Chemotherapy for retinoblastoma

Chemotherapy uses drugs to destroy cancer cells. These drugs target rapidly dividing cells throughout the whole body. This means that chemotherapy kills cancer cells but it can also damage healthy cells.

With most types of chemotherapy, the drugs travel through the blood to reach and destroy cancer cells all over the body, including cells that may have broken away from the primary tumour. This is described as systemic therapy.

Sometimes chemotherapy is used as a regional therapy. Regional therapy is given to a specific area of the body.

Chemotherapy is usually used to treat retinoblastoma. Your childʼs healthcare team will use what they know about the cancer and about your child’s health to plan the drugs, doses and schedules.

Chemotherapy may be used alone or along with other cancer treatments. Chemotherapy may be used to:

• destroy cancer cells in the body
• shrink a tumour before other treatments such as surgery (called neoadjuvant chemotherapy)
• destroy cancer cells left behind after surgery and reduce the risk that the cancer will come back (recur) (called adjuvant chemotherapy)
• prepare for a stem cell rescue to treat advanced retinoblastoma that has spread outside the eye (called extraocular retinoblastoma) or come back outside the eye
• relieve pain or control the symptoms of advanced retinoblastoma (called palliative chemotherapy)

Chemotherapy may affect how puberty develops in children. It can eventually affect their fertility, which is the ability to get pregnant or get someone pregnant. If possible, talk to the healthcare team about fertility options before treatment begins.

Chemotherapy for retinoblastoma can be given as systemic or regional therapy.

Systemic chemotherapy is often used to shrink a tumour before other treatments such as cryotherapy, thermotherapy, laser surgery or radiation therapy. It may also be used after these treatments to destroy any cancer cells left behind.

The chemotherapy drug combination used for systemic therapy is carboplatin, etoposide and vincristine.

Systemic chemotherapy is often given by a needle in a vein (intravenously or by IV). Usually a special device called a central venous catheter is used to safely give the drugs. Itʼs put in place at the start of chemotherapy and left until treatment is finished. Find out more about a central venous catheter.

The following kinds of regional chemotherapy may be used to treat retinoblastoma. Children may be given a general anesthetic or sedative depending on the type of chemotherapy used.

Intra-arterial chemotherapy is injected into the main artery that carries blood to the eye (called the ophthalmic artery). A thin, long, hollow, flexible tube (called a catheter) is inserted into a large artery on the inner thigh and slid up to the ophthalmic artery. Chemotherapy is then given through the catheter into the ophthalmic artery. The drugs melphalan, carboplatin and topotecan may each be used alone or in combination for intra-arterial chemotherapy.

Intravitreal chemotherapy is injected into the jelly-like substance in the eye (called the vitreous humour). It’s used to treat cancer that has spread throughout the eye. Intravitreal chemotherapy may be used in combination with systemic chemotherapy and intra-arterial chemotherapy. The drugs melphalan and topotecan may each be used alone or in combination for intravitreal chemotherapy.

Periocular (subtenon) chemotherapy is injected into the tissues around the eye. The drugs topotecan and carboplatin may be used for periocular chemotherapy.

Intrathecal chemotherapy is given to the brain and spinal cord (called the central nervous system, or CNS). Intrathecal chemotherapy is given through a lumbar puncture into the space containing the cerebrospinal fluid (CSF). Intrathecal chemotherapy is used to treat retinoblastoma that has spread to the brain. The drug topotecan may be used for intrathecal chemotherapy.

High-dose chemotherapy may be used to treat retinoblastoma that is outside of the eye (called extraocular retinoblastoma).

After high-dose chemotherapy, a stem cell transplant is done to replace the stem cells that are damaged or destroyed by the chemotherapy drugs. This is called a stem cell rescue. The stem cell transplant uses stem cells from your childʼs own blood (called an autologous stem cell transplant). The stem cells are collected from the blood before high-dose chemotherapy is given. The drugs doxorubicin and cyclophosphamide may be used for high-dose chemotherapy and stem cell rescue.

Find out more about a stem cell transplant.

Side effects of chemotherapy will depend mainly on the drug, the dose, how itʼs given and your child’s overall health. Tell the healthcare team if your child has any side effects you think might be from chemotherapy. The sooner you tell them of any problems, the sooner they can suggest ways to help your child deal with them.

Common side effects of systemic chemotherapy for retinoblastoma include:

• hair loss
• sore mouth and throat
• loss of appetite
• nausea and vomiting
• low blood cell counts
• diarrhea
• constipation
• fatigue
• increased risk of infections
• increased risk of bleeding (low platelet count)

There are fewer side effects from regional chemotherapy than from systemic chemotherapy because regional chemotherapy usually doesn’t affect the entire body. Common side effects of regional chemotherapy for retinoblastoma include:

• detached retina
• swelling in the eyelid
• bleeding inside the eye
• drooping eyelid
• loss of eyelashes or eyebrows
• weakening of the muscles that move the eye
• eye and vision problems

Other side effects, called late effects, can develop months or years after treatment for retinoblastoma. Find out more about the late effects of treatments for retinoblastoma.

Find out more about chemotherapy and side effects of chemotherapy. To make the decisions that are right for your child, ask the healthcare team questions about chemotherapy.

Details on specific drugs change regularly. Find out more about sources of drug information and where to get details on specific drugs.