About 39.2% of men and women will be diagnosed with cancer at some point in their lifetime, based on the most recent data from the National Cancer Institute. That’s roughly 2 in 5 people. But that single number doesn’t tell you much about your own risk, which varies enormously depending on your age, sex, lifestyle, and family history.
Overall Lifetime Risk
The 39.2% figure represents a population average across all cancer types, ages, and backgrounds. It includes everything from highly treatable skin cancers to rarer aggressive forms. This number has remained relatively stable over recent years, though survival rates have improved significantly for many types.
Your individual risk could be meaningfully higher or lower than that average. A lifelong nonsmoker at a healthy weight with no family history of cancer faces very different odds than someone with multiple risk factors. The sections below break down what shifts those odds in either direction.
How Age Changes the Picture
Cancer is overwhelmingly a disease of aging. The median age at diagnosis is 67, meaning half of all cancers are detected after that point. Among people under 20, fewer than 26 out of every 100,000 develop cancer in a given year. By ages 45 to 49, that climbs to about 350 per 100,000. Once you pass 60, the rate exceeds 1,000 per 100,000.
This steep climb happens because cancer typically requires multiple DNA mutations to accumulate in the same cell before it turns malignant. The longer you live, the more times your cells divide, and the more opportunities those errors have to pile up. It also means that if you’re in your 20s or 30s worrying about cancer, your near-term risk is quite low, even though your lifetime risk still reflects decades of future exposure.
Risk for the Most Common Types
A few cancers account for a large share of diagnoses. Knowing the lifetime risk for each puts the overall 39.2% figure in better context.
- Breast cancer (women): About 13.0% of women will be diagnosed at some point, making it the most common cancer in women.
- Prostate cancer (men): About 13.2% of men will be diagnosed, making it the most common cancer in men.
- Colorectal cancer: About 3.9% of men and women will be diagnosed. Risk rises sharply after age 50, though rates have been increasing in younger adults in recent years.
These numbers are averages. A woman with a BRCA1 gene mutation, for instance, faces a breast cancer risk several times higher than 13%. A man with a strong family history of prostate cancer is similarly above the baseline.
How Much Is Genetic?
Inherited gene mutations directly cause up to 10% of all cancers. These are cases where a parent passed down a faulty copy of a gene that normally helps prevent tumors, giving cancer a head start. Well-known examples include BRCA mutations linked to breast and ovarian cancer, Lynch syndrome linked to colorectal and other cancers, and certain mutations tied to thyroid or kidney cancers.
The remaining 90% or more arise from random DNA copying errors that accumulate over a lifetime, or from damage caused by outside forces like tobacco smoke, UV radiation, or chronic infections. Even in families where cancer seems common, shared lifestyle and environmental exposures often play as large a role as shared genes.
Factors You Can Actually Control
A major global analysis published in 2024 found that 37.1% of all new cancer cases, about 7.1 million worldwide, were linked to 30 modifiable risk factors. In practical terms, roughly 4 in 10 cancers have a preventable component. The split between sexes is notable: nearly half of cancers in men (45.4%) were tied to modifiable risks, compared with about 3 in 10 in women (29.7%).
The single biggest modifiable risk factor is smoking, responsible for 15.1% of all cancer cases globally. Among men specifically, smoking accounted for 23.1% of new cancers. Among women, the leading modifiable risk was preventable infections (such as HPV and H. pylori), associated with 11.5% of cases, followed by smoking at 6.3%.
After tobacco and infections, the next most significant factors were:
- Alcohol consumption: 3.2% of all cases globally, with a higher share in men (4%) than women.
- High body mass index: A meaningful contributor especially for women, linked to 3.4% of female cancers. Excess body fat raises levels of hormones and inflammatory signals that promote cell growth.
Workplace exposures to carcinogens, things like asbestos, diesel exhaust, certain industrial chemicals, and radiation, account for an estimated 2 to 8% of cancers worldwide. People in construction, mining, manufacturing, and firefighting face higher occupational risk.
Putting Your Own Risk in Perspective
The 39.2% lifetime figure is a starting point, not a destiny. Several realities make it less alarming than it first sounds. First, “lifetime” means over 80-plus years. Your risk in any given year, especially before age 50, is quite small. Second, many of the cancers captured in that statistic are highly treatable when caught early. Prostate cancer, for example, has a five-year survival rate above 97%.
Your personal risk profile depends on a combination of things you can’t change (age, sex, inherited genes) and things you can (whether you smoke, how much you drink, your weight, whether you stay current on vaccines like HPV, and whether you follow recommended screening schedules). The data consistently shows that not smoking, maintaining a healthy weight, limiting alcohol, and getting vaccinated against cancer-causing infections represent the highest-impact steps you can take. Together, those four factors cover the vast majority of preventable cancer risk.
If cancer runs in your family, especially the same type across multiple close relatives or cancer diagnosed at unusually young ages, genetic counseling can clarify whether you carry a hereditary mutation and what additional screening or prevention options make sense for you.