Retinoblastoma

Retinoblastoma

Overview

Retinoblastoma is a kind of eye cancer that starts as a growth of cells in the retina. The retina is the light-sensitive lining on the inside of the eye.

The retina is made up of nerve tissue that senses light as it comes in through the front of the eye. The light causes the retina to send signals to the brain. The brain interprets the signals as images.

Retinoblastoma happens most often in young children. It's usually diagnosed before age 2. It most often affects one eye. Sometimes it happens in both eyes.

There are several treatments for retinoblastoma. For most children, treatment doesn't require removing the eye to get rid of the cancer. The outlook for children diagnosed with retinoblastoma is quite good.

Types of retinoblastoma

There are three types of retinoblastoma:

Unilateral: This means “one-sided,” so it affects one eye only.

Bilateral: This means “two-sided,” so it affects both eyes.

Trilateral: This means you have cancer in three places. Each eye reflects one of those places. The third place is in the pineal gland inside your brain. (Cancer affecting that gland is called pineoblastoma.)

About 60% of retinoblastoma cases are one-sided. Bilateral and trilateral cases make up the other 40%.

Symptoms

Because the condition is typically diagnosed before age 3, children often can’t describe their symptoms or what they’re experiencing. Instead, the symptoms are visible changes in eye appearance or differences in how your child behaves.

Leukocoria

The earliest and most common symptom of retinoblastoma is the pupil of your eye appearing white (leukocoria) or pale-colored in certain settings, especially seen in photos taken in dim places that also use a flash for illumination. It can happen in one or both eyes.

Other symptoms of retinoblastoma

While retinoblastoma commonly happens in children before they can talk, there are also other signs and symptoms that can signal its development, including:

Eyes that have trouble following movement or don’t follow it at all.

Misaligned eyes (strabismus).

Pain (it may cause your child to cry more or be fussier than usual, or they might have trouble sleeping or feeding).

Enlarged eye (buphthalmos).

Bulging eye (proptosis).

Blood in the front chamber of your eye (hyphema).

Infection, swelling or inflammation of your eye or surrounding tissue (orbital cellulitis).

Causes

Retinoblastoma is a type of cancer where retinal cells malfunction and start to multiply uncontrollably. As they do, they can form tumors and damage surrounding tissues. If they keep growing unchecked, eventually, those malfunctioning cells spread (metastasize) beyond the original tumor, and cancer appears in other places in your body.

The malfunction that causes healthy cells to turn into retinoblastoma starts in your DNA.

Your cells use DNA like a cookbook. You inherit DNA from both of your biological parents, so it’s like they each give you part of their cookbook, so you can make a full cookbook of your own.

But sometimes, you can have an error in your DNA. Your cells only know how to follow the recipes in the book exactly, so a DNA error means your cells only know how to make the recipe incorrectly. That can cause those cells to grow and multiply uncontrollably.

Experts recommend genetic testing and counseling for children with retinoblastoma regardless of whether or not it was inherited. They also recommend testing for biological siblings and other family members.

The mutation that causes retinoblastoma affects RB1, a tumor suppressor gene. Tumor suppressor genes are responsible for normal development of the tissues (retina). They act like brakes and control cell reproduction and growth processes. A mutation in RB1 means your retinal cells can grow uncontrolled into a tumor. Retinoblastoma can also happen with “deletion” of chromosome 13p, which is the location of the RB1 gene.

In rare instances, people can have a benign retinal growth called a retinoma. These are like precursors to retinoblastoma, but they stop growing for some reason. Later in life, a retinoma may start growing again and turn into retinoblastoma.

There are two main ways that DNA errors that cause retinoblastoma can happen:

Sporadic: This is when an error happens while your cells copy a parent’s DNA. It’s like accidentally introducing a typo while hand-copying a recipe. The recipe you copied from was sound, but the new error means your recipe is now incorrect. Sporadic cases of retinoblastoma affect one eye only.

