Survival rates are often used by doctors as a standard way of discussing a person’s prognosis (outlook). Some patients with cancer want to know the survival statistics for people in similar situations, while others may not find the numbers helpful, or may even not want to know them. 

The 5-year survival rate refers to the percentage of patients who live at least 5 years after their cancer is diagnosed. Of course, many people live much longer than 5 years (and many are cured). Although many patients live much longer than this, it isn’t always an indication that the cancer has been cured, as some thymus tumors are very slow growing, and others may return in some people several years after treatment.

To get 5-year survival rates, doctors have to look at people who were treated at least 5 years ago. Treatment may have improved since then which could result in a more favorable outlook for people now being diagnosed with thymus cancer.

Survival rates are often based on previous outcomes of large numbers of people who had the disease, but they cannot predict what will happen in any particular person’s case. Many other factors may affect a person’s outlook, such as the histologic type of thymus cancer, the treatment received, whether it was completely removed with surgery, and the patient’s age. Your doctor can tell you how the numbers below may apply to you, as he or she is familiar with your particular situation.

Because thymus cancers are not common, it is hard to find accurate survival rates based on the stage of the cancer. The numbers below come from a large series of patients treated in Japan between 1990 and 1994. They look separately at patients with thymoma (types A, AB, and B) and thymic carcinoma (type C thymoma). Also, these are observed survival rates. People with thymus cancer can die of other things, and these numbers don’t take that into account.

There's always research going on in the area of thymic tumors. Scientists are looking for causes of thymic tumors, and doctors are working to improve treatments.

Because thymic tumors are rare, more information from clinical trials is needed to decide which treatments are best for each type and stage. For instance, the role of chemotherapy in treating thymomas is still being explored. New treatments are also being developed and tested. For example, it's been suggested that hyperthermic intrathoracic chemotherapy (called HITHOC) during surgery might be useful in late stage thymic cancers. But more research is needed.

Researchers are looking for more accurate ways of predicting how aggressive a tumor is so the best treatment can be chosen. Improving imaging tests may also help doctors better decide which tumors can be safely removed with surgery.

Some studies are looking to see if treating with chemotherapy (chemo) and/or radiation before and/or after surgery can help keep thymus cancer from coming back.

Removing or destroying all the cancer cells is not the only goal in treating thymomas. Some paraneoplastic syndromes may persist even after the tumor has been treated. Researchers are studying the causes of these syndromes and the best ways to treat them.

While chemotherapy can often help shrink thymus cancers, it doesn't always work and can have serious side effects. Chemo drugs work by attacking fast-growing cells, which is the main cause of their side effects. As researchers have learned more about what makes cancer cells different from normal cells, they have been able to make drugs that target these differences. Many of these drugs are already being used to treat other cancers. Researchers are trying to learn more about the genetic changes in thymus cancer cells. And studies are needed to look at how targeted therapies might be used to treat these cancers. These targeted therapies include anti-angiogenesis drugs (which affect tumors by limiting their blood supply) and anti-growth factor drugs (which interfere with substances some cancer cells make to stimulate their own growth). Some of these drugs are already being used to treat other cancers, and are being studied for use against thymus cancers. These include cetuximab, sunitinib, avelumab, pembrolizumab, erlotinib, and bevacizumab. Others being studied are not yet approved to treat any type of cancer.

If there is a reason to think you might have a thymus tumor, your doctor will ask you about symptoms and use one or more exams or tests to check for one. Certain signs and symptoms might suggest that a person may have a thymus tumor, but tests are needed to know for sure.

Medical history and physical exam

If you have signs or symptoms that suggest you might have a thymus tumor, your doctor will want to take a complete medical history to check for symptoms. You will also be asked about your general health.

A physical exam provides information about possible signs of thymic cancer and other health problems. Patients with thymic cancer will sometimes have a fullness that the doctor can feel in the lower neck area.

