Medical Oncologist
CION Cancer Clinics
ATM mutation: which cancers it raises, and by how much | CION Cancer Clinics
An inherited ATM fault mainly raises the chance of breast cancer in women, and also raises the chance of pancreatic and prostate cancer. The rise is real but moderate, clearly smaller than with BRCA1 or BRCA2. This page sets out each cancer linked to ATM, how strong the evidence is for each, and why your own risk depends on your family as much as on the gene. At CION Cancer Clinics, our oncologists explain what a gene result means for you and your family, and plan the checks that follow.
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Medically reviewed by Dr. Naresh GunduConsultant Medical Oncologist · MBBS, DNB (Internal Medicine), DM (Medical Oncology, AIIMS) · last reviewed September 2026, next review due September 2027
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On this page
- Which cancers does an ATM mutation raise?
- How strong is the link for each cancer?
- How does a counsellor estimate your own risk?
- The words that describe ATM risk, in plain language
- How does ATM compare with BRCA1 and BRCA2?
- Four things people assume about ATM, and what is true
- What this page cannot tell you
- Common questions about ATM cancer risks
The short answer
Which cancers does an ATM mutation raise?
Breast cancer is the clearest. Women with a faulty ATM copy have a moderately raised lifetime risk, well above the general population but below BRCA1 or BRCA2. Pancreatic cancer is also raised in carriers of both sexes, and prostate cancer in men. For other cancers the evidence is weak or mixed.
Moderate risk, in plain terms
Doctors group cancer genes into high, moderate and low risk. ATM sits in the middle. That means the gene matters and changes screening, but it does not usually justify the preventive surgery sometimes discussed for BRCA carriers. Most women carrying ATM never develop breast cancer.
Why the numbers differ between websites
Lifetime risk figures come from studies of different families, countries and variants. Some ATM changes carry more risk than others, and a strong family history pushes the figure up. That is why the number on one website rarely matches another, and why a counsellor works out an estimate for you rather than quoting an average.
A raised risk is not a diagnosis. It is a reason to be checked earlier and more carefully.Cancer by cancer
How strong is the link for each cancer?
The evidence is not equally strong for every organ, and it helps to know which is which.
Breast
The strongest and best-studied link, in women. Yearly breast imaging, started earlier than usual, is the standard response.
What it usually changes
- Breast imaging starts earlier
- MRI is added in some plans
- Surgery is decided on family history, not ATM alone
Pancreas
A raised risk, shown in several studies. Screening is not offered to every carrier. It is usually considered only when a close relative has had pancreatic cancer, and then in a specialist programme.
Prostate
Men carrying ATM have a raised risk, and some studies suggest their cancers may more often be the aggressive kind. An earlier conversation about PSA testing is reasonable. The evidence is still growing.
Ovary and others
A small rise in ovarian cancer risk has been suggested, but it is not strong enough for guidelines to advise removing the ovaries. Links with stomach, bowel and other cancers remain uncertain.
Not sure whether this applies to you?
Ask an oncologistHow your figure is worked out
How does a counsellor estimate your own risk?
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The exact variant is checked
Most ATM faults stop the gene working entirely. A few specific changes behave differently and may carry more or less risk. Your report names which you have.
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Your family tree is drawn out
Who had breast, pancreatic, prostate or other cancers, on both sides, and at what age. A strong family history can outweigh the gene in shaping your risk.
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Your own history is added
Your age, sex, past breast biopsies and any previous cancer all feed into the estimate.
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A risk model may be used
Some counsellors use computer tools that combine all of this into one figure. These tools were mostly built on Western families and should be read with that in mind.
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The plan follows the estimate
A higher estimate brings closer screening. A lower one may mean ordinary screening for your age, with a clear point at which to review it.
On your report
The words that describe ATM risk, in plain language
- Moderate-penetrance gene
- A gene where a fault raises risk clearly, but not to the level of BRCA1 or BRCA2.
- Lifetime risk
- Your chance of developing a cancer at any point over a normal lifespan. It is not the chance of getting it this year.
- Relative risk
- How many times higher your risk is than the average person's. It often sounds bigger than it feels in daily life.
- Truncating variant
- A change that cuts the gene short so it stops working. Most ATM faults on reports are this kind.
- Missense variant
- A change that swaps one building block. A few ATM missense changes carry a higher breast risk. Many are uncertain.
- Heterozygous
- One faulty copy and one working copy. Almost all adult ATM results describe this.
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Side by side
How does ATM compare with BRCA1 and BRCA2?
ATM
BRCA1 or BRCA2
Moderately raised breast risk
High breast risk
Ovarian risk small, if any
Ovarian risk clearly raised
Preventive surgery not advised on the gene alone
Preventive surgery often discussed
Breast screening starts earlier
Breast screening starts much earlier
Commonly believed
Four things people assume about ATM, and what is true
"ATM is just as dangerous as BRCA."
It is not. ATM raises breast cancer risk moderately, and the ovarian link is weak. Treating an ATM result as though it were BRCA can lead to surgery that brings no clear benefit.
"I am a man, so ATM does not matter to me."
Men carrying ATM have a raised risk of pancreatic and prostate cancer, and can pass the fault to daughters and sons. A man's result matters to him and to his whole family.
