Goals of Treatment ~
The goals of treatment for a child with retinoblastoma are threefold
1. to save the child’s life
2. to save at least one eye
3. to protect the vision
There are several ways to treat retinoblastoma depending on the size, location and multiplicity of tumors as well as the child’s age, status of the opposite eye and systemic condition. The treatment methods include chemoreduction, thermotherapy, laser photocoagulation, cryotherapy, plaque radiotherapy, external beam radiotherapy and enucleation. These are often used in combination.
Chemoreduction is a method of using intravenous chemotherapy to reduce retinoblastoma to a small size so that the residual tumors can be eradicated with focal treatment methods like thermotherapy or cryotherapy. Chemoreduction is used in nearly all children with bilateral retinoblastoma and about 25% of children with unilateral retinoblastoma. This technique involves delivery of intravenous chemotherapy each month for 6 months. The delivery takes about 2 days of each month and is usually performed in Philadelphia at Children’s Institute of Philadelphia. Each chemotherapy session is coupled with an examination under anesthesia so that treatment of the tumor scars can be done the same day.
Retinoblastoma before chemoreduction
Retinoblastoma after chemoreduction
Thermotherapy is a laser method in which the residual tumor is heated for 5 to 15 minutes to a temperature that kills the cells. It is focal so that the surrounding tissue is unaffected. It typically leaves no external scars on the eye, but some children might show an irregular pupil after treatment.
Laser photocoagulation ~
Laser photocoagulation is a method to treat a small retinoblastoma by closing the blood vessels to the tumor with heat. This causes no external scars on the eye, but leaves a small scar on the retina.
Cryotherapy involves the use of a probe the size of a pencil placed on the eye to deliver a focal freeze for about 1 minute through the wall of the eye into a tumor inside the eye. Surrounding tissue is usually unaffected from this treatment. It typically leaves no external scars on the eye, but the eye is often swollen for 2 or 3 weeks.
Plaque radiotherapy ~
Plaque radiotherapy is a method of giving focal x-ray treatment to a small part of the eye by using a piece of metal, called a plaque. The plaque has implanted radiation and it is sutured temporarily onto the eye directly over the retinoblastoma. The child stays in the Institute for several days (usually 3 to 7 days) while the radiation plaque is in place. The radiation dose to the retinoblastoma is quite focal and limited to the eye itself with little radiation elsewhere to the body. After the correct dose is given, the plaque is removed in the operating room and the child is discharged. Eye drops will be prescribed to be used 3 times a day for 3 weeks. The eye heals well over a few weeks. Long term concerns include vision loss from cataract or retinal swelling. We have not seen radiation related second cancers following plaque treatment.
External beam radiotherapy ~
External beam radiotherapy is a method of x-ray treatment to the entire eye by a radiation machine. This is available at only a few experienced centers worldwide. It takes about 4 weeks (Monday through Friday) in which small doses of radiation are given to achieve the final dose. External beam radiotherapy can cause the eye to feel irritated, dry, look red and the patient might loose the eyelashes temporarily. This generally resolves, but the child is also at risk for long term problems like vision loss from cataract or retinal swelling. There is also a risk for radiation related second cancers, especially in children with bilateral retinoblastoma.
Enucleation is a method of removing the entire eyeball. The eyelids and muscles of the eye remain. This is used for eyes that have large tumors or eyes that have developed painful glaucoma. All other methods of treatment are considered before advising enucleation, but many patients have life-threatening large tumors that necessitate enucleation. Following enucleation, an implant is placed in the empty orbit and allowed to heal for 1 or 2 months. Then, an artifical eye (prosthesis) is made to match the remaining eye. The cosmetic appearance is generally outstanding with a natural appearance and comfortable fit as well as some movement of the eye. Protective lenses made of polycarbonate are advised to be worn at all times in the form of glasses during the day or goggles during activities or sports.
Child with left prosthesis.
Recommended reading for vision in one eye is a book entitled “A Singular View. The Art of Seeing with One Eye“ by Frank Brady, available online at www.amazon.com.