Thymomas are often suspected if you have signs and symptoms associated with myasthenia gravis, hypogammaglobulinemia, or red cell aplasia .

Imaging tests

Imaging tests use x-rays, magnetic fields, or radioactive substances to create pictures of the inside of your body. Imaging tests may be done for a number of reasons, including:

• To help find a suspicious area that might be cancer
• To learn how far cancer may have spread
• To help see if treatment is working
• To look for signs that cancer has come back

Chest x-ray

A chest x-ray may be the first imaging test a doctor orders if he or she suspects a problem in the middle of the chest. It may be able to show if there is a tumor in the chest. In some cases, a chest x-ray may find tumors when the person is having the x-ray done for another reason. But some thymomas are small or in places that may not show up on a chest x-ray. If your doctor is still suspicious or if a change is seen on the chest x-ray, a CT scan may be ordered.

Computed tomography (CT) scan

A CT scan uses x-rays to make detailed, cross-sectional images of your body. Unlike a regular x-ray, a CT scan creates detailed images of the soft tissues in the body. A chest CT with contrast is often used.

CT scans can also be used to guide a biopsy needle precisely into a suspected tumor or metastasis. This is called a CT-guided needle biopsy.

Magnetic resonance imaging (MRI) scan

Like CT scans, MRI scans provide detailed images of soft tissues in the body. But MRI scans use radio waves and strong magnets instead of x-rays.

MRI of the chest may be done to look more closely at thymus tumors. They are most often used for people who have a CT scan for medical reasons (like problems with the IV contrast). MRI images are also particularly useful in looking for cancer that may have spread to the brain or spinal cord.

Positron emission tomography (PET) scan

For a PET scan, you are injected with a slightly radioactive form of sugar, which collects mainly in cancer cells. A special camera is then used to create a picture of areas of radioactivity in the body. The picture is not detailed like a CT or MRI scan, but a PET scan can look for possible areas of cancer spread in all areas of the body at once.

A PET scan can help give the doctor a better idea of whether a change seen on another imaging test is a tumor or not. If you have already been diagnosed with cancer, your doctor may use this test to see if the cancer has spread to lymph nodes or other parts of the body. A PET scan can also be useful if your doctor thinks the cancer may have spread but doesn’t know where.

Certain machines are able to perform both a PET and CT scan at the same time (PET/CT scan). This lets the doctor compare areas of higher radioactivity on the PET scan with the more detailed pictures of that area on the CT. Combined PET/CT is used more often than PET (alone) in looking at thymomas.

Blood tests

Blood tests can’t be used to diagnose thymomas, but they may be helpful in some situations. For example, blood tests may be done to look for certain antibodies if myasthenia gravis (MG) or another autoimmune disorder is suspected. Other blood tests might be done to make sure a mass in the middle of the chest isn’t a germ cell tumor or part of the thyroid gland.

If a thymoma is diagnosed, blood cell counts and blood chemistry tests are done to get an idea of a person’s overall health, especially if surgery is planned. Also, tests for myasthenia gravis will be done before any surgery. This is because MG is very common in people with a thymoma, and, if not treated, it can cause problems with the drugs used during surgery. People getting chemotherapy need regular blood tests to make sure the drugs aren’t having unwanted effects on the bone marrow, kidneys, or other organs.

Biopsy procedures

Although signs, symptoms, and imaging tests can suggest that a thymic tumor is likely, doctors can’t be certain of the diagnosis without looking at the tumor under a microscope.

For most cancers, taking out a small piece of the tumor (known as a biopsy) is needed to confirm whether a tumor is present and, if so, to determine its type. For thymomas, this is rarely done because doctors can usually tell that the tumor is very likely a thymoma based on how it looks on imaging tests. Because of this, doctors often remove the entire tumor rather than do a biopsy. This provides tissue for a diagnosis and treats the tumor at the same time. The specimen is sent to the lab after surgery to confirm the diagnosis. See Surgery For Thymus Cancer for more information.

