Retinoblastoma

 

Retinoblastoma

Overview

Retinoblastoma is an eye 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 made up 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.

A rare form of eye cancer, retinoblastoma is the most common form of cancer affecting the eye in children. Retinoblastoma may occur in one or both eyes.

Symptoms

Because retinoblastoma mostly affects infants and small children, symptoms aren't common. Signs you may notice include:

·         A white color in the center circle of the eye (pupil) when light is shone in the eye, such as when someone takes a flash photograph of the child

·         Eyes that appear to be looking in different directions

·         Poor vision

·         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, discuss it with your doctor if you're planning to have children.

Causes

Retinoblastoma occurs when nerve cells in the retina develop genetic mutations. These mutations cause the cells 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.

For most instances of retinoblastoma, it's not clear what causes the genetic mutation that leads to cancer. However, it's possible for children to inherit a genetic mutation from their parents.

Retinoblastoma that is inherited

Gene mutations that increase the risk of retinoblastoma and other cancers can be passed from parents to children.

Hereditary 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 to pass the increased risk of retinoblastoma on to the children. If one parent carries a mutated gene, each child has a 50% 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. Hereditary retinoblastoma also tends to occur in both eyes, as opposed to just one eye.

Complications

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 may design a personalized follow-up appointment schedule for your child that includes frequent eye exams.

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, especially pineoblastoma, a type of brain tumor. For this reason, children with inherited retinoblastoma may have regular exams to screen for other cancers.

Prevention

Doctors aren't sure what causes most instances of retinoblastoma, so there's no proven way to prevent the disease.

Prevention for families with inherited retinoblastoma

If your child is diagnosed with retinoblastoma, your doctor may recommend genetic testing to determine whether the cancer was caused by an inherited gene mutation. Your doctor may recommend that you meet with a genetic counselor who can help you decide whether to undergo genetic testing.

Genetic testing enables families to know whether their children may have an increased risk of retinoblastoma, so medical care can be planned accordingly. For instance, eye exams may begin soon after birth or, in some situations, before a baby is born. That way, retinoblastoma may be diagnosed very early — when the tumor is small and a chance for a cure and preservation of vision is still possible.

Genetic testing can be used to determine whether:

·         Your child with retinoblastoma is at risk of other related cancers.

·         Your child with retinoblastoma may carry a gene mutation that can be passed to his or her future children.

·         Your other children are at risk of retinoblastoma and other related cancers.

·         You and your partner have the possibility of passing the genetic mutation on to future children.

Diagnosis

Tests and procedures used to diagnose retinoblastoma include:

·         Eye exam. Your eye doctor will conduct an eye exam to determine what's causing your child's signs and symptoms. For a more thorough exam, the doctor may recommend using anesthetics to keep your child still.

·         Imaging tests. Scans and other imaging tests can help your child's doctor determine whether retinoblastoma has grown to affect other structures around the eye. Imaging tests may include ultrasound and magnetic resonance imaging (MRI), among others.

Treatment

The best treatments for your child's retinoblastoma depend 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. The goal of treatment is to cure the cancer. When possible, doctors try to choose treatments that won't result in removal of the eye or a loss of vision.

Chemotherapy

Chemotherapy is a drug treatment that uses chemicals to kill cancer cells. In children with retinoblastoma, chemotherapy may help shrink a tumor so that another treatment, such as cryotherapy or laser therapy, may be used to treat the remaining cancer cells. This may improve the chances that your child won't need surgery to remove the eye.

Types of chemotherapy used to treat retinoblastoma include:

·         Chemotherapy that travels through the entire body. Chemotherapy drugs that are given through a blood vessel will travel throughout the body to kill cancer cells.

·         Chemotherapy injected near the tumor. A specialized type of chemotherapy, known as intra-arterial chemotherapy, delivers the medicine directly to the tumor through a tiny tube (catheter) in an artery supplying blood to the eye. The doctor might put a tiny balloon in the artery to keep the medicine close to the tumor.

·         Chemotherapy administered into the eye. Intravitreal chemotherapy involves injecting chemotherapy drugs directly into the eye.

Radiation therapy

Radiation therapy uses high-powered energy, such as X-rays and protons, to kill cancer cells. Types of radiation therapy used in treating retinoblastoma include:

·         Local radiation. During local radiation, also called plaque radiotherapy or brachytherapy, the treatment device is temporarily placed near the tumor.

