Retinoblastoma is the most common cancer of the eye in children worldwide. Affecting 1 in every 12,000 to 15,000 children, it is typically seen around two years of age, although not infrequently seen as early as six months and as late as five years of age. Retinoblastoma is a tumour that arises from the retina. The retina is the inner lining in the back of the eye that enables us to see. Retinoblastomas are the most common primary paediatric ocular neoplasm. When diagnosed and treated early, over 90-95% of children are survivors, functioning as normal children, going to school and participating in all activities like normal children. However, when left untreated or poorly treated, almost all children with confirmed retinoblastoma have spread of disease outside the eye(s) into the eye socket or the brain, and eventually to other parts of the body resulting in death.
It is most commonly presented as an altered light reflex in the affected eye (white reflex, leucocoria) typically seen in a flash photograph of a child in the first 1 - 2 years of life, as seen in Figure 1 below.
Fig. 1 Leukoria (white coloured pupillary reflex) is present in the right eye due to retinoblastoma
Other manifestations include a new onset ‘cross eye’ (‘squint’, strabismus), a red eye that does not respond to treatment, or an eye that doesn’t see. Late manifestations include an enlarged eye compared to the other side or bulging eye(s). Advanced disease is presented as an irritable, sick child, failing to thrive, seizures or swelling in other parts of the body from spread of the disease (metastasis). This condition, almost always results in death unless treated aggressively. Parents are the first to notice any of the early features mentioned above and thus should seek early attention with an eye specialist or paediatrician.
When any of the above signs and symptoms are present, the eye specialist usually performs a preliminary examination followed by either an examination under anaesthesia or sedation. Typically the diagnosis is made exclusively on clinical examination based on the appearance and characteristics of the tumour. An ultrasound scan is often also used to look for ‘calcification’, measure the size and spread of tumour outside the eye. All retinoblastomas are documented with a special fundus camera (RetcamR) for documentation, family education, communication with other specialists and when necessary, for a second opinion as well. When the disease is suspected to have spread outside the eye, or if Retinoblastoma is present in both eyes, an imaging of the orbit (eye socket) and brain is performed to rule out spread outside the eye and the presence of a rare third tumor in the brain (pinealoblastoma). In patients who are presented late with obvious spread outside the eye, a lumbar puncture for analysis of the fluid surrounding the brain (CSF) and bone marrow may also be performed to confirm spread of the disease.
The priorities in the treatment of retinoblastoma are in order of preservation of life, eye, and then vision. Close teamwork between a multidisciplinary team comprising of the ophthalmologist, paediatric oncologist, geneticist, interventional radiologist and pathologist is essential to achieving those goals. At present, the goal of preventing mortality has largely been met, and retinoblastoma is now the most curable paediatric cancer.