If the tumor can't be removed completely during surgery, a biopsy might be done to confirm the diagnosis. This helps the doctor decide if more treatment is needed after surgery.

If the doctor suspects a different type of tumor, a biopsy (usually a needle biopsy) might be done before surgery.

See Testing Biopsy and Cytology Specimens for Cancer to learn more about the types of biopsies, how the tissue is used in the lab to diagnose cancer, and what the results may show.

Many thymic tumors are found on an x-ray or scan done for some other reason, before the patient has symptoms. The rest are brought to the attention of a doctor after a person starts to have symptoms. These may be related to the tumor itself, or they may be part of a paraneoplastic syndrome.

Although these signs and symptoms might be caused by thymus tumors, they can also be caused by other conditions. Still, if you have any of these problems, it’s important to see your doctor right away so the cause can be found and treated, if needed.

Symptoms caused by the tumor

The thymus is in the middle of the chest, near the airways and certain blood vessels. Tumors in the thymus can press on nearby structures, causing symptoms such as:

• Shortness of breath
• Cough (which may bring up bloody sputum)
• Chest pain
• Trouble swallowing
• Loss of appetite
• Weight loss

The thymus is near the superior vena cava, the main blood vessel bringing blood from the head and upper body to the heart. Tumors that press on this vessel can cause symptoms of superior vena cava syndrome, which can include:

• Swelling in the face, neck, and upper chest, sometimes with a bluish color
• Swelling of the visible veins in this part of the body
• Headaches
• Feeling dizzy or light-headed

Paraneoplastic syndromes

These are conditions that are related to the cancer but that are not caused directly by the tumor mass. For example, people with thymomas may develop autoimmune diseases, where the immune system starts to attack the body itself. Part of the normal function of the thymus is to help keep the immune system in check, which may help explain why this happens.

Myasthenia gravis: About 30% to 65% of people with thymomas also have myasthenia gravis (MG). This is by far the most common autoimmune disease associated with thymomas. In this disease, the immune system forms antibodies that block the chemical signals that signal the muscles to move. This causes severe muscle weakness. People with MG tire easily. They may notice problems climbing stairs or walking long distances.

Although patients have decreased muscle strength throughout the body, symptoms caused by weakness of the muscles of the eyes, neck, and chest may be the most troublesome. Weakness of the eye muscles can cause blurred or double vision and drooping eyelids, while weak neck muscles can lead to problems with swallowing. Weakness of the chest muscles and diaphragm can cause problems breathing and shortness of breath.

Many people with thymomas have MG, but most people with MG don’t have thymomas. Many people with MG have other, noncancerous abnormalities of the thymus gland. Myasthenia gravis can be treated by removing the thymus (whether or not a thymoma is present) or with medicines that either strengthen the chemical signals to muscles or weaken the immune attack on the muscles.

Red cell aplasia: Red cell aplasia, in which the body’s ability to make new red blood cells is severely reduced, occurs in about 5% of thymoma patients. Red blood cells carry oxygen from the lungs to other tissues of the body. Reduced red blood cell production causes anemia (low red blood cell counts). Symptoms of anemia can include weakness, dizziness, shortness of breath, and tiring easily. The usual treatment is to remove the thymus gland.

Hypogammaglobulinemia: Hypogammaglobulinemia is a disorder in which the body makes low amounts of infection-fighting antibodies (also known as gamma globulins). This leaves the person susceptible to infections. About 5% to 10% of thymoma patients develop hypogammaglobulinemia. About 10% of patients with hypogammaglobulinemia have a thymoma. Removing the thymus does not help correct this disease.

Other autoimmune diseases: Many other autoimmune diseases have also been linked to thymoma. However, they are much less common than myasthenia gravis, pure red cell aplasia, or hypogammaglobulinemia. Some examples include:

• Systemic lupus erythematosus
• Polymyositis
• Ulcerative colitis
• Rheumatoid arthritis
• Sjogren (Sjögren) syndrome
• Sarcoidosis
• Scleroderma

Most people who have these autoimmune diseases do not have a thymoma.

