Rhabdomyosarcoma (rab-doe-my-oh-sahr-KOE-muh) is a rare cancer that starts as a growth of cells in soft tissue. Rhabdomyosarcoma is a type of soft tissue sarcoma. Soft tissues connect, support and surround other structures in the body. Soft tissues include muscle, fat, blood vessels, nerves, tendons and the linings of the joints.

Rhabdomyosarcoma is the most common soft tissue sarcoma in children. But teenagers and adults can get it too.

Rhabdomyosarcoma can start almost anywhere in the body. It often starts in the:

• Head and neck.
• Urinary system, such as the bladder.
• Reproductive system, such as the vagina, uterus and testes.
• Arms and legs.

The prognosis, also called the outlook, is different from person to person. It generally is better when the cancer has not spread far from where it started. Age, where the tumor starts, tumor size and whether there are specific gene changes in the cancer cells also affect the outlook. Rhabdomyosarcoma in children differs from rhabdomyosarcoma in adults in the types that are more common and in the overall outlook. Children generally have a better outlook than adults do.

Types

Rhabdomyosarcoma has four main types. The type is based on how the cancer cells look under a microscope and whether the cancer has specific gene changes. These differences can affect the treatment plan.

• Embryonal rhabdomyosarcoma is the most common type in children. It often starts in the head and neck or the urinary or reproductive systems. Its cells can vary in how they look. Some look more like mature muscle cells. Others look like very immature cells and not yet like muscle cells.
• Alveolar rhabdomyosarcoma is different from embryonal rhabdomyosarcoma in a number of ways. It's more common in older children, teenagers and adults than in young children. And it often starts in the arms, legs or trunk instead of the head and neck. Alveolar rhabdomyosarcoma gets its name because its cells often grow in groups separated by bands of tissue. This makes a pattern that can look like the tiny air sacs in the lungs, called alveoli. Many alveolar rhabdomyosarcomas also have a gene change called a FOXO1 fusion. This gene change can help diagnose alveolar rhabdomyosarcoma and affect the outlook.
• Spindle cell-sclerosing rhabdomyosarcoma is not a common type of rhabdomyosarcoma. It may start in the head, neck, arms, legs or trunk. This type can happen in infants and tends to have a good outlook when it does. This type also can happen in teenagers or adults and may act aggressively. The cells in spindle cell-sclerosing rhabdomyosarcoma may be long and narrow, also called spindle shaped. Some tumors may have dense, scarlike tissue in them.
• Pleomorphic rhabdomyosarcoma is a rare type that mostly affects adults, especially older adults. It often starts in the arms or legs. It also can start in the trunk. The term pleomorphic means that the cancer cells can look very different from one another in shape and size. This type tends to be aggressive and harder to treat. The treatment approach for pleomorphic rhabdomyosarcoma may be different from the approach for other types of rhabdomyosarcoma.

Signs and symptoms of rhabdomyosarcoma can differ depending on where the cancer starts and how large the tumor grows.

General symptoms

As a rhabdomyosarcoma grows, it may cause:

• A noticeable lump or swelling.
• Pain.

You can't tell whether a lump is a sarcoma simply by how it looks or feels.

Head and neck

Symptoms may include:

• Bleeding from the nose, throat, ears or eyes.
• Changes in vision.
• Eye that bulges.
• Stuffy nose.
• Earache.
• Headache.

Urinary or reproductive systems

Symptoms may include:

• Bleeding from the vagina.
• Blood in the urine.
• Needing to urinate more often.
• Trouble urinating.
• Constipation.

Arms and legs

Symptoms may include:

• Arm or leg pain.
• Arm or leg weakness.
• One arm or leg area that looks bigger than the same area in the other arm or leg. This may even cause clothing to feel tighter in that area.

Belly or pelvis

Symptoms may include:

• Constipation.
• Swelling of the belly.
• Vomiting.

When to seek care

Many signs and symptoms of rhabdomyosarcoma are usually caused by something else. Still, make an appointment with a healthcare professional for:

• A lump, swelling or other symptom that does not go away or gets worse.

Also, have a lump checked if it:

• Continues to grow.
• Is larger than about 2 inches (5 centimeters).
• Feels like it is deep beneath the skin.

Do not wait for a lump to become painful before seeing a healthcare professional. A soft tissue sarcoma lump may not hurt.

It's not clear what causes rhabdomyosarcoma. It starts when a soft tissue cell develops changes in its DNA. A cell's DNA holds the instructions that tell a cell what to do.

In healthy cells, the DNA gives instructions that help control when cells grow, multiply and die. In cancer cells, DNA changes give different instructions. The changes can tell the cancer cells to grow and divide when they should not or to keep living when healthy cells would die. This causes too many cells to build up.

