Research Paper on Retinoblastoma: Common Eye Cancer in Young Children

Introduction

Retinoblastoma is a common eye condition seen in children that affect one out of 20 children born. Every year, approximately 10 to 14 million children under the age of five years are affected by this condition. In the United States, for instance, every year, over 200 cases occur. Retinoblastoma is a condition that accounts for 11% of cancer cases to children at tender ages (Dimaras et al., 2012). Out of the total, only 3% of kids of 15 years and below are diagnosed with cancer. The condition is also a malignant tumour that grows at the embryonic neural retina (Dimaras et al., 2012). The tumours noticed are sometimes bilateral or unilateral, multifocal or unifocal. The essay will elaborate more on Retinoblastoma, the molecular structure and the treatment options.

Is your time best spent reading someone else’s essay? Get a 100% original essay FROM A CERTIFIED WRITER!

Save 25%

The nonhereditary and hereditary forms of the condition can either be familial or sporadic. Based on the intraocular growth, the invasion of the structures develops within the world and spread to specific metastatic sites (Correa & Berry, 2018). For instance, in developed countries, the spread of Retinoblastoma is unrealistic. However, in the undeveloped nations, the disease is uncommon and so the significant cause of mortality and morbidity. The condition is also a paradigm of a genetically inherited cancer due to the hypotheses of carcinogenesis. The reason why the disease is not familial is that Retinoblastoma develops in two random mutations but once cell found in the retina.

Prevalence

Various incidence of Retinoblastoma is estimated in individual countries and populations. The most common of this called the intraocular is known to afflict children. It is estimated that the condition affects countries in different variations from 3.4 to 50 cases per every newborn baby (Dimaras et al., 2015). In America, for instance, 11.8 cases of the young child below five years were prone to this disease (Dimaras et al., 2015). Most patients below that age are diagnosed when they reach 18 months. In this presentation, one-thirds are bilateral, and two -thirds unilateral.

According to Dimaras (2015), every year, the world receives more than 1500 of retinoblastoma cases. In India, for instance, an estimated 20% of patients are diagnosed with Retinoblastoma. Patients that have Retinoblastoma are put in categories depending on if their mutation is somatic or germline. Generally, the presence of the condition predicts whether the disease is secondary to a natural or germline mutation. Patients with bilateral disease are only 15% of the total people that are diagnosed as compared to the remaining percentage that gets it through the germline mutation (Dimaras et al., 2015). However, there is no racial bias for Retinoblastoma as it is known to affect both females and male.

The Molecular Structure That Leads to Retinoblastoma

Retinoblastomas that develop due to the familial cases are known to have a genetic underpinning that grows to a cancerous condition. However, the genetic status of the tumour was elucidated a few years ago. For instance, in 1971, the mechanism for tumorigenesis in people diagnosed with Retinoblastoma was believed to have mutations in both normal and copies of the gene. They are known to affect retinal (Dimaras et al., 2012). However, the recurring mutation in-activities only affect one copy of the gene. Such mutation activities occur in the germline or somatic cells. The second type of mutation takes place in the somatic cells, particularly in the retina.

The mutation that takes place in the germline cells makes the patient go through a heritable form of Retinoblastoma. Ninety per cent of such cases show that the new variations formed are without a family history. For Germline cases, all body cells carry one copy of the retinoblastoma gene is mutated and represents about 40% of the cancer cases (Dimaras et al., 2012). Patients that are diagnosed with the germline disease also have a multifocal and bilateral tumour. Such patients are also prone to secondary tumours such as primitive neuroectodermal tumours located in the brain. Therefore, 45% of children that are diagnosed with Retinoblastoma either inherited it, or they have a ninety per cent chance of penetrance (Dimaras et al., 2012).

When the RB genes occur at the same time in the somatic cell at the retina, then the condition is not heritable. Still, rather since it turns to be sporadic Retinoblastoma, later the patient will be diagnosed with unilateral disease. Even though tumours in this condition are nonhereditary and sporadic, only 15% of patients have the germline mutation (Dimaras et al., 2012). Also, children that are diagnosed with unilateral diseases, the condition turns to be bilateral. Therefore determining if the diagnosis is germline through the serum genetic testing, the patient needs to go through the clinical management process.

Pathology

Retinoblastoma is a medium-sized high nuclear molecule marked with mitotic and apoptotic activities, that consist of blue eosin and hematoxylin stains. The tumour cells then grow to replace the retina by feeding on the eye's vessels. Immediately the tumour grows above the vascular supply. They go through the necrosis process with calcification (Kandalam, Mitra, Subramanian & Biswas, 2010). The Necrotic cell then turns to a pink stain and the calcification portrays a hint of purple or violet colour. The tumours then grow to large foci or sheets that are undifferentiated.

