With timely detection and care by multidisciplinary teams using current treatment protocols, more than 95% of patients can be successfully treated before the cancer spreads outside the eye. Retinoblastoma is fatal if untreated.

It is important to remember that each case of retinoblastoma, and each child with retinoblastoma, is unique. A treatment plan will be developed specifically for the affected child. Depending on the size and location of tumors, there are many treatment options available for retinoblastoma. These include laser therapy, cryotherapy, chemotherapy, radiotherapy (both plaque and external beam), and enucleation. Regardless of the treatment options implemented the child will be monitored vigilantly through examinations under anaesthesia (EUAs). The interval between EUAs will vary from every three weeks to six months depending on tumor activity and treatment options employed. What follows is a brief description of some of the treatment options available for retinoblastoma contained within the eye.

More detailed information can be obtained by reviewing the Treatment chapter of the “National Retinoblastoma Strategy Guidelines for Care” http://pubservices.nrc-cnrc.ca/rp-ps/inDetail.jsp?jcode=cjo&lang=eng&vol=44&is=S2.

If you would like more information on any of these treatments, the risks or potential complications, please consult your physician.

FOCAL THERAPY

Focal therapy refers to a group of treatments that are applied directly to the eye. Focal therapy can be used as a primary therapy for tumors that are small and are not situated close to the centre of vision or the optic nerve. If the tumor is too large to be treated with focal therapy, the child may first receive chemotherapy to shrink the tumor. Focal therapy can then applied to residual tumor.

Focal therapy is performed during an EUA while the child is asleep. Focal therapy sessions must be repeated many times until all remaining signs of active tumor have disappeared. A notable side effect to focal therapy is scarring of the retina that will have an effect on the child’s vision.
There are three types of focal therapy used to treat retinoblastoma: laser therapy, cryotherapy and radioactive plaque (brachytherapy).

Laser Therapy

Laser therapy uses heat (in the form of a laser) to physically destroy tumor cells. During an EUA the laser is directed to the affected areas of the retina through the child’s pupil, widely dilated by use of pharmaceutical drops. Laser therapy is used for small tumors, residual tumor after chemotherapy, and recurrences after chemotherapy. Laser therapy is painless for the child, although the eye may be red following treatment.

Cryotherapy

Cryotherapy is primarily used to treat small peripheral retinoblastoma tumors and for peripheral recurrences after chemotherapy.
Cryotherapy uses a special instrument held against the outside of the eyeball, at the point nearest the tumor to repeatedly freeze and thaw the tumor. It is the actual thawing process that kills the tumor cells as ice crystals pierce the tumor membranes destroying the cells.
Following treatments the child’s eye(s) might be quite swollen and sore. Medication may be prescribed to alleviate discomfort.

Radioactive Plaque (Brachytherapy)

A radioactive plaque is a small disc that is surgically attached to the outer part of the eyeball, directly over the tumor. The disc contains a small amount of radioactive material that delivers a low dose of radiation directly to the tumor. The plaque is generally left in place for between two and five days before being surgically removed. Radioactive plaques are used to treat small isolated tumors situated well away from the optic nerve and/or centre of vision. Plaques are often used for tumors that have not responded to laser or cryotherapy. A possible long-term side effect to a radioactive plaque is the development of a cataract. In most cases, once the retinoblastoma is under control the cataracts can be corrected with surgery.

CHEMOTHERAPY

Chemotherapy is the treatment of cancer using a combination of specific anti-cancer drugs.

Systemic Chemotherapy
Unlike focal therapy where treatment is given directly to the eye, chemotherapy is given to the entire body through the bloodstream. Chemotherapy can be an effective treatment for retinoblastoma tumors that are too large to be controlled by laser and cryotherapy alone. Chemotherapy is also used to treat tumors that are located very near the optic nerve or centre of vision. It can reduce the size of tumors without scarring large and visually essential areas of the retina. While chemotherapy is very effective, it is not enough to eliminate all active tumor. When the tumors have shrunk to a smaller size and/or away from visually important areas, treatment will be completed by laser and/or cryotherapy.
Chemotherapy is given intravenously through a device called a port-o-cath. A port-o-cath is a small device that is surgically inserted under the skin on the child’s chest and is attached to large blood vessels. The chemotherapy drugs are delivered via the port-o-cath directly into the bloodstream without risk of harm to the surrounding tissues. The chemotherapy drugs travel through the bloodstream to enter the blood supply of the tumor where they begin to destroy it. If systemic chemotherapy is being considered, parents will have in depth conversations with a doctor specializing in the treatment of cancer, and specifically chemotherapy (an oncologist), who will outline the treatment plan, drugs to be used and their possible side effects, and both short and long-term follow up requirements.

Local Chemotherapy (Sub-Tenon’s Carboplatin Injections)
Local chemotherapy refers to the injection of one of the chemotherapy drugs (Carboplatin) behind the eye. This method of treatment offers an increased dose of chemotherapy directly reaching the tumor and is used to address difficult-to-treat tumors, often located close to the optic nerve or centre of vision. The injections are given while the child is asleep during an EUA. The incision is so small that it does not require stitches, and generally heals on its own in a few days. Treatments are repeated every three weeks for several months. This type of treatment generally causes significant swelling that can last between two and five days. A cool compress may help ease the child’s discomfort, or, in some cases anti-swelling medication may be used.