The cancer cells might form a mass called a tumor. The tumor can grow into and destroy healthy tissue. In time, cancer cells can break away and spread to other parts of the body. When cancer spreads, it's called metastatic cancer.

Some types of rhabdomyosarcoma have specific gene changes in the cancer cells. These changes can help identify the type of rhabdomyosarcoma and may help guide treatment decisions. But for most people with rhabdomyosarcoma, there is no known cause or inherited condition that explains why the cancer happened.

Most people with rhabdomyosarcoma do not have a known risk factor.

Factors that may increase the risk include:

• Younger age. Rhabdomyosarcoma happens most often in children and teenagers.
• Inherited cancer syndromes. Some cancer syndromes passed down through families can increase the risk of rhabdomyosarcoma. These include Li-Fraumeni syndrome, neurofibromatosis type 1, Costello syndrome, Noonan syndrome, Beckwith-Wiedemann syndrome and DICER1 syndrome.

Rhabdomyosarcoma diagnosis usually begins with a physical exam. Based on the results, the healthcare team might recommend other tests. These may include imaging tests and a procedure to remove a sample of cells for testing. A biopsy is used to confirm the diagnosis.

Imaging tests

Imaging tests make pictures of the inside of the body. They can help show the location and size of a rhabdomyosarcoma.

Tests may include:

• Computerized tomography (CT) scan.
• Magnetic resonance imaging (MRI).

CT and MRI also may be used later to look for cancer that has spread.

Biopsy

A biopsy is a procedure to remove a sample of tissue for testing in a lab. A biopsy for rhabdomyosarcoma needs to be done in a way that won't cause problems with future surgery. For this reason, it's a good idea to seek care at a medical center that sees many people with this cancer.

Types of biopsy procedures used to diagnose rhabdomyosarcoma include:

• Core needle biopsy. This method uses a needle to remove tissue samples from the tumor. Healthcare professionals usually try to take samples from several parts of the cancer.
• Surgical biopsy. In some cases, your healthcare professional might suggest surgery to get a larger sample of tissue. This may be needed if a core needle biopsy does not provide enough tissue or a clear diagnosis.

A pathologist with experience diagnosing rhabdomyosarcomas should look at the biopsy sample. The pathologist looks at the tissue under a microscope to see if the cells are cancerous. Other tests in the lab show more details about the cancer cells, such as what type of rhabdomyosarcoma cells they are. Understanding the type is important because it can affect treatment decisions.

Gene testing the tumor

A biopsy sample also may be tested for gene changes. If the tumor cells have gene changes, it may help make clear what type of rhabdomyosarcoma you have. There are many types of gene changes, such as the fusion of two genes. Some fusions have a good outlook. Others have a poor outlook.

Gene changes also can affect treatment recommendations. For example, rhabdomyosarcoma with a FOXO1 gene fusion with the PAX gene can have a poor outlook and may need more treatment compared with rhabdomyosarcoma without the FOXO1 fusion.

Staging tests

After rhabdomyosarcoma is diagnosed, the care team does tests to find out how much cancer is in the body and whether it has spread. This process is called staging. The results help the care team plan treatment.

Tests used for staging may include:

• CT scan. A CT scan can help show if cancer has spread to organs such as the lungs.
• MRI. An MRI scan can help show tumors located in the head, neck, arms and legs, and nearby structures such as blood vessels and nerves.
• Positron emission tomography (PET) scan. PET scans may be used to look for cancer in bones, lymph nodes and other parts of the body.
• Bone marrow biopsy and aspiration. This test can help show if cancer is in the bone marrow.
• Lymph node biopsy. This test checks for cancer spread to lymph nodes. The healthcare team chooses what lymph nodes to test partly based on where the tumor started.
• Lumbar puncture. This procedure, also called a spinal tap, removes some of the fluid around the brain and spinal cord. That fluid is tested for cancer cells. It may be used for some head and neck tumors if imaging shows cancer may have reached tissues around the brain or spinal cord.

Rhabdomyosarcoma treatment depends on the tumor's location, stage and risk group and whether it has gene changes. Treatment usually combines chemotherapy with surgery, radiation therapy or both.

Surgery

The goal of surgery is to remove all the cancer cells. But that's not always possible if the rhabdomyosarcoma has grown around or near organs. If the surgeon can't safely remove all the cancer, your healthcare team can use other treatments to kill cancer cells that might be left. This might include chemotherapy and radiation. Sometimes these treatments are given first to shrink the tumor before surgery.

Chemotherapy

Chemotherapy treats cancer with strong medicines. Almost everyone with rhabdomyosarcoma gets chemotherapy, even after surgery that removes all of the tumor. Chemotherapy can treat any cancer cells that may remain in the body.

