indiacancer.org - Retinoblastoma

Retinoblastoma

		What is the Retina?
		What is Retinoblastoma?
		How is Retinoblastoma detected?
		What are staging and grading?
		How is Retinoblastoma treated?
		What are the side effects of treatment for Retinoblastoma?
		What is the importance of follow up?

What is the Retina?

The retina is a lining of nervous tissue located at the back of the two eyes. It is a photosensitive layer, that is, it is responsible for sensing light and forming images.

The Eye (Cut Section)

What is Retinoblastoma?

This is a cancer of the retina. Although it can occur at any age, it generally occurs before 5 years of age. It maybe unilateral, that is, only on one side, or bilateral, that is, in both eyes. Usually, the tumor is confined to the eye socket without spreading to the adjacent tissues.

Retinoblastoma has a tendency to be hereditary, i.e., it can run in families, but this is not always the case. If hereditary, it usually occurs at an younger age and tends to be bilateral.

Because it is hereditary, the siblings of patients, i.e., brothers and sisters, should also have periodic check ups, and may have to go in for genetic counseling to determine their chances of developing the disease.

If a child has a hereditary retinoblastoma, there is a higher chance of him / her developing a second cancer after several years. So medical checks throughout life are mandatory.

How is Retinoblastoma detected?

Usually the lesion is quite obvious, with the child having a white or discolored bulging tumor in one or both eyes, which may have no vision at all.

What are staging and grading?

	These are terms with which you must become familiar, if you are dealing with any form of cancer. When we stage a cancer, we try to establish carefully degree of spread of the cancer and if indeed there is spread, to what extent and involving which organs. The grading of a cancer is a microscopic issue, in which the pathologist lets you know how aggressive this particular type of cancer is; well differentiated means less aggressive, moderately differentiated intermediately aggressive and poorly differentiated more aggressive. Both grading and staging help your clinician to establish the prognosis or how serious your disease is and what is going to be the likely outcome. Staging may require additional imaging tests such as CT Scan, MRI, Sonography of the abdomen, IVU, Bone scan or chest X-ray.
		Intraocular retinoblastoma Cancer is restricted to one or both eyes and has not spread to adjacent or distant tissues.
		Extraocular retinoblastoma Cancer has spread beyond the eyes, either in adjacent tissues or to distant places.
		Recurrent retinoblastoma This is a disease which has come back after the primary therapy for the retinoblastoma is over. It may recur in the eye itself or in other parts of the body.

How is Retinoblastoma treated?

