The short answer
Cancer becomes more common with age because gene changes build up over a lifetime and the body's ability to repair DNA goes down. Age is the most important risk factor overall, according to NCI.
Age is the most important risk factor for cancer overall.
Gene changes accumulate in cells over many years.
The body's ability to repair damaged cells declines with age.
Cancer can still occur at younger ages, including in children.
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The simple version
Age is the single biggest risk factor for cancer. Cancer risk climbs sharply as people get older. This is true for cancer overall, and for most individual cancer types. This does not mean cancer is inevitable with age. It means the odds shift, and knowing that can help you take screening seriously as you get older.
How much the risk actually changes
The numbers make the pattern clear. Among people under age 20, cancer strikes fewer than 26 people out of every 100,000 each year. Among people 60 and older, that number climbs past 1,000 per 100,000. The median age at cancer diagnosis overall is 67. For specific cancers, the typical age at diagnosis varies: 63 for breast cancer, 66 for colorectal cancer, 68 for prostate cancer, and 71 for lung cancer.
Why this happens
NCI says that most often, cancer-causing genetic changes accumulate slowly as a person ages, leading to a higher risk of cancer later in life. Cells have ways of fixing damaged DNA, and NCI says the body's ability to do this goes down as we age. This is part of the reason why there is a higher risk of cancer later in life.
What this means for you
Getting older is not something you can avoid, and this is not a reason for alarm. Ask your doctor which cancer screening tests are recommended for you.
The pattern across common cancers
The median age at diagnosis differs by cancer type, but all of the common ones above are typically diagnosed in later life.
Cancer at a younger age still happens
None of this means younger people are safe from cancer. Age is a strong pattern, not a rule that applies to every person or every cancer. Do not dismiss a persistent symptom just because you feel too young for cancer to be likely.
What to do with this information
You cannot change your age, but you can talk with your doctor about what is right for you. Tell your doctor about your family's cancer history.
What to ask your doctor
Ask what cancer screening tests are recommended for your age, and when to start. Ask whether your family history changes that timeline for you specifically. Ask what symptoms, at any age, should prompt a visit rather than a wait-and-see approach.
Sources
Common questions
Why does age raise cancer risk so much?
Cancer develops after gene changes build up in a cell. The longer a person lives, the more time those changes have to accumulate, which is why risk climbs with age.
Does the body change with age too?
Yes. NCI says the body's ability to repair damaged DNA goes down as we age, which is part of the reason for higher cancer risk later in life.
Does this mean young people don't get cancer?
No. Cancer can occur in children and young adults. It is much less common than in older adults.
Can anything offset age-related risk?
You cannot change your age. Ask your doctor about screening and other steps that are right for you.
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Written by: Cancer ExplainedSources last checked: 2026-07-14 what this meansLast updated: 2026-10-16Next planned review: 2028-07-14
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How this page was created
Cancer Explained does not originate medical claims. Every page restates guidance already published by the National Cancer Institute, the CDC, the USPSTF and the FDA, in plain language, with the source cited so you can check the original yourself. AI does the translating and organizing; automated checks test claims, citations, clarity and safety before anything publishes, and this is translation and navigation, not clinical judgment. Nothing here is personal medical advice, and no page can account for your particular situation.
Editorial status: Source checked — This page was written with AI assistance and then compared with the sources listed on it, looking for statements those sources do not back up. That check is not a sentence-by-sentence record and can miss errors. It is not a medical review, and it does not confirm the page is complete or right for your situation.
Human medical review: not completed. Pages here are not signed off by a clinician before they publish. That is not an oversight we are quietly working around: we restate published guidance and cite it, so the authority belongs to the source rather than to us, and every page names where its claims come from — you can verify us instead of trusting us. Where a volunteer clinician has reviewed a page, their name and credentials appear on it; where no name appears, no clinician has checked it. We are glad to have reviewers and are recruiting them, and we do not hold pages back waiting for one. Use this site to understand your situation and to ask better questions of the people treating you.
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