Retinoblastoma

The retina is a thin layer of nerve tissue that lines the back of the eye. It turns light into signals that travel to the brain along the optic nerve. Retinoblastoma is a cancer that forms in the retina. It can be in one eye (unilateral) or in both eyes (bilateral). MedlinePlus Genetics says about one in three children with retinoblastoma has cancer in both eyes.

It is a cancer of the very young. The U.S. National Cancer Institute (NCI) says two-thirds of cases are found before age 2. Children with cancer in both eyes are usually diagnosed in their first year of life.

Doctors describe retinoblastoma by where the cancer is. Intraocular retinoblastoma is still inside the eye. Extraocular retinoblastoma has spread outside it. It may be in the tissue around the eye, the brain and spinal cord, or other parts of the body such as the bones, bone marrow or liver. This difference shapes treatment more than anything else.

Almost all retinoblastomas are caused by changes in a gene called RB1. This gene normally works like a brake on cell growth. When both copies of RB1 stop working in a young retina cell, the cell can divide out of control and form a tumor.

There are two forms. In the heritable form, one changed copy of RB1 is in every cell of the body from the start. NCI says this is 25% to 30% of cases. The change can come from a parent, but most often it is new: it happened in an egg or sperm cell, or very early in pregnancy. All children with cancer in both eyes, and about 15% of children with cancer in one eye, are thought to have this form.

In the nonheritable form, which is 70% to 75% of cases, both RB1 changes happen by chance and only in the eye. It usually affects one eye and cannot be passed on to the child's own children. A blood test for RB1 changes, together with genetic counseling, shows which form a child has. Once the family's exact change is known, brothers, sisters and other relatives can be tested for it.

The most common first sign is a white pupil (leukocoria). Instead of the usual red reflection, the pupil looks white, and parents often first see it in a flash photo. The next most common sign is eyes that point in different directions (crossed eyes, or strabismus). Other signs include a red or painful eye, a larger-than-normal eyeball, or a cloudy look to the colored part of the eye.

Without treatment, the tumor keeps growing. It can grow through the wall of the eye into the tissue around it, or along the optic nerve toward the brain. It can also get into the bloodstream. Spread through the blood most often reaches the bones and bone marrow, and less often the liver. In high-income countries, few children are diagnosed after the cancer has spread. In poorer countries it is much more common.

Children with the heritable form face extra risks. NCI says 5% to 15% of them develop a separate tumor in the brain, usually in the pineal gland, which is called trilateral retinoblastoma. It typically appears between 20 and 36 months of age. They also have a higher chance of other cancers later in life, such as bone and soft tissue sarcomas, melanoma, and lung or bladder cancer. Radiation treatment, especially before age 1, raises that risk further.

Much of the care happens while the child is asleep under general anesthesia. Most eye exams, freezing treatment, eye removal and intra-arterial chemotherapy are done this way. Treatments are often repeated. Boston Children's Hospital says intra-arterial chemotherapy takes three to four sessions for each eye on average, about four weeks apart.

Follow-up lasts for years. Children with the heritable form can keep forming new tumors for a few years, so their eye exams are usually done every 2 to 4 months for at least 28 months. Brain MRI scans may be done to look for trilateral retinoblastoma. CT scans are usually avoided, to limit radiation. A child who has an eye removed wears an artificial eye, and Boston Children's Hospital says these children can still play sports with protective eyewear.

Late effects can include problems with seeing or hearing. If an eye is removed, the bone around it may change in shape and size until an artificial eye is fitted. This is most likely in children younger than 3. Some children have changes in mood, thinking, learning or memory. Survivors of the heritable form need lifelong checks for second cancers. Genetic counseling helps families plan eye exams for brothers, sisters and future children. Babies born to a parent who had retinoblastoma have their first eye exam in the first month of life.

No donor is involved in the usual care of retinoblastoma. Most children are treated with chemotherapy, eye treatments, surgery or radiation, and never need a stem cell transplant.

When high-dose chemotherapy is used for cancer that has spread outside the eye, the stem cells given back are the child's own, collected before the high-dose treatment (autologous). They do not come from a relative or a registry volunteer. European transplant experts (EBMT) do not list retinoblastoma in their 2025 recommendations, and NMDP's transplant consultation guidelines do not list it either. EBMT says donor (allogeneic) transplants for children with solid tumors should only be explored in clinical trials at very experienced centers.

People who join a blood stem cell registry help patients with other conditions, such as leukemia, who need a donor's cells.