Cancer

The cancer burden#

Cancer is the second leading cause of death in the US and the leading cause among people younger than 85. The American Cancer Society (ACS) projects 2,114,850 new cases and 626,140 deaths in 2026, and about 39% of men and women will be diagnosed with an invasive cancer in their lifetime.

Death rates have fallen since 1991, averting 4.8 million deaths, through less smoking, earlier detection, and better treatment. Lung cancer still kills more Americans than colorectal and pancreatic cancer, the next two, combined.

Rising cancer in younger adults#

Colorectal cancer incidence in adults 20 to 49 rose about 3% a year from 2013 to 2022, and it is now the leading cause of cancer death in Americans younger than 50. A 2024 analysis of 23.6 million diagnoses found 17 of 34 cancer types becoming more common in each younger generation, including pancreatic, kidney, small intestine, and uterine cancers. Obesity, diet, and the gut microbiome are suspects; nothing is proven.

The practical lessons: get a first colonoscopy at 40 rather than the guideline age of 45 (see Colorectal cancer), and never dismiss a symptom like rectal bleeding because you feel too young.

Lowering your risk#

A 2024 ACS study attributed 40.0% of cancer cases and 44.0% of cancer deaths in US adults 30 and older to potentially modifiable risk factors. Most have their own chapters; the table shows their share of cancer.

Risk factors you can change#

Smoking. Not smoking is the most powerful cancer prevention step Strong. People who quit before 40 avoid about 90% of the excess risk of death from continuing, and quitting later still helps.

Weight and activity. The World Health Organization's cancer agency (IARC) found sufficient evidence that excess body fat causes 13 cancers, including colorectal, postmenopausal breast, uterine, kidney, liver, and pancreatic. In 1.44 million adults, the most active had lower risk of 13 cancers (observational) Moderate.

Alcohol. Risk rises with every drink, with no safe threshold for cancer; see Avoiding harm.

Sun. In an Australian trial of 1,621 adults, daily sunscreen halved new melanomas over the next decade (11 vs 22) Moderate.

Diet. IARC classifies processed meat as a Group 1 carcinogen and red meat as "probably carcinogenic"; each 50 g of processed meat a day (about two slices of ham) raised colorectal cancer risk about 18%. The highest fiber eaters have 15–30% less colorectal cancer in observational studies Moderate.

Infections. These cancers are unusually preventable.

• HPV vaccine Strong. Swedish women vaccinated before 17 had 88% less invasive cervical cancer, and Scotland recorded no cervical cancers in women vaccinated at 12 or 13. It is routine through 26, and worth getting through 45 if you may have new partners (a shared decision in the guidelines); see HPV. HPV also causes anal, throat, and penile cancers, so the vaccine matters for men too.
• Hepatitis B and C cause liver cancer. Hepatitis B has a vaccine, and hepatitis C pills cure more than 95% of people in 8 to 12 weeks. Every adult should have at least one hepatitis C test (guideline minimum: USPSTF, once from 18 to 79).
• H. pylori stomach infection and HIV also raise cancer risk; see Digestive health for who should be tested for H. pylori, and Infections and vaccines.

Radon. This radioactive soil gas causes about 21,000 US lung cancer deaths a year, the leading cause in never-smokers. Home tests are cheap; see Avoiding harm.

Medicines for high-risk people. Women at increased breast cancer risk should discuss tamoxifen, raloxifene, or aromatase inhibitors Strong. In Lynch syndrome, 600 mg of aspirin daily cut colorectal cancer by about a third over 10 years (CAPP2 trial) Moderate. Both decisions belong with a specialist.

What doesn't prevent cancer#

Daily aspirin for healthy adults Negative. The USPSTF's 2022 aspirin advice no longer counts cancer prevention as a reason to take it, and in 19,114 older adults in the ASPREE trial, aspirin was linked to more advanced cancers and higher cancer death. Lynch syndrome is the exception.

Hereditary risk and genetic testing#

About 5–10% of cancers are caused by a harmful variant inherited from a parent. For carriers the risk can be very high, and knowing changes screening and prevention.

Who should consider testing#

Detailed criteria come from the National Comprehensive Cancer Network (NCCN), but they flag the same patterns the NCI lists:

• A relative with a known harmful variant.
• Cancer at a young age, such as colon cancer before 50 or breast cancer at 50 or younger.
• Several relatives on one side with the same or related cancers (breast and ovarian; colon and uterine).
• More than one primary cancer in one person, or cancer in both breasts or both kidneys.
• Ovarian, pancreatic, male breast, or metastatic prostate cancer in the family.
• Ashkenazi Jewish ancestry with any of the above.

