India carries the biggest burden of Retinoblastoma globally, with an estimated 1500 new cases annually, which account for almost 20% of total Retinoblastoma population. Regular screening of the children at risk should be done , so that Retinoblastoma can be identified as early as possible. Some guidelines to help parents understand disease and its management.
What is Retinoblastoma ?
Retinoblastoma is an eye cancer, seen in children less than 5 years of age, though it may present be later in some cases. Early treatment has excellent results for survival, nearly 100%. The delay in treatment is the major reason why survival is poor and is is universally fatal if not treated.
Why retinoblastoma occurs ?
The risk of developing retinoblastoma in the lifetime of a newborn baby is 1 in 18,000 to 30,000 . In the United States, there are reported 3.6 cases for each million children under the age of 15 years. we do not have the exact data from Indian population.
Retinoblastoma gene RB1
- Heritable Retinoblastoma these account for about 1 in every 3 patients of Retinoblastoma. it means that a mutation in the Retinoblastoma gene RB1 is present in each and every cell of the body including sperms and eggs. these cases often present in both the eye and patients may have the same disease in other relatives also.
- Non-heritable Retinoblastoma These account for about 2 out of every 3 patients of Retinoblastoma. It means that the Retinoblastoma gene RB1 inherited by the child are normal at birth but in early childhood, both copies of the RB1 gene in certain retinal cells acquire mutations. these cases often present in one eye only and is not seen in other relatives.
World map representing cases of Retinoblastoma and treatment centers
Why should children be screened for Retinoblastoma?
It is a cancer and delayed identification and initiation of treatment causes loss of eyesight, eye or even death. if the disease is identified in early stage, it can be cure and sight as well as life of child can be saved. At-risk children should be screened very early in life by regular eye examinations so as to diagnose the cancer in its initial stages. It has been scientifically proven that early identification of the disease is associated with less advanced disease and better outcome in terms of saving vision and the eye.
Does every new born child needs to be screened ?
Who should be screened?
All offspring, twins and siblings of Retinoblastoma patients should complete retinal examination for earliest identification of the disease. Other relatives need not be screened.
Current recommendations were:
- At-risk children should undergo genetic testing
- The child’s age and risk level should determine the frequency of serial dilated fundus exams, which should be performed by a physician
- Newborns at high risk should be screened every 2 to 4 weeks during their first 2 months of life, whereas newborns with intermediate or low risk should be screened monthly.
- high risk means
- Bilateral Retinoblastoma diagnosed in any of the parents.
- intermediate risk means
- siblings of a patient diagnosed with bilateral Retinoblastoma
- children of a person whose one of the siblings has Bilateral Retinoblastoma
- children of a patient of Unilateral Retinoblastoma
- low risk means
- siblings of a patient diagnosed with Unilateral Retinoblastoma
- children of a person whose one of the siblings has Unilateral Retinoblastoma
- children of a person whose one of the siblings had a children with Bilateral Retinoblastoma
- Necessary exam frequency declines as the child ages and may be discontinued at age 7 for children without an RB1 mutation
- Children who carry an RB1 mutation should be screened indefinitely, every 1 to 2 years.
How is screening for Retinoblastoma done?
Complete eye examination is done by a trained ophthalmologist / eye surgeon with or without anaesthesia.
credit: National Eye Institute, NIH
Genetic testing of Retinoblastoma.
The test which can predict the occurrence of Retinoblastoma in future, can help to save the vision of the patient and avoid unnecessary (and invasive) eye examinations for first person who develop disease (proband) in a facility and their close relatives. The disease exhibits a hereditary and a non-hereditary occurrence. One third of all children which have Retinoblastoma had a heritable tendency to develop tumors. The mutation in Retinoblastoma gene RB1 predisposes the retinal cells to undergo to malignant transformation, resulting in the disease occurrence. A child born to a parent with mutation in Retinoblastoma gene RB1 has a 45% chance of developing Retinoblastoma. These patients, multiple tumors and often in both the eyes. 15% of the patients, who have tumor in one eye, are also heritable. Siblings (brother and sister of patients with bilateral or unilateral Retinoblastoma have a risk of 3% and 0.5%, respectively, to have Retinoblastoma.
Genetic testing services of Retinoblastoma, available in India.
There are many hospitals which are offering the genetic testing for Retinoblastoma. At Shankar netralaya, Channai, this test cost around 12000 INR for a family of four (parents and two children). There are few private labs, which are also offering at price of about 30,000 INR per person. Genetic screening cost one sixth of the cost of clinical testing to rule out Retinoblastoma in a person.
Can we prevent Retinoblastoma from happening in a child?
As per our present understanding of the disease, there are no known avoidable risk factors for Retinoblastoma. So there is no way to prevent it. If a child has developed Retinoblastoma, it’s important to realize that it is not his fault.
some type of gene changes put the child at risk of developing Retinoblastoma. if any member in the family ever had Retinoblastoma, genetic screening may help in identifying the child art greater risk of developing Retinoblastoma in life.
How does Retinoblastoma present in a child?
Credit : Dr. Santosh Honavar
Clinical presentation of Retinoblastoma in India.
Clinical presentation of Retinoblastoma in India is different from what is reported from developed world. it is primarily because of late identification of tumor in children.
The most common presenting signs of Retinoblastoma in Indian population are
1. White color reflex in center part of eye ( 75-81%) (leukocoria ) can be seen in video above(Credit : Dr. Santosh Honavar).
2.Out ward protrusion of eye ball. ( 5-17%) (proptosis) ( can be seen in the boy featured video above at 44 sec (Credit : Dr. Santosh Honavar)
Some of the children may have skewed eye( strabismus ) ( < 10%) or red eye ( <10%) as presenting sign of disease.
in India, the average age of presentation/diagnosis of a child with Retinoblastoma is around 2 years and 6 months. Out of all the children 55-60% are boys, and rest are girls. Around 35-40 % of children have tumor in both the eyes, and rest have it in one of the eyes.
Signs and Symptoms of Retinoblastoma in developed world is slightly different.
Also read : Retinoblastoma Screening : Indian Scenario.
What is the treatment for Retinoblastoma?
The most common modalities of primary treatment are the cancer drugs ( systemic chemotherapy) which is used to manage two third of the patients.Unfortunately one third of the patient might need removal of their eye at some stage of the treatment.
Outcome of treatment ( survival)
EXCELLENT: In India, scientific studies report that more than 90 percent children are completely cured of the disease with the available treatment.