Chemotherapy (chemo) is the use of anti-cancer drugs to treat cancer. Chemo can be given in different ways to treat retinoblastoma.
Chemo drugs can be injected into a vein (IV) or given by mouth. These drugs enter the bloodstream and reach throughout the body. This is known as systemic chemotherapy.
Systemic chemo is given in cycles, with each treatment followed by a rest period to give the body time to recover. Each chemo cycle typically lasts for a few weeks, and the total length of treatment is often several months.
Some of the chemo drugs used to treat retinoblastoma include:
Most often, 2 or 3 drugs are given at the same time. A standard combination is carboplatin, vincristine, and etoposide, although for very small tumors, only carboplatin and vincristine may be enough. Other drugs might be used if these are not effective.
Sometimes instead of systemic chemotherapy, the chemo is injected directly into the ophthalmic artery, the main artery that supplies blood to the eye. In this newer technique, a very thin catheter (a long, hollow, flexible tube) is inserted into a large artery on the inner thigh and slowly threaded through the blood vessels all the way up into the ophthalmic artery. (This is done with the child asleep under general anesthesia.) The chemo is then infused into the artery. The drug used most often is melphalan, but other drugs such as carboplatin and topotecan can also be used. This process may then be repeated every few weeks, depending on how much the tumor shrinks.
Because the chemo is put directly into the artery feeding the eye, doctors can use much smaller doses of chemo drugs (less than 10% of the doses used for systemic chemo). Therefore, there are fewer side effects from the chemo.
Results so far with this technique in eyes with advanced tumors have been promising, generally with good tumor control and few side effects. In many cases it has allowed doctors to save an eye that otherwise would have needed to be removed.
In this newer approach, a tiny needle is used to inject a chemo drug (typically melphalan or topotecan) directly into the vitreous humor, the jelly-like substance inside the eye. This is sometimes used (along with systemic or intra-arterial chemo) to treat tumors that are widespread within the eye and have not been helped by other treatments.
Chemo may be used in different situations:
Systemic chemo: Chemo drugs can affect cells in the body other than cancer cells, which can lead to side effects.
The side effects of chemo depend on the types and doses of drugs used, and how long they are given. Possible short-term side effects include:
Most of these side effects go away after treatment is finished. There are often ways to lessen these side effects. For example, drugs can be given to help prevent or reduce nausea and vomiting. Be sure to discuss any questions about side effects with your child’s cancer care team, and let them know if your child has side effects so they can be managed.
Along with the effects listed above, certain chemo drugs can cause specific side effects. For example:
Intra-arterial chemo: Much lower doses of chemo are used in this approach, so the side effects tend to be limited to the eye area. Possible side effects include:
Possible long-term side effects are not yet clear, as this technique is still fairly new. Treatment might affect the small blood vessels in and around the eye, although it’s not yet known if this might affect vision as the child gets older. This approach also exposes the child to some radiation, because real time x-rays are used to help guide the catheter into place. It’s not yet clear if (or how much) this might raise cancer risk later in life.
Intravitreal chemo: As with intra-arterial chemo, the side effects from this newer technique seem to be limited to the eye and nearby areas. Each treatment might damage the retina slightly, which might affect vision.
In the past, there was concern that placing a needle into the eye to give the chemo might open a small hole that could allow tumor cells to spread outside of the eye. However, studies have found that this risk is very low,
and doctors now use techniques that lower this risk even further.
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Last Revised: December 3, 2018