Retinoblastoma
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Top Contributors - Kapil Narale and Kim Jackson
Introduction[edit | edit source]
Retinoblastoma is the most common ocular cancer that occurs in the pediatric population. It is lethal if it is left untreated. [1]
Epidemiology[edit | edit source]
In high-income countries, retinoblastoma is known to be a curable disease, with close to 100% chance of survival. However, in middle- and low-income countries, the prognosis is extremely low. In addition, more than 80% of cases occur in these countries. [1]
It is estimated that the majority of retinoblastoma cases occur in Asia (53%), then Africa (29%), Latin America (8%), North America (3%), and Europe (6%). With this information it is seen that global retinoblastoma patient survival is <30%. It is seen that the survival rate is 40% (23‑70%) in low‑income countries, while it is 79% (54‑93%) in upper‑middle‑income countries. [1]
Assessment[edit | edit source]
Prior to examining the patient, a thorough assessment must be completed. If there is any family history of the condition, a germline mutation may be present, and the child may need to undergo systemic chemotherapy to prevent pineoblastoma, even with a unilateral presentation of the disease. [1]
An in-depth evaluation is warranted prior to determining the degree of the necessary treatment, and minimise and prevent from any secondary complications. [1]
The treatment decision for retinoblastoma is dependent on the International Classification of Retinoblastoma (ICRB) classification (similar to the ICF), the presence of extraocular clinical factors, germline test results, family psychosocial status, and available medical facility resources. If there is presence of a germline disease, genetic testing should be conducted in all cases of retinoblastoma, for the patient and the rest of their family. [1]
All patients should go through a baseline high‑resolution simple and contrast‑enhanced magnetic resonance imaging (MRI) of the brain and orbits. Special attention should be given for pineoblastoma or any features of disruption to the optic nerve. [1]
As a part of the assessment, complete blood count, urine sample, and a general physical examination are performed by the pediatric oncologist. Subsequent to the general physical examination, a detailed examination using anesthesia is conducted, where ICRB staging is confirmed, and the first treatment can be administered. [1]
Treatment[edit | edit source]
The response to the initial treatment can be an indication of long‑term outcome progressions. The decision made by the ocular oncologist, in regards to treatment, would be crucial, as the therapy provided would need to be a sufficient strength, while minimising any secondary toxic effects. [1] Enucleation has been the preferred mode of treatment, for advanced retinoblastoma, in low-middle-income countries. however, over the last 30 years, the globe-savaging techniques have been used. [1]
Although the management of retinoblastoma may differ from place to place, and from clinic to clinic, the overall structure of treatment involves a similar framework. [1]
Various treatment methods for retinoblastoma are discussed below:
Intravenous Chemotherapy[edit | edit source]
IVC is an important mechanism for retinoblastoma therapy. It consists of 2-4 chemotherapeutic agents, which are given monthly via a central or peripheral catheter for 6-9 continuous cycles. The most commonly used method consists of 3 drugs, vincristine, etoposide, carboplatin (VEC). There ae cases where cyclophosphamide may replace vincristine when tehre may be a concernf or neurotoxicity. Despite this, vincristine is more likely to cause myelosupression and hemorrhagic cytitis.
Intravenous chemotherapy is known to effectively reduce tumor size, therefore can be referred to as chemoreduction.
Focal consolidation with thermotherapy, involving cryotherapy or transpupillary thermotherapy, can help with tumor control. Cryotherapy followed by chemotherapy is seen to heighten drug availability to the intraocular spaces when given within 48 hours of the thermal disruption.
Indications for IVC consist of, patients with bilateral disease, confirmed germline mutation, family history of retinoblastoma, or instances with possible optic nerve or choroidal invasion. Another indication t o use IVC would be patients weighing less than 6 kg that are waiting to receive intra‑arterial chemotherapy (IAC). This is referred to as ‘bridge therapy’. As well, IVC acts as protection with preventing long‑term secondary cancers, metastases, and pineoblastoma.
Signs, symptoms, and side effects
Intra-Arterial Chemotherapy (IAC)[edit | edit source]
Resources[edit | edit source]
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