Thymus cancer is also called thymus gland cancer. It is a rare cancer. The thymus gland is in the chest, between the lungs and behind the breastbone. It makes white blood cells called T lymphocytes.
Types of thymus cancer
There are 2 types of thymus cancer:
- Thymoma – this cancer is more common and is usually diagnosed in people between the ages of 50 and 60. It can also occur at a younger or older age. Some thymomas grow very slowly and may not have spread outside the thymus when they are diagnosed. Others may have spread outside the thymus.
- Thymic carcinoma – this cancer is much rarer and usually grows more quickly than a thymoma. It can develop in people of any age. It is more likely to spread to other parts of the body and can be more difficult to treat.
Symptoms of thymus cancer may include:
- chest pain
- a cough that does not go away
- coughing up blood
- becoming breathless or wheezy
- difficulty swallowing
- a hoarse voice
- swelling of the face, neck, or arm.
These symptoms can be caused by other conditions, but it is important to have them checked by your doctor.
Sometimes thymus cancer has no symptoms but is found when people are having tests for something else. For example, it might show up when someone has a routine chest x-ray. Or it may show up when you have a CT scan for another reason. For example, in someone who has myasthenia gravis.
If you have symptoms of thymus cancer, your GP will refer you to a hospital specialist if they:
- are unsure what the problem is
- think your symptoms may be caused by cancer.
At the hospital, the specialist doctor will ask you about your symptoms and general health before examining you. You may have the following tests:
X-rays use high-energy rays to take pictures of the inside of your body. Your doctor can use an x-ray of your chest to look at your thymus gland.
Some thymus cancers are small or in places that may not show up on a chest x-ray, so you may also have a CT scan.
Blood tests are not used to diagnose thymus cancer, but they can be helpful to look at your overall health. If you have symptoms of thymus cancer, then you may have a blood test to look for antibodies in your blood. These are sometimes found if you have myasthenia gravis or other autoimmune diseases linked to thymus cancer.
Further tests for thymus cancer
A doctor may be able to diagnose thymus cancer using the tests above. But sometimes they need to collect a sample of tissue or cells (biopsy) from your thymus. If you have a small thymoma found early on a CT scan you can usually have surgery straight away without a biopsy.
There are different ways of taking a biopsy. After the cells or tissue samples are removed they are examined under a microscope by a doctor (called a pathologist). They check for cancer cells. The results of the biopsy tell your doctor:
- the type of thymus cancer you have
- how the cells look compared with normal cells (the grade of the cancer).
A biopsy can be done during the following tests:
CT-guided needle biopsy
A doctor (radiologist) uses a CT scan to find the exact area for taking the biopsy. They give you an injection of local anaesthetic into the skin to numb the area. The doctor passes a thin needle through the skin into the thymus area and removes a sample of cells. The biopsy should not be painful, but it may be uncomfortable. You may feel some pressure for a short time during it. The biopsy will only take a few minutes, but the entire test will usually take 30 to 60 minutes.
If the doctor cannot get a sample of cells using a needle biopsy, you may have a mediastinoscopy. This allows the doctor to examine the area in the centre of your chest called the mediastinum. You will have it under a general anaesthetic, so you may need to stay in hospital overnight.
The doctor makes a small cut in the skin at the base of the neck. They pass a long thin tube through the cut into the chest. The tube has a camera on the end. This shows a picture of the area on a screen. The doctor can take samples of tissue from the thymus through the tube.
Sometimes a thoracoscopy may be used. You will have this under a general anaesthetic.
The doctor makes 1 or 2 small cuts in the chest. They pass a thin tube called a thoracoscope through one of the cuts into the chest and take a sample of tissue from the thymus. Sometimes doctors use a camera attached to the tube so they can see the area more clearly. This is called a video-assisted thoracoscopy.
If any fluid has collected in the area, the doctor can remove it by inserting a long tube that drains the fluid into a bottle (chest drain). A nurse usually takes the drain out after 1 to 3 days. You will need to stay in hospital until it is taken out.
Waiting for test results can be a difficult time. We have more information that may help.
The results of your tests tell your doctor more about the size and position of the cancer and whether it has spread. This is called staging.
A doctor will also look at the cancer cells under a microscope to get an idea of how quickly the cancer might grow or spread. This is called grading.
Knowing the stage and grade of thymus cancer helps doctors decide the best treatment for you.
A team of specialists will meet to discuss the best possible treatment for you. This is called a multidisciplinary team (MDT).
