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What is retinoblastoma?

Cancer starts when cells in the body begin to grow out of control. Cells in nearly any part of the body can become cancer. 

Retinoblastoma is a type of cancer that starts in the retina, which is in the back part of the eye. This cancer is most often found in young children. 

To understand retinoblastoma, it helps to know a little about the eye. The front of the eye has a clear lens with an iris (the colored part of the eye that acts like a camera shutter). In the middle of the iris is a small hole called the pupil, through which light enters the eye.

The light going into the eye hits the retina, which is the inner layer of cells in the back of the eye. It is made up of special light-sensing cells. These cells are connected to the brain by the optic nerve, which runs out the back of the eyeball. The pattern of light (image) that reaches the retina is sent through the optic nerve to the brain, allowing us to see.

Retinoblastoma starts in the cells in the retina. This cancer almost always starts because of a change (mutation) inside the cells in a gene called RB1. The RB1 gene change leads to the cells growing out of control. 

Most often, retinoblastoma occurs in only one eye. But a small number of children will have tumors in both eye (called bilateral retinoblastoma).

Different types of retinoblastoma

There are 2 main forms of retinoblastoma, based on which cells have the RB1 gene change:

In the heritable (hereditary) form, all of the cells in the child’s body have the RB1 gene change. Children with this form are much more likely to develop tumors in both eyes, and are also at higher risk for some other types of cancer.

In the non-heritable (non-hereditary) form, the changes in the RB1 gene are only in the cancer cells. These children develop tumors in only one eye, and they are not at higher risk for other types of cancer.

Questions to ask the doctor

• How sure are you that my child has retinoblastoma?
• Is there a chance it’s not retinoblastoma?
• Would you please write down the kind of tumor you think my child has?
• What will happen next?

How does the doctor know my child has retinoblastoma?

Retinoblastoma is often found when it causes certain signs or symptoms. 

White pupil reflex: This is the most common early sign of retinoblastoma. When you shine a light in the eye, the pupil (the dark spot in the center of the eye) should look red because of the blood vessels in the back of the eye. But in an eye with retinoblastoma, the pupil often looks white or pink instead. This might be noticed after a flash photo is taken, or it might be noted by the child’s doctor during a routine eye exam.

Lazy eye: Sometimes the eyes don’t seem to look in the same direction, a condition often called lazy eye. There are many possible causes of this in children. Lazy eye is more likely to be caused by a mild weakness of the muscles that control the eyes, but it can also be caused by retinoblastoma.

Other symptoms might include:

• Vision problems
• Eye pain
• Redness in the white part of the eye
• Bleeding in the front part of the eye
• Bulging of the eye
• A pupil that doesn’t get smaller in response to bright light
• A different color in each iris

Many of these are more likely to be caused by something else. Still, if your child has signs or symptoms that could be from retinoblastoma, the doctor will want to get a medical history to find out more about the symptoms, and will do a physical exam.

Your child’s doctor might want your child to be seen by an ophthalmologist (a doctor of eye diseases), who will look at the eye more closely. This doctor will use special lights and magnifying lenses to look inside the eye. Usually, the child needs to be under general anesthesia (asleep) during the exam so that the doctor can take a careful look.

Other tests might be needed as well.

Tests that may be done

Ultrasound of the eye: This is often the first test done if the doctor thinks your child has an eye tumor. The test uses sound waves to make pictures of organs inside the body, such as the eye. This test doesn't hurt and does not use radiation, but the child may need to be given medicine to help keep them calm or even asleep so the doctor can get a good look at the eye and the nearby structures.

MRI scan: This test uses radio waves and strong magnets to make detailed pictures of the inside of the body. Most children will have an MRI if retinoblastoma has been found. This test doesn’t use radiation, but the child may need to be given medicine to help keep them calm or even asleep during the test.

CT or CAT scan: This test uses x-rays to make detailed pictures of the inside of the body. MRI is often done instead of a CT scan in children with retinoblastoma, because it doesn’t use radiation. But a CT scan might be done if it’s not clear that the child has retinoblastoma.
Bone scan: Most children with retinoblastoma don’t need this test. But it can help show if the has spread to the skull or other bones. 

