Atypical Teratoid/Rhabdoid Tumor (ATRT), from the CureRays guide library.

ATRT is a rare, fast-growing brain tumor of very young children; cure is possible with intensive, coordinated treatment — surgery, multi-drug chemotherapy, and carefully shaped radiation — delivered urgently and tailored to the child's age.

What it is.

Atypical teratoid/rhabdoid tumor, or ATRT, is a rare and aggressive brain tumor that occurs mostly in infants and children under three years old, though it can occasionally appear in older children and adults. It can develop anywhere in the brain or spine but often forms in the cerebellum and brainstem at the back of the head, or near the fluid-filled spaces of the brain. Because it grows quickly and can block the flow of cerebrospinal fluid, ATRT often causes symptoms over a short time — headaches, vomiting, sleepiness, loss of balance, or, in babies, a head that grows too fast and fussiness. A hallmark of ATRT is the loss of a tumor-suppressor gene (most often SMARCB1, sometimes SMARCA4), and confirming this change helps doctors make the diagnosis with certainty. ATRT can spread through the cerebrospinal fluid to other parts of the brain and spine, so treatment must consider the whole nervous system, not just the original tumor. Historically ATRT was very difficult to treat, but modern intensive, multi-part treatment programs have meaningfully improved outcomes, especially for older children whose brains can tolerate radiation. Because nearly all patients are very young, the goal is to treat this aggressive tumor swiftly and effectively while doing everything possible to protect a developing brain. Because the gene change can sometimes be inherited, genetic counseling is an important part of care.

How radiation treats it.

Radiation therapy uses precisely aimed high-energy beams to damage the DNA inside tumor cells so they can no longer grow and divide. ATRT is sensitive to radiation, and for children old enough to receive it safely, radiation is an important part of curative treatment — studies show it improves survival. When the tumor is localized, radiation is focused tightly on the area where the tumor was; when it has spread through the cerebrospinal fluid, the whole brain and spine may be treated at a lower dose with a focused boost. The central challenge is that most children with ATRT are infants and toddlers whose brains are still developing and are highly vulnerable to radiation's long-term effects on thinking, growth, and hormones. To balance cure against these risks, teams individualize the approach: older children typically receive radiation as part of treatment, while the youngest children may have radiation delayed, reduced, or focused only on the tumor area, with intensive chemotherapy — sometimes high-dose chemotherapy with stem-cell rescue — used to control the disease in the meantime. Modern planning with intensity-modulated radiation and, where available, proton therapy allows the dose to be delivered effectively while sparing as much healthy tissue as possible. Because ATRT grows quickly, treatment is started urgently, and the radiation oncologist designs each plan to control this aggressive tumor while protecting the child's long-term development as much as possible.

The ways we can treat it.

Focal (tumor-bed) radiation. For localized ATRT, radiation is shaped tightly around the area where the tumor was, delivering an effective dose while sparing surrounding healthy brain — the preferred approach when the disease has not spread.

Craniospinal irradiation when the tumor has spread. If cells have seeded the cerebrospinal fluid, the entire brain and spine are treated at a lower dose with a focused boost, used in children old enough to tolerate it.

Proton therapy. Proton beams stop at a set depth, so they can treat the tumor while sparing nearby healthy brain and, when treating the spine, the organs in front of it — especially valuable for protecting a young child's development.

High-dose chemotherapy with stem-cell rescue to spare radiation. In infants too young for brain radiation, very intensive chemotherapy supported by the child's own stem cells is used to control the tumor while delaying or avoiding radiation to the developing brain.

Questions we hear often.

Why does treatment start so quickly? ATRT grows fast and can spread through the spinal fluid, so doctors begin evaluation and treatment urgently. Prompt, coordinated care by a pediatric neuro-oncology team — often within a clinical trial — gives the best chance of controlling the tumor.

Can my baby avoid radiation? In very young children, doctors often delay, reduce, or limit radiation to protect the developing brain, leaning on surgery and intensive chemotherapy — sometimes high-dose chemotherapy with stem-cell rescue — first. Whether and when radiation is used depends on the child's age, how the tumor responds, and whether it has spread. Proton therapy, when available, helps spare healthy tissue.

Is ATRT inherited? The gene change behind ATRT (most often in SMARCB1) can sometimes be inherited, which is why genetic counseling and testing are offered. This can explain why the tumor developed and identify family members who may benefit from monitoring.

This guide is informational only. It is not medical advice — please confirm anything here with your care team.