Retinoblastoma is a rare type of cancer that affects the retina, the thin layer of tissue at the back of the eye that is responsible for transmitting visual signals to the brain. Retinoblastoma is most commonly diagnosed in children, and it is one of the most common types of childhood cancer.

The cause of retinoblastoma is not fully understood, but it is believed to be caused by mutations in the genes that control the growth and division of cells in the retina. These mutations can be inherited from a parent or can occur spontaneously during development.

Symptoms of retinoblastoma can include a white glow or white color in the center of the eye, a crossed or lazy eye, and vision problems. Diagnosis typically involves a comprehensive eye exam, including an examination of the retina, and may involve imaging tests such as ultrasound or MRI.

Treatment for retinoblastoma depends on the size and location of the tumor, as well as the extent of cancer. Treatment options may include chemotherapy, radiation therapy, cryotherapy (freezing the tumor), laser therapy, or surgery to remove the affected eye. In some cases, a combination of treatments may be used.

Early diagnosis and treatment are important in achieving a good outcome for patients with retinoblastoma. Children who have been diagnosed with retinoblastoma may require ongoing monitoring to detect any potential recurrence or complications from treatment. Additionally, genetic counseling may be recommended for families who have a history of retinoblastoma.

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.

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.

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.