Genetic testing: Sometimes a blood test might be done to look for the RB1 gene change in cells outside the eye. This can help tell if a child has the heritable form of retinoblastoma, which can affect the type of follow-up a child needs after treatment. It might also affect if other children in the family need to be tested.

Lumbar puncture (spinal tap): Retinoblastoma can sometimes spread to the surface of the brain. This test might be done to look for cancer cells in the fluid that surrounds the brain (the cerebrospinal fluid or CSF). The child is given medicine before this test so they will be asleep. The doctor then puts a small, hollow needle between the bones of the spine to withdraw a small amount of CSF, which is sent to the lab for testing. Most children with retinoblastoma don’t need this test.

Bone marrow biopsy: This test might be done to see if the cancer has spread to the bone marrow, which is the soft, inner part of certain bones. The test is usually not needed unless the cancer has grown outside the eye and doctors think it might have spread to the bone marrow. The child is first given medicine so they will be asleep during the test. The bone marrow samples are usually taken from the back of the hip bone using long, hollow needles. The samples are then sent to a lab to be tested for cancer cells.

Questions to ask the doctor

• Who will do these tests?
• Where will they be done?
• Who can explain them to us?
• How and when will we get the results?
• Who will explain the results to us?
• What do we need to do next?

How serious is my child’s cancer?

If your child has retinoblastoma, the doctor will want to find out some key pieces of information to help decide how to treat it. The most important of these are:

• The stage of the cancer, which is based on how much cancer is within the eye, and if the cancer has spread outside of the eye
• The chance of saving sight in the eye (and saving the eye itself) 
• Whether the cancer is in just one eye or in both eyes

Staging systems describe how serious the cancer is and help doctors determine which treatment to use. They divide retinoblastomas into groups, based on the chance of saving the eye.

The staging of retinoblastoma can be confusing. Be sure to ask your child’s doctor if you have any questions about the stage of your child’s cancer.

Questions to ask the doctor

• Where exactly is the cancer?
• How big is the cancer?
• Can all of the cancer be removed?
• Can the vision in the eye (and the eye itself) be saved?
• Has the cancer spread anywhere else?
• What is the stage of the cancer?
• How do these things affect our treatment options?
• What will happen next?

What kind of treatment will my child need?

The main types of treatment for retinoblastoma are:

• Surgery
• Radiation treatment
• Laser treatment
• Cryotherapy (freezing)
• Chemotherapy (chemo)

Surgery

For most children with retinoblastoma, surgery is not the first treatment. But if the tumor has already grown large enough so that the sight in the eye can’t be saved, or if other treatments have not worked, surgery to remove the entire eye (known as enucleation) might be the best treatment option. 

During the surgery, an implant is usually put in to take the place of the eyeball. The implant is attached to the muscles that moved the eye, so it should move the same way as the eye would have. A few weeks later, a specialist known as an ocularist will create an artificial eye for your child. This is a thin shell, like a very big contact lens, that will match the size and color of the remaining eye. It fits over the implant and under the eyelids. Once it’s in place, it will be very hard to tell it apart from the real eye.

Side effects of surgery

Any type of surgery can have risks and side effects, such as bleeding or infections. Ask your child’s doctor or nurse what to expect. If your child has any problems, let them know. Doctors and nurses who treat children with retinoblastoma should be able to help you with any problems that come up.

The most obvious side effect is the loss of sight in that eye, although most often it has already been lost because of the cancer.

Removing the eye also can affect the future growth of bone and other structures around the eye socket, which can make the area look somewhat sunken. Using an implant can sometimes lessen this effect. (Some other types of treatment might also cause this side effect.)

Radiation treatment

Radiation uses high-energy rays (like x-rays) to kill cancer cells. Two types of radiation treatments can be used to treat children with retinoblastoma.

