What is Retinoblastoma?
A cancerous tumor that develops in the tissues of the retina is known as retinoblastoma (Eye or Retinal) cancer. Retina is basically located at the back of the eye that senses light and is responsible for sending images to the brain. The condition of retinoblastoma generally happens in those children who are up to 5 years old. It is also regarded as an early childhood cancer that even affects newborn babies. The retinoblastoma can even spread to the bone marrow, lymph nodes or bones.
Types of Retinoblastoma
Unilateral Retinoblastoma : This type of retinoblastoma accounts for almost 75% of cases and it usually affects only one eye. Unilateral retinoblastoma can be either sporadic or hereditary. Sporadic generally happens in those children who are over age 1 and accounts for almost 75-80% of unilateral retinoblastoma cases.
Bilateral Retinoblastoma : Bilateral retinoblastoma is an indication of a genetic influence and it affects not one but both the eyes. This disease can be inherited from a parent who are having it but at the same time does not show any symptoms. This condition can be diagnosed early at a young age as compared to unilateral disease.
Trilateral Retinoblastoma : Intracranial tumor also develops in those children who have inherited retinoblastoma. This tumor originates in primitive nerve cells and is considered as rare that accounts for only 5% of patients having bilateral retinoblastoma.
Causes of Eye Cancer
The development of genetic mutations in the nerve cells of the retina results in retinoblastoma. This results in the continuous growing and multiplying of these cells as compared to healthy cells that would gradually die. A tumor is formed due to a continuous build-up of mass of cells. The condition of retinoblastoma can further affect the eye and also some nearby structures. Retinoblastoma may spread to different parts of the body such as spine and brain. There is no specific cause of genetic mutations that results in retinoblastoma. It is sometimes assumed that children may inherit this genetic mutation from their parents.
Symptoms of Retinoblastoma
The first or the initial sign of retinoblastoma is the appearance of cloudy white pupil that looks like yellow or silvery white in the bright light and is known as cat’s eye reflex or leukocoria. Some other symptoms are –
- Decreased vision or poor vision
- Wandering or poorly aligned eye called as strabismus
- Large than normal pupil
- Reddish pupil that is associated with pain
- Different colored irises
Stages of Retinoblastoma
Recurrent Retinoblastoma : This stage is marked by the cancer that has again come back after being treated or it has spread in the eye or to also different body parts.
Extraocular Retinoblastoma : This cancer has spread beyond the eye or is limited to the tissues near the eye. Extraocular retinoblastoma can even spread to central nervous system, lymph nodes or bone marrow.
Intraocular Retinoblastoma : This cancer is limited to the eye and may have localized to the retina or has spread to other structures that include optic nerve head, choroid, anterior chamber and ciliary body. Intraocular retinoblastoma will not spread further than the eye into the tissues surrounding the eye or to different body parts.
Diagnosis of Retinal Cancer
Biopsy and Bone Marrow Aspiration : This test involves the insertion of a hollow needle into the breastbone or hipbone for removing a small piece of bone, bone marrow and blood. The bone, bone marrow and blood are examined under a microscope in order to observe signs of cancer.
Eye Exam with Dilated Pupil : This eye exam involves the use of medicated eye drops for dilating the pupil so as to enable the doctor to see through the pupil and lens to the retina. A light is used for examining the eye from within that also includes the optic nerve and the retina. This eye exam is performed under anesthesia and this test depends on the age of the child.
Lumbar Puncture : Lumbar puncture is a medical procedure that is used for collecting cerebrospinal fluid from the spinal column. A needle is placed in the spinal column for this purpose and this entire process is known as spinal tap or LP. When the cancer has spread out from the eye then the procedure of lumbar puncture is required.
CT scan (CAT scan) : This test helps in making detailed images of the areas within the body including the eye that are taken from many angles. The computer prepares these pictures that are linked to an x-ray. The tissues or organs can be seen more clearly by swallowing or injecting a dye into a vein. This process is also known by computerized axial tomography, computed tomography and computerized tomography.
Ultrasound Exam : Sound waves are used in the ultrasound exam for creating images of the eye. The placement of a device is then done on the eye to receive and emit sound waves. High-frequency waves then enters into the eye and bounces off the tissue. A picture is then created when these echoes are read by the ultrasound. An enlarged retinoblastoma tumor can be best examined by this test.
Magnetic Resonance Imaging (MRI) : A computer, magnet and radio waves are used in this procedure for making detailed images of the areas within the body like the eye. Nuclear magnetic resonance imaging (NMRI) is the other name of this procedure.
Treatment of Retinoblastoma Cancer
A number of treatment options are available for retinoblastoma that include –
Surgery : The surgical procedure is performed when the tumor has grown so much that cannot be treated with any other means. This procedure helps to prevent the spreading of the cancer to different areas of the body. A surgeon removes the eyeball and places an eye implant into the eye socket. This eye implant is then attached with the eye muscles. The implanted eyeball will be moved by the eye muscles just like it moves the natural eye. This implanted eye cannot see. The placement of a custom-made artificial eye is done on the eye implant after some weeks of the surgery. This artificial eye is matched with the healthy eye of a child. Gradually, it sits at the back of the eyelids and is clipped on the eye implant. When the eye implant is moved by the eye muscles then it will look as if the child is moving this artificial eye.
Radiation Therapy : This therapy makes use of high-energy radiation beams for destroying cancer cells. This therapy can be delivered internally that uses a small disc of radioactive material which is stitched near or in the tumor. This then radiate the tumor when it is being left for a specific period of time. External beam radiation is primarily used in the case of advanced retinoblastoma. High-energy beams of radiation are given by using a machine that is placed outside the body. This powerful radiation is directed onto the tumor for destroying it.
Thermotherapy (a heat treatment) : This procedure makes use of ultrasound, microwaves or laser devices for delivering extreme heat on the cancer cells for destroying them.
Chemotherapy : Specific types of drugs are used for killing the cancer cells. The injection of these drugs is done into a vein that travels in the entire body. It also helps in shrinking the tumor of retinoblastoma that has spread to the other areas of the body or outside the eyeball.
Cryotherapy (a cold treatment) : Extreme cold is used in this procedure for destroying cancer cells. Liquid nitrogen (a very cold substance) is placed near or in the cancer cells. The liquid nitrogen is removed when the cells freeze that softens the cells. These cancerous cells eventually die when this process is repeated for few times.
Laser Photocoagulation (laser therapy) : Blood vessels that are responsible for supplying nutrients and oxygen to the tumor are destroyed by using a laser. Cancer cells will gradually die as they are not getting any oxygen and nutrients.