Retinoblastoma is a cancer of the retina, a light-sensitive layer of tissue in the eye. While it is rare, it is the most common malignant tumor that starts in the eye in children.
Only about 350 retinoblastoma cases are diagnosed each year in the United States. It usually occurs before age five. Most of these cases are in children under two.
Between 25% to 40% of retinoblastoma cases are hereditary. In these cases, the patient has a mutation in a gene known as RB1. When healthy, this gene stops tumors from forming. The mutated RB1 gene allows tumors like retinoblastoma to develop.
In the hereditary form of the disease, the 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 type of retinoblastoma can be passed down to the next generation. It usually develops before age one.
The other 60% to 75% of cases are sporadic retinoblastoma. In these patients, the RB1 mutation is found only in the cancer cells. This form of the disease 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 type of retinoblastoma is more likely to occur in children over age one.
Types of retinoblastoma
Retinoblastoma is categorized based on whether it is in one eye or two.
Unilateral retinoblastoma affects one eye. It makes up 60% to 75% of cases. About 85% of these are the sporadic form of the disease. The rest are hereditary.
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.
Another type of the disease is primitive neuroectodermal tumor (PNET) retinoblastoma, also called trilateral retinoblastoma. This occurs when an associated tumor forms in primitive nerve cells in the brain. PNET retinoblastoma is only found in children with hereditary retinoblastoma. It affects just 5% of these patients.
Intraocular vs. extraocular
Retinoblastoma is also classified by whether it is confined to the eyeball or eyeballs. Learning whether the cancer has spread outside these structures plays an important role in forming a treatment plan.
Intraocular retinoblastoma can be found in patients with either unilateral or bilateral disease. Intraocular means the tumor has not spread outside the eyeball or eyeballs. Cancer cells may be only in the retina or may be in other parts of the eyeball such as the choroid, ciliary body, or part of the optic nerve.
Extraocular retinoblastoma means the cancer has spread beyond the eyeball or eyeballs. It may be found in nearby tissue (such as the eye socket or orbit) or it may have spread to the central nervous system (brain and spinal cord), liver, the bone marrow or lymph nodes.
Retinoblastoma risk factors
A risk factor is anything that increases your chance of developing a disease. Risk factors for retinoblastoma include:
- Age: Most retinoblastomas are diagnosed in children age five and under, typically before age two.
- Family history: Retinoblastoma can be caused by a mutation in the RB1 gene, which suppresses tumor formation. This mutation can be passed down from parent to child.
Learn more about 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.
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Why choose MD Anderson for retinoblastoma treatment?
At MD Anderson's Children's Cancer Hospital, retinoblastoma patients have access to every treatment for the disease. These include:
- Intra-arterial chemotherapy
- Intravitreal chemotherapy
- Therapy for advanced metastatic disease, including high dose chemotherapy with stem cell rescue
- Proton therapy
- Brachytherapy
- Laser therapy
- Surgery
- Specialized ocular pathology and tissue harvesting
Many of these treatments are offered through our partnership in the Retinoblastoma Center of Houston. This group brings together retinoblastoma experts from four leading institutions in the Texas Medical Center. Together, they provide retinoblastoma patients with the best possible care. Patients benefit from a team of specially trained physicians who follow your child throughout treatment, all the way to survivorship. Patients also have access to clinical trials offering innovative new treatments for retinoblastoma, including trials conducted through the Children’s Oncology Group.
These experts communicate closely with each other, and with you, to ensure comprehensive, personalized care. For patients with particularly complex cases, the Retinoblastoma Center of Houston holds regular tumor board meetings where experts from its four institutions discuss these patients and form customized treatment plans. This group even helps oncologists around the country develop treatments plan for their retinoblastoma patients.
MD Anderson retinoblastoma patients are also supported by a team of health care professionals dedicated to your child's treatment. These include nurses, physician assistants, physical therapists and others.
And at MD Anderson, you are surrounded by the strength of one of the nation’s top ranked cancer centers. We have all the support and wellness services needed to support the whole family, from programs like child life and art-in-medicine for patients, to support groups and social work counseling for caregivers.
Being positive is the best medicine you can take.
MD Anderson's Children's Cancer Hospital