Whenever possible, surgery is used to treat thymus cancers. If you have thymus cancer, one of the first things your doctor will do is to try to figure out if the cancer is completely resectable (removable) with surgery. Imaging tests are used to do this.

The most common surgery for thymus tumors is complete removal of the thymus gland (including any tumor). This is called a thymectomy. In most cases the surgery is done through a median sternotomy. This is an incision (cut) down the middle of the chest that splits the sternum (breast bone) and allows the whole thymus and tumor to be removed.

The surgeon will also try to remove any areas of tumor spread outside of the thymus. So, if the tumor has grown into nearby structures, the surgeon may need to remove parts of those structures, as well. This could mean removing parts of the pleura (tissue coating the lung), pericardium (the sac containing the heart), nerves, the superior vena cava (a large vein leading to the heart), and/or lung.

Some doctors might suggest surgery even if the tumor cannot be completely removed, as is the case with many stage III thymomas and with most stage IV thymomas. In these cases, the doctor might take out as much tumor as possible (called debulking), and then recommend further treatment with radiation therapy and/or chemotherapy. But not all doctors agree that surgery to remove some and not all of the cancer can help people live longer. In some cases, chemotherapy may be given before surgery to try to shrink the tumor so that it can be more easily and completely removed.

Possible side effects of surgery for thymus cancer

Possible complications depend on the extent of the surgery and your health beforehand. Serious problems can include excessive bleeding, wound infections, and pneumonia.

You will need to stay in the hospital for several days after surgery. Because the surgeon usually will have to open your chest for the operation, the incision will hurt for some time after surgery. Your activity will be limited for at least a month or two.

Some people may need to have part or all of a lung removed. If your lungs are in good condition (other than the presence of the cancer) you can usually go back to normal activities after a lobe or even an entire lung has been removed. If you already have lung problems such as emphysema or chronic bronchitis (which are common among heavy smokers), you may become short of breath with activities after surgery.

For more general information about surgery, see Cancer Surgery.

Chemotherapy (chemo) uses anti-cancer drugs that are given intravenously (IV or into a vein), as an injection (shot), or by mouth. These drugs enter the bloodstream and reach the whole body, making this treatment useful for cancer that may have spread to organs beyond the thymus.

Chemo may be used in these situations:

• It may be given after surgery to try to kill any cancer cells that may have been left behind because they were too small to see. This is called adjuvant treatment.
• It may be given before surgery to try to shrink tumors so that they can be completely removed. This is called neoadjuvant therapy.
• Chemo may be the main treatment for people who have advanced cancer or are not healthy enough for surgery. .
• Chemo is sometimes combined with radiation to help it work better. This is known as chemoradiation or chemoradiotherapy.

Doctors give chemo in cycles, with each period of treatment followed by a rest period to allow the body time to recover. Chemo cycles generally last about 3 to 4 weeks, and treatment typically involves 4 to 6 cycles. Chemo is often not recommended for people in poor health, but advanced age by itself is not a barrier to getting chemo.

Several chemo drugs may be used in the treatment of thymomas and thymic carcinomas, including:

• Doxorubicin (Adriamycin^®)
• Cisplatin
• Carboplatin
• Cyclophosphamide (Cytoxan^®)
• Ifosfamide (Ifex^®)
• Vincristine (Oncovin^®)
• Etoposide (VP-16)
• Paclitaxel (Taxol^®)
• Pemetrexed (Alimta^®)
• 5-fluorouracil (5-FU)
• Gemcitabine (Gemzar^®)

The corticosteroid drug prednisone is often given with chemo.

These drugs are usually given in combination to try to increase their effectiveness. For example, the combination of cisplatin, doxorubicin, and cyclophosphamide (called CAP) with or without prednisone is often used to treat thymoma. The combination of carboplatin and paclitaxel may be used to treat thymic carcinoma.

