aCase 21a

by Dr.Chua & Dr. Alhady
 

An Iban boy of 3-year and 8-month old presented in October, 2005 with a six-month history of progressive left proptosis (Figure 1). There was no family history. An urgent CT scan revealed an infiltrative tumour involving the whole globe and orbit with optic nerve and intracranial extension (Figure 2). An orbital biopsy was performed to differentiate between two main possible diagnosis: retinoblastoma versus rhabdomyosarcoma. The histologic report showed features of retinoblastoma and the patient was started on chemotherapy. The family was informed of the poor prognosis and further surgical treatment was not thought necessary.

Figure 1. Left massive proptosis.

Figure 2. CT scans showing an infiltrating tumour occupying the whole

globe and orbit with extension into the anterior and middle cranial fossa.

He received a full course of chemotherapy for retinoblastoma. He also underwent orbital radiotherapy to eliminate any remaining tumours. When seen in February, 2006, the proptosis showed remarkable resolution (Figure 3). Repeated CT scans revealed shrinkage of the ocular and orbital tumours as well as disappearance of the intracranial lesion.

Figure 3. Left enophthalmos due to significant shrinkage of the tumour.

Figure 4. Remarkable shrinkage of the orbital lesion and disappearance of the intracranial lesions.

 

a. What is the survival rate of retinoblastoma?

The mortality from retinoblastoma shows great variation between different regions of the world. In developed countries such as the USA, Japan and Europe, the survival rate of retinoblastoma exceeds 90% with modern treatment^1,2,3,4. The survival rate is much lower in developing countries and the main factor for the increased mortality is delayed diagnosis⁵.

 

In Sarawak, the Paediatric Oncology Unit in Sarawak General Hospital, Kuching has been treating all cases of retinoblastoma in the state since 1997. There were 22 cases of retinoblastoma between 1997 and 2005 in Sarawak (unpublished date). The mortality rate was 75%. Only 63% of the patients presented before 3 years of age and the average age of diagnosis was 28.7 months which is higher than the corresponding 16 - 21.5 months of age in Western countries.

 

Educating the primary care health workers and parents regarding the early signs of retinoblastoma is important in early diagnosis. Screening of siblings and children of retinoblastoma patients is also an important part of management. In our Sarawak data, none of the patients have parents with retinoblastoma. This may be explained by the poor survival rate of retinoblastoma in children in the past.

b. How would you manage this case?

Our patient appeared to have responded well to the chemotherapy without significant complications. In our data, most patients with intracranial lesions succumbed to the disease during chemotherapy as a result of uncontrolled cerebral oedema and bleeding.

 

As the lesions show significant shrinkage, we decide to follow the patients with regular MRI scans without any surgical intervention for the time being.

 

Reference:

1. The Committee for the National Registry of Retinoblastoma. Survival rate and risk factors for patients with

  retinoblastoma in Japan. Jpn J Ophthalmol 1992;36:121–131.

2. Moll AC, Kuik DJ, Bouter LM, et al. Incidence and survival of retinoblastoma in the Netherlands: a register

    based study 1862–1995. Br J Ophthalmol 1997;81:559–562.

3. Tamboli A, Podgor MJ, Horm JW. The incidence of retinoblastoma in the United States: 1974 through 1985.

    Arch Ophthalmol 1990;108:128–132.
 

4. Sanders BM, Draper GJ, Kingston JE. Retinoblastoma in Great Britain 1969–80: incidence, treatment, and

    survival. Br J Ophthalmol 1988;72:576–583.

5. Erwenne CM, Franco EL. Age and lateness of referral as determinants of extraocular retinoblastoma.

    Ophthalmic Pediatr Genet 1989;10:179–184.