AT and Cancer

People with Ataxia Telangiectasia (AT) have a higher risk of developing certain types of cancer. This page explains why the risk is increased, what symptoms to look out for, and how cancer is managed in people living with AT.

Children and adults with Ataxia Telangiectasia (AT) have a significantly increased risk of developing cancer. Figures* published in 2011 from the UK and the Netherlands suggest an incidence of approximately 22%, with around 65% of cases occurring during childhood [1]. Data from a French cohort published in 2015 reported a similar incidence of about 25% [2].

The ATM (Ataxia Telangiectasia Mutated) gene plays a crucial role in DNA repair. In individuals with AT, this gene does not function properly and fails to produce the necessary protein, leading to impaired DNA repair and an increased risk of cancer developing.

Important Information About Cancer and AT

For people with AT and their families, as well as professionals involved in their care, it is important to be aware of the possibility of cancer development and that any unusual or different symptoms be reported and investigated by a doctor as soon as possible. Please see our Cancer Statement for more information.

Understanding Cancer Risk in AT

Key questions below to help you understand how cancer relates to AT.

Why does AT increase cancer risk

AT affects the body’s DNA repair system, which can lead to cell changes that increase cancer risk. The immune system may also be weaker, making it harder to fight abnormal cells.

What cancers are more common

People with AT are more likely to develop:
 
Lymphoma, leukaemia, breast cancer in adult women with AT (see our AT and Breast Cancer information), and occasionally other cancers, though these are less common.

What symptoms should we look for

For people with AT and their families, as well as professionals involved in their care, it is important to be aware of the possibility of cancer development and that any unusual or different symptoms be reported and investigated by a doctor as soon as possible. Please see our Cancer Statement for more information.
 
Symptoms can vary, but may include: unexplained tiredness, persistent infections, swollen glands, unusual bruising or bleeding, and ongoing pain or discomfort. Any persistent or concerning symptoms should be checked by a doctor.

How is cancer treated in people with AT

Treatment may need to be adapted because people with AT can be more sensitive to certain therapies. Specialists familiar with AT will help plan the safest and most effective approach.

Are treatments different for people with AT

Yes. Some treatments may need lower doses or alternative approaches. Care teams will work together to balance effectiveness with safety. Treating cancer in children and adults with AT can be particularly challenging. This is due to heightened sensitivity to conventional treatments such as radiotherapy, as well as complications arising from weakened immune systems. However, growing knowledge and clinical experience in managing cancer in individuals with AT have improved care. We can provide contact details of clinicians with relevant expertise to support local medical teams in delivering appropriate treatment.
In February 2026 we published our new guide to Best Clinical Care, which can be viewed here, see pages 21–25 for more information on AT and Cancer. (This has been written for the care of children with AT however it is still relevant for adults).

We’re here to support you

If you have AT and have been diagnosed with cancer – or if you have
any questions about anything on this page – please get in touch with our Support Team.
You can contact Kay Atkins or Anne Murray on 01582 760733,
or email [email protected].

*References supporting the figures in the introduction:
1. Reiman A, Srinivasan V, Barone G et al. Lymphoid tumours and breast cancer in ataxia telangiectasia; substantial protective effect of residual ATM kinase activity against childhood tumours. Br J Cancer. 2011 Aug 9;105(4):586-91. doi: 10.1038/bjc.2011.266. Epub 2011 Jul 26.
2. Suarez F, Mahlaoui N, Canioni D et al. Incidence, presentation, and prognosis of malignancies in ataxia telangiectasia: a report from the French national registry of primary immune deficiencies. J Clin Oncol. 2015 Jan 10;33(2):202-8. doi: 10.1200/JCO.2014.56.5101. Epub 2014 Dec 8.