Atypical Teratoid Rhabdoid Tumor (ATRT) is a rare and aggressive form of cancer that originates in the central nervous system. This fast-growing tumor primarily affects infants and young children, often diagnosed before the age of three years. Understanding ATRT, its causes, and treatment approaches can provide a foundational understanding for families navigating this condition.
Causes and Risk Factors
Atypical Teratoid Rhabdoid Tumors are linked to genetic changes within tumor cells. The most common genetic alteration involves the SMARCB1 gene, also known as INI1. This gene normally functions as a tumor suppressor, controlling cell growth and preventing tumor formation. Less frequently, mutations in the SMARCA4 gene can also cause ATRT.
In the majority of ATRT cases, these genetic mutations are sporadic, arising by chance within tumor cells and not inherited. This sporadic nature can alleviate concerns about genetic predisposition. Rarely, an inherited condition called rhabdoid tumor predisposition syndrome can increase the risk of ATRT, but this accounts for a small percentage of diagnoses.
Symptoms and Diagnosis
ATRT symptoms vary depending on the child’s age and tumor location. As these tumors grow quickly, symptoms often appear suddenly and worsen rapidly. Common signs include persistent headaches (worse in the morning or improving after vomiting), nausea, vomiting, increased head size in infants, or a bulging soft spot (fontanel).
Other indicators can include:
Changes in activity levels (fatigue or lethargy)
Problems with balance, coordination, or walking
Unusual eye or face movements
Changes in personality and behavior (increased irritability)
Because these symptoms can mimic other common childhood illnesses, a healthcare provider will recommend testing if symptoms persist or worsen.
Diagnosis begins with a neurological exam to assess reflexes, balance, and coordination. If a brain tumor is suspected, imaging scans like MRI and CT are performed. These scans identify the presence and location of a mass. Definitive diagnosis is made through a biopsy, where a tissue sample is surgically removed. Pathologists examine this tissue for specific cellular characteristics, and genetic testing confirms the absence or abnormality of the SMARCB1 protein, a hallmark of ATRT.
Treatment Approaches
Treatment for Atypical Teratoid Rhabdoid Tumors involves an intensive, multi-modal strategy, combining several therapeutic approaches. The specific plan is tailored to factors such as the child’s age, the tumor’s size and location, and whether the cancer has spread. A multidisciplinary team of specialists, including neurosurgeons, neuro-oncologists, and radiation oncologists, develops the most appropriate course of action.
Surgery is the first line of treatment, with the primary goal being “maximal safe resection.” This means removing as much of the tumor as possible without causing significant neurological damage. While complete removal is sometimes achievable, the location and aggressive nature of ATRTs can make this challenging. Surgery also provides the tissue sample needed for a definitive diagnosis and genetic analysis.
Following surgery, chemotherapy is a fundamental component of treatment, often involving multiple powerful drugs. Chemotherapy aims to shrink any remaining tumor cells and kill cancer cells that may have spread. This often involves high-dose chemotherapy regimens, followed by a stem cell transplant to help the child recover from the intense treatment. This intensive approach is designed to combat the aggressive nature of ATRT.
Radiation therapy targets and eliminates any residual cancer cells after surgery and chemotherapy. Its application in ATRT treatment requires careful consideration, particularly for very young children (under three years old). Doctors must weigh the benefits of eradicating cancer cells against the potential long-term developmental effects that radiation can have on a developing brain. The extent of radiation depends on whether the tumor was localized or if it had spread.
Prognosis and Current Research
Historically, Atypical Teratoid Rhabdoid Tumor has been a difficult cancer to treat, with challenging outcomes. However, advancements in intensive therapies have led to improving survival rates for children with ATRT. Factors influencing a child’s prognosis include age at diagnosis, the extent of surgical removal, and whether the cancer had spread. Older children and those with localized tumors from which most can be removed tend to have better outcomes.
ATRT remains an area of active and focused research, offering hope for future treatment improvements. Clinical trials are continuously exploring novel therapeutic approaches beyond the standard multi-modal treatments. Researchers are investigating targeted therapies, which are designed to specifically attack the unique genetic weaknesses found within ATRT cancer cells. Immunotherapy is another promising avenue, aiming to harness the body’s own immune system to recognize and fight the tumor. These ongoing studies provide a forward-looking perspective, working towards more effective and less toxic treatments for children with ATRT.