Retinoblastoma is a condition that affects the retina of the eye. The cells in the retina grow abnormally and eventually develop a tumor. These cells multiply in different parts of the patient’s eye and later spread to their brain and spine. It is one of the most common cancers affecting children.
The eye begins development before birth. In the early phases of development, eyes have cells known as retinoblasts. These cells multiply to form new cells that occupy the retina. These cells stop mutating and become mature cells. In some cases, instead of maturing, the retinoblasts continue growing abnormally until they form a cancer called retinoblastoma.
- Congenital retinoblastoma
- Sporadic retinoblastoma
Causes and Risk Factors
The development of retinoblastoma begins with the mutation of the RB1 gene. Normally, this gene prevents cells from growing abnormally; however, a change in this gene causes it to have the opposite effect. The type of retinoblastoma that a child develops will depend on the area where the RB1 gene has transformed.
A child with congenital retinoblastoma has abnormal RB1 genes in their entire body including both retinas. In sporadic retinoblastoma, the abnormality of the RB1 gene affects one retina. These gene mutations can be passed from a parent to their child.
Some of the risk factors for retinoblastoma include:
- Age - Many cases of retinoblastoma involve children who are below 3 years old.
- Hereditary - A child whose parent had congenital retinoblastoma is likely to get this condition.
Signs & Symptoms
The first tell-tale sign of retinoblastoma is a pupil that looks white. For example, in a photo, a child with the condition will have one pupil that is glowing white instead of red when light is focused on it. Other symptoms include:
- Swollen eyes
- Red eyes
- Eyes that look in different directions
- Eyes that appear larger than normal
To diagnose retinoblastoma, an eye professional will examine the patient’s eye using a magnifying lens. The examination will be performed in an area where there is strong light. If it appears like the patient has cancer, the professional will want to know how large the tumor is and if it has spread. To establish this, any of these tests may be performed:
- Ultrasound – The sound waves form pictures of the patient’s eye
- Magnetic resonance imaging (MRI) scan – Powerful radio waves and magnets are used to form detailed images of the patient’s eye
- Computed tomography (CT) scan – X-rays taken from various angles to provide detailed information about the condition of the patient’s eye
The treatment is aimed at saving the patient’s vision depending on the size of the tumor and whether it has affected other areas.
- Chemotherapy – This is a drug treatment aimed at killing cancer cells. It helps shrink the tumor to allow other treatments to be used to fight the present cancer cells.
- Radiation therapy – This involves the use of beams of energy to destroy cancer cells. A small radioactive material is fixed near the tumor to kill the cells. In some cases, it is applied from outside where huge beams of energy are focused on the tumor.
- Laser therapy – In this treatment, a laser is used to disable the blood vessels that are feeding on the tumor and as a result kill the cancerous cells.
- Cold treatment (cryotherapy) – A cold substance like liquid nitrogen is applied to freeze the cancer cells. After the cells freeze, the liquid nitrogen is withdrawn and the cells are left to thaw out. This procedure helps kill cancer cells.
- Heat treatment (thermotherapy) – This is where extreme heat is applied on the cancer cells to destroy them.
If a tumor is too large, and other treatments have failed to contain it, surgery may be the remaining option. During surgery, the eyeball is removed to prevent the cancer from moving to other parts of the body. The surgeon will replace the infected eyeball with an implant. The implant does not support vision. A few weeks later, an artificial eye will be placed on the implant.
In most cases, children who have received treatment for retinoblastoma stand the risk of the cancer reoccuring. The child should visit the eye doctor regularly for follow up exams. Typically, these exams involve eye tests for the first couple of years after the retinoblastoma is treated.
Children who have inherited retinoblastoma risk developing some other forms of cancer in their bodies after treatment. This is the reason doctors recommend that children with the inherited form of this disease go through regular tests for early detection in case of other cancers.
In families where children stand a risk of inheriting retinoblastoma, it may be impossible to prevent the condition. However, experts recommend genetic testing and counseling to enable families to identify the children who have a high risk of getting retinoblastoma. Eye tests need to be conducted early when the tumor is still small and when there is a chance of preserving vision. Genetic testing also helps couples to determine the possibility of transferring the genetic mutation to their future children.