"Nobody in my family had cancer, so my result is a mistake."
Moderate-risk faults often sit quietly in families for generations. Small families, early deaths from other causes and relatives who were never diagnosed can all hide a pattern. The result is still real.
"I should have my breasts removed to be safe."
Guidelines do not recommend preventive mastectomy on an ATM result alone. It may be discussed if the family history is very strong. Risk-reducing surgery is one option among several, and our pages on it explain the trade-offs.
Being straight with you
What this page cannot tell you
It cannot give you a personal risk figure. That needs your exact variant, your family tree and your own history, weighed by someone trained to do it. What your specific variant means is a question for the counsellor who ordered the test.
It cannot settle what the evidence has not
ATM has been studied for less time, and in fewer families, than BRCA. Studies of Indian carriers are small, and most risk figures come from Europe and North America. Pancreatic and prostate risks in particular are still being refined. Where the answer is uncertain, a good counsellor will say so plainly.
Who this does not apply to
If your report lists an ATM variant of uncertain significance, it is not a positive result, and none of these risks should be applied to you. If your ATM result came from a tumour test rather than a blood test, it may not be inherited at all. Tumour testing is covered in our targeted therapy pages.
If you are holding an ATM report and are not sure what kind it is, call the helpline and someone will arrange for it to be read properly.Questions we are asked
Common questions about ATM cancer risks
How much does ATM raise breast cancer risk?
Moderately. Carriers have a lifetime breast cancer risk clearly above the general population, but below that of BRCA1 or BRCA2 carriers. The figure varies by study and by family history, which is why a counsellor works out an estimate for you rather than quoting a single number from the internet.
Should I have an MRI as well as a mammogram?
Many plans for ATM carriers add breast MRI to yearly mammograms, especially where the family history is strong. The start age and the mix of scans depend on your risk estimate. Your breast team will set it out. MRI availability and cost near your district are worth asking about.
Does ATM raise ovarian cancer risk?
Possibly a little, but the evidence is not strong enough for guidelines to recommend removing the ovaries on an ATM result alone. If ovarian cancer runs in your family, that history may change the plan, and your counsellor will discuss it with you.
Should I be screened for pancreatic cancer?
Usually only if a close blood relative has had pancreatic cancer. Then screening with MRI or an endoscopic ultrasound may be offered in a specialist programme. Screening every ATM carrier is not recommended, because the tests have limits and can lead to unnecessary procedures.
Does ATM change my breast cancer treatment?
It can. Your surgeon and oncologist will want to know the result before planning. It rarely rules out any standard option, including radiotherapy, but it can shape the discussion about the other breast. Some newer drugs are also being studied for ATM-related cancers.
Should my brothers and sons be tested?
They can be. If a parent carries the fault, each child has a one in two chance of carrying it. For men, the result matters for pancreatic and prostate checks and for their own children. Testing is a personal choice, and a counsellor can help the family decide who goes first.
Will my ATM result affect my insurance?
India has no dedicated law on genetic discrimination in insurance, and the position has been argued in court rather than settled by statute. Read proposal forms carefully, and raise the question with your counsellor before relatives are tested, not afterwards.
Where can I get my ATM result explained in Telugu?
A genetic counsellor can go through the report with you and your family in Telugu. Call the CION helpline and describe what your report says. Someone will arrange a counselling appointment at the centre nearest you.
Your Specialists
Meet CION's oncologists. Bring your family history or genetic report to them.
Our medical oncologists see people with a strong family history of cancer, arrange genetic counselling and testing where it fits, and plan the checks that follow.
Medical Oncologist
Dr. C. Raghavendra Reddy
MBBS(Gold Medal), DNB(General Medicine), DM(Medical Oncology)(Gold Medal)
Medical Oncologist
Dr. Bharati Devi Gorantla
MBBS, MD(General Medicine), DM(Medical Oncology)(Adyar,Chennai), ECMO, MRCP SCE(UK)
Medical Oncologist
Dr. Owais Mohammed
MBBS, MD (General Medicine), DrNB (Medical Oncology), ECMO, MRCP SCE (Medical Oncology) (UK)
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Sources
- MedlinePlus Genetics — ATM gene
- National Cancer Institute — Genetics of Breast and Gynecologic Cancers (PDQ)
- National Cancer Institute — Genetics of Prostate Cancer (PDQ)
- NCCN — Genetic/Familial High-Risk Assessment: Breast, Ovarian, Pancreatic, and Prostate
This page is general information, not a prescription. Do not change or stop any treatment based on what you read here. If anything is worrying you, contact your own treating team — or call our helpline and we will help you reach the right specialist.
Keep reading
Related pages
The ATM gene: what it does and why it mattersHow the gene works before it goes wrongSurveillance for ATM carriersThe checks that follow from these risksATM and pancreatic and prostate riskA closer look at the two risks men often missATM positive: what happens nextThe first steps after a positive result
Talk to us
Want to know what your ATM result means for you?
A genetic counsellor can turn your report and family history into a personal estimate and a screening plan. We can arrange that conversation, in Telugu if you prefer. One helpline serves every CION centre.