Singh and Kashyap (2018), discovered that proto-oncogenes transform the treatment of cancer. Retinoblastoma tumors, however, have a different mutagenic pathway because the tumors are caused by mutation while some initiated through the amplification during chemotherapy. In the management of Retinoblastoma, the vital role of pathology is to identify the pathological features which predispose to the extraocular relapse. Such invasions include the sclera, optic nerve or the choroid (Kandalam, Mitra, Subramanian & Biswas, 2010). Even though the consensus on the ocular oncologists is not clear, such features are important to determine if the child will need adjuvant chemotherapy to prevent relapse of the disease.

Treatment Options

Before the 1990's the external beam radiotherapy treatment what the only method of treating Retinoblastoma. However, since it had high disappointing recurring rates, chemotherapy procedure was then limited to handle metastatic cases (MayoClinic, 2018). After some time, the clinicians noticed how significant EBRT was in the prevalence of the secondary tumours, particularly in patients that were diagnosed with germline mutations. This is because of approximately 38% of patients that had hereditary. Retinoblastoma was also diagnosed with a 26% long term mortality rate (MayoClinic, 2018).

In 1990, the first mouse model of treating Retinoblastoma was developed to develop the retina. Since this model had limitation such as disrupting the human Retinoblastoma, another mouse strain was engineered on 1992 to maximize the treatment (Dyer, Galindo & Wilson, 2005). The risk of the second malignancy is that it increases the EBRT process, particularly if the patient has not reached one year old.

The idea of using EBRT then coincided when the chemotherapeutic regimens began to be used because of their improved toxicity in children. The systematic chemotherapy was then developed to treat Retinoblastoma because it can shrink the tumour through consolidative therapy treatment (Dyer, Galindo & Wilson, 2005). However, shrinking tumours increases the chances of local treatments but not for large tumours. The focal treatment, in this case, was used to destruct the tumour cells and also to break down the ocular blood barrier to increase the penetration of the chemotherapeutic agents into the eye (Dyer, Galindo & Wilson, 2005).. Currently, the systemic chemotherapy together with the local therapy, is used as options in the treatment of Retinoblastoma.

Screening

According to the American Academy of Pediatrics, all infants, children, and neonates must be checked if they have the red reflex conditions while still at the neonatal nursery during a health supervision visitation routine (Meel, Radhakrishnan & Bakhshi, 2012). The procedure of conducting the red reflex test is done in a dark or dimly lit room with a direct retinoscope or ophthalmoscope from a 1.5-meter distance from the patient. As known, Leukocoria is a representation of Retinoblastoma. All children and infants that are diagnosed with the red reflex must be referred to the ophthalmologists who have the expertise in pediatric examinations (Meel, Radhakrishnan & Bakhshi, 2012).

The screening of a newborn baby by an ophthalmologist is important of the family history on the condition is revealed. Siblings and offspring's families that have the same history need to be screened and examined regularly while growing up until no retinoblastoma mutation is seen (Meel, Radhakrishnan & Bakhshi, 2012). Genetic counselling of families that have a history of Retinoblastoma is also vital because it can assist in determining whether other members are prone to get the disease in the future.

Clinical Presentation

When Retinoblastoma is recognized early, it can maximize the vision of the patient as well as the rate of surviving. Any child in this case that has Retinoblastoma must undergo through various diagnosis, especially if the symptoms turn as red-eye, Leukocoria, strabismus or cellulitis (MayoClinic, 2018). Children with leukocoria condition must go through different diagnosis because the disease is known to bring tumour. Strabismus, on the other hand, may show signs of developing Retinoblastoma (MayoClinic, 2018). If the patient, therefore, goes through the evaluation, they should go through a full dilated ophthalmic examination.

There are very rare cases where Retinoblastoma, especially when it has pain, mimic endophthalmitis and intraocular inflammation, vitreous haemorrhage, orbital cellulitis and uveitis (Manjandavida et al., 2019). The condition appears when the patient has a tumor but through the diffuse infiltrating form. This means that periorbital inflammation is not a good prognostic sign when cancer has become big, and the eye is exposed to massive necrosis. Patients with Retinoblastoma can also experience local invasion into the sclera and choroid that may spread along the optic nerve and then directly to the orbit. The condition can also metastasize hematogenously to the liver, central nervous system and liver.

General Treatment

The primary reason for treating Retinoblastoma is to preserve the globe, life and the vision of the patient. The priorities also include minimizing complications and side effects because the patients are very young. Enucleation, in this case, becomes the only definitive way of treating intraocular Retinoblastoma, especially if the patient shows signs of unilateral disease and poor visual symptoms (Dyer, Galindo & Wilson, 2005). The modalities of treating this condition include systematic chemotherapy with intra-arterial chemotherapy and consolidation modalities.

Small tumours can be treated using consolidation therapy. These include hyperthermia, plaque irradiation, laser photocoagulation and cryotherapy. However, external beam radiation therapy is not used because it has side effects, and it does not work well with children. EBRT treatment is good for seeding and treating recurring tumours in adults (Manjandavida et al., 2019). Also, the intravitreal chemotherapy can be added in treating conditions that are needed by the external beam radiation therapy.

Intra-Arterial Chemotherapy

The demand for chemotherapeutics has existed for a while. From subconjunctival injection and intravitreal injection to the fibrin sealant, most doctors have alwa...