Cancer Screening: Which Tests Are Recommended, and When

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What is cancer screening?

Cancer screening is testing for cancer in people who have no symptoms of it. The goal of an early detection test is to find disease at a stage where treatment tends to work better, or to find growths that could turn into cancer later. A cancer check, a screening exam, a cancer blood test: different names, same job.

Scale is what makes the question worth asking. About 2,001,140 new cancer cases and 611,720 cancer deaths were projected in the United States for 2024, and cancer mortality has been falling since 1991. That decline belongs to several forces at once: less smoking, earlier detection for some cancers, and better treatment. Screening is one contributor, not the whole story.

Screening vs. diagnostic testing: what's the difference?

A screening test looks for cancer before symptoms appear and is not meant to diagnose cancer. A diagnostic test is what happens next: it exists to find out what is causing a symptom or an unusual screening result. No screening result, on its own, rules cancer in or out.

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Which cancer screenings are recommended, and when?

Four cancers have screening tests with proven benefit for average-risk adults: breast, cervical, colorectal, and lung. Everything else falls into one of two buckets, either screening reserved for people with a defined higher risk, or tests that simply are not established for routine use.

Expert bodies do not always agree on the details, so the same cancer can carry two defensible start ages and two defensible intervals. Where that happens, both positions are worth knowing, because the choice between them is usually a personal one.

Breast cancer screening

The clearest guideline disagreement in cancer screening is about when mammography should start. One position: screening mammography every two years for women aged 40 to 74. The other: regular mammography beginning at 45, annually from 45 to 54 and then biennially or annually from 55, with the option to start at 40 for women who want to. Two questions remain genuinely open, with evidence judged insufficient on supplemental ultrasound or MRI for dense breasts and on screening women 75 and over.

One belief worth retiring: the clinical breast exam. It is not recommended as screening for average-risk women at any age.

Cervical cancer screening

Cervical screening has two attributed positions, and they differ on both the start age and the preferred test. The first sets cytology every three years from 21 to 29, then from 30 to 65 either cytology every three years, high-risk HPV testing alone every five years, or cotesting every five years. The second, issued in 2020, starts at 25 and makes primary HPV testing every five years the preferred strategy, a sign of how steadily HPV testing is displacing the Pap smear.

This is also the one place where risk-reduction framing is genuinely earned. Cervical screening can find precancer that is managed before it ever becomes cancer, lowering the likelihood of invasive disease, and cervical cancer deaths fell from 2.8 to 2.3 per 100,000 women between 2000 and 2015.

Colorectal cancer screening

Colorectal screening is now recommended for all adults 50 to 75 and for adults 45 to 49, and the reason the age moved down is a genuine shift in who is getting the disease. An estimated 10.5% of new colorectal cancers occur in people under 50, and incidence among adults 40 to 49 rose almost 15% between 2000-2002 and 2014-2016, part of a documented rise in early-onset colorectal cancer. The age-45 recommendation first appeared in 2018, three years before it became broader consensus.

There is no single colorectal test. The accepted menu splits into stool-based options, including annual FIT, and structural exams, including colonoscopy every 10 years. The benefit is real and smaller than most people assume: among 84,585 adults, an invitation to colonoscopy lowered 10-year colorectal cancer risk from 1.20% to 0.98%, an 18% relative reduction, with no statistically significant effect on colorectal cancer death and only 42% of those invited actually going.

Lung cancer screening

Lung screening is the most eligibility-driven test on the list: annual low-dose CT for adults 50 to 80 with a 20 pack-year smoking history who currently smoke or quit within the past 15 years. A second guideline keeps the age and pack-year criteria but drops years-since-quitting entirely, so people who quit decades ago remain eligible, and it asks that low-dose CT follow a shared decision-making conversation rather than a default yes.

Two randomized trials point the same direction. Low-dose CT reduced lung cancer mortality by 20.0% compared with chest radiography in one, and a second found a 24% relative reduction in men alongside a 2.1% referral rate for suspicious nodules.

Prostate cancer screening

For men 55 to 69, PSA screening is an individual decision made after discussing the benefits and harms, and PSA screening is not recommended for men 70 and over. Expert groups generally advise against routine PSA testing for average-risk men, largely because of overdiagnosis and false positives.

"Individual decision" sounds vague until the numbers are on the table. Screening is associated with about 1.3 fewer prostate cancer deaths and about 3 fewer metastatic cases per 1,000 men screened over roughly 13 years. Against that, about 1 in 5 men who have a radical prostatectomy develop long-term urinary incontinence, and 2 in 3 develop long-term erectile dysfunction.

Screenings that depend on your risk, not your age

Some screening is triggered by a person's risk profile rather than by a birthday, and certain tests are suggested only for people with a high risk of a specific cancer.

The organizing principle is easy to miss: a test being available does not make it a screening test. Several familiar tests are not recommended for average-risk adults, either because the evidence is unresolved or because the harms outweigh what they find.

Family history and inherited risk

Risk-based screening starts with a risk assessment, not with a test. Brief familial risk assessment is recommended for women with a personal or family history of breast, ovarian, tubal, or peritoneal cancer, or an ancestry associated with BRCA1/2 mutations, with genetic counseling and testing only if that assessment points there. For everyone else, routine risk assessment and testing are not recommended.