Possible side effects of chemotherapy for thymus cancer

Chemo drugs work by attacking cells that are dividing quickly, which is why they work against cancer cells. But other cells in the body, such as those in the bone marrow, the lining of the mouth and intestines, and the hair follicles, also divide quickly. These cells are also likely to be affected by chemo, which can lead to certain side effects.

The side effects of chemo depend on the type and dose of drugs you are given and how long they are used. Side effects can include:

• Hair loss
• Mouth sores
• Loss of appetite
• Nausea and vomiting
• Fatigue and weakness

Chemo can also affect the blood forming cells of the bone marrow, leading to:

• Increased chance of infections (due to low white blood cell counts)
• Easy bruising or bleeding (due to low blood platelet counts)
• Fatigue and weakness (due to low red blood cell counts)

Side effects usually go away over time after treatment ends and there are often ways to lessen them. For instance, drugs can be used to help prevent or reduce nausea and vomiting. If you do have side effects, be sure to ask your doctor or nurse about medicines to help reduce or manage them.

Some drugs can have other side effects. For example, cisplatin and paclitaxel can damage nerves (called neuropathy). This can sometimes lead to pain, burning or tingling sensations, sensitivity to cold or heat, or weakness in the hands and feet. Cisplatin can also affect the nerves of the ear, leading to hearing loss. In most cases these problems improve or even go away once treatment is stopped, but they may last a long time in some people. You should report this, as well as any other side effects or changes you notice while getting chemotherapy, to your medical team so that you can get prompt treatment for them. In some cases, the doses of the chemotherapy drugs may need to be reduced or treatment may need to be delayed or stopped to keep the effects from getting worse.

Octreotide

A drug called octreotide (Sandostatin^® and Sandostatin LAR^®) may also help some people with advanced thymoma. This is not a typical chemo drug. It's a man-made version of a hormone called somatostatin. The drug works in some cases because it attaches to the thymoma cells and causes them to stop growing or die. Side effects of this drug can include pain or burning at the injection site, stomach cramps, nausea, vomiting, headaches, dizziness, and fatigue. It is also linked to increased risk of gallstones.

More information about chemotherapy

To learn more about how chemotherapy is used to treat cancer, see Chemotherapy.

To learn about some of the side effects listed here and how to manage them, see Managing Cancer-related Side Effects.

Cancer survivors can be affected by a number of health problems, but often their greatest concern is facing cancer again. If a cancer comes back after treatment it is called a “recurrence.” But some cancer survivors may develop a new, unrelated cancer later. This is called a “second cancer.” No matter what type of cancer you have had, it is still possible to get another (new) cancer, even after surviving the first.

Unfortunately, being treated for cancer doesn’t mean you can’t get another cancer. People who have had cancer can still get the same types of cancers that other people get. In fact, certain types of cancer and cancer treatments can be linked to a higher risk of certain second cancers.

Survivors of thymus cancer can get any type of second cancer, but they have an increased risk of:

• Non-Hodgkin lymphoma
• Salivary gland cancer
• Liver cancer
• Soft-tissue sarcoma

Follow-up after treatment

After completing treatment for thymus cancer, you should still see your doctor regularly. You may have tests to look for signs the cancer has come back or spread. Experts do not recommend any additional testing to look for second cancers in patients without symptoms. Let your doctor know about any new symptoms or problems, because they could be caused by the cancer coming back or by a new disease or second cancer.

Survivors of thymus cancer should follow the American Cancer Society guidelines for the early detection of cancer and stay away from tobacco products. Smoking increases the risk of many cancers.

To help maintain good health, survivors should also:

• Achieve and maintain a healthy weight
• Adopt a physically active lifestyle
• Consume a healthy diet, with an emphasis on plant foods
• Limit consumption of alcohol to no more than 1 drink per day for women or 2 per day for men

These steps may also lower the risk of some cancers.

