Diseases & Conditions

Retinoblastoma

Retinoblastoma is a cancer that begins in the retina — the sensitive lining on the inside of your eye. Retinoblastoma most commonly affects young children, but can rarely occur in adults.

Your retina is comprised of nerve tissue that senses light as it comes through the front of your eye. The retina sends signals through your optic nerve to your brain, where these signals are interpreted as images.

Although a rare form of cancer, retinoblastoma is the most common cancer affecting the eye in children. The National Cancer Institute estimates about 300 children are diagnosed with retinoblastoma each year in the United States.

Signs of retinoblastoma include:

• A white color in the center circle of the eye (pupil) when light is shined in the eye, such as when taking a flash photograph
• Eyes that appear to be looking in different directions
• Eye redness
• Eye swelling

When to see a doctor
Make an appointment with your child's doctor if you notice any changes to your child's eyes that concern you. Retinoblastoma is a rare cancer, so your child's doctor may explore other more common eye conditions first.

If you have a family history of retinoblastoma, ask your pediatrician when your child should begin regular eye exams to screen for retinoblastoma.

Retinoblastoma occurs when nerve cells in the retina develop genetic mutations that cause them to continue growing and multiplying when healthy cells would die. This accumulating mass of cells forms a tumor. Retinoblastoma cells can invade further into the eye and nearby structures. Retinoblastoma can also spread (metastasize) to other areas of the body, including the brain and spine.

In the majority of cases, it's not clear what causes the genetic mutations that lead to retinoblastoma. However, it's possible for children to inherit a genetic mutation from their parents.

Inherited retinoblastoma
Gene mutations that increase the risk of retinoblastoma and other cancers can be passed from parents to children. Inherited retinoblastoma is passed from parents to children in an autosomal dominant pattern, which means only one parent needs a single copy of the mutated gene in order to pass the increased risk of retinoblastoma on to the children. If one parent carries a mutated gene, each child has a 50 percent chance of inheriting that gene.

Although a genetic mutation increases a child's risk of retinoblastoma, it doesn't mean that cancer is inevitable.

Children with the inherited form of retinoblastoma tend to develop the disease at an earlier age. Inherited retinoblastoma also tends to occur in both eyes, as opposed to just one eye.

Long-term side effects of cancer treatment
Treatments for retinoblastoma may cause long-lasting side effects in young children. What long-term side effects your child is at risk of will depend on what treatments are used.

Ask your child's doctor what long-term complications could occur in your child and what signs and symptoms to watch for. In some cases, doctors can predict what health problems your child may be at risk of in the future. In other cases, treatments are relatively new and doctors don't yet know what the long-term risks will be.

Recurrent retinoblastoma
Children treated for retinoblastoma have a risk of cancer returning in and around the treated eye. For this reason, your child's doctor will schedule follow-up exams to check for recurrent retinoblastoma. The doctor will design a personalized follow-up exam schedule for your child. In most cases, this will likely involve eye exams every few months for the first few years after retinoblastoma treatment ends.

Additionally, children with the inherited form of retinoblastoma have an increased risk of developing other types of cancers in any part of the body in the years after treatment. For this reason, children with inherited retinoblastoma require long-term follow-up with a cancer doctor (oncologist).

What treatments are best for your child's retinoblastoma depends on the size and location of the tumor, whether cancer has spread to areas other than the eye, your child's overall health and your own preferences. When possible, your child's doctor will work to preserve your child's vision.

Chemotherapy
Chemotherapy is a drug treatment that uses chemicals to kill cancer cells. Chemotherapy can be taken in pill form, or it can be delivered through a vein. Chemotherapy drugs travel throughout the body to kill cancer cells.

In children with retinoblastoma, chemotherapy may help shrink a tumor so another treatment, such as brachytherapy, cryotherapy, thermotherapy or laser therapy, may be used to treat the remaining cancer cells. This may improve the chances that the child won't need surgery.

Chemotherapy may also be used to treat retinoblastoma that has spread to tissues outside the eyeball or to other areas of the body.

Radiation therapy
Radiation therapy uses high-energy beams, such as X-rays and others, to kill cancer cells. Two types of radiation therapy used in treating retinoblastoma include:

• Internal radiation (brachytherapy). During internal radiation, the treatment is placed in or near the tumor. Internal radiation for retinoblastoma uses a small disc made of radioactive material. The disk is stitched in place and left for a few days while it slowly gives off radiation to the tumor. Placing radiation near the tumor reduces the chance that treatment will affect healthy eye tissue. It also allows doctors to use higher doses of radiation.
• External beam radiation. External beam radiation delivers high-powered beams to the tumor from a large machine outside of your child's body. As your child lies on a table, the machine moves around your child, delivering the radiation. External beam radiation can cause side effects when radiation beams reach the delicate areas around the eye, such as the brain. For this reason, external beam radiation is typically reserved for children with advanced retinoblastoma and those for whom other treatments haven't worked.

Laser therapy (laser photocoagulation)
During laser therapy, a laser is used to destroy blood vessels that supply oxygen and nutrients to the tumor. Without a source for fuel, cancer cells may die.

Cold treatments (cryotherapy)
Cryotherapy uses extreme cold to kill cancer cells. During cryotherapy, a very cold substance, such as liquid nitrogen, is placed in or near the cancer cells. Once the cells freeze, the cold substance is removed and the cells thaw. This process of freezing and thawing, repeated a few times per cryotherapy session, causes the cancerous cells to die.

Heat treatments (hyperthermia)
Thermotherapy uses extreme heat to kill cancer cells. During thermotherapy, heat is directed at the cancer cells using ultrasound, microwaves or lasers.

Surgery
Surgery for retinoblastoma includes:

• Surgery to remove the affected eye (enucleation). During surgery to remove the eye, surgeons disconnect the muscles and tissue around the eye and remove the eyeball. A portion of the optic nerve, which extends from the back of the eye into the brain, also is removed.
• Surgery to place an eye implant. Immediately after the eyeball is removed, the surgeon places a special ball — made of plastic or other materials — in the eye socket. The muscles that control eye movement are attached to the implant. After your child heals, the eye muscles will adapt to the implanted eyeball, so it may move just as the natural eye did. However, the implanted eyeball cannot see.
• Fitting an artificial eye. A few months after surgery, a custom-made artificial eye can be placed over the eye implant. The artificial eye can be made to match your child's healthy eye. The artificial eye sits behind the eye lids and clips onto the eye implant. As your child's eye muscles move the eye implant, it will appear that your child is moving the artificial eye.

Side effects of surgery include infection and bleeding. Removing an eye will affect your child's vision, though most children will adapt to the loss of an eye over time.

Clinical trials
Clinical trials are studies to test new treatments and new ways of using existing treatments. While clinical trials give your child a chance to try the latest in retinoblastoma treatments, they can't guarantee a cure. Ask your child's doctor whether your child is eligible to participate in clinical trials. Your child's doctor can discuss the benefits and risks of enrolling in a clinical trial.