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Retinoblastoma (Latin Retinoblastoma) is the most common intraocular malignant neoplasm in children. The first symptom of the disease is the appearance of a white glare in the eye, which is the easiest way for parents to see in the pictures taken of the child. What are the causes and other symptoms of retinoblastoma? How is this eye cancer treated? What's the prognosis?

Contents:

  1. Retinoblastoma - the most common malignant neoplasm of the eyeball in children
  2. Retinoblastoma - causes
  3. Retinoblastoma - symptoms
  4. Retinoblastoma - diagnosis
  5. Retinoblastoma - treatment
  6. Retinoblastoma - prognosis

Retinoblastoma(Latin Retinoblastoma) is a malignant neoplasm of the eye, specifically an intraocular tumor, the development of which is caused by mutations that deactivate copies of the RB1 gene encoding the retinoblastoma protein. It is a genetically determined cancer.

Retinoblastoma - the most common malignant neoplasm of the eyeball in children

Retinoblastoma occurs almost exclusively in children, accounting for 3% of all malignant neoplasms in children under 15 years of age. The frequency of its occurrence is about 1 in 15,000 children.

In 60% of cases, retinoblastoma is a neoplasm that affects one eyeball. In the case of a unilateral tumor, children aged about 2 years often suffer from the disease. 15% of these cases are congenital tumors. Bilateral tumors, affecting both eyeballs, occur earlier, around 1 year of age, bilateral tumors are usually congenital.

Retinoblastoma - causes

Retinoblastoma is a genetically determined cancer. In the human body, there are genes that inhibit the development of certain types of cancer, the so-called anti-oncogenes. One of them is the anti-oncogene RB1, located on chromosome 13 of the human genome.

A mutation of this anti-oncogene causes the development of retinoblastoma. In the case of a family history of retinoblastoma, the probability of passing the mutation to a child is approximately 50%.

Despite the fact that retinoblastoma is a genetically determined cancer, as many as 60% of children with cancer develop cancer despite the lack of a family history of this disease.

This is because such a genetic disorder often arises spontaneously in the child's genome over the course of life, despite the lack of a defective gene passed on by the parents.

Retinoblastoma -symptoms

The earliest symptom of retinoblastoma is white pupillary glare, the so-called leukocoria. In its early stages, it is only visible under good lighting and at a certain angle. Often, early leukocoria can be seen in flash photography.

Another early symptom is strabismus that has not occurred in the child before. Other symptoms of retinoblastoma include purulent exudate or haemorrhage into the anterior chamber of the eye, as well as goiter, i.e. enlargement of one eyeball due to increased intraocular pressure.

Orbital connective tissue inflammation and exophthalmos may also occur.

Symptoms of retinoblastoma also depend on the type of tumor growth, duration of the disease, or the degree of infiltration of surrounding tissues.

There are 3 types of tumor growth:

  • Endophytic, when the tumor splits around the inner layer of the retina and grows towards the back of the eye, the so-called vitreous
  • Exophytic, where a tumor grows in the area of ​​the inner layer of the retina towards the front, causing it to detach, often resulting in blindness
  • A flat infiltrate, characterized by a diffuse growth on the surface of the retina, such a neoplasm is diagnosed very late, in the form of inflammation and post-inflammatory complications.

Retinoblastoma tends to metastasize mainly through the bloodstream, it can also invade the optic nerve and thus spread to the brain. The tumor also infiltrates the orbital bones. Distant metastases are most often found in the brain and skull bones, as well as in the cervical lymph nodes.

In addition to retinoblastoma, there are also 3 other types of neoplasms associated with growth within the retina.

The first one is retinoma, it is a benign neoplasm found in patients with the RB1 mutation. It is a tumor within the retina that does not infiltrate or enlarge, and does not tend to become malignant. It was considered a mild manifestation of the RB1 mutation.

Three-sided retinoblastoma is a type of retinoblastoma that involves simultaneous involvement of both eyes and the presence of embryonic pineal disease. It is a tumor that occurs in the pineal gland, the internal gland in the brain.

The main task of the pineal gland is to produce a hormone - melatonin, which regulates the human circadian rhythm. The type and structure of the embryonic pineal tumor resembles a retinoblastoma.

The RB1 mutation is present in all patient cells, not only in the retina. Its presence increases the risk of developing other neoplasms, therefore, if retinoblastoma is found, regular preventive examinations should be implemented.for the rest of your life. The most common locations of tumors coexisting with retinoblastoma include:

  • soft tissues of the head (24%)
  • skull bones (18%)
  • leather (15%)
  • brain (8%)

Retinoblastoma - diagnosis

The basic diagnostic method is fundus examination, i.e. indirect colonoscopy. Based on this examination, as many as 85% of retinoblastoma cases can be diagnosed. An ultrasound examination of the eye is also helpful, which allows to assess the size of the tumor and the degree of retinal detachment.

