You’ve heard of blood cancer, cancer of the lungs, mouth, colon, cervix and breast. But cancer of the eyes? If you ask people at random, most of them would be incredulous that cancer can strike the eyes. Retinoblastoma affects a large number of children between the ages of one and five.
Till a few decades ago, this rare cancer that attacks the retina was considered fatal. Of late, however, early detection and medical and technological advances have turned that tide. Today, nine of 10 child patients can be cured in ‘advanced’ countries. In Europe, for instance, the five-year survival rate in children suffering from retinoblastoma went up from 85% in the 1970s to 90% in the 1980s and stood at 91% in the 1990s even while the incidence of retinoblastoma for the same period fell from 3.6 per million in the 1970s to 3.1 per million in the 1990s (Source:The Cancer Atlas published by the American Cancer Society).
Ocular oncology is a relatively new field of ophthalmology, and that perhaps explains to some extent why in India ocular oncologists see more of advanced retinoblastoma. An alarming number of general practitioners and even general ophthalmologists are not too knowledgeable about it. Says Dr Santosh Honavar, ocular oncologist at the L.V. Prasad Eye Institute, Hyderabad: “Delayed diagnosis of retinoblastoma is a problem unique to the developing world, and a problem that historically has poor prognosis.”
If detected early, the spread of cancer can be arrested, salvaging the eye, optimizing residual vision and, in extreme cases, saving a life. About 95% of children with retinoblastoma can be saved and vision kept useful in about 85% if the tumour is detected before the cancer destroys vital parts of the eye or spreads to other parts of the body, says Honavar.
Sadly, we still lose children to cancer that begins in the eye. In India, adds Honavar, cancer is among the leading causes of death among children below 14. Retinoblastoma and other eye cancers account for about 20-30% of all cancers; of these, about 30% cases are in children. In every 10 cases of retinoblastoma in children in India, about seven are unilateral or in one eye. While the disease can affect both eyes, cases where one eye is affected are generally detected by the time the children are about two or three years old. Those with both eyes affected are diagnosed between one and two years and seldom after they turn five.
An attentive adult, whether a member of the family, a doctor or a teacher, can save a child’s life. Take, for instance, the case of New Delhi’s Krish, who completed a year this March. He was about two months old when his parents took him to a paediatrician for diarrhoea.
One look at his eyes which could not coordinate, and the doctor suspected trouble. A specialist diagnosed retinoblastoma in both eyes. Krish was completely blind, a fact that his parents had not suspected since they did not know the symptoms. Treated for over 10 months, Krish has got back 50% vision in one eye and 20% in the other. He awaits a cataract surgery in June, after which he should be able to see better.
One of the surest indicators of retinoblastoma is to look at a photograph taken with a flash. Many parents have missed the healthy red glint in the child’s eye and consulted the doctor reporting a white reflex, only to confirm retinoblastoma. While most children with retinoblastoma appear like any other, attentive parents should watch out for the cat’s eye or a pupil that looks white and reflects light in what is called the cat’s eye reflex. Some children have a squint or persistent redness that comes with the cornea being clouded over, while some may have problems with their vision, even though they do not complain of pain in most cases. It may be difficult for the parents to detect poor vision in one eye, so check if the child resents closure of one eye at random. “This simple test can be done at home while the child is at play or watching television,” suggests Honavar. Some mothers suspect something wrong when they observe the eye bulge or move unnaturally.
What goes wrong and where?
As with some other cancers, retinoblastoma can be caused by the faulty Rb gene, which makes children more prone to bilateral retinoblastoma (affecting both eyes). That is why children born into a family with a history of retinoblastoma ought to be screened regularly till they are five years old. About one out of three cases are genetic, but several DNA mutations develop later in life. The retinoblastomas that are not inherited generally affect one eye. There is no conclusive evidence about what causes retinoblastoma. Nor is there any proven way of preventing retinoblastoma except by prenatal genetic diagnosis, which is recommended when there is a family history of the disease. So, till further research provides any conclusive answers, technically speaking, any child can get retinoblastoma even though statistics say that about one in 15,000 to one in 18,000 live births are diagnosed with it.
Although ocular oncologists work towards a day when they can restore complete vision and save the lives of every child, sometimes the treatment has to be guided by the fact that it is most important to stop the spread of cancer, even if vision cannot be preserved.
If the eye is removed, new techniques ensure implantation of a life-like prosthetic eye identical to the other eye that can even move on volition.
Retinoblastoma, when completely cured, does not often recur later in life. Nor does the treatment leave any significant long-term side effects. Which means, in a couple of years from now, Krish will be packing his books for school.
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