Atypical Teratoid Rhabdoid Tumor (ATRT)

What is ATRT?

Atypical teratoid/rhabdoid tumor (ATRT or AT/RT) is a rare, fast-growing tumor of the brain or spinal cord. There are fewer than 100 new cases of ATRT in the United States each year.

ATRT most often occurs in children age 3 and younger. It is the most common malignant central nervous system (CNS) tumor in infants under 1 year old.

ATRTs can occur throughout the brain and spinal cord. In children, about half of ATRTs develop in the cerebellum or brain stem. ATRTs can spread through the cerebrospinal fluid (CSF) to other parts of the brain and spinal cord.

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

Symptoms of ATRT

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

ATRT symptoms may include:

• Morning vomiting
• Headaches or excessive crying in early mornings, which may get better after vomiting
• Bigger head size in infants
• More fullness of the fontanel ("soft spot" at the top of the skull)
• Lower activity level or decreased alertness
• Unusual eye or face movements
• Excessive sleepiness 
• Loss of balance when sitting, standing, or walking
• Changes in personality or behavior
• Irritability

Risk factors and causes of ATRT

ATRTs are closely related to tumors that occur in other places in the body, such as the kidney (rhabdoid tumor of the kidney). ATRTs are slightly more common in males than females.

ATRT is a type of embryonal tumor. These tumors are thought to begin in immature cells in the brain of a developing baby. About half of embryonal tumors in infants under 1 year old are ATRTs.

Gene changes in ATRT 

Certain gene changes (mutations) are linked to ATRT. Most ATRTs are related to a mutation in the SMARCB1 gene (also called INI1). Rarely, malignant rhabdoid tumors can be caused by a mutation in the SMARCA4 gene (also called BRG1). 

Rhabdoid tumor predisposition syndrome (RTPS): Some children with ATRT may have the gene mutation not only in their tumor cells but also in all other cells of their body. This is called rhabdoid tumor predisposition syndrome or RTPS. These mutations can happen by chance in the patient, or they can be inherited from their parents. 

Genetic testing and genetic counseling are important for family members and patients with rhabdoid tumors. RTPS can increase the risk of benign (not cancerous) tumors called schwannomas and rhabdoid tumors in other parts of the body. 

Diagnosis of ATRT

Grading and staging of ATRT

The tumor’s grade is based on how abnormal the cancer cells look under a microscope. The more abnormal the cells look, the higher the grade. Higher-grade tumors are more likely to grow quickly and may need more aggressive treatment. ATRT is a high-grade (grade 4) tumor. This means it is fast-growing. 

The stage shows how far the cancer has spread. Staging includes imaging tests like MRI scans of the brain and spine to check for tumor spread, as well as a lumbar puncture to look for cancer cells in the cerebrospinal fluid. In about 15–30% of patients, the disease has already spread at diagnosis. ATRT usually spreads to the CSF or the meninges (leptomeningeal metastases).

Treatment of ATRT

ATRT treatment depends on the tumor’s size and location, the child’s age, and the extent of spread of disease. Most patients get multiple types of treatment, which include a combination of surgery, chemotherapy, and radiation therapy. ATRT treatment is often through a clinical trial.

Radiation therapy for ATRT

Radiation therapy is sometimes used along with other treatments. Its use depends on the child’s age. Radiation uses high-energy x-rays or other kind of radiation to kill the cancer cells or stop them from growing. Radiation therapy can affect brain development, especially in children ages 3 or younger. The dose of radiation or plan of care may be different for very young children.

Chemotherapy for ATRT

Chemotherapy (chemo) is often used along with surgery and radiation to treat ATRT. Chemotherapy may be given into a vein or into the cerebrospinal fluid (intrathecal chemotherapy). 

Treatment for ATRT usually involves a combination of chemotherapy drugs. These may include:

Targeted therapy for ATRT

Targeted therapies work by acting on, or targeting, certain gene mutations of tumor cells. There are no known effective targeted therapies for ATRT. Children with recurrent ATRT may be eligible for clinical trials using targeted therapy. Targeted therapies studied in ATRT include alisertib and tazemetostat. 

Supportive care for ATRT

A child with ATRT may need steroid or anti-seizure medicines to help manage symptoms. Patients being treated with chemotherapy and radiation therapy may also need medicine to control nausea and vomiting. 

Prognosis for ATRT

The 5-year survival rate for children with ATRT is about 50% in the United States. The survival rate depends on the age at diagnosis and how much the disease has spread. Patients whose tumor has spread and are less than 3 years old at diagnosis have less than 10% survival rate with current treatments. 

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

Support for patients with ATRT

Your child will need follow-up care, lab tests, and regular imaging scans. The care team will set a schedule based on your child’s needs and how well they respond to treatment.

It is important to balance quality of life with cancer-directed therapy. Talk to your care team about possible problems and ways to help manage them. 

Palliative care and quality-of-life services can help families:

• Manage symptoms and side effects
• Have difficult conversations
• Make decisions that meet family wishes with goals of care

ATRT patients and family members should have genetic testing and counseling. Children with rhabdoid tumor predisposition syndrome (RTPS) have a greater risk of developing rhabdoid tumors. These children need regular medical care and ultrasound exams of the kidneys to watch for kidney tumors.

Children treated for ATRT should be monitored for treatment-related health problems. These may include:

• Problems with learning, thinking, and memory
• Endocrine problems
• Secondary cancers

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

Questions to ask your care team

• What treatment options are available for ATRT?
• What are the possible side effects of each treatment?
• What can be done to manage side effects?
• Should we consider a clinical trial for ATRT?
• What is the prognosis for ATRT?
• What supportive care therapies or services are available?
• Should we consider genetic testing?

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