Across the globe, frequency of RB is about one in twenty-thousand births and is the third most common type of cancer in children. If detected early, like any other cancer, RB is completely curable. Early detection is a routine in the Western world, whereas in India due to poor social awareness, it is diagnosed at an advanced stage, leading to loss of vision of one or both eyes and could be fatal at times. Luckily, RB majority of the times affects one eye of the child but at times, at least in a third of the children could have both eyes affected.
With minimal attentiveness, public could easily suspect RB at a very early stage by noticing white reflection in the pupil, called leukocoria. This could be more easily picked in a child’s photo with the white reflex instead of red reflex. Other signs and symptoms of RB, include squint or cockeye, persistent eye pain, redness, or irritation and blindness or poor vision, in the affected eye. A common man could detect this by simply closing an eye of the child with one hand and if the eye is sighted then a young child would push the person’s hand away, whereas if the child has poor vision then it would not push the hand away.
GENETICS AND BIOLOGY OF RETINOBLASTOMA
RB is a genetic disease that could be inherited in ten percent of the family, passing from one generation to the other, called autosomal dominant. Genetic code error or mutation in RB gene is the cause for the disease. Cell multiplication happens like driving a car, so there are genes that activate cell multiplication in the retina and when it is optimal RB gene acts like a brake and stops the activity. However, with a mutation RB gene produces defective RB protein and it is not functional resulting in excessive cell multiplication that could lead to the formation of the cancer, hence RB is a cancer or tumor suppressor gene. When the gene mutation happens at the formation of the fertilized ovum then it is germinal, which could affect each and every cell of the body and therefore could lead to cancer in other parts of the body, but this is very rare in real life situation.
Biologically, we have two copies of RB gene, basically one copy from each parent. For the cancer to be established, we have to lose both the copies in our retinal cells. Both the genes could lose their function by multiple biological cellular mechanisms in early childhood, when retina is actively multiplying. However, after four or five years of age, retina stops multiplication and therefore RB invariably does not occur after five years of age.
RB is a one-hundred percent curable disease provided it is detected early and managed by experienced ophthalmologists. However, if it is not treated appropriately, this cancer could spread beyond the eye mostly affecting the brain and other parts of the body, by which we could result in loss of the child. In the Western world hardly a child loses its sight due to RB because of early detection not only due to increased social awareness but also because of genomic tests. However, in our country due to lack of awareness amongst general public and parents, children not only lose their eye but also sadly their life, leaving pain and agony to the parents and loss to the community. Advanced clinical and genomic centers are bringing the same change that happened in the Western world, several decades ago, to our country.
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