Retinoblastoma ( cancer of eye): An ultimate patients guide

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Retinoblastoma ( cancer of eye): An ultimate patients guide

India carries the biggest burden of Retinoblastoma globally, with an estimated 1500 new cases annually, which account for almost 20% of the 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 the disease and its management.

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What is Retinoblastoma?

Retinoblastoma is 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 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 every million children under the age of 15 years. we do not have the exact data from the Indian population.

Retinoblastoma gene RB1

Mutations in the Retinoblastoma gene RB1 cause most cases of Retinoblastoma.

TYPES

Heritable Retinoblastoma accounts 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 are 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 is normal at birth but in early childhood, both copies of the RB1 gene in certain retinal cells acquire mutations. These cases are often present in one eye only and are not seen in other relatives.

Distribution of the patients across the world. The majority of patients reside in low and middle-income countries, while the majority of Retinoblastoma Centers are in high-income countries.

Why should children be screened for Retinoblastoma?

It is cancer and delayed identification and initiation of treatment causes loss of eyesight, eye, or even death. if the disease is identified in an early stage, it can be a cure, and sight as well as the life of child can be saved. At-risk children should be screened very early in life by regular eye examinations so as to diagnose cancer in its initial stages. It has been scientifically proven that early identification of the disease is associated with less advanced disease and better outcomes in terms of saving vision and the eye.

Does every newborn child need to be screened?

Who should be screened?

All offspring, twins, and siblings of Retinoblastoma patients should complete a retinal examination for the 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 child 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?

A complete eye examination is done by a trained ophthalmologist/eye surgeon with or without anesthesia.

Genetic testing of Retinoblastoma.

The test which can predict the occurrence of Retinoblastoma in the future, can help to save the vision of the patient and avoid unnecessary (and invasive) eye examinations for the first person who develops disease (proband) in a facility and their close relatives. The disease exhibits a hereditary and non-hereditary occurrence. One-third of all children who have Retinoblastoma had a heritable tendency to develop tumors. The mutation in Retinoblastoma gene RB1 predisposes the retinal cells to undergo malignant transformation, resulting in the disease occurrence. A child born to a parent with a mutation in the 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 a 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 genetic testing for Retinoblastoma. At Shankar netralaya, Chennai, this test cost around 12000 INR for a family of four (parents and two children). There are few private labs, which are also offering a 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 types 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’s art greater risk of developing Retinoblastoma in life.

How does Retinoblastoma present in a child?

Clinical presentation of Retinoblastoma in India.

Clinical presentation of Retinoblastoma in India is different from what is reported from the developed world. it is primarily because of the late identification of tumors in children.

The most common presenting signs of Retinoblastoma in the Indian population are

White color reflex in the center part of the eye ( 75-81%) (leukocoria ) can be seen in the video above(Credit: Dr. Santosh Honavar).

2.Outward protrusion of the eyeball. ( 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 the rest are girls. Around 35-40 % of children have tumors in both the eyes and rest have it in one of the eyes.

Signs and Symptoms of Retinoblastoma in the developed world are slightly different.

Also read Retinoblastoma Screening: Indian Scenario.

What is the treatment for Retinoblastoma?

The most common modalities of primary treatment are cancer drugs ( systemic chemotherapy) which is used to manage two-third of the patients. Unfortunately, one-third of the patient might need the removal of their eye at some stage of the treatment.

The outcome of treatment ( survival)

EXCELLENT: In India, scientific studies report that more than 90 percent of children are completely cured of the disease with the available treatment.