	A lot depends on the patient's constitution, the grade of his disease and its staging. Patients are usually treated by a team of specialists which utilizes a multipronged approach. This includes an oncosurgeon and a radiotherapist. The plan of treatment is tailored to fit a patient's requirements. If necessary, chemotherapy may become an add on. Treatment strategies. The bastion of treatment for retinoblastoma is surgery. Surgery usually involves removal of the eyeball, and this surgery is known as enucleation. It is a mutilating but necessary procedure. An artificial eyeball is usually put as a prosthesis afterward in the empty eye socket. The alternative local therapy to surgery is radiation therapy. This involves the use of high energy, penetrative rays to destroy cancer cells. It affects cancer cells only in the zone treated. Radiation therapy is also employed for palliation i.e. control of symptoms alone in an advanced cancer. Radiation therapy can also be used in adjunct to surgery or chemotherapy, either before or after. Teletherapy or external radiation is given via a machine remote from the body while brachytherapy or internal radiation is given by implanting a radioactive source within the involved tissues. Patients may or may not require both modalities of radiation. Radiotherapy, after initial planning, usually takes just 5 to 10 minutes per day, 5 days a week for about 6 weeks. This time period is flexible depending upon the modality of radiation used. Besides local therapy, the best attempt to control cancer cells circulating in the body and lodged at places other than the eye is by using systemic therapy (therapy which affects the entire systems of the body) which is in the form of injections or oral drugs. This form of treatment is called chemotherapy. This form of treatment is given in a cyclical manner (each set of drugs is repeated usually after every 3-4 weeks). Chemotherapy can also be used in combination with surgery, radiotherapy or both, either before or after. Cryotherapy uses extreme cold to kill cancer cells. Photocoagulation uses a Laser (Light Amplification by Stimulated Emission of Radiation) beam to destroy nutrient supplying blood vessels to the tumor. For intraocular retinoblastoma, the following treatment options can be entertained: Unilateral disease If it is a large tumor with no vision remaining.
		Enucleation
	If there is some vision remaining
		Teletherapy
		Photocoagulation
		Cryosurgery
		Brachytherapy
	Bilateral disease
		Enucleation of the eye with more cancer, and teletherapy to the other eye.
		Teletherapy to both eyes, if there is some vision in both eyes.
	For extraocular retinoblastoma, the following treatment options can be entertained:
		Radiotherapy with intrathecal chemotherapy (intrathecal chemotherapy is given in the thecal space, which is the space between the lining of the spinal cord and the brain)
		High dose chemotherapy with peripheral stem cell rescue (One type of autologous transplant is called a peripheral blood stem cell rescue transplant. In this, the patient's blood is passed through a machine that removes the immature cells from which all blood cells develop (the stem cells) and then returns the blood to the patient. This procedure, known as leukapheresis, usually takes 3 to 4 hours to complete. The stem cells are now treated with drugs to kill any cancer ingredient in them and are then cryogenically frozen until they can be transplanted to the patient. This may be done in association or disassociated from an autologous bone marrow transplant.)
	For recurrent retinoblastoma, the treatment depends on the site and the extent of recurrence or progression. If the disease is back in one eye, the following treatment options can be entertained:
		Enucleation.
		Teletherapy.
	If back in both eyes:
		Chemotherapy.

What are the side effects of treatment for Retinoblastoma?

	Unfortunately treatment for cancer does cause damage to the healthy tissues. Please ask the clinician about any possible side effects before any form of treatment commences. Enucleation is a mutilating but necessary procedure. An artificial eyeball is usually put as a prosthesis afterward in the empty eye socket. The effects of radiation depend upon the dose of radiation, the size of the area radiated, and the number and size of each fraction. The commonest side effect is extreme fatigue. Although bed rest is good, most radiotherapists advise the patient to be as mobile as possible. Another common problem is that of radiation dermatitis in which the skin covering the radiated area becomes red, dry, itchy, and may show signs of scaling off. This will slowly settle down after radiation ceases, but there may be a permanent 'bronzing' of the skin. It is important to note here that this skin problem is associated only with teletherapy or external radiation therapy. Radiation also may cause nausea and vomiting, diarrhea, urinary discomfort. There may also be a fall in the white blood cells, which are needed by humans to fight infection. Usually the radiotherapist can suggest the drugs and diet necessary to alleviate such problems. The various drugs in chemotherapy cause a varied spectrum of side effects. The severity and variability of these symptoms are very individualistic, changing from patient to patient. Some of the common side effects are:
		Skin rashes.
		Loss of hair.
		Diarrhea.
		Vomiting.
		Tingling and numbness in the fingers and toes.
		Hearing loss.
	Most are temporary and recede after therapy is over. Hair growth gradually starts after cessation of chemotherapy. The medical oncologist will usually be able to reduce the severity and spectrum of these side effects. The psychology of the patient is very important during therapy. Better psychologically prepared the patient is, better are his chances of having decreased side effects. The patient should drink large quantities of water while the therapy is in progress, and preferably avoid uncooked or raw food. Water should be filtered or boiled. Any relative or person who has any sort of infection such as common cold should be asked to desist from coming close to the patient.

What is the importance of follow up?

The importance of follow-up cannot be overemphasized. It is a fatal fallacy to assume on the patient's part that once the primary or the first phase of treatment is over, then he or she is cured. It must be stressed here that cancer has a notorious proclivity of coming back again and again. The only way to fight this is to pick up any problem when it is still early, so that it can be nipped in the bud. And the only way to do this is to follow up when the doctor calls you for the next visit. Each such visit will include a detailed history, a physical examination (including an internal i.e. a rectal or vaginal examination), a chest x-ray, an ultrasonography or a CT scan, and various other blood studies as indicated.