Inherited: This is when one or both biological parents have DNA with the error. Your cells copy their DNA correctly, but that also includes the pre-existing typo. Retinoblastoma has autosomal dominant inheritance. That means you have roughly a 50% chance of inheriting the gene if one parent has it and a 75% chance if both parents have it. But biological parents may not have retinoblastoma even if their child has the inherited form. That’s because some people are carriers, meaning they have the mutation without it causing them to have the condition.

Inheriting a gene mutation also determines what form of retinoblastoma your child has. Inherited cases are usually bilateral and less often unilateral.

A sibling of a child with retinoblastoma also has an increased chance of developing it. When both parents are unaffected by retinoblastoma, biological siblings of the affected child have a 4% to 7% risk of having retinoblastoma, too.

Risk factors

Risk factors for retinoblastoma include:

Young age. Retinoblastoma is most common in very young children. It's typically diagnosed by age 2. Retinoblastoma that happens later in life is very rare.

DNA changes that run in families. DNA variations that increase the risk of retinoblastoma can be passed from parents to children. Children with these inherited DNA changes tend to get retinoblastoma at a younger age. They also tend to have retinoblastoma in both eyes.

Complications

Children with retinoblastoma can develop complications.

Cancer that comes back

After treatment, there is a risk that the cancer might come back in the eye or near it. For this reason, your child's healthcare team will create a plan of follow-up appointments. Your child's follow-up plan will depend on the treatments your child received. A typical plan might involve eye exams every few months for the first few years after treatment.

Increased risk of other cancers

Children with the form of retinoblastoma that can run in families may have a higher risk of getting other kinds of cancer.

The risk of these cancers is increased:

Bone cancer.

Bladder cancer.

Breast cancer.

Hodgkin lymphoma.

Lung cancer.

Melanoma.

Pineoblastoma.

Soft tissue sarcoma.

Your child's healthcare team might recommend tests to screen for these other types of cancers.

Prevention

There's no way to prevent retinoblastoma.

Some retinoblastomas are caused by DNA changes that run in families. If retinoblastoma runs in your family, tell your healthcare professional. Together you might consider genetic testing to look for variations in your DNA that increase the risk of retinoblastoma. Your health professional might refer you to a genetic counselor or other healthcare professional trained in genetics. This person can help you decide whether to undergo genetic testing.

If your children have an increased risk of retinoblastoma, care can be planned to manage that risk. For instance, eye exams may begin soon after birth. That way, retinoblastoma may be diagnosed very early. These screening tests could find the cancer when it is small and has a greater chance of being cured.

If you haven't had children, but are planning to, talk with your healthcare team about your family history of retinoblastoma. Genetic testing might help you and your partner understand whether there is a risk of passing DNA variations to your future children. Your healthcare team may have options to help you manage this risk.

Diagnosis

Retinoblastoma diagnosis often starts with an eye exam. Imaging tests can help show the size of the cancer.

Eye exam

A healthcare professional carefully examines your child's eyes during an eye exam. This might involve testing your child's vision and using a special light to look inside the eye. Sometimes very young children find it hard to hold still for a thorough eye exam. Your healthcare team might recommend medicine to put the child in a sleep-like state so the exam can be completed. The results of the eye exam give your healthcare team clues about what's causing your child's symptoms.

Imaging tests

Imaging tests make pictures of the inside of the body. For retinoblastoma, imaging tests are used to look at the eye and the area around it. The images might show the size of the cancer and whether it has grown beyond the eye. Imaging tests may include ultrasound and MRI, among others.

Genetic testing

Genetic testing uses a sample of blood or saliva to look for variations in the DNA. Genetic testing for retinoblastoma looks for variations in a part of the DNA called the RB1 gene.

Everyone with retinoblastoma has variations in the RB1 gene in their cancer cells. But some children with retinoblastoma have the RB1 gene variations in all of the cells in their bodies. This can happen if parents pass DNA variations to their child. The variations also can happen if something changes the RB1 gene as the child develops in the womb.

If genetic testing shows your child has variations in the RB1 gene in all of the cells in the body, this helps the healthcare team plan your child's treatment. Having variations in the RB1 gene in all of the cells also raises the risk of other kinds of cancer. Screening tests can help watch for those other kinds of cancer.

