DIAGNOSIS
After a suspected case, a thorough examination is crucial for a precise diagnosis and forms the basis for further steps.
If the paediatrician or ophthalmologist finds indications of a retinoblastoma through medical history, physical examination and/or eye examination (e.g. the so-called Brückner test), he or she should immediately (i.e. within a few days) refer the patient to a hospital that specializes in this form of cancer (ophthalmological and paediatric oncology treatment facility).
If a retinoblastoma is suspected, various examinations are necessary, firstly to confirm the diagnosis, but also to determine which form of retinoblastoma is involved (hereditary or non-hereditary) and how far the disease has spread.
Eye mirror examination
The most important examination for detecting a retinoblastoma is the ophthalmoscopic examination (fundoscopy).
This involves examining the fundus of both eyes using ophthalmoscopes and a strong light source.
If a retinoblastoma is present, the extent of the disease can also be assessed with the aid of an ophthalmoscopy, which serves as the basis for staging. For example, the number, size and location of existing tumors as well as possible spread beyond the retina or within the vitreous body are taken into account.
The examination is performed under anesthesia with the pupil maximally dilated (mydriasis).
Imaging procedures and further examinations
In order to determine the exact extent of the tumor (“staging”), additional imaging techniques such as ultrasound (sonography) and magnetic resonance imaging (MRI) are used. The ultrasound examination is used, for example, to measure the tumor.
An MRI of the eye socket and the skull can be used to determine whether the disease only affects the eye (in this case it is referred to as an intraocular retinoblastoma) or whether it has already spread to the eye shells, the optic nerve and/or the brain (extraocular retinoblastoma).
A “trilateral retinoblastoma” (retinoblastoma with simultaneous brain tumor) can also be detected in this way. When a retinoblastoma is first diagnosed, every child should also be examined by a pediatric oncologist.
In rare cases, for example in the case of extremely advanced disease and/or prior to chemotherapy, further examinations may be required (e.g. a chest X-ray, an examination of the cerebrospinal fluid (lumbar puncture), the bone marrow (bone marrow puncture) and/or the bones (skeletal scintigraphy)).
Once all the examinations required before starting therapy have been completed, the medical team can decide together with you which treatment measures will best help your child.
Genetic diagnostics
As it cannot be ruled out in any patient that a hereditary form of retinoblastoma is present, human genetic counseling and, with consent, a molecular genetic analysis of the blood (genetic test) is always carried out as part of the initial diagnosis. The DNA contained in the blood is examined for the presence of retinoblastoma-typical genetic changes (mutations) in the retinoblastoma gene.
If corresponding changes are found, this is an indication that the child has a hereditary retinoblastoma.
In such a case, the diagnosis is not limited to the affected child.
The patient’s siblings and parents also need to undergo genetic testing and, if necessary, ophthalmological examinations in order to clarify the risk of the disease within the family and take appropriate preventive and control measures.
Good to know
Genetic counseling and diagnostics are an integral part of the care of children with retinoblastoma and their families.
Early detection with known hereditary disease
Today, in families with retinoblastoma diseases (familial retinoblastoma), it is possible to test whether a child has inherited the defective gene immediately after birth (the probability of this is 50%).
The prerequisite is that the mutation present in the family has been identified. This is not always possible, as changes in the retinoblastoma gene can be very diverse.
If the child has inherited the mutation or if there is uncertainty about this, an ophthalmological examination is urgently recommended so that tumors can be detected and treated as early as possible.
Sources: Maria Yiallouros, editorial team kinderkrebsinfo.de