What is retinoblastoma?
Retinoblastoma is a cancer that develops in the retina. The retina is a structure that absorbs light at the back of the eye. Send images to the brain. In short, the retina allows us to see. It usually develops in childhood, usually before the age of 5.
This occurs when nerve cells in the retina change, increasing in size and number. The cells eventually form a tumor. The cells generally spread in and around the eye. They can also spread to other parts of the body, including the brain and spine.
It usually affects young children, although it can sometimes occur in adults. Children with retinoblastoma can inherit a gene that causes the disease from their parents. These children get it at an earlier age and in both eyes.
To plan treatment for retinoblastoma, your pediatrician wants to know the correct size and location of the tumors to decide the stage of the disease.
- Intraocular: Cancer is found in one or both eyes, but it does not spread beyond the eye to the tissues around the eye or to other parts of the body.
- Extraocular: Cancer has spread beyond the eye, usually through the optic nerve. It can be limited to the tissues around the eye or it can spread to other parts of the body.
- Trilateral: In some patients with bilateral retinoblastoma, a corresponding tumor develops in the pineal gland at the base of the brain. The presence of these tumors can lead to other neurological symptoms and requires neuroimaging of the brain for diagnosis. The presence of trilateral retinoblastoma must be diagnosed immediately because its existence requires different treatment modalities.
- Recurrent: A recurrent disease means that cancer has come back or progressed after treatment. It can reappear in the eye or elsewhere on the body.
The first clue and the obvious symptom is that the eye does not see well. In particular, your generally black pupil may appear white. In one photo, instead of “red eyes,” a child with retinoblastoma has a pupil that glows white when light shines on it.
Other symptoms include:
- An eye or eyes that appear larger than normal
- Cloudiness or discoloration in the middle of the eye
- Eye pain
- Eyes that cross or look in different directions
- Redness in the white of the eye
- Vision problems
These symptoms can also be due to less serious problems. But see your doctor as soon as possible for any problems with your child’s eyes.
- Children with congenital retinoblastoma have an abnormality in the RB1 gene. It presents in two forms. This mutation can be inherited from parents, even if they have never had retinoblastoma, they are the “carrier” of the mutated gene or the germline mutation of these genes during fetal development. Germline mutation means any change in developing cells after pregnancy.
- Children with congenital retinoblastoma are at increased risk of developing retinoblastoma in both eyes and may also have multiple tumor sites in the eye.
- They may also be at higher risk for other cancers, including retinoblastoma, a tumor of the pineal gland at the base of the brain.
- It occurs most often in young children.
- It also occurs as a result of the RB1 gene, but only in one cell of the eye
- These children usually only develop a tumor in one eye
- It occurs more often in older children
Every cell in the body contains a gene called RB1, which provides instructions for making a protein called PRB. This protein acts as a tumor suppressor, which means that it regulates cell growth and prevents cells from dividing too quickly or out of control. Children who grow retinoblastoma have one or more changes in the RB1 gene in the cells of the retina.
Cells that contain the mutated gene cannot make functional PRB protein, so they divide in an unregulated manner to form a tumor. In a small percentage of children with retinoblastoma, there is not a large fraction of the genetic material, and the chromosomal changes involve many genes, including RB1. Affected children often have intellectual disabilities, slow growth, and distinctive facial features (such as prominent eyebrows, a small nose, and abnormal ears with a broad nasal bridge).
The first step is to examine the enlarged fundus and carefully evaluate the retina and other structures of the eye. In children 2 months to 5 years, it is usually tested under anesthesia. The following tests are usually done:
- Ophthalmoscopy: Examine the inside of the eye with a magnifying glass and light
- Slit-lamp biomicroscopy: Examine the inside of the eye with a powerful beam of light and a microscope
- Fluorescence angiography: The process of looking at the blood vessels and blood flow within the eye
Ophthalmologists may use one or more of these imaging tests:
- Ultrasound: Ultrasound of the eye to evaluate the size of the tumor, the involvement of other structures of the eye, and the presence of fluid in the retina.