Treatment

Common retinoblastoma treatments include chemotherapy, cold therapy and laser therapy. Radiation therapy may be another option. Surgery to remove the eye can treat retinoblastoma, but it's only used in certain situations.

Which treatment is best for your child's retinoblastoma depends on several factors. These factors include the size and location of the cancer, and whether cancer has spread beyond the eye. Your healthcare team also considers your child's overall health and your own preferences.

Chemotherapy

Chemotherapy treats cancer with strong medicines. It's often the first treatment for retinoblastoma. Other treatments might be needed after chemotherapy to kill any cancer cells that remain.

Types of chemotherapy used to treat retinoblastoma include:

Chemotherapy that travels through the entire body. Chemotherapy medicines can be given through a vein or in pill form. These medicines travel throughout the body to kill cancer cells. Giving the medicines in this way is called systemic chemotherapy. Treatment is typically given monthly for several months.

Chemotherapy put into an artery near the cancer. Chemotherapy medicines can be put into an artery near the eye. To get the medicine to the right place, a thin tube is inserted through the skin and into an artery in the groin. The tube is advanced through the body until it gets near the eye. Then the medicine is released through the tube. Giving the medicine in this way is called intra-arterial chemotherapy. It lets the healthcare team give the medicine directly to the eye. Treatment is typically done monthly for a few months.

Chemotherapy injected in the eye. Sometimes chemotherapy medicines are injected in the eye with a needle. This way of giving the medicines is called intravitreal chemotherapy. It's typically used after other kinds of chemotherapy. It might be used when some cancer remains after other treatments or when the cancer comes back.

Cold therapy

Cold therapy, also called cryotherapy, uses extreme cold to damage cancer cells. It's typically used after chemotherapy to kill any cancer cells that are left. For very small retinoblastomas, cryotherapy might be the only treatment needed.

During cryotherapy, a very cold instrument is placed on the eye. This causes the nearby cells to freeze. Once the cells freeze, the instrument is removed. This causes the cells to thaw. This process of freezing and thawing is repeated a few times in each cryotherapy session.

Laser therapy

Laser therapy uses a laser light to heat up and damage the cancer cells. The medical term for this procedure is transpupillary thermotherapy. It's typically used after chemotherapy to kill any cancer cells that are left. For very small retinoblastomas, laser therapy might be the only treatment needed. Treatments are typically repeated every few weeks until there are no signs of active cancer in the eye.

Radiation therapy

Radiation therapy treats cancer with powerful energy. Types of radiation therapy used in treating retinoblastoma include:

Placing a radiation device on the eye. A device that emits radiation can be placed on the eye. This kind of radiation is called plaque radiotherapy. It uses a small disk that holds radioactive material. The disk is stitched into place on the eye and left for a few days while it slowly gives off radiation to the cancer.

Placing radiation near the cancer reduces the chance that treatment will affect healthy tissues outside the eye. This type of radiation therapy is typically used for cancers that don't respond to chemotherapy.

Using a machine to aim radiation at the eye. Radiation can be given to the retinoblastoma using a machine that aims energy beams at the cancer. The energy beams can be made of X-rays, protons or other kinds of radiation. As your child lies on a table, the machine moves around your child, delivering the radiation. This kind of radiation is called external beam radiation. Treatments typically happen daily for several weeks.

External beam radiation can cause side effects if the 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 retinoblastoma that extends beyond the eye.

Eye removal surgery

When other treatments haven't worked or when the retinoblastoma is too large to be treated by other methods, surgery to remove the eye may be used. 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. Surgery to remove the eye is called enucleation. 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 in the eye socket. The ball is called an implant. The muscles that control eye movement are sometimes attached to the implant.

After your child heals, the eye muscles will adapt to the implant. It may move just as the natural eye did. However, the implant can't 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 the appearance of 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.

Risks of surgery include infection and bleeding. Removing an eye will affect your child's vision. Most children adapt to the vision changes over time. Your child will need to take extra caution to protect the healthy eye. For example, after surgery, children should wear protective glasses or sport goggles while playing sports.

Type of Doctor Department : An ophthalmologist