RADIOTHERAPY

Worldwide, radiotherapy is now rarely given as the primary treatment for retinoblastoma due to the high risk of inducing second primary, non-retinoblastoma cancers, cosmetic side effects, and the fact that excellent results are achievable with other treatment options.
Scientific studies indicate that patients with heritable retinoblastoma (see the genetics section) who were treated with external beam radiation (EBR), particularly before the age of one, have an increased risk (up to 50%) of developing a second non-retinoblastoma cancer over their lifetime.
Notwithstanding the risks, EBR remains a useful treatment for retinoblastoma when chemotherapy and focal therapy have failed to control the tumor(s), the tumor has spread beyond the eye or in the attempt to save the last eye which has some visual potential.
Radiation therapy is a painless, invisible form of energy (like X-rays) used as a medical treatment. Treatments are usually given for several minutes each day, over a period of several weeks. During radiation treatment for retinoblastoma the child wears a mask that has been moulded specifically for him. The mask prevents the child from moving during treatment and allows a more precise delivery of the radiation dose. Some children may need to be sedated to help keep them still during treatment.
When the radiation treatment is complete the child will continue to undergo EUAs at various intervals to monitor the effects of the radiation. The benefits of radiation treatment are not seen immediately and may continue to show up for several months.
Regardless of when EBR is being considered as treatment for retinoblastoma, the potential benefits of radiation therapy must be weighed against the potential risks for each patient.

ENUCLEATION

The process of removing an eye while leaving muscle tissue intact is known as enucleation.  For many cases of retinoblastoma, and particularly unilateral cases, enucleation is considered the primary treatment.  Removal of the eye in unilateral, non-heritable cases is curative.  While the child will suffer some peripheral vision loss as a result of the removal of an eye, the risks associated with attempted treatment, including spread of the tumor beyond the eye, are generally viewed as too great.  Removal of the eye also spares the child invasive chemotherapy and its inherent risks.  Bilateral cases of retinoblastoma, because of the threat of complete vision loss, are often treated more aggressively.  An eye is generally removed only if there is a significant threat of the tumor spreading beyond the eye. 

Can you tell which eye is real and which is the prosthesis?

The enucleation surgery normally lasts about two hours and is performed under a general anasthetic. The actual orbital implant, the shape of a ball, is inserted into the socket and the muscles are then attached around it to provide mobility to the artificial eye. The orbital implant will remain in place for life unless complications occur. For this reason the largest ball possible is fitted for young children so that the eye socket will have adequate support as it grows.

After the eye is removed, extensive bandages are placed on the eye to keep pressure on the socket to prevent swelling. These bandages are removed before the patient is discharged normally about 48 hours after the surgery.  Bruising and swelling of the surrounding tissue is common.

It is normal for doctors to place a temporary conformer into the socket immediately after the enucleation. This allows the tissues to properly heal before a permanent prosthesis is fitted for the child, about 6-8 weeks later.  The conformer may either be clear or painted like an eye.  While every effort will be made to enhance cosmetic appearance, how well it fits is the priority in selecting a conformer.

Once healed, a mould will be taken of the child’s socket which is then used by an ocularist to produce a prosthesis specifically for the child. The mould may be taken during an examination under anesthetic or at the ocularist’s office with the child awake.  The prosthetic sits under the eye lid and over the conjunctiva and muscles that contain the orbital implant. The tissue inside the eye is pink in colour and closely resembles that of the tissue found inside of one’s mouth.   The ocular prosthetic will match as closely as is possible your child’s natural eye, and is important to stimulate normal socket growth as the child grows.

Prosthetic Eyes

The creation of a prosthetic eye for your child is part art, part science.  A mould will be made of your child’s socket after it has healed following removal of the eye, and at any time a new eye is needed.  From the mould a prosthetic eye will be crafted.  The prosthesis itself is normally made of either plastic or silastic.   The iris is hand painted to ensure an exact match, and the eye is veined for a realistic appearance. 

A child’s prosthesis should be replaced every few years to ensure optimal fit and appearance.  It is possible to have the prosthesis modified, or “built-up” until a new eye can be made.   Children, particularly small children, grow very quickly, and frequent visits to the ocularist may be necessary for children under five (perhaps as often as every three or four months).  In adulthood the prosthesis is normally replaced once every 3-5 years. It may be necessary to have an ocularist polish the prosthesis annually to keep protein and bacteria build up to a minimum.

The prosthesis can easily be removed from the socket by hand, or by using a small, specially designed suction cup.  It is generally recommended to take the eye out once a month for cleaning, but beyond that the eye can be left in place. In fact, excess handling may cause the eye socket to become irritated.

A list of ocularists in Canada can be found on the Canadian Society of Ocularists website at www.cso-sco.ca.