Retinoblastoma is a cancer of the eye that originates in the retina, the most sensitive part of the eye. It usually affects children before 5 years of age but can rarely occur in adults.
Associated Anatomy of Retinoblastoma
The retina of the eye
Causes of Retinoblastoma
These are considered the most common cause of retinoblastoma. RB1 gene has been associated with normal cell growth during the eye development before the birth, while the baby is still in the mother’s womb. Mutation in the RB1 gene is associated with retinoblastoma.
The defective RB1 gene could be passed on to the child, leading to the development of retinoblastoma in early childhood.
Signs or Symptoms of Retinoblastoma
The first sign of retinoblastoma is an abnormal-looking eye. The black part in the center of the eye appears white. The other signs and symptoms of retinoblastoma include the following:
Discoloration of the eye
Pain in the eye
Eyes appearing larger than usual
Loss of vision
Eyes look in different or cross directions
Redness in eye white
Inflammation of the eye
Possible Treatments of Retinoblastoma
Treatment choice depends on the stage, size, and location of the tumor. The primary aim is to save eyesight, and the following treatment options are available:
A preferred treatment option is to reduce the size and kill the cancer cells. Drugs could be injected into the eye or associated blood vessels.
Using a supercooled metal to freeze and kill tumor cells.
Using a special laser to destroy tumor cells with heat.
Used for small tumors to destroy blood vessels (those supply tumors) using high-intensity laser light.
Use of high beam radiations to kill the tumor cells or sew a disc containing radioactive substance into the eye. It is usually done when all other options have failed.
Surgery is preferred in large tumors when removing the tumor, and the eye is the only option left.
Risk Factors of Retinoblastoma
The common risk factors for retinoblastoma include:
Most of the children with retinoblastoma develop in it before the age of 5, and occurrence is rare after 6 years of age.
The risk of cancer increases in children with a family history of retinoblastoma.
Advanced age of the father or exposure of father to radiation therapy
Diet low in fruits/vegetables during pregnancy or exposure of the mother to gasoline exhaust during pregnancy
Retinoblastoma can be classified into the following 5 groups based on the international staging for intraocular retinoblastoma:
Group A: Tumors less than 3 mm are limited to the retina and not close to other eye structures such as optic disc and foveola.
Group B: Tumors that are limited to the retina and are either more than 3 mm or are close to the optic disc and foveola.
Group C: Tumors with a small spread under the retina and to the vitreous humor (jelly-like material in the eye).
Group D: Tumors with a large spread under the retina and to the vitreous humor, leading to retinal detachment.
Group E: Large tumors extending in front of the eyes and causing complete loss of vision.
Typical Tests for Retinoblastoma
Diagnosis of retinoblastoma includes physical examination followed by examination using strong lights, reflex response, and magnifying lens. Further, an eye specialist may recommend undergoing an eye ultrasound to confirm the diagnosis. Additionally, A CT scan or magnetic resonance imaging (MRI) could be used to confirm the diagnosis, location of cancer, and staging.
Primary Prevention of Retinoblastoma
Prevention includes working on the potential risk factors of retinoblastoma. The following preventive steps can be taken:
If you are planning a baby, and you have a family history of retinoblastoma, it is important to discuss the risk with your doctor and think of alternative solutions to become parents.
For expecting couples
Expecting mothers should take good care during pregnancy and avoid exposure to dangerous chemicals or fumes such as gasoline and diesel exhausts. Male partners should avoid smoking, exposure to radiation at the workplace, or hazardous chemicals.
Secondary Prevention of Retinoblastoma
Once you or your child has undergone surgery and/or any other treatment for retinoblastoma, the focus shifts to avoiding any complications or recurrences. The following preventive measures can help delay the recurrence or other complications:
Follow-ups should be made as per the schedule to assess the recovery, vision, risk of recurrence, and overall quality of life.
Always look for symptoms of recurrence or complications and seek immediate medical attention.
A well-balanced diet helps in quick recovery, and an antioxidant-rich diet could reduce the risk of recurrences or complications.
Being aware of the disease and having realistic expectations helps in better planning and management.
Differential Diagnosis of Retinoblastoma
Symptoms of retinoblastoma could mimic some other disorders or conditions such as vitreous hemorrhage, astrocytic hamartoma (another type of retinal tumor), toxocariasis, cataract, retinopathy of prematurity, retinal nerve fiber myelination, Coat’s disease, etc. Hence, a differential diagnosis is required to rule out other medical conditions.
Retinoblastoma is a rare disorder, and it usually occurs in children below 5 years of age. It is the commonest of eye cancers and usually affects one eye. However, in every 3rd child with retinoblastoma, it can occur in both eyes.
Expected Prognosis of Retinoblastoma
Early diagnosis increases the chances of cure and better recovery. The prognosis depends upon the age of the child, location of cancer, size of cancer, number of eyes impacted. The majority of children respond well to the treatment, and the cure rate of retinoblastoma treatment is more than 90%.
Natural Progression of Retinoblastoma
Untreated retinoblastoma will start progressing to advanced stages and affecting tissues and organs beyond the retina, such as the brain, spinal cord, or other distant organs.
Pathophysiology of Retinoblastoma
Development of the eyes in the fetus starts while still in the mother’s womb. During the normal developmental stage, retinoblasts are the cells that continue to multiply until a certain stage and then mature into retinal cells. However, in some cases, retinoblasts continue to multiply due to defects in the genetic makeup, and the growth is out of control. This leads to the formation of retinoblastoma.
Possible Complications of Retinoblastoma
The most common complications of retinoblastoma include vision loss and complete blindness. Retinal detachment, necrosis of the retina, and involvement of optic nerves are complications that could follow retinoblastoma. Other complications include recurrence following the treatment and metastasis when cancer starts spreading to other tissue and organs such as the brain and spinal cord, making the treatment more difficult.