Your cancer doctor or specialist nurse will explain the different treatments and their side effects. They will also talk to you about the things you should consider when making treatment decisions.
You may have some treatments as part of a clinical trial.
Your treatment will depend on:
- the type of tumour
- the stage and grade of tumour
- your general health.
Usually the aim of treatment is to remove or destroy the cancer and reduce the chance of it coming back. The main treatments for thymus cancer are explained below.
Surgery for thymus cancer
Surgery is the main treatment for thymus cancer. The surgeon removes the thymus, or as much of it as possible. This operation is called a thymectomy. Removing the thymus gland usually has no effect on your immune system.
The type of operation you have depends on the stage of cancer.
Radiotherapy for thymus cancer
Radiotherapy uses high-energy rays to destroy cancer cells, while doing as little harm as possible to normal cells. If all of the tumour can be removed with surgery, you may not need radiotherapy. Most people with thymic carcinoma need radiotherapy after surgery. You will not start radiotherapy until your surgery wounds have fully healed.
You may have radiotherapy:
- if it was not possible to remove all of the cancer after surgery
- if there were cancer cells close to the edges (margin) of the removed tissue
- as your main treatment if the cancer cannot be removed with surgery
- with chemotherapy (chemoradiation). This can cause more severe side effects, so you need to be well enough to cope with it.
You may have treatment in short sessions from Monday to Friday over 4 to 6 weeks. Side effects may include:
- feeling tired
- mild skin reactions
- difficulty swallowing
- feeling sick
- poor appetite.
Side effects usually disappear a few weeks or months after treatment has finished. There are other side effects of radiotherapy and it is important to be aware of these. We have more information about the side effects of radiotherapy.
Chemotherapy for thymus cancer
Chemotherapy uses anti-cancer (cytotoxic) drugs to destroy cancer cells. It may be given:
- before surgery, to shrink the cancer and make surgery easier
- after surgery, to reduce the risk of cancer coming back
- with radiotherapy (called chemoradiation) if surgery is not possible
- to help control symptoms if the cancer has spread (palliative chemotherapy).
You will usually have a combination of drugs. The most common chemotherapy drugs for treating thymus cancer are:
You may have a combination of cisplatin, doxorubicin and cyclophosphamide drugs (called CAP). Your cancer doctor or nurse will talk to you about your treatment. They will explain the possible side effects and how they can be managed or controlled.
Targeted therapies or immunotherapies
Doctors are trying to find out how helpful targeted therapies and immunotherapy drugs are in treating thymus cancers. These are not currently standard treatments for thymus cancer so they may not be widely available throughout the UK. Sometimes they may be given in a clinical trial.
If a treatment drug is not available on the NHS, there may be other ways you can access it. Your doctor can talk to you more about this.
You will have regular follow-up appointments after treatment. These may continue for several years. You may have tests such as CT scans.
After treatment, some people are cured of thymus cancer. But for others, cancer may come back after treatment. If this happens, you may be able to have further treatment. If you have any problems or notice new symptoms between appointments, let your cancer doctor or nurse know as soon as possible.
Everyone has their own way of dealing with illness and the different emotions they experience. You may find it helpful to talk things over with family and friends or your doctor or nurse. There are also support organisations that you may find helpful.
You may get anxious between appointments. This is natural. It may help to get support from family, friends or a support organisation.
Macmillan is also here to support you. If you would like to talk, you can:
Well-being and recovery
Even if you already have a healthy lifestyle, you may choose to make some positive lifestyle changes after treatment.
Making small changes such as eating well and keeping active can improve your health and wellbeing and help your body recover.
Below is a sample of the sources used in our thymus cancer information. If you would like more information about the sources we use, please contact us at firstname.lastname@example.org
ESMO Annals of Oncology. Thymic Epithelial Tumours: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up: 2015. Available from https://www.esmo.org/guidelines/guidelines-by-topic/lung-and-chest-tumours/thymic-epithelial-tumours (accessed July 2021)
Marx A, Chan JK, Coindre JM, et al. The 2015 World Health Organization Classification of Tumours of the Thymus: Continuity and Changes. Journal of Thoracic Oncology 2015; 10: 1383-95 (accessed July 2021)
International Thymic Malignancy Interest Group (ITMIG): About Thymic Tumours - symptoms, staging, standard treatment options. Available from https://itmig.org/about-thymic-tumors (accessed July 2021)
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