Computed tomography allows the detection of characteristic calcifications within the tumor and infiltration outside the eyeball. Magnetic resonance imaging is not a method used in the diagnosis of retinoblastoma, because it does not detect the presence of calcifications, but only confirms the presence of a tumor within the eyeball.

Magnetic resonance imaging is, however, useful in recognizing infiltration into tissues outside the eyeball, as well as in detecting distant metastases.

Since retinoblastoma tends to metastasize to the bone and brain, it is not uncommon for a bone marrow biopsy or CSF to be performed.

In the case of the diagnosis of retinoblastoma, it is also important to identify the presence of the RB1 mutation. This is important for the treatment of the patient, but also for the care of siblings and, in the future, children of the sick.

If a child suffers from retinoblastoma and has an RB1 mutation, genetic testing of siblings should be considered in order to exclude the RB1 mutation.

Retinoblastoma - treatment

Modern methods of treatment allow not only the preservation of the eyeball, but often also good vision. There is currently no generally used treatment for retinoblastoma. Different centers have their own treatment regimens in which different methods are preferred. Even so, the general principles of treatment are similar.

There are two basic methods of treatment: systemic treatment and local treatment.

In most cases, treatment begins with chemotherapy, i.e. a systemic method aimed at reducing the tumor mass, and then implementing a selected local method in order to destroy the remaining tumor foci.

The exception are small tumors located around the periphery of the retina, then local methods are used immediately, without chemotherapy.

Among the local methods, the following are distinguished:

  • cryotherapy - this method is effective for small tumors, up to 3 mm. It consists in the rapid freezing of the tumor, which causes its disintegration
  • laser photocoagulation - a method similar to cryotherapy,however, instead of low temperature, a laser beam is used, which additionally destroys the tumor's vascularization.
  • laser thermochemotherapy - involves the use of a diode laser and a laser beam similar to infrared. High temperature causes tumor necrosis. As an auxiliary, chemotherapy is administered before the procedure and the tumor is laser photocoagulated under the microscope, i.e. its local destruction with the use of a laser.
  • radiotherapy - this group includes brachytherapy, i.e. a procedure that involves sewing plates with a radioactive isotope onto the eyeball. It is a method used for large tumors when less invasive methods have not worked. Teleradiotherapy, on the other hand, consists in irradiating the eyeball from the external field. This method is used for large tumors or those located on the posterior pole of the eyeball.

The most radical method of treating retinoblastoma is the complete removal of the eyeball, i.e. enucleation. This method is used very rarely and under strictly defined conditions. The indications for eyeball removal are divided into

  • absolute - when the procedure should be performed regardless of the condition of the other eye. These include:
    • retrobulbar infiltrate found in computed tomography
    • complete filling of the eyeball with a tumor with secondary glaucoma and dissemination in the anterior chamber.
  • Relative - When the other eye is he althy or can be treated successfully. Such indications include:
    • tumor filling more than half of the knob
    • complete retinal detachment
    • tumor recurrence along the vitreous base
    • dissemination in the vitreous.

In the case of removal of the eyeball in a child, it is extremely important to use an orbital implant, which enables the proper development of the orbital socket and symmetrical development of the face.

Retinoblastoma - prognosis

Survival for retinoblastoma alone is now very good in patients with unilateral or bilateral tumors; in Western countries the cure rate is around 95%.

Individual prognosis depends, inter alia, on on the stage of neoplastic changes, their location, susceptibility to treatment, and the presence of secondary neoplasms.

Much better prognosis is in the form of monocular disease. It should be remembered that after treatment of retinoblastoma, children should be examined by an ophthalmologist every 3-6 months up to the age of 6, and every year thereafter.

It is important that having the RB1 mutation increases the risk of developing other cancers, so after completing the treatment,remember to perform preventive examinations in accordance with the doctor's recommendations.

Retinoblastoma is a dangerous disease, but thanks to careful observation of the child, it can be successfully noticed in the early stages. If you notice any disturbing glare in the eyes, especially in photos with a flash, or a strabismus that has not occurred before, you should contact a pediatrician or general practitioner who will carefully examine the child and order appropriate tests.

Read also:

  • Eye melanoma: the most common malignant neoplasm of the eye
  • Benign eye cancers - how to recognize their symptoms?
  • Eye diseases and sight defects - symptoms, causes and treatment
About the authorBow. Agnieszka MichalakA graduate of the First Faculty of Medicine at the Medical University of Lublin. Currently a doctor during postgraduate internship. In the future, she plans to start a specialization in pediatric hematooncology. She is particularly interested in paediatrics, hematology and oncology.

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Category:

Oncology