Many chemotherapy medicines exist. Treatment often involves a combination of medicines. Most chemotherapy medicines are given through a vein. Some come in pill form. Which medicines are used and how much treatment is needed depend in part on the cancer's risk group.

Chemotherapy also can be used before other treatments. The chemotherapy can help shrink a cancer to make it easier to do surgery or radiation therapy.

Radiation therapy

Radiation therapy treats cancer with powerful energy beams. The energy can come from X-rays, protons and other sources.

Radiation therapy may be recommended after surgery and chemotherapy. It can help kill cancer cells that might be left. Radiation also may be used instead of surgery. For example, it may be used if the cancer is in an area where surgery isn't possible because of nearby organs.

Radiation therapy also may be used to shrink tumors and relieve symptoms such as pain or trouble breathing when cancer has spread and cannot be cured.

Treatment side effects

Rhabdomyosarcoma treatment can cause many side effects. Some may happen right away. Others may affect you years later. The risks depend on the treatments used, the doses, the area of the body treated and age.

Surgery can change how a part of the body looks or works. Some people may need rehabilitation after surgery. Radiation therapy can affect the growth of bones and other tissues, especially in children. Over time, it may cause symptoms such as limited joint movement or scarring of soft tissue.

Chemotherapy can cause different side effects depending on the medicines used. Some medicines used for rhabdomyosarcoma can affect the nerves, the bladder and the ability to have children in the future, called fertility. Chemotherapy and radiation therapy also can increase the risk of another cancer later in life.

Your healthcare team can explain the short- and long-term effects that are most likely with your treatment plan.

Clinical trials

Clinical trials are studies of new treatments or new ways of using existing treatments. Clinical trials can offer a chance to try the latest treatments. The risk of side effects might not be known. Ask your healthcare professional if you might be able to be in a clinical trial.

A diagnosis of rhabdomyosarcoma can bring up many feelings. With time, you'll find ways to cope. Until then, it might help to:

• Learn enough about rhabdomyosarcoma to make decisions about care. Ask your healthcare professional about this type of sarcoma, including treatment options. Learning what to expect may make treatment decisions feel more manageable. If your child has cancer, ask the healthcare team for help talking with your child about the cancer and treatment.
• Find someone to talk with. Find a good listener who is willing to listen to you talk about your hopes and fears. This may be a friend or family member. Meeting with a counselor, medical social worker, clergy member or cancer support group also may be helpful. For children and teens, a child life specialist also may help them understand and cope with cancer and treatment.
• Ask others for support. If you have trusted friends, family or community members, those relationships may help you deal with rhabdomyosarcoma. For example, family or friends might help with things such as taking care of your home while you're in the hospital. They also can give emotional support when you feel overwhelmed. Your care team also can help connect you with support services and resources. Help children stay in touch with friends. This could be through video chats or text messages.

Start by making an appointment with your or your child's primary care professional. If there's a concern about rhabdomyosarcoma, you or your child may be referred to a cancer specialist.

For a child or teenager with rhabdomyosarcoma, ask about a children's cancer center. A children's cancer center can help you find support and specialists. Children and teenagers with rhabdomyosarcoma should be treated by a team with experience in treating childhood cancers. Children's cancer centers have teams of specialists experienced in treating cancers in children and teenagers and may offer clinical trials and newer treatments.

A team of specialists for rhabdomyosarcoma may include:

• Orthopedic surgeons who specialize in operating on cancers that affect the bones or muscles, also called orthopedic oncologists.
• Other surgeons, depending on where the cancer is and the age of the person who needs treatment. Examples are pediatric surgeons, head and neck surgeons, gynecologists, or urologists.
• Specialists who treat cancer with chemotherapy or other medicines. These might be medical oncologists or, for children, pediatric oncologists.
• Specialists who treat cancer with radiation, called radiation oncologists.
• Specialists who study tissue to diagnose the type of cancer, called pathologists.
• Rehabilitation specialists who can help in recovery after surgery, called physical medicine and rehab.

What you can do

Before the appointment, make a list of:

• Symptoms, such as pain, feeling tired or losing weight.
• Any medicines, vitamins and supplements you take, including the dose and how often you take them.
• Key personal information, including other medical conditions or surgeries, any major stresses, or recent life changes.

It also can be helpful to:

• Bring previous scans or X-rays, the images and reports, and any other medical records that might be helpful.
• Consider taking a relative or friend along to help you remember all the information you get during the appointment.
• Make a list of questions to ask the healthcare professional to make the most of your time.

