About Retinoblastoma and Treatments

Retinoblastoma is a cancer that arises from the retina, a light-sensitive layer of cells in the back of the eye that sends nerve impulses along the optic nerve to the brain, which forms a visual image. The cancer usually affects children younger than 5 years of age; the average age of diagnosis is 12 to 18 months.

Approximately 300 children in the United States develop retinoblastoma each year. With current treatments, the survival rate is greater than 95%. Early detection and intervention are essential to prevent the cancer from spreading.

Below are some important terms related to retinoblastoma and its treatment.

Exam under anesthesia

An exam performed while a child is asleep under general anesthesia to conduct specialized testing, including photographs and ultrasound imaging of the eyes.

Extraocular muscles

Muscles attached to the outside of the eyeball that control eye movement.

Genetic (hereditary) form of retinoblastoma

Ten percent of children who get retinoblastoma have a family history; 90% develop the disease without any family history. Forty percent of children with retinoblastoma have a genetic or hereditary form of the disease, even if no one in their family has the disease. These children are at risk of developing retinoblastoma in both eyes. Their doctors will closely watch both eyes during the treatment course. Those with hereditary retinoblastoma have a 45% risk of passing it to their offspring.

Leukocoria

An abnormal white reflection in the pupil, also known as white pupillary reflex, which can often be seen in photographs. A normal retinal reflex has a red-orange glow. Many serious eye diseases, including retinoblastoma, can cause leukocoria, so an ophthalmologist must evaluate this finding.

Malignant

When abnormal cells divide without control, and in particular, invade adjacent tissues and other parts of the body.

Oculoplastic surgeon

A surgeon specializing in diseases of the orbit (bones of the eye socket), lacrimal gland (responsible for tears), and eyelids. These surgeons often perform reconstructive and cosmetic procedures around the eyes.

Ocular Implant

An implant placed into the eye socket after an eyeball is surgically removed. The most commonly used implants have many tiny pores, which allow blood vessels to integrate with the implant. Some implants also have holes that allow extraocular muscles to be sutured to the implant. Other times, the surgeon might suture the muscles to the sclera (the white outer coating of the eye) that encases the implant. The integration of extraocular muscles allows for some movement that corresponds with movements of the other eye.

Ocular Prosthesis

Also known as an artificial eye, an ocular prosthesis is placed over an implant and fits under the eyelids. It is custom-made for each patient to provide a natural appearance.

Ocularist

A specialist trained in the fabrication and fitting of ocular prostheses.

Treatments

Options may include cryotherapy, enucleation, intraarterial or intravitreal chemotherapy, laser photocoagulation, or plaque brachytherapy.

Cryotherapy:

A freezing treatment that uses a metal probe to freeze cancer cells from the outside of the eye to the inside directly over the tumor on the retina. It is generally used for smaller tumors toward the peripheral edge of the retina or if laser treatment is not effective.

Enucleation:

The surgical removal of the entire eye. During the procedure, a surgeon removes the eye and places an implant in the eye socket. Extraocular muscles are attached to the implant, and the prosthesis is usually fitted 6-10 weeks after surgery. Medical experts recommend enucleation for large or advanced tumors.

• Primary enucleation: The first and only treatment to prevent the further spread of the tumor.

• Secondary enucleation: Enucleation after alternative treatments have failed.

Intra-arterial chemotherapy:

Chemotherapy delivered directly to the artery supplying blood to the eye. The procedure is performed under general anesthesia. The surgeon punctures the artery around the hip and inserts a catheter into the artery supplying the eye to deliver the chemotherapy medicine slowly. The procedure requires repeated cycles.

Intravitreal chemotherapy:

Chemotherapeutic medications delivered directly into the gel (vitreous) in the back of the eye under general anesthesia. This treatment reaches tumor cells or satellite tumors that are in the vitreous and cannot be treated well with other forms of chemotherapy. A small dose of chemotherapy is injected with a tiny needle. On withdrawing the needle, cryotherapy is used to prevent any cells from spreading.

Laser photocoagulation:

A laser treatment that uses heat to destroy cancer cells. The laser beam is aimed through the dilated pupil to the retina. Laser treatment may be used alone for smaller tumors or combined with chemotherapy for larger tumors. There is usually minimal discomfort for the patient after laser treatment.

Plaque brachytherapy:

A radiation treatment in which radioactive, rice-sized pellets, or “seeds,” are placed very close to the tumor for a short period. This kind of radiation treatment provides a large dose of radiation to the tumor, minimizing the radiation exposure to the rest of the body. Surgery is performed under general anesthesia to suture a small, gold disc holding radioactive seeds to the eye. The disc, or plaque, is removed after 3-5 days via a second surgery.