Inherited risk is rarer than the conversation around it suggests. BRCA1/2 mutations occur in roughly 1 in 300 to 500 women and account for 5-10% of breast cancers and 15% of ovarian cancers.

Skin, liver, and ovarian screening

Three tests, three different verdicts. For skin, the evidence is insufficient to judge the balance of benefits and harms of a clinician's visual skin examination in adults without symptoms, which means the question is unresolved, not that skin checks are discouraged. Melanoma makes up about 1% of skin cancers but causes most skin cancer deaths, and people with darker skin are more often diagnosed at later stages.

Liver surveillance shows what a well-aimed test looks like. In people with cirrhosis, surveillance was associated with more early-stage detection, more curative treatment, and better survival, with 8.8-27.5% experiencing mostly mild surveillance-related harms. Ovarian screening shows the opposite: it is not recommended for women without a known high-risk hereditary syndrome because it does not reduce ovarian cancer deaths and can lead to unnecessary surgery. That is why CA-125 and transvaginal ultrasound are not routine screening tests.

What about multi-cancer detection blood tests?

Multi-cancer early detection blood tests look for cancer signals from a single blood draw, no such test has FDA approval, and whether these tests help people without symptoms is still unknown and being tested in randomized trials. Where they are used, they sit alongside guideline-recommended screening rather than in place of it.

What that looks like in a screening population is worth seeing in full. Among 6,621 adults aged 50 and over without signs or symptoms of cancer, a cancer signal was detected in 92 people (1.4%). Of those, 35 were true positives and 57 were false positives, and the median time to a diagnostic answer was 79 days: 57 days for true positives, 162 days for false positives. A positive signal buys months of follow-up testing, not an answer.

The central limitation shows up in a different group. Among patients urgently referred with possible cancer symptoms, which is not a screening population, the test showed 66.3% sensitivity and 98.4% specificity, with sensitivity climbing from 24.2% in stage I to 95.3% in stage IV. Detection is weakest for exactly the early-stage disease screening exists to catch.

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How to read your result: normal, abnormal, and what comes next

An abnormal or positive screening result does not mean a person has cancer. It means more testing is needed to find out what caused the result, and most of the time the answer is something other than cancer.

Here is the usual sequence:

1. The screening result returns, either normal or abnormal.
2. A repeat or confirmatory test may be done, such as a second mammogram view or a repeat stool test.
3. Diagnostic imaging or a biopsy follows if the finding warrants it.
4. The outcome is either a cancer diagnosis or an all-clear.

The waiting has a cost, and it is worth naming honestly rather than dramatizing. False-positive mammogram results raised short-term anxiety measured shortly after screening, but the difference had disappeared by 12 months, with no measurable decrement in health utility. Women who had a false positive were more likely, not less, to intend to screen again.

The limits of screening: false positives, false negatives, and overdiagnosis

Screening carries real harms alongside its benefits, and knowing the four main ones is what makes an informed choice possible.

• False positive. A result that suggests cancer when none is present. In lung screening, 24.2% of low-dose CT screens were positive and 96.4% of those positives were false.
• False negative. A result that misses cancer that is actually there, which is why a normal result is not a guarantee.
• Overdiagnosis. Finding a cancer that would never have caused symptoms or harm in a person's lifetime, estimated at 15.4% of screen-detected breast cancers, about 1 in 7, under biennial screening from 50 to 74.
• Overtreatment. The treatment of an overdiagnosed cancer, with all of its side effects and none of its benefit.

Over a screening lifetime, those single-test numbers compound. Across 903,495 women, the 10-year cumulative probability of at least one false-positive recall was 49.6% with tomosynthesis versus 56.3% with digital mammography under annual screening, and 35.7% versus 38.1% under biennial screening. Interval and age move that number far more than the machine does. Overdiagnosis is best read as a range rather than a single figure, with estimates spanning 0% to 54% across studies and 11% to 22% within randomized trials.

The clearest illustration of why earlier is not automatically better comes from ovarian screening. Among 202,562 postmenopausal women followed for a median of 16.3 years, annual CA-125-based screening shifted stage at diagnosis, with 47.2% more stage I disease, and still produced no significant reduction in ovarian or tubal cancer deaths. Diagnosing the same cancer earlier stretches the time a person is known to have it, so survival can look longer without anyone living longer. That is lead-time bias, and it is the reason survival statistics alone never settle whether a screening test works.

How to decide what screening is right for you

Choosing a screening test is a shared decision between a person and their clinician, weighing individual risk against the specific benefits and harms of that test. It is why several guidelines call explicitly for a shared decision-making conversation instead of a default yes.

Five questions make that conversation more useful:

• What can this test find, and what can it miss?
• What happens if the result comes back abnormal?
• How likely is a false positive for someone my age and risk level?
• Does my personal or family history change the recommendation?
• When should the test be repeated?

Pair your cancer screening schedule with a Superpower blood panel

Guideline-recommended cancer screening is the part of your health that runs on a schedule set by age and risk, and nothing replaces it. A broad baseline of blood work sits alongside that schedule as context on how the rest of your body is doing. Superpower tracks 150+ lab tests over two blood draws across metabolic, hormonal, and organ health — an annual draw plus a built-in retest of key markers later in the year — and members can add the Grail Galleri Multi-Cancer Test, a single-draw blood test that screens for signals of 50+ cancers and is used alongside, not instead of, guideline-recommended screening.