Whether the appointment is for you or for your child, your questions might include:

• What type of rhabdomyosarcoma is this?
• Where is the tumor and has the cancer spread?
• Are more tests needed?
• What are the treatment options?
• What is the cancer's stage and risk group? What do those mean?
• What is the goal of treatment?
• What are the chances that treatment will cure this cancer?
• What are the side effects and risks of each treatment?
• How much experience does your team have with treating rhabdomyosarcoma?
• Are there clinical trials to think about?
• Will treatment affect being able to have children? If so, do you offer ways to preserve that ability?
• Are there brochures or other printed material that I can have? What websites do you suggest?

What to expect from your doctor

Your healthcare professional will likely ask you questions. Questions might include:

• What symptoms worry you?
• When did you notice these symptoms?
• Are the symptoms constant, or do they come and go?
• Have the symptoms changed over time?
• How severe are the symptoms?
• What, if anything, seems to make the symptoms better?
• What, if anything, seems to make the symptoms worse?

After diagnosis, your care team may assign a stage to the cancer. For children, the care team also may assign a clinical group and risk group. Together, these groupings help your care team plan treatment and understand your prognosis.

Staging terms

Stage describes how much cancer there is and how far it has spread. For rhabdomyosarcoma, stages range from 1 to 4. A lower stage usually means the cancer is more limited. Stage 4 means the cancer has spread far from where it started. Where the tumor started also affects the stage. Some areas in the body, such as the head and neck and the area around the eye, have a better outlook.

Healthcare professionals use a TNM system to help assign a stage to the rhabdomyosarcoma. TNM stands for:

• T: The size of the initial tumor and whether it has spread from where it started.
• N: Whether the cancer has spread to nearby lymph nodes.
• M: Whether the cancer has spread to distant parts of the body.

Clinical groups

Rhabdomyosarcoma that is not the pleomorphic type also is assigned to a clinical group. While stage describes the cancer before treatment, a clinical group describes what cancer is left after the first surgery or biopsy. Clinical groups also include the extent of the cancer. Cancer cannot always be fully removed.

• Group 1. The tumor was fully removed. And the cancer has not spread beyond the area in which is started.
• Group 2. The tumor was removed. However, microscopic cancer cells are at the edges of the removed tissue or in nearby lymph nodes. The cancer has not spread beyond nearby lymph nodes.
• Group 3. Some of the tumor that's large enough to be seen with the eye remains in the body after biopsy or surgery. The cancer does not seem to have spread beyond nearby lymph nodes.
• Group 4. Like stage 4, group 4 means the cancer has spread to distant parts of the body.

Risk groups

After staging, for people under age 21, the care team also assigns rhabdomyosarcoma to a risk group. This reflects the risk of rhabdomyosarcoma returning, also called recurring, after treatment.

When assigning a risk group, the care team thinks about:

• Where the tumor started.
• How large the tumor is.
• Whether the cancer has spread, including if nearby lymph nodes have cancer.
• How much tumor is left after surgery or biopsy.
• Whether gene changes are found, especially a FOXO1 fusion.
• A person's age.

The main risk groups are:

• Very low risk and low risk. These cancers have the best outlook and are more likely to be cured.
• Intermediate risk. These cancers often can be cured. But they also have a higher chance of recurrence than cancers that are low or very low risk.
• High risk. These cancers have the highest risk of recurring and a less positive outlook. They are harder to cure.

Your care team can explain what your rhabdomyosarcoma's stage, clinical group and risk group are and what they mean for you and your treatment.

Cancer survival rates tell you the percentage of people who survive a certain type of cancer for a specific amount of time. Cancer statistics often use a five-year relative survival rate. This rate compares survival among people with the cancer and survival among people in the general population.

Children with rhabdomyosarcoma generally have a better outlook than do teens and adults with rhabdomyosarcoma.

Survival rates are based on large groups of people. Your outlook may be different based on a number of factors. These include the type of rhabdomyosarcoma you have, what treatments you receive and how well those treatments work.

For children and young adults, estimated five-year survival by risk group is:

• Very low risk. More than 90%.
• Low risk. About 70% to more than 90%.
• Intermediate risk. About 50% to 70%.
• High risk. About 20% to 30%.

Rhabdomyosarcoma recurrence five or more years after successful treatment is uncommon, but it can happen.

Stage 4 survival

Stage 4 rhabdomyosarcoma means the cancer has spread to distant parts of the body. Many people with stage 4 rhabdomyosarcoma are in the high-risk group. High-risk rhabdomyosarcoma usually has a five-year survival rate of about 20% to 30%.

The survival rates can give you a general idea of how people with rhabdomyosarcoma have done over time. But they cannot show exactly what will happen for one person. Your healthcare team can explain what the survival statistics may mean for your specific situation.