Local radiation for retinoblastoma uses a small disk containing seeds 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 tissues outside the eye. This type of radiotherapy is typically used for tumors that don't respond to chemotherapy.

·         External beam radiation. External beam radiation delivers high-powered beams to the tumor from a large machine outside of the 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.

Laser therapy (transpupillary thermotherapy)

During laser therapy, a heat laser is used to directly destroy the tumor cells.

Cold treatment (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 in each cryotherapy session, causes the cancerous cells to die.

Eye removal surgery

When the cancer is too large to be treated by other methods, surgery to remove the eye may be used to treat retinoblastoma. In these situations, eye removal may help prevent the spread of cancer to other parts of the body. Eye removal 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 sometimes 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. Several weeks 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 eyelids. 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. Your child may need to wear special shatter-resistant glasses and sport goggles at all times to protect the remaining eye.

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.

Coping and support

When your child is diagnosed with cancer, it's common to feel a range of emotions — from shock and disbelief to guilt and anger. Everyone finds his or her own way of coping with stressful situations, but if you're feeling lost, you might try to:

·         Gather all the information you need. Find out enough about retinoblastoma to feel comfortable making decisions about your child's care. Talk with your child's health care team. Keep a list of questions to ask at the next appointment.

Visit your local library and ask for help searching for information. Consult the websites of the National Cancer Institute and the American Cancer Society for more information.

·         Organize a support network. Find friends and family who can help support you as a caregiver. Loved ones can accompany your child to doctor visits or sit by his or her bedside in the hospital when you can't be there.

When you're with your child, your friends and family can help out by spending time with your other children or helping around your house.

·         Take advantage of resources for kids with cancer. Seek out special resources for families of kids with cancer. Ask your clinic's social workers about what's available.

Support groups for parents and siblings put you in touch with people who understand what you're feeling. Your family may be eligible for summer camps, temporary housing and other support.

·         Maintain normalcy as much as possible. Small children can't understand what's happening to them as they undergo cancer treatment. To help your child cope, try to maintain a normal routine as much as possible.

Try to arrange appointments so that your child can have a set nap time each day. Have routine mealtimes. Allow time for play when your child feels up to it. If your child must spend time in the hospital, bring items from home that help him or her feel more comfortable.

Ask your health care team about other ways to comfort your child through his or her treatment. Some hospitals have recreation therapists or child-life workers who can give you more specific ways to help your child cope.

Preparing for your appointment

Start by making an appointment with your child's doctor or pediatrician if your child has any signs or symptoms that worry you. If an eye problem is suspected, you may be referred to a doctor who specializes in treating eye cancer (ocular oncologist).

Because appointments can be brief, and because there's often a lot of information to discuss, it's a good idea to be prepared. Here's some information to help you get ready, and what to expect from your child's doctor.

What you can do

·         Be aware of any pre-appointment restrictions. At the time you make the appointment, be sure to ask if there's anything you need to do in advance, such as restrict your child's diet.

·         Write down any symptoms your child is experiencing, including any that may seem unrelated to the reason for which you scheduled the appointment.

·         Write down key personal information, including any major stresses or recent changes in your child's life.

·         Make a list of all medications, vitamins or supplements your child is taking.

·         Take a family member or friend along. Sometimes it can be difficult to remember the information provided during an appointment. Someone who accompanies you may remember something that you missed or forgot.

·         Write down questions to ask your child's doctor.

Your time with your child's doctor is limited, so preparing a list of questions ahead of time can help you make the most of the time. List your questions from most important to least important in case time runs out. For retinoblastoma, some basic questions to ask your child's doctor include:

·         What kinds of tests does my child need?

·         What is the best course of action?

·         What are the alternatives to the primary approach that you're suggesting?

·         Should my child see a specialist? What will that cost, and will my insurance cover it?

In addition to the questions that you've prepared to ask your child's doctor, don't hesitate to ask other questions during your appointment.

What to expect from your child's doctor

Your child's doctor is likely to ask you a number of questions. Being ready to answer them may allow more time to cover other points. Your child's doctor may ask:

·         Has your child ever had cancer before?

·         Does your family have a history of cancer?

·         Does your child have any siblings? How old are they? Have they ever had an eye exam?

·         When did your child begin experiencing symptoms?

·         Have your child's symptoms been continuous or occasional?

·         How severe are your child's symptoms?

·         What, if anything, seems to improve your child's symptoms?

·         What, if anything, appears to worsen your child's symptoms?