Brachytherapy (plaque radiotherapy)

This treatment can be used for some small tumors. A small amount of a radioactive substance is put into a small gold or lead carrier (known as a plaque), which is shaped like a very small bottle cap. During a short operation, the plaque is sewn in place on the outside of the eyeball where the tumor is, using tiny stitches. It is left there for several days, and then removed during a second operation. The radiation travels a very short distance, so most of it will be focused only on the tumor. The child typically stays in the hospital while the plaque is in place.

Side effects of brachytherapy

The main concern with this treatment is damage to the retina or optic nerve, which can affect sight many months later. But advances in treatment may make this problem less likely.

External radiation

This treatment focuses radiation beams from a source outside the body on the cancer. This was once a common treatment for retinoblastoma. But because of the side effects it can cause, it is now most often used only for cancers that aren’t well-controlled with other treatments.

Radiation is usually given 5 days a week for several weeks. Each treatment is much like getting an x-ray, but the dose of radiation is stronger. For each session, your child will lie on a special table while a machine delivers the radiation from precise angles.

The actual treatment each day lasts only a few minutes, but the setup time – getting your child into place for treatment – takes longer. The child’s head is positioned in a custom-fitted mold that is similar to a cast used to treat broken bones. The treatment isn’t painful, but young children may be given medicine to make them sleep so they will stay still during treatment.

Side effects of external radiation

Short-term problems might include effects on nearby skin areas, which can range from mild sunburn-like changes and hair loss to more severe skin reactions. These side effects tend to go away after a short while.
Radiation can also damage other nearby structures. This might lead to cataracts (clouding of the lens of the eye) and damage to the retina or optic nerve, which could reduce vision. Radiation can also slow the growth of bones and other structures near the eye, which can affect the way the area around the eye looks.

Radiation can also raise the risk of getting a second cancer in the area. This is very important in children with the heritable form of retinoblastoma, who already have an increased risk of other types of cancer.

Newer forms of radiation treatment can target the tumor more precisely, which may make some of these side effects less likely than in the past.

Laser treatment

Lasers are very focused beams of light that can be used to heat and destroy tumors. Two main types of laser treatment can be used to treat small retinoblastoma tumors.

Laser photocoagulation

In this type of treatment, a laser beam is aimed through the pupil and focused on the blood vessels that surround and supply the tumor. The laser destroys them by heating them. This treatment is only for smaller tumors toward the back of the eye.

Your child will be given medicine to make them sleep during treatment. The treatment is usually given 2 or 3 times, with about a month in between each one.

Side effects of laser photocoagulation

Laser therapy can sometimes damage the retina. This can lead to blind spots or might cause the retina to detach from the back of the eyeball, which can affect sight.

Transpupillary thermal therapy (TTT)

This treatment is also just called thermotherapy. It uses a different type of laser that is aimed right at the tumor to heat and kill the tumor cells. The laser isn’t quite as hot as the one used in photocoagulation, so some of the blood vessels on the retina may be spared.

This treatment can be used alone for very small tumors. For larger tumors, it can be used along with chemo or with radiation. Heat seems to help these other treatments work better.

Your child will be given medicine to make them sleep during treatment. The treatment is usually given 3 times, with about a month in between each one.

Side effects of TTT

This treatment can sometimes cause part of the iris (the colored part of the eye) to shrink. Other effects might include clouding of part of the eye lens or damage to the retina, which might affect vision.

Cryotherapy (freezing)

For this treatment, the doctor puts a small, very cold metal probe on the eye to kill the retinoblastoma cells by freezing them. This can only be used for small tumors toward the front of the eye.

Your child will be given medicine to make them sleep during treatment. The treatment is usually given 2 or 3 times, with about a month in between each one.

Possible side effects

This treatment can cause the eye and eyelid to swell for a few days. It might also damage the retina, which can lead to blind spots or cause the retina to detach from the back of the eyeball, which can affect sight.

Chemo

Chemotherapy (chemo) is the use of drugs to treat cancer. It might be used:

• As the first treatment, to shrink the tumor and help other treatments work better
• After other treatments, to lower the chance of the cancer coming back
• If the cancer has spread to other parts of the body

Chemo can be given in different ways to treat retinoblastoma.

