Growth factors for acute myeloid leukaemia

Growth factors are natural substances that stimulate the bone marrow to make blood cells. Doctors can now make some growth factors artificially and use them as treatments. They increase the number of white blood cells and stem cells in the blood. A commonly used growth factor is filgrastim (G-CSF or Neupogen).

You have growth factors as an injection under the skin. This is usually in the tummy (abdomen), or into an arm or a leg. You may have growth factors as part of your treatment for two reasons

• To help you make white cells more quickly after chemotherapy
• To produce extra stem cells before having stem cells collected (a stem cell harvest).

Chemotherapy kills off your healthy white blood cells, as well as the leukaemic ones. You are at risk of infection while your white cell count is low. If you get an infection, your body is not able to fight it off as well as usual. So infections can make you more ill than they normally would. They can even be life threatening. A low level of white cells is called ‘neutropenia’. You may have growth factors while you have neutropenia, to help your white blood cell count go up more quickly.

Some doctors prefer not to give you growth factors. Early research into routine use of growth factors has shown that they may help the white cell count to recover. But they actually don’t make much difference to the overall number of infections people have. Or to the number of courses of antibiotics they need.

Doctors call this a stem cell harvest. You may have growth factors to prepare you for this.

Daily growth factor injections make your bone marrow grow many more stem cells than normal. These extra stem cells spill over into the bloodstream. They can then be collected by a machine. They will be frozen and kept until you need to have them back as a stem cell transplant, after intensive chemotherapy. There is more information about stem cell transplants in the 'about cancer treatment' section of CancerHelp UK.

Growth factor injections can have side effects. Some people have itching around the injection site. You may have some pain in your bones after you have had a few injections. Your bone marrow is making so many blood cells that it can get quite crowded and make your bones ache. You can usually control the pain easily with a mild painkiller, such as paracetamol. It usually lasts a few days.

Some people get a high temperature (fever) when they have growth factors. Tell your doctor if this happens to you, because fever can also be a sign of infection.