Gliadel implants are a new way of giving a chemotherapy drug called carmustine to people with certain types of brain tumour. They are mainly used for high-grade gliomas when surgery to remove or reduce the size of (debulk) the tumour is possible. At present, Gliadel implants are not a standard treatment in the UK and so are not widely available.

This information describes Gliadel implants, how they are used, and some of the possible side effects. Although carmustine (the drug used in the implant) has been available for a long time, this is a new way of giving it. This treatment is not suitable for everyone with a high-grade brain tumour. At present it is licensed for people who are going to have major brain surgery. They may have just been diagnosed with a high-grade glioma or their brain tumour may have come back following previous treatment.

If you have any further questions you can ask your doctor or nurse at the hospital where you are having your treatment, or speak to one of our cancer support service nurses.

Gliadel implants are small wafers, or discs (about the size of a five pence coin), which slowly dissolve after they are placed in the brain. They contain the chemotherapy drug carmustine (also known as BCNU). As the implants dissolve, the drug is slowly released and treats tumour cells that could not be removed by surgery.

Gliadel implants are placed inside the brain during an operation to remove or debulk the tumour. This means having an operation called a craniotomy, which involves opening the skull. You will need a general anaesthetic for this surgery. The surgeon will cut the scalp and the piece of skull over the tumour, remove the tumour itself and then place up to eight implants in the space where the tumour was. This means that chemotherapy can be delivered directly to the site of the brain tumour. The surgeon will then replace the piece of skull and stitch the flap of scalp back in place.

There is more detailed information about brain surgery in our section on brain tumours. 

The implants dissolve slowly over 2–3 weeks, releasing carmustine into the surrounding brain tissue. This means it is not necessary to have the implants removed. This type of treatment is only given once.

Each person’s reaction to treatment is different. Some people have very few side effects, while others may experience more. The side effects described here will not affect everyone who has Gliadel implants. We have outlined some of the possible side effects, so you can be aware of them if they occur.

Surgery

There are always risks from any type of surgery to the brain and these risks may be very slightly increased if you have Gliadel implanted. However, you may have experienced some of the side effects mentioned here either as a result of the brain tumour itself, or as a result of the surgery (rather than the Gliadel implant). It is important to report any new or worsening symptoms to your doctor such as:

• seizures
• confusion or disorientation
• fever
• pain/headaches
• rash
• visual disturbance
• problems with infection (the risk of this is slightly higher in people who have had Gliadel implants as opposed to surgery alone).

It can be alarming to see a list like this but it is important to remember that these risks are not common. We have listed them just so that you can be aware of what to look out for. Your neurosurgeon should talk things over with you before your operation and can answer any questions you may have about what the treatment involves and possible side effects.

Chemotherapy  

The amount of carmustine which gets into the bloodstream is so small that any side effects of chemotherapy are likely to be less than when the drug is given by tablets, or by injection into a vein.

Carmustine can reduce the production of white blood cells by the bone marrow, making you more prone to infection. You will therefore be asked to have a blood test to check that your bone marrow is working well and producing enough blood cells around ten days after the implants are inserted.

If you are worried about any symptoms which you think may be due to the treatment, even if they are not listed here, you can discuss them with your doctor or nurse specialist.

Risk of blood clots Cancer can increase your risk of developing a blood clot (thrombosis), and having chemotherapy may increase this risk further. A blood clot may cause symptoms such as pain, redness and swelling in a leg, or breathlessness and chest pain. Blood clots can be very serious so it is important to tell your doctor straightaway if you have any of these symptoms. However, most clots can usually be successfully treated with drugs to thin the blood. Your doctor or nurse can give you more information.

Other medicines It is unlikely that chemotherapy given in this way will interact with any other drugs you may be taking. However, it is important that your doctor is aware of any medicines that you take, including over-the-counter drugs, complementary therapies and herbal drugs.

Fertility It is possible that treatment with Gliadel implants may cause permanent infertility. You may wish to discuss fertility preservation with your specialist before starting treatment.

ContraceptionIt is not advisable to become pregnant or father a child while having treatment with Gliadel implants as the developing foetus may be harmed. It is necessary to use effective contraception while taking this drug, and for at least six months afterwards. You may wish to discuss this with your doctor.

Breast feeding is not advised while having treatment with Gliadel implants.

This section is based on our Gliadel implants factsheet which has been compiled using information from a number of reliable sources, including:

• Westphal M, et al. Gliadel wafer in initial surgery for malignant glioma: long-term follow-up of a multicenter controlled trial. Acta Neurochirurgica, 2006. 148: 269–275.
• Carmustine 7.7mg implant (Gliadel). Scottish Medicines Consortium. 2005.
• Westphal M, Hilt et al. A phase 3 trial of local chemotherapy with biodegradable carmustine (BCNU) wafers (Gliadel) wafers) in patients with primary malignant glioma. Neuro-Oncology 5,  2003. 79–88.
• Brem H, et al. Placebo-controlled trial of safety and efficacy of intraoperative controlled delivery by biodegradable polymers of chemotherapy for recurrent gliomas. Lancet. 2003. 345: 1008–1012.

For further references, please see general bibliography.