can go home when you’ve recovered from the anaesthetic. You may have a sore throat for a couple of days.

A biopsy is when doctors remove a sample of cells or tissue from the affected area, and a pathologist examines the sample under a microscope for any cancer cells.

The sample may be taken during a nasendoscopy or laryngoscopy. A biopsy can be taken from hard to reach areas using a fine needle to collect the sample. An ultrasound or CT scan (see Imaging tests) can help the doctor guide the needle. Biopsy results are usually available in about a week. If the cancer can’t be diagnosed from the sample of tissue, the mass may be removed and checked for signs of cancer during surgery.

The lymph nodes in the neck are often the first place cancer cells spread to outside the primary site. To see whether the cancer has spread, some or all of the lymph nodes are removed and checked for cancerous cells.

The first lymph node cancer cells spread to is known as the sentinel node. There can be more than one sentinel node. A small amount of radioactive material is injected near the tumour to find the sentinel node. A scan is taken to show which node the substance flows to first. This node will be removed for testing.

If the sentinel nodes are clear of cancer cells, the cancer has not spread to the lymph nodes. If one or more sentinel nodes contain cancer cells, a neck dissection may be needed.

Overview of the lymph nodes

Lymph nodes, also called lymph glands, are small, bean-shaped structures that are part of the lymphatic system. These are a key part of the immune system, which helps protect the body against disease and infection. Lymph nodes are found throughout the body, including in the head and neck area. The majority run down the sides of the neck and under the jaw.

You may need x-rays of your head and neck to check for tumours or damage to the bones. X-rays are quick and painless and may
include the following:

• Orthopantomogram (OPG) – This type of x-ray is used to examine the jaw and teeth of people with mouth cancer.
• Chest x-ray – Sometimes used to check the general health of people with mouth, pharyngeal or laryngeal cancer, or to see whether the cancer has spread to the lungs. However, most people have a CT or PET scan to look at these areas.

You will usually have at least one of the tests described below:

CT scan

A CT (computerised tomography) scan uses x-rays to take pictures of the inside of your body and then compiles them into one detailed, cross-sectional picture. Before the scan, you may have an injection of dye (called contrast) into one of your veins, which makes reading the scan more accurate. It may make you feel flushed and hot for a few minutes.

For the scan, you will need to lie still on a table that moves in and out of the CT scanner, which is large and round like a doughnut. The scan itself takes about 10 minutes.

MRI scan

An MRI (magnetic resonance imaging) scan uses a powerful magnet and radio waves to build up detailed cross-sectional pictures of the inside of your body. Let your medical team know if you have a pacemaker or any other metal implant, as some types can interfere with an MRI. As with a CT scan, a dye may be injected into your veins before an MRI scan. During the scan, you will lie on a treatment table that slides into a large metal tube that is open at both ends.

The noisy, narrow machine makes some people feel anxious or claustrophobic. If you think you may become distressed, mention this beforehand to your medical team. You may be given medicine to help you relax, and you will usually be offered headphones or earplugs. MRI scans usually take between 30 and 90 minutes.

PET scan

A PET (positron emission tomography) scan is usually recommended to help diagnose oral, pharyngeal or laryngeal cancer, or to see if the cancer has spread. A PET scan is a specialised imaging test that is available at some major hospitals.

Before the scan, you will be injected with a glucose solution containing some radioactive material. You will be asked to wait for 30–90 minutes as the solution spreads through your body. You will need to lie still during this time. The glucose solution gathers in cells, including cancer cells, which are using more energy. These show up as “hot spots” during the scan. However, a PET scan can find hot spots that are not cancer. The scan itself takes about 30 minutes.

Ultrasound

An ultrasound is sometimes used, especially to look at the thyroid, salivary glands and lymph glands in the neck.

For this scan, you will lie down and a gel will be spread over your neck. A small device called a transducer is moved over the area. The transducer sends out soundwaves that echo when they encounter something dense, like an organ or tumour. The ultrasound images are then projected onto a computer screen. An ultrasound is painless and takes about 15–20 minutes.

Cancer of unknown primary (CUP), is a metastatic cancer (cancer that has spread) with an unknown starting point. If CUP first shows up as a tumour in the head or neck, doctors may call it metastatic neck cancer and treat it like a head and neck cancer.

Access more information about CUP.