• Optic Nerve (Pathway) Glioma in Children

    An optic nerve glioma (also called an optic pathway glioma) is a slow-growing brain tumor that arises in or around the optic nerve, which connects the eye to the brain. As the tumor progresses, it presses on the optic nerve, causing a child’s vision to worsen. Blindness can occur but only in about 5 percent of cases. While these are serious tumors, they have a high cure rate.

    Nearly 75 percent of optic nerve gliomas, which may affect one or both eyes, occur in children younger than 10, with most younger than 5 years of age at the time of diagnosis. Optic nerve gliomas account for 5 percent of all childhood brain tumors. Because the optic system is located near the hormone center of the brain, these tumors can affect the body's endocrine functions, such as hormone production, salt and water balance, appetite, and sleep.

    Optic Nerve Glioma Treatment at Dana-Farber/Boston Children's

    Children with optic nerve gliomas are treated at Dana-Farber/Boston Children's through our Glioma Program – one of the world’s largest pediatric glioma treatment programs. Our internationally-recognized pediatric brain tumor specialists have extensive expertise in treating all types of gliomas, including optic nerve gliomas. Our glioma specialists – a team of neuro-oncologists, surgeons, pathologists, and radiation oncologists – focus solely on the care of children diagnosed with gliomas. Our program also offers families the chance to have their child's tumor molecularly profiled (as long as a biopsy can be taken), which may help identify opportunities for targeted treatment (precision medicine).

    How are optic nerve gliomas classified?

    Optic nerve gliomas are a type of glioma, slow growing tumors that arise from glial cells in your child's brain. Glial cells are responsible for supporting and nourishing the neurons in the brain.

    Gliomas are divided into four grades, depending on the tumor cells' appearance under microscope; the higher a tumor's grade number, the more severe it is. Grades 1 and 2 are considered low-grade gliomas and account for about two-thirds of all pediatric tumors. Grades 3 and 4 are considered high-grade gliomas.

    What are the symptoms and causes of optic nerve gliomas?

    Brain tumors can cause a variety of symptoms in children based on their age and the location of the tumor. Keep in mind that the symptoms of an optic nerve glioma may resemble other more common conditions or medical problems, such as needing glasses to correct poor vision. It is important to consult your child's physician for a diagnosis.

    The most common optic pathway glioma symptoms are:

    • Vision problems such as squinting, difficulty reading, or turning to see things out of the corner of the eye.
    • Proptosis (eyeball protrusion), which occurs when the tumor has grown to the extent that it is pushing the eye outward from the socket. Usually an eye with proptosis has very little vision.
    • Hormonal problems, including abnormal growth, weight gain or loss, endocrine dysfunction (such as having to urinate frequently), or early puberty.

    As a parent, you undoubtedly want to know what may have caused your child’s tumor. In most cases, the cause of optic nerve gliomas is not known. 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.

    Optic pathway gliomas are more common in kids who have a genetic condition called neurofibromatosis 1. NF1 can cause tumors to form, and optic pathway gliomas occur in about 15% of children with this disease. In these cases, about two-thirds of the time, the tumor stops growing and disappears forever on its own without treatment.

    How are optic nerve gliomas diagnosed?

    The first step in treating your child is forming an accurate and complete diagnosis. Optic pathway gliomas can move throughout different parts of the brain and spine. There is a blood brain barrier that serves to keep infections out and also ends up keeping tumors in. It is very rare, below 5 percent of the time, for the glioma to move beyond the brain and spine.

    Optic nerve gliomas are typically diagnosed using a combination of imaging and vision testing. Your child's doctor will likely order tests including:

    • A complete physical examination
    • Computed tomography (CT or CAT) scan – a diagnostic imaging procedure that uses a combination of X-rays and computer technology to produce cross-sectional images (often called slices), both horizontally and vertically, of the body. CT scans are more detailed than general X-rays. For optic pathway glioma, a CT scan of the brain is usually done.
    • Vision testing: An ophthalmologist (vision specialist) examines your child and conducts comprehensive testing of his eyesight. This information is used in conjunction with MRI findings to make an accurate diagnosis.
    • NF1: If a child has neurofibromatosis 1, vision is followed closely. If it starts to worsen, a doctor may order a magnetic resonance imaging (MRI) scan to confirm the diagnosis.
    • Magnetic resonance imaging (MRI), a diagnostic procedure that produces detailed images of the structures within the brain and spine. An MRI uses a combination of large magnets, radiofrequencies, and a computer to analyze organs and structures within the body.

    There may be other diagnostic tests that your doctor will discuss with you depending on your child's individual situation. After we complete all necessary tests, our experts meet to review and discuss what they have learned about your child's condition. Then we will meet with you and your family to discuss the results and outline the best possible treatment options.

    What are the treatments for optic nerve gliomas?

    Your child's physician will determine a specific course of treatment based on several factors, including:

    • Your child's age, overall health, and medical history
    • The type, location, and size of the tumor
    • The extent of the disease
    • Your child's tolerance for specific medications, procedures, or therapies
    • How your child's doctors expects the disease to behave

    Most often, optic pathway glioma is treated with chemotherapy – a drug treatment that works by interfering with the cancer cell's ability to grow or reproduce – to shrink the tumor and stabilize or improve vision.

