Intra-Arterial Chemotherapy (IAC)
Intra-arterial chemotherapy is delivered directly into the eye, via a catheter inserted into the femoral artery.
When Intra-Arterial Chemotherapy Is Used
As primary therapy, IAC can be used to treat medium to large sized intra-ocular retinoblastoma.
This treatment can only be used when the optic nerve is clearly seen to be normal, and there is no suggestion of risk that tumour can spread outside the eye.
As salvage therapy, IAC can be effective to control residual, vision-threatening tumour, as long as there is no suggestion of risk that cancer can spread outside the eye.
Intra-arterial chemotherapy should be considered only at a highly experienced retinoblastoma treatment centre that has a clinical research process in place to carefully document the potential benefits and complications.
How Intra-Arterial Chemotherapy Is Given
The child receives a general anaesthetic.
An interventional radiologist passes a micro-catheter through the femoral artery (in the groin) up to the ophthalmic artery carrying blood to the eye to be treated. Fluoroscopy (x-ray imaging) guides the catheter through the body to the ophthalmic artery.
Chemotherapy, either one drug or combinations of melphalan, topotecan, and/or carboplatin, is infused over 30 minutes, after which the catheter is removed.
On waking, the child must lay flat for 4-6 hours to prevent bleeding following the catheterization.
Anti-cancer drugs can be delivered directly into the eye, without the side effects associated with systemic chemotherapy, and without the risks associated with inserting a needle into the eye containing cancer.
Fluoroscopy exposes the child to radiation. This is not recommended for children with a known or suspected constitutional RB1 mutation as radiation exposure increases life-long risk of developing other cancers.
Observed ocular side effects include swelling of the optic nerve, retinal detachment, bleeding, ophthalmic artery spasm, loss of blood supply to the eye and irreversible loss of vision.
Transient side effects of the procedure include eyelid swelling, a droopy eyelid and increased blood flow to the forehead.
Risk of Under Treatment
When cancer fills the eye, microscopic cancerous cells may invade the optic nerve or the outer layers of the eye, and this will not be seen on eye exam. The only way to know if cancer cells have spread outside the eye is to examine the eye under a microscope after it has been surgically removed. This pathology examination helps doctors know if the child needs chemotherapy to treat cancer outside the eye, to protect their life.
Intra-arterial chemotherapy does not treat cancerous cells that may have already spread to the outer layers of the eye or to the optic nerve. A child in this situation treated with IAC may appear to have an excellent response to treatment, but relapse with cancer in the brain or bone marrow some months or year later.
Extraocular retinoblastoma is extremely difficult to treat, even with aggressive chemotherapy and bone marrow transplant. Some children have died following apparently successful IAC treatment that delayed vital eye removal surgery.
Further Reading From Our Blog
October 2022: Under-Treatment and Over-Treatment of Retinoblastoma
September 2018: Intra-Arterial Chemotherapy (IAC) for Retinoblastoma Made Simple
September 2018: Always Life Before Eye – So Why Are Curable Children Dying?
May 2017: Visualizing Cancer Treatment
Questions To Ask the Doctors
- Is my child’s cancer at risk of spreading outside the eye?
- Is this treatment part of a clinical trial?
- Can I have a copy of the clinical trial protocol?
- How many times have you done this procedure?
- What side effects have you observed?
- What side effects have been reported?
- How many of your patients relapsed with cancer outside their eye after IAC?
- How do you know there is no risk to my child’s life in doing IAC?
- What chemotherapy drugs will you use?
- Will my child need more than one IAC treatment?
- How often will you treat the eye/s?
- Will my child receive other treatments in combination with IAC?
- How will you combine these treatments?
- How might this treatment impact my child’s vision?
- What follow-up care will my child receive?
- Will my child be followed by a paediatric oncologist?