Optic Nerve Glioma (Optic Pathway Glioma)

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 may occur 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 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.

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 nerve glioma symptoms are:

• Vision problems
• Proptosis (eyeball protrusion), which occurs when the tumor is pushing the eye outward from the socket
• Hormonal problems, including abnormal growth and weight gain or loss

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 could have been done or avoided that would have prevented the tumor from developing.

Optic nerve gliomas are more common in kids who have a genetic condition called neurofibromatosis 1 (NF1). NF1 can cause tumors to form, and optic nerve gliomas occur in about 15 percent 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.

The first step in treating your child is forming an accurate and complete diagnosis. Optic nerve 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
• Vision testing
• NF1 — If a child has neurofibromatosis 1, vision is followed closely
• Magnetic resonance imaging (MRI)

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, we will meet with you and your family to discuss the results and outline possible treatment options.

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 nerve 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 their 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 nerve gliomas. But if your child's tumor is resistant to chemotherapy, radiation may also be an option.

Children with optic nerve gliomas are treated at Dana-Farber/Boston Children's Cancer and Blood Disorders Center 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.

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 nerve 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 a progressive or recurrent tumor, they may be eligible for a number of experimental therapies available through these groups or from one of our independent clinical investigators.