See Second Cancers in Adults for more information about causes of second cancers.

Although thymic tumors are the most common tumors in the anterior mediastinum (the front part of the chest cavity), overall they are rare. They occur at a rate of only 1.5 cases for every million people each year in the US. This works out to about 400 cases per year (the exact number diagnosed each year is not known).

Survival statistics for thymomas are discussed in Survival rates for thymus cancer.

A risk factor is anything that affects your chance of getting a disease such as cancer. Different cancers have different risk factors. For example, exposing the skin to strong sunlight is a risk factor for skin cancer. Smoking is a risk factor for lung cancer and many others.

But risk factors don’t tell us everything. Having a known risk factor, or even several risk factors, does not mean that you will get the disease. And many people who get the disease may not have had any known risk factors.

No specific inherited, environmental, or lifestyle risk factors have been strongly linked to thymoma or thymic carcinoma. Some studies have suggested a possible link with exposure to radiation to the upper chest area, but this has not been confirmed. The only known risk factors are age and ethnicity.

Age

The risk of this type of cancer goes up with age. This type of cancer is rare in children and young adults, is seen more often in middle-aged adults, and is most common in those in their 70s.

Ethnicity

In the US, this cancer most common in Asians and Pacific Islanders and least common in Whites and Latinos. It is more common in African Americans than in Whites.

Not much is known about why thymus cancers develop in some people but not in others. Researchers have found some DNA changes that occur more often in thymus cancer cells than in normal cells. (DNA is the chemical in each of our cells that makes up our genes — the instructions for how our cells function.) However, they are still not certain why these changes occur in some people, exactly how the changes occur, and how the changes might cause cancer to form.

Because we do not know what causes most thymic cancers, it is not yet possible to know how to prevent them.

Screening is testing for a disease like cancer in people without any symptoms. Thymus cancers are uncommon, and there are no widely recommended screening tests for them. Still, these cancers can sometimes be found early.

About 4 out of 10 people with thymomas have no symptoms when their tumor is found. In most of these cases the tumor is seen by chance on a test (like a chest x-ray or CT scan) that is done for some other reason.

Thymomas are often associated with symptoms that are not directly caused by the tumor mass itself. These are called paraneoplastic syndromes (tumor-related conditions). Some of these paraneoplastic syndromes, such as myasthenia gravis, red cell aplasia, and hypogammaglobulinemia, are described in How Is Thymus Cancer Diagnosed? These conditions can be very important in diagnosing some thymomas early because they may be present while the tumor is still at an early stage.

It’s important to have frank, open discussions with your cancer care team. They want to answer all of your questions, no matter how minor they might seem. Here are some questions you might want to ask:

• What kind of thymic tumor do I have?
• Is it cancer?
• Has the cancer spread beyond the thymus?
• What is the stage (extent) of my cancer, and what does that mean in my case?
• Can the tumor be removed with surgery? (Is it likely to be resectable?)
• Are there other tests that need to be done before we can decide on treatment?
• How much experience do you have treating this type of cancer?
• Should I get a second opinion?
• What treatment choices do I have? What do you recommend? Why?
• What’s the goal of treatment?
• What risks or side effects are there to the treatments you suggest?
• What should I do to be ready for treatment?
• How long will treatment last? What will it involve? Where will it be done?
• How will treatment affect my daily activities?
• What are the chances my cancer will recur (come back) with these treatment plans?
• What would we do if the treatment doesn’t work or if the cancer recurs?
• What type of follow-up might I need after treatment?

Along with these questions, be sure to write down some of your own. For instance, you might want to know more about recovery times so you can plan your work schedule. Or you may want to ask about clinical trials .

Keep in mind, too, that doctors are not the only ones who can give you information. Other health care professionals, such as nurses and social workers, may have the answers to your questions. You can find more information about working with with your health care team in The Doctor-Patient Relationship.