Chronic myeloid leukaemia (CML)

Risks and causes of chronic myeloid leukaemia (CML)

We don’t know what causes most cases of chronic myeloid leukaemia (CML). But we do know that exposure to radiation can increase your risk of developing CML.

What is a risk factor?

Anything that can increase your risk of getting a disease is called a risk factor.

Different cancers have different risk factors. Having one or more of these risk factors doesn't mean you will definitely get that cancer.

High energy radiation (ionising radiation)

Exposure to high energy (x-rays or gamma rays) is linked to a very small increased risk of developing . CML is one type of acute leukaemia. This could be through medical tests such as x-rays and , or having for cancer.

The health risks of radiation from tests such as x-rays are generally very low and it is important you have these tests to get the right diagnosis and treatment. Doctors keep your exposure to radiation as low as possible and only do them when they are necessary.

Although having radiotherapy in the past has been linked with an increased risk of cancer, the risk is balanced by the need to treat the original cancer.

Find out more about ionising radiation and cancer

Are there other causes?

Stories about possible cancer causes are often in the media and it can be hard to know what’s true and what’s not. You may have heard of something that isn’t included here. This is because we only include a risk factor in this information if it is supported by good quality evidence.

Find out about common cancer myths and questions on the causes of cancer

Reducing your risk

There are ways you can reduce your risk of cancer.

Find out more about reducing your risk

Last reviewed: 19 Jun 2025

Next review due: 19 Jun 2028

Symptoms of CML

Many people with chronic myeloid leukaemia (CML) won't have any symptoms at all. Some of the common symptoms can include feeling full or tummy discomfort, swollen lymph nodes, feeling weak and weight loss.

Getting diagnosed with CML

You usually start by seeing your GP if you have symptoms that could be due to CML. Or your GP might arrange to see you if you have had an abnormal blood test result. They will then decide whether to refer you for further tests or to see a specialist.

Survival for CML

Survival for chronic myeloid leukaemia (CML) depends on several factors including age. These figures can only give you a general guide about survival for CML.

Daily life and CML

CML will always be part of your life. It is different to other types of cancer that go away when treatment ends. Find out about daily life and support with CML.

What is CML?

Chronic myeloid leukaemia (CML) is a type of cancer that affects the blood and bone marrow. It usually develops very slowly.

CML main page

CML starts in the white blood cells called granulocytes. It often develops slowly and treatment can keep it under control for many years. Find out more.