JOIN USRetinoblastoma is one of the few cancers that can be completely cured if caught at the right time, says Dr P Mahesh Shanmugam.
All of us have, at some point or the other, seen a cat’s glare in a vehicle’s head lights. If a similar glint is seen in an infant’s or a child’s eye, it may indicate the presence of a cancerous eye tumour called retinoblastoma.
Retinoblastoma, fortunately, is rare. It occurs in one in 18,000 live births. This is a malignant tumour that arises from the light sensitive layer forming the inner coats of the eye (retina).
As in any malignancy, this tumour can spread out of the eye and if untreated, can cause death of the child. If diagnosed and treated early, the eye and vision of the child can be saved. This makes recognition of this disease a necessity, despite its rare occurrence.
The tumour may cause loss of vision in the early stages. As the patient is an infant, parents tend to remain unaware of the disease in their child’s eye until the tumour grows to such an extent to cause pain and redness of the eye.
Until this stage, the tumour may not cause any symptom but most often causes “white reflex” or the “cat’s eye reflex”. As the tumour grows within the cavity of the eye, it is not seen as a growth on the outside of the eye and this could lead to a delay in recognition of the problem.
The ‘white reflex’ is caused by the white colour of the tumour reflecting the light entering the eye. Depending on the location of the tumour, the reflex may be present only when the child moves his/her eye ball at a particular angle. This reflex can often be noticed in photographs, the pupil of one eye appearing dilated and white rather than appearing red.
The presence of a white reflex does not always mean that the child is harbouring a retinoblastoma tumour. Cataract, one that occurs rarely in children, and other congenital retinal disorders may also be responsible for the white reflex.
However, any white reflex has to be investigated thoroughly as this is the way retinoblastoma presents itself most often. It is wise to have an ophthalmologist look at it and rule out the presence of a tumour. It can also be present as a squint and as mentioned earlier, a painful, red eye. Hence a child with a squint has to be evaluated to rule out retinoblastoma.
The condition commonly affects one eye. Retinoblastoma can also run in families if it affects both eyes of the child. In case of familial retinoblastoma, the offspring of the patient has a 40 per cent risk of developing a tumour.
Familial retinoblastoma occurs due to a genetic defect and genetic testing of the parent can confirm the familial nature of the disease. If the defect can be identified in the parent, it is possible to diagnose the risk for retinoblastoma in a future offspring.
Retinoblastoma is usually diagnosed in children between one to two years of age. It is rarely present at birth, especially in familial cases.
It causes loss of vision depending on its location. If it were to grow in the central part of the retina, which is the site of fine vision, it can cause early loss of vision, a white reflex and a squint. If the tumour is more peripheral, it may grow to a substantial size before causing loss of vision or the white reflex.
The ophthalmologist usually subjects the child with suspected retinoblastoma to an examination under anaesthesia, as children do not typically co-operate for a detailed examination. The pupils of the child have to be dilated for evaluation as the tumour is within the inner cavity of the eye. Tests such as the ultrasound and CT or MRI scan also aid in diagnosing this disease.
As in any cancer, this tumour, if left untreated, spreads to other parts of the body and can cause death. It commonly spreads to the brain first through the optical nerve (one that connects the brain to the eye). It can also spread to the bones, liver and other organs.
Any cancer is usually treated with three types of treatment.
*Surgical removal of the affected part
*Radiation treatment
*Treatment with specific anti-cancer drugs.
This is also true for retinoblastoma. The treatment usually depends on the size, location and amount of vision left in the eye. Traditionally, the eye with the tumour is removed surgically, if only one eye is affected and there is no scope of vision in the eye.
Around the world, lesser number of eyes with retinoblastoma are being removed now as compared to earlier. This is due to the advances in treatment such as systemic chemotherapy where the medicines are given intravenously.
Newer forms of chemotherapy such as intra-arterial chemotherapy are known to be quite effective.
It is essential for the parents of a child with retinoblastoma tumour to be checked by an ophthalmologist. This is because the tumour may rarely stop growing by itself and may not have caused any signs or symptoms of existence in either parent. Unless examined thoroughly, this fact may be missed.
Though it is unlikely to cause harm at a later stage, the future children of this parent hold a greater risk of developing the tumour. Children with a familial form of the tumour are also at an increased risk of developing other cancers such as that of the bone, blood cancer etc.
It is a long, arduous route to cure retinoblastoma, but it can be achieved. Retinoblastoma is one of the curable cancers with appropriate, timely treatment.
More than 90 per cent of the cases survive the tumour with appropriate treatment. As in any disease, early diagnosis and treatment is the key to success.
(The writer is head of Vitreoretinal and Ocular Oncology Services, Sankara Eye Hospitals.)