Atypical Teratoid / Rhabdoid Tumor (AT/RT)

What is AT/RT?

Atypical teratoid/rhabdoid tumor (AT/RT) is a fast-growing tumor of the brain and spinal cord. It accounts for about 1–2% of central nervous system (CNS) tumors in children. There are about 75–80 new cases of AT/RT each year in the United States. AT/RT most often occurs in young children under age 3. It is the most common malignant CNS tumor in infants under 1 year old. 

AT/RTs can occur throughout the brain and spinal cord. In children, about half of AT/RTs develop in the cerebellum or brain stem. AT/RTs can also spread through the cerebrospinal fluid to other parts of the brain and spinal cord.

AT/RT treatment usually involves a combination of therapies. These may include surgery, chemotherapy, and radiation therapy. Even with current treatments, AT/RT is hard to cure.

Symptoms of AT/RT

Signs and symptoms of AT/RT can vary based on the child’s age and tumor location. The tumors grow quickly. Symptoms may also worsen rapidly. 

AT/RT symptoms may include:

• Nausea and vomiting
• Headache, which is often worse in the morning or improves after vomiting
• Lower activity level or alertness
• Feeling tired or sleepy 
• Loss of balance or problems walking
• Unusual eye or face movements
• Changes in personality or behavior
• Irritability
• Bigger head size in infants
• More fullness of the fontanel ("soft spot" at the top of the skull)

Risk factors and causes of AT/RT

Most AT/RTs occur in children ages 3 and younger. But these tumors may also occur in older children and adults. AT/RTs are closely related to tumors that occur in other places in the body such as the kidney (rhabdoid tumor of the kidney). AT/RTs are slightly more common in males than females.

AT/RT is a type of embryonal tumor. These tumors are thought to begin in fetal cells in the brain of a developing baby. About half of embryonal tumors in infants under 1 year old are AT/RTs.

Certain changes in genes and chromosomes within the tumor cell are linked to AT/RT. Gene change may be passed from a parent to a child. But we do not usually know why these changes happen.

Gene changes in AT/RT

AT/RT is a type of rhabdoid tumor. Malignant rhabdoid tumors have a common abnormal gene. More than 95% of AT/RTs are related to a change in the SMARCB1 gene (also known as INI1, SNF5, and BAF47 gene). About 1–2% of the time, malignant rhabdoid tumor is caused by a mutation in the SMARCA4 gene.

In most cases, the gene mutation occurs only in the tumor cells. But about 25–30% of children with AT/RT have the gene change in every cell of their body. These children have rhabdoid tumor predisposition syndrome (RTPS). This mutation can be passed down from a parent. It could also be a new mutation that happens by chance.

Genetic testing and counseling are important for family members and patients with rhabdoid tumors. RTPS can increase the risk of benign tumors called schwannomas and rhabdoid tumors at a different site. Whether RTPS increases the risk of developing other cancers in later life is an area of research. 

Learn more about RTPS:

• Rhabdoid Tumor Predisposition Syndrome - St. Jude Children's Research Hospital
• Rhabdoid tumor predisposition syndrome - Genetics Home Reference
  

Grading and staging of AT/RT

Staging of AT/RT requires an MRI of the brain and spine. Doctors will also do a lumbar puncture to look for tumor cells in the cerebrospinal fluid or CSF. Tumors are classified as newly diagnosed or recurrent.

AT/RT is a high-grade (grade 4) tumor. It spreads quickly. In about 15–30% of patients, the disease has already spread at diagnosis. It usually spreads to the CSF or to the meninges (leptomeningeal metastasis).

Treatment of AT/RT

AT/RT treatment depends on the tumor’s size and location, the child’s age, and the spread of disease. Most patients get multiple types of treatment. AT/RT treatment is often through a clinical trial.

A child with AT/RT may need steroid and anti-seizure medicines to help manage symptoms. Palliative care and support services such as rehabilitation, psychology and social work can help patients and families manage symptoms, promote quality of life, and make care decisions. 

Your child may need extra support to address issues with learning, development, and coping with cancer.

Prognosis for children with AT/RT

AT/RTs are fast-growing and difficult to treat. The long-term outlook for children with AT/RT is usually poor. But advances in therapy have helped some children.

The 5-year survival rate for children with AT/RT is about 50%. But this varies widely based on the age at diagnosis and whether the cancer has already spread at diagnosis. Children under 3 years old whose disease has spread have the worst prognosis. Their chance of a long-term cure without the use of radiation therapy is less than 10%.

Your child's doctor is the best source of information about your child's case.

Support for patients with AT/RT

It is important to balance quality of life with cancer-directed therapy. Talk to your care team about expected problems and ways to help manage them. Palliative care or quality-of-life services can help you do the following:

• Manage symptoms
• Navigate difficult conversations
• Make decisions that align family wishes with goals of care

Your child will need follow-up care, lab tests, and routine imaging to see if the cancer returns or progresses. The care team will set a schedule based on your child’s needs and treatment response.

AT/RT patients and family members should have genetic testing and counseling. Children with RTPS have an increased risk of developing rhabdoid tumors. These children need regular medical care and ultrasound exams of the kidney to watch for kidney tumors.

Children treated for AT/RT should be monitored for adverse effects of treatment. These may include:

• Problems thinking and reasoning
• Endocrine problems
• Secondary cancers

Talk to your doctor about risks related to your child’s specific treatments.

Questions to ask your care team

• What are our treatment options?
• What are the possible side effects of each treatment?
• What can be done to manage side effects?
• Will my child need to be in the hospital for treatment?
• Where is the treatment available? Is it close to home or will we have to travel?
• What support services are available to my child? To my family?

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