Retinoblastoma

Retinoblastoma is a cancer of the retina, a light-sensitive layer of tissue in the eye. Among children, it is the most common malignant tumor that starts in eye. Still, it is very rare, with only about 250 to 300 cases diagnosed each year in the United States. It usually occurs before age five, and most of these cases occur in children under two. The disease accounts for 3% of cancers in children.

Twenty-five percent to 40% of retinoblastoma cases are hereditary. In these cases, the patient has a mutation in a tumor suppressor gene known as RB1. This mutation is found in the DNA in every cell of the patient’s body. It is usually inherited from a parent, but it also can be a new mutation that starts with the patient. In both cases, this form of the disease can be passed down to the next generation. This type of retinoblastoma usually develops before age 1.

Sporadic retinoblastoma makes up the other 60% to 75% of cases. It is not inherited or passed down. Instead, a single cell mutates seemingly at random. It then begins dividing and eventually grows into a malignant tumor. This form of the disease usually occurs in children over age 1.

Types of Retinoblastoma

Unilateral retinoblastoma affects one eye and accounts for 60% to 75% of cases. About 85% of these diagnoses are the sporadic form of the disease. The rest are hereditary cases.

Bilateral retinoblastoma affects both eyes. It is almost always hereditary. Patients with bilateral retinoblastoma are typically diagnosed at a younger age (less than one year old) than those with unilateral disease.

PNET (primitive neuroectodermal tumors) retinoblastoma occurs when an associated tumor forms in primitive nerve cells in the brain. This form of the disease occurs only in children with hereditary retinoblastoma. It affects just 5% of patients with bilateral retinoblastoma. It also is known as trilateral retinoblastoma.

Some cases of retinoblastoma can be passed down from one generation to the next. Genetic counseling may be right for you. Learn more about the risk to you and your family on our genetic testing page.

Retinoblastoma starts in the eye, and that’s where its symptoms can first be seen. Retinoblastoma symptoms include:

• An opaque white area in the pupil (known as leukocoria), caused by the tumor reflecting light. This can often be seen in pictures taken with flash photography. Children with this condition should be seen by an ophthalmologist as soon as possible. Even in cases that aren’t connected to retinoblastoma, the condition can threaten the patient’s vision.
• Problems with eye movement, such as crossed eyes (strabismus)
• Decreased vision in one eye
• Eye pain
• A larger-than-normal eyeball
• Lazy eye
• Redness of the eye

Retinoblastoma is rare. If your child has these symptoms, they probably are caused by a less serious condition. However, it is a good idea to talk to your doctor to rule out other health problems.

There are several different procedures doctors can use to diagnose retinoblastoma, including:

• Funduscopic eye exam: The patient is anesthetized and the pupils dilated so the retina can be examined
• Ultrasound of the eye
• Magnetic resonance imaging (MRI) scan
• Blood tests
• DNA and/or genetic testing

If there is family history of retinoblastoma, young children should get regular exams to see if any tumors have formed. A diagnosis may be made before there are any symptoms. The earlier the diagnosis, the better the patient’s outcome is likely to be.

Retinoblastoma Staging and Grouping

Staging is process doctors use to find out if cancer has spread within the eye or to other parts of the body. Doctors use the information gathered during the staging process to plan a patient’s treatment.

While there are several staging systems for retinoblastoma, learning whether the cancer has spread plays the biggest role in forming a treatment plan. (source: National Cancer Institute)

Stages of Retinoblastoma

Intraocular retinoblastoma: Cancer is found in one or both eyes. It may be only in the retina or also may be in other parts of the eye such as the choroid, ciliary body, or part of the optic nerve. Cancer has not spread to tissues around the outside of the eye or to other parts of the body.

Extraocular retinoblastoma: Cancer has spread beyond the eye. It may be found in tissues around the eye or it may have spread to the central nervous system (brain and spinal cord) or to other parts of the body such as the bone  marrow or lymph nodes.

Ophthalmologists also use a scale, called grouping, that classifies the eye or eyes with the disease. An eye can be grouped from A to E (best to worst) based on the chance that the eye itself can be saved.

Our Treatment Approach

Experts at MD Anderson have partnered with physicians at three other leading institutions to form the Retinoblastoma Center of Houston. This group forms one of the world's foremost teams of experts in caring for retinoblastoma. They will work together to develop a customized a treatment plan just for your child.

Specialized Expertise

The team that treats your child for retinoblastoma will include a number of highly trained doctors, including oncologists, surgical oncologists and radiation oncologists. MD Anderson patients will also get skilled care from a group of dedicated professionals such as advanced practice nurses, physician assistants, therapists and social workers.

We offer a range of clinical trials for retinoblastoma. We are on the forefront of discovering new and better ways to treat retinoblastoma, and this can translate to better chances for successful treatment for your child.

Our Retinoblastoma Treatments

Doctors who treat retinoblastoma will tell you they have three goals, in order: Save the life. Save the eye. Save the vision. To achieve these goals, they can use the following treatments:

Laser treatment uses lasers to destroy the tumor. This is very effective for small tumors that are confined to the retina and do not involve the optic disc or the area near it, called the macula, which is the most important part of the retina for vision.

Cryotherapy uses a small probe to kill the tumor by freezing it. This is also a good option for small peripheral tumors.

Chemotherapy kills cancer cells or stops them from dividing. For retinoblastoma, chemotherapy may be used to shrink the tumor, making treatments like laser or cryotherapy more effective. For cancers that have spread outside the eye, doctors may prescribe high dose chemo with stem cell rescue. This is an aggressive treatment that uses stem cells to replenish blood cells destroyed by powerful chemotherapy drugs. Retinoblastoma chemotherapy is usually delivered in one of four ways:

• Intravenous: The drug is injected into a blood vessel and is pumped throughout the body.
• Intra-arterial: A catheter is inserted into a blood vessel near the groin and then steered through the body up to the eye, where chemo is directly delivered.
• Intravitreal: Chemotherapy is injected directly into the eye.
• Periocular: The drug is placed around the eye.
  

Radiation therapy is a very effective treatment for retinoblastoma. Radiation treatments for retinoblastoma include plaque therapy, where a disk with radioactive seeds is implanted on the outside of the eye near the tumor. Another option is proton therapy, a very advanced and precise treatment that limits healthy tissue’s exposure to radiation.

Enucleation surgery, or removal of the eye, may be performed when the tumor fills more than half the eye, when other structures in the eye are involved or when the retina is detached. Children who undergo this procedure are fitted with an ocular implant and later an artificial eye. Thanks to advances in detection and treatment, enucleation is not used as often as it once was.