AT/RT - Atypical Teratoid Rhabdoid Tumor
How Dana-Farber/Boston Children's Cancer and Blood Disorders Center approaches the treatment of atypical teratoid rhabdoid tumors (AT/RT)
Patients who have atypical teratoid rhabdoid tumors are treated through Dana-Farber/Boston Children's Cancer and Blood Disorders Center, New England's largest and most active pediatric brain tumor treatment center. Our team provides advanced treatment options for young patients with AT/RT and other brain tumors.
What is an atypical teratoid rhabdoid tumor?
An atypical teratoid rhabdoid tumor, often called AT/RT, is a very rare and fast-growing tumor of the central nervous system. If your child has been diagnosed with an ependymoma, there are a number of things that you should know:
- AT/RT's are part of a larger group of malignant tumors called rhabdoid tumors, which can occur outside of the brain in the kidneys, liver or other locations.
- In most cases, AT/RT is associated with a specific genetic mutation (INI1) that can occur spontaneously or be inherited.
- AT/RT can occur anywhere in the brain but are most commonly found in cerebellum (base of the brain) and brain stem (the part of the brain that controls basic body functions).
- This type of tumor usually occurs in children under 3 but it can sometimes occur in older children and adults.
- AT/RT was previous thought to be a type of medulloblastoma. However, it is now known to be a separate type of tumor and is treated differently.
- AT/RT represents only 1 to 2 percent of childhood brain tumors.
What causes atypical teratoid rhabdoid tumor?
As a parent, you undoubtedly want to know what may have caused your child's tumor. More than 90 percent of cases of AT/RT are associated with a genetic defect. However, the cause of this abnormality is not known.
- This genetic mutation (INI1) may be inherited, in which case tumors may also occur in the kidneys and other parts of the body.
- This defect may also occur spontaneously.
It's important to understand that these and other brain tumors most often occur with no known cause. There's nothing that you could have done or avoided doing that would have prevented the tumor from developing.
What are the symptoms of atypical teratoid rhabdoid tumor?
AT/RT grows very rapidly and, as a result, symptoms can develop quickly over days or weeks. Common symptoms of AT/RT include:
- headache (especially upon waking in the morning)
- nausea and vomiting
- fatigue and lethargy
- trouble with balance and coordination
- increased head size in infants (hydrocephalus)
Your child's symptoms may vary based on his age and the location of the tumor.
The symptoms of a brain tumor may resemble other, more common conditions or medical problems. Always consult your child's physician for a diagnosis.
How are atypical teratoid rhabdoid tumors classified?
For many tumors, we use a system of classification called "staging," that physicians use to evaluate cancers. However, there is currently no standardized classification system for AT/RT. The tumor may be:
- localized, occurring in only one location in the brain
- disseminated, spread to multiple locations in the brain, central nervous system or body
In addition, these tumors are classified as:
- newly diagnosed
- recurrent (returning after initial treatment)
Using a variety of diagnostic tests, your child's physician will gather as much information as possible about your child's tumor and will discuss treatment options with you and your family.
How is atypical teratoid rhabdoid tumor diagnosed?
We may perform a number of tests to determine the type of tumor your child has and whether it has spread. These may include:
- physical exam — including neurologic function tests of reflexes, muscle strength, eye and mouth movement, coordination and alertness.
- magnetic resonance imaging (MRI) — to produce detailed images of organs and structures within the body and/or spine.
- computerized tomography scan (also called a CT or CAT scan) — to capture a detailed view of the body, and check for other tumors in the chest, abdomen and pelvis.
- biopsy (or tissue sample) — a sample taken from the tumor during surgery to provide definitive information about the type of tumor
- lumbar puncture (also called an LP or spinal tap) — to remove a small sample of cerebrospinal fluid (CSF) and determine if any tumor cells have started to spread. In young children, this procedure is often performed under sedation.
- ultrasound — to determine whether tumors have developed in other places in the body, especially the kidneys
- genetic testing — to look for a specific genetic defect often associated with AT/RT
How is treatment for AT/RT determined?
If your child has been diagnosed with AT/RT, you'll naturally want to know how your child's physician may treat the tumor. Specific treatment to cure AT/RT will depend on:
- type, location, and size of the tumor
- extent of the disease
- your child's age, overall health and medical history
- how your child's doctors expect the disease to progress
- your child's tolerance for specific medications, procedures or therapies
What are the treatments for AT/RT?
There are a number of treatments that your child's physician may recommend. Some of them help to treat the tumor while others are intended to complications of the disease or side effects of the treatment. If your child is diagnosed with AT/RT, treatment may include:
Surgery may be performed by one of our experienced pediatric neurosurgeons to confirm the diagnosis of AT/RT (biopsy) or to remove as much of the tumor as possible (resection).
- In the case of biopsy, tumor specimens are examined by one of our neuropathologists to determine the exact diagnosis.
- Due to the rapid growth and spread of AT/RTs, complete removal of the tumor by resection is generally not possible.
In addition to surgery, your child may receive precisely targeted and dosed radiation therapy in order to kill cancer cells left behind after surgery. This treatment is important to control the local growth of tumor. If the AT/RT has spread, we may recommend radiation to the whole brain and spinal cord, depending on your child's age and the tumor location.