Systemic chemo

Chemo drugs can be injected into a vein (IV) or given by mouth. These drugs enter the bloodstream and reach throughout the body. Most often, 2 or 3 chemo drugs are given at the same time.

This type of chemo is given in cycles, with each treatment followed by a rest period to give the body time to recover. Each chemo cycle lasts for a few weeks, and the total length of treatment is often several months.

Intra-arterial chemo

Chemo can be injected right into the main artery that supplies blood to the eye (the ophthalmic artery). For this treatment, the child is given medicine to make them sleep. A very thin catheter (a long, flexible tube) is put into a large artery on the inner thigh and slowly threaded through the blood vessels all the way up into the ophthalmic artery. The chemo is then infused into the artery. This may be repeated every few weeks, depending on how much the tumor shrinks.

Because the chemo is put right into the artery feeding the eye, doctors can use much smaller doses of chemo drugs, so there are fewer side effects.

Intravitreal chemo

In this approach, a tiny needle is used to inject a chemo drug right into the vitreous humor, which is the jelly-like substance inside the eye. This is sometimes used (along with other types of chemo) to treat tumors that are widespread within the eye and haven’t been helped by other treatments. 

Side effects of chemo

The side effects of chemo depend on how it’s given and the types and doses of drugs used.

Systemic chemo can make your child feel very tired, sick to their stomach, or cause their hair to fall out. It can also make them more likely to get infections, and it might also cause other problems. These tend to go away after treatment ends.

Intra-arterial chemo side effects tend to be limited to the eye area. They might include swelling around the eye, bleeding inside the eye, a drooped eyelid, and loss of eyelashes. It might also cause other problems.

Intravitreal chemo might damage the retina slightly, which might affect vision.

There are ways to treat most chemo side effects. If your child has side effects, talk to the cancer care team so they can help.

Clinical trials

Clinical trials are research studies that test new drugs or other treatments in people. They compare standard treatments with others that may be better.

If you would like to learn more about clinical trials that might be right for your child, start by asking the doctor if your child’s clinic or hospital conducts clinical trials. See Clinical Trials to learn more.

Clinical trials are one way to get the newest treatments. They are the best way for doctors to find better ways to treat cancer. But they might not be right for everyone. If your child’s doctor talks to you about a clinical trial, it’s up to you whether to take part.

What about other treatments that I hear about?

When your child has retinoblastoma, you might hear about other ways to treat it or treat symptoms from it. These may not always be standard medical treatments. These treatments may be vitamins, herbs, diets, and other things. You may be curious about these treatments.

Some of them might help, but many have not been tested. Some have been shown not to help. A few have even been found to be harmful. Talk to your doctor about anything you’re thinking about using, whether it’s a vitamin, a diet, or anything else.

Questions to ask the doctor

• Do we need any other tests before we can decide on treatment?
• What treatment do you think is best for my child?
• What’s the goal of this treatment? How likely is it to cure the cancer?
• Will treatment include surgery? If so, who will do the surgery?
• Will my child need other types of treatment, too?
• What will these treatments be like?
• What’s the goal of these treatments?
• What side effects could my child have from these treatments?
• What can we do about side effects that my child might have?
• Is there a clinical trial that might be right for my child?
• What about vitamins or diets that friends tell me about? How will we know if they are safe?
• How soon do we need to start treatment?
• What should we do to be ready for treatment?
• Is there anything we can do to help the treatment work better?
• What’s the next step?

What will happen after treatment?

You’ll be glad when treatment is over. But it’s hard not to worry about the cancer coming back. Even if it never comes back, you might still worry about it. For years after treatment ends, your child will still need to see the doctor. At first, these visits may be every few months. Then, the longer your child is cancer-free, the less often the visits are needed.

Be sure your child goes to all of these follow-up visits. Your doctors will ask about symptoms, do physical exams, and may have tests done to see if the tumor has come back. They may also test to see if the cancer or its treatment has caused any long-term problems. If needed, they will help you and your child learn to deal with the changes.