- MRI: MRI of the brain (magnetic resonance imaging) for brain tumors that occur along with retinoblastoma. CT scans are generally avoided because children with retinoblastoma are at risk for radiation exposure.
- Genetic testing: Genetic testing to find out if a child has an inherited mutation, which can guide treatment, follow-up, and testing of family members and children.
If your child has retinoblastoma, the healthcare team will develop a treatment plan for your child. It depends on specific information about your child’s health and cancer. The goals of retinoblastoma treatment are to cure cancer, keep it as concentrated as possible, and reduce the risk of side effects.
Your child may be offered one or more of the following treatments for retinoblastoma.
Photocoagulation: The laser is used to destroy the blood vessels that feed the tumor.
Cryosurgery: Cryosurgery is commonly used to treat retinoblastoma that does not extend beyond the eye. Cryosurgery uses intense cold to freeze and kill cancer cells. It can be used to treat small tumors or tumors that remain after chemotherapy. It can also be used to treat recurrent (recurrent) retinoblastoma within the eye.
Thermotherapy: Thermotherapy is commonly used to treat intraocular retinoblastoma. Thermotherapy uses a microwave, ultrasound, or infrared radiation to provide heat and kill cancer cells. It can be used to treat small tumors or tumors that remain after chemotherapy. It can also be used to treat retinoblastoma that comes back to the eye.
Laser surgery: Laser surgery is usually used to manage intraocular retinoblastoma. Laser surgery uses a laser (a powerful beam of light) to heat and kill cancer cells. It can be used to treat small tumors or tumors that remain after chemotherapy. It can also be used to treat retinoblastoma that comes back to the eye.
Chemotherapy: Chemotherapy involves the administration of fluids through a vein (intravenous injection), orally, or into the eye or around the brain and spinal cord (called intrathecal chemotherapy). This powerful dose of anticancer drugs helps to multiply or slow cancer cells.
Radiation therapy: Radiation can be given externally or internally. External support radiation therapy uses x-rays to kill cancer cells. Internal or local radiation therapy, which places small amounts of radioactive material in or near the tumor to kill cancer cells.
Enucleation: This is surgery to remove the eye.
Retinoblastoma is recurrent in most cases. The doctor will maintain the following routine after treatment. However, if it is not diagnosed in time, it can spread to other parts of the body.
In most cases, doctors don’t know exactly what causes retinoblastoma, so there is no proven way to prevent the disease. Prevention for families with hereditary retinoblastoma
In families with hereditary retinoblastoma, it cannot be prevented. However, genetic testing allows families to determine which children are at higher risk for it, so eye exams should begin at an early age. Therefore, it can be diagnosed much earlier, when the tumor is small and it is still possible to cure and preserve vision.
If your doctor confirms that your child’s retinoblastoma is caused by an inherited genetic mutation, he or she can refer your family to a genetic counselor.
Genetic testing can be used to confirm that:
- Your child with retinoblastoma is at risk for other related cancers
- Your other children are at risk for retinoblastoma and other related cancers, so they can start eye exams at a young age
- You and your partner will likely pass the genetic mutation on to future children
A genetic counselor can discuss the risks and benefits of genetic testing and help you determine whether you, your partner, or your other children will be tested for a genetic mutation.
More than 90 percent of children live more than five years after having retinoblastoma. After treatment to save the eye, the amount of vision that remains in the affected eye varies greatly, depending on the size and location of the tumor.
Patients with inherited forms of retinoblastoma are more likely to develop other cancers over time. Therefore, close follow-up after treatment is necessary for these patients.
When to contact the doctor
Make an appointment with your pediatrician if you notice any changes in your child’s eyes that are related to you. It is rare cancer, so your pediatrician may explore other common eye conditions first.
If you have a family history of retinoblastoma, ask your pediatrician when to start routine eye exams to screen your child for retinoblastoma.