    If the tumor has affected your child's endocrine system (a network of gland controlling hormones), he or she may also need hormone replacement therapy, possibly for the rest of his or her life.

    While surgery is not commonly performed for this type of brain tumor, it can sometimes relieve symptoms and/or improve vision. Our expert pediatric neural surgeons have a wealth of experience in determining whether surgery is the right option.

    Most of the time, chemotherapy can stop the progression of optic pathway gliomas. But if your child's tumor is resistant to chemotherapy, radiation may also be an option. Radiation therapy uses high-energy rays (radiation) from a specialized machine to damage or kill cancer cells and shrink tumors.

    Our cancer treatment center has specialists who deliver complementary or alternative medicines. These treatments, which may help control pain and side effects of therapy, include:

    • Acupuncture/acupressure
    • Therapeutic touch
    • Massage
    • Herbal supplements
    • Dietary recommendations

    Talk to your child's physician about whether complementary or alternative medicine might be a good option for your child.

    What is the latest research on optic nerve gliomas?

    Scientists at both Dana-Farber Cancer Institute and Boston Children’s Hospital are conducting numerous research studies to better clinicians' understanding and treatment of brain tumors and gliomas. Our research program offers patients unparalleled access to clinical trials in which children can receive the newest treatments. We are consistently one of the most well funded pediatric brain tumor centers in the United States, and we pride ourselves on rapidly bringing our discoveries to the aid of our patients.

    Dana-Farber/Boston Children's houses the Pediatric Low-Grade Astrocytoma (PLGA) Program, the world's only multidisciplinary clinical and research program dedicated to pediatric low-grade gliomas. Established in 2007 with support from the PLGA Foundation, the program takes a multifaceted approach to finding more effective, less toxic treatments and a cure for children battling brain tumors, and has become the standard bearer for the research and care of pediatric brain tumors. Our pediatric neuro-oncologists, including Pratiti (Mimi) Bandopadhayay, MBBS, PhD, are actively contributing to these efforts. Our program has contributed to international research efforts that have identified genomic drivers that contribute to the growth of pilocytic astrocytoma. Specifically, we have identified genes that are commonly mutated in pilocytic astrocytoma. These findings are guiding clinical trials examining the activity of new drugs specifically for children with optic pathway glioma.

    Clinical Trials

    Clinical trials, or research studies evaluating new treatment approaches, are a major offering at Dana-Farber/Boston Children’s. Clinical trials are very important for children with hard-to-treat or relapsed conditions.

    It’s possible that your child will be eligible to participate in one of the Glioma Program’s current brain tumor clinical trials. In addition to launching our own clinical trials, we also offer trials available through collaborative groups such as the Children's Oncology Group (COG) and the Pacific Pediatric Neuro-Oncology Consortium (PNOC). We are also the New England Phase I Center of the Children's Oncology Group. If your child has progressive or recurrent tumor, she may be eligible for a number of experimental therapies available through these groups or from one of our independent clinical investigators.

    What is the long-term outlook for optic nerve gliomas?

    The survival rate for optic pathway gliomas is near 90 percent. Older children and those with neurofibromatosis 1 have better outcomes.

    If death does occur, it’s not from the tumor itself, but from the damage on the hypothalamus from the pressure applied by the tumor. A damaged hypothalamus could result in a loss of control of salt levels. High salt levels can cause death.

    The odds of complete blindness from these tumors is less than 5 percent, but children may experience a smaller field of vision as a result of the tumor, which means they do not have peripheral vision. The best predictor of how much vision your child will have is how good his or her vision was when he was diagnosed. Generally, better original vision correlates with better vision following treatment. Additionally, children who are relatively young at diagnosis tend to preserve their vision better than older kids.

    In many cases, any damage to your child's vision may be reversed. If the nerve is squeezed and the squeezing stops, it will regain its former shape and start to work again like a sponge. But if the squeezing goes on for longer than around six months, there’s less of a chance that the nerve will recover and there is a high risk for blindness.

    Optic nerve glioma recurrence may take place many years after initial treatment. A glioma usually recurs in the same place as the original tumor but can also occur in other parts of the brain or spinal cord. Local radiation therapy is the usual treatment. Chemotherapy and radiation therapy are options for patients who have only been treated surgically.

    What kind of long-term care will my child need for optic nerve glioma?

    Because these tumors can recur or spread and because cancer survivors face unique life-long health challenges, we will generally see your child for a follow-up MRI every three months for a year, then every six months for another year, and then yearly after that. Throughout, your child will have a vision exam every three months. Follow up care is crucial and is overseen by our brain tumor survivorship clinic.

    These brain tumors do not directly affect a child’s intelligence. However, since much of learning is through seeing, such as reading a book, a child may have challenges learning in the classroom. We will work with your child’s teachers to make sure the classroom can accommodate his learning needs.

    Patients may benefit from the Low Vision Service at Boston Children's Hospital to help find the best visual aids for your child. Additionally, there is the Vision Therapy Service which may help to improve vision through therapy.

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