- Because AT/RT often occurs in children younger than 3, we may recommend reducing the intensity of radiation therapy or avoiding it all together.
- Children over 3 generally receive radiation therapy as a part of treatment.
- Radiation therapy can cause long-term effects. Your child's physician will work with our pediatric radiation oncologists to determine the optimal dose of radiation that will be effective in treating the tumor while also minimizing side effects.
Chemotherapy is the use of drugs that interfere with the cancer cell's ability to grow or reproduce. Your child's physician may recommend chemotherapy before surgery in order to help shrink the tumor and make complete removal more likely.
While chemotherapy can be quite effective in treating certain cancers, the agents don't differentiate healthy cells from cancer cells. Because of this, there can be side effects during treatment. Being able to anticipate these side effects can help the care team, parents, and child prepare, and, in some cases, prevent these symptoms from occurring.
Chemotherapy is systemic treatment, meaning it is introduced into your child's bloodstream and travels throughout the body to kill cancer cells. Your child may be given chemotherapy:
- orally, as a pill to swallow
- intramuscularly, as an injection into the muscle or fat tissue
- intravenously, directly to the bloodstream (also called IV)
- intrathecally, directly delivering the chemotherapy into the spinal column with a needle
In the case of AT/RT and other brain tumors, intrathecal chemotherapy is often an important part of treatment as it allows these medications to be delivered directly to the central nervous system to treat the tumor.
Stem cell transplant
Inside many of the body's bones is a special tissue called bone marrow that produces a number of important blood cells. Bone marrow transplantation (also called a stem cell transplant) is a therapy for children with cancer or other diseases that affect the bone marrow. In some cases, your child's physician may recommend stem cell transplant as a treatment for AT/RT.
- The goal of stem cell transplant is to transfuse healthy bone marrow cells into your child after his unhealthy bone marrow has been eliminated.
- The use of stem cell transplantation allows children with aggressive cancers, such as AT/RT, to receive higher doses of chemotherapy.
What is the expected outcome (prognosis) after treatment?
AT/RT is a very difficult tumor to cure and, unfortunately, the outcomes remain poor. In general, older children with AT/RT tend to do better than young children. Cure rates for children over 3 are about 70 percent, while cure rates for children younger than 3 remain below 15 percent.
Survivors of pediatric brain tumors may face physical, psychological, social and intellectual challenges related to their treatment and will require ongoing assessment and specialized care.
To address the needs of these patients, Dana-Farber/Boston Children's established the Stop & Shop Family Pediatric Neuro-Oncology Outcomes Clinic.
Today, more than 900 pediatric brain tumor survivors of all ages are followed by the Outcomes Clinic, a multi-disciplinary program designed to address long-term health and social issues for families and survivors of childhood brain tumors. Some of the post-treatment services provided by the Outcomes Clinic include:
- MRI scans to monitor for tumor recurrences
- intellectual function evaluation
- endocrine evaluation and treatment
- neurologic assessment
- psychosocial care
- hearing, vision monitoring
- ovarian dysfunction evaluation and treatment
- motor function evaluation and physical therapy
- complementary medicine
As a result of treatment, children may experience changes in intellectual and motor function. Among several programs addressing these needs are the School Liaison Program and Back to School Program, which provide individualized services to ease children's return to school and maximize their ability to learn.
In addition to providing thorough and compassionate care, our Pediatric Neuro-Oncology Outcomes Clinic specialists conduct innovative survivorship research and provide continuing education for staff, patients and families.
Research and Innovation
Because AT/RT is so rare, these tumors are difficult to study. As a result, Dana-Farber Cancer Institute and Boston Children's Hospital collaborates with other institutions in the Boston-area and around the country to improve our current understanding of this condition and offer new treatments to children with AT/RT.
Currently, researchers at Dana-Farber/Boston Children's are working with the Children's Hospital of Philadelphia and the Broad Institute of MIT and Harvard to learn more about the molecular characteristics of acute teratoid rhabdoid tumors.
In addition, researchers in the Brain Tumor Program are collaborating with physicians and researchers that treat other types of rhabdoid tumors in order to study the effectiveness of current treatments and to establish new, more standardized treatments for all types of rhabdoid tumors.
Children's doctors and scientists have made many breakthrough discoveries about diseases like polio and leukemia; our ongoing innovative research continues to push the boundaries of the way pediatric medicine is practiced.
It's possible that your child will be eligible to participate in one of Dana-Farber/Boston Children's current clinical trials. Most children with a diagnosis of AT/RT will be treated as part of a clinical trial. These studies are useful for a multitude of reasons: Some trials are designed to evaluate the effectiveness of a particular drug, treatment or therapy on a specific disease; others help doctors to better understand how and why certain conditions occur.
If your child's physician recommends participation in a clinical trials, that likely means that your child's physician believes that the plan outlined in that trial represents the absolute best, latest care your child can possibly receive.
And participation in any clinical trial is completely voluntary: We will take care to fully explain all elements of the treatment plan prior to the start of the trial, and you may remove your child from the medical study at any time.
The Pediatric Brain Tumor Program at Dana-Farber/Boston Children's participates in several multi-center national clinical trials.