If any of these apply, see a genetic counselor now Moderate. Guideline minimum: the USPSTF recommends a family-history risk tool for women with a personal or family history of breast, ovarian, tubal, or peritoneal cancer or high-risk ancestry, and genetic counseling and testing for those who screen positive. It recommends against routine BRCA testing for everyone else.

The case for testing everyone#

The optimal plan is a one-time clinical-grade multigene panel for every adult, ideally by 30, whatever your family history Moderate. It should cover at least BRCA1, BRCA2, PALB2, and the Lynch syndrome genes, ordered through a clinician or genetic counselor so a positive result comes with a plan.

The reason is that family history misses most carriers. When a Pennsylvania health system sequenced 50,726 patients, 82% of BRCA carriers had never been tested, and about half of those with full histories did not meet testing guidelines. In Nevada, 90% of carriers of BRCA, Lynch, or familial hypercholesterolemia variants had not been identified, and only 25% reported a relevant family history. Testing young matters, because the payoff is earlier MRI, colonoscopy, and preventive surgery: a 2023 US model found population testing for BRCA, Lynch, and familial hypercholesterolemia cost-effective under 40 (about $68,600 per quality-adjusted life-year at 30) but seldom at 50, and a UK and US model found testing all women 30 and older more cost-effective than testing by family history.

The caveats: these are models, not trials; no study has shown that testing everyone lowers deaths; and uncertain results and gaps in insurance protection are real (see below). Guideline minimum: as of October 2026 no US guideline recommends testing people without a personal or family history, so insurers may not pay; ask the lab for its self-pay price before you test.

Counseling, cost, and privacy#

• Counseling first. A genetic counselor reviews your family tree, picks the test, and explains what positive, negative, and uncertain results mean. Many work by video; see the NSGC directory.
• Cost. Insurance usually covers testing when you meet criteria; one large lab says 9 in 10 of its patients pay $0 (company data).
• Uncertain results. A "variant of uncertain significance" is usually reclassified as harmless and should not drive decisions.
• Privacy. Federal law bars genetic discrimination in health insurance and employment, but not in life, disability, or long-term care insurance. Some people buy those policies before testing.

What a positive result changes#

• Screening: annual breast MRI from 25 to 30 for BRCA carriers, frequent colonoscopy for Lynch syndrome, whole-body MRI for Li-Fraumeni.
• Surgery: removing the ovaries and tubes after childbearing lowers ovarian cancer risk in BRCA carriers; some choose preventive mastectomy. Both are irreversible.
• Medicines: aspirin for Lynch syndrome; risk-reducing drugs for some women at high breast cancer risk.
• Family: each first-degree relative has a 50% chance of sharing the variant, and a known family result makes their testing simple.

Screening by cancer type#

Screening means testing people without symptoms. It helps only when early treatment changes the outcome and the benefit outweighs false alarms and overdiagnosis (finding cancers that would never have caused harm). Randomized trials have cleared that bar for a handful of cancers. The optimal plan starts earlier or tests more often than the US Preventive Services Task Force (USPSTF) where specialty societies or strong data support it, and no more often where extra testing adds harm.

Colorectal cancer#

Screening prevents colorectal cancer, not just finds it, because removing polyps stops cancer before it starts Strong. Screening from 45 to 75 prevents an estimated 24 to 28 colorectal cancer deaths per 1,000 people.

The optimal plan Weak (the start age and interval are expert judgment; the benefit of screening itself is proven):

1. First colonoscopy at 40. Colorectal cancer is now the leading cancer killer under 50 (see above), colonoscopy is the one test that both finds and removes polyps, and prevention-focused physicians such as Peter Attia start at 40. Before 45 your plan may not cover it as screening, so ask first.
2. Choose a high-quality endoscopist. Ask for their adenoma detection rate (the share of screening exams that find a precancerous polyp): the 2024 US standard is at least 35%, and each 1-point rise meant 3% fewer cancers between exams in 314,872 colonoscopies. Follow the bowel prep exactly.
3. Repeat every 5 years if it is normal. A single colonoscopy misses about 26% of adenomas and 27% of serrated polyps, and in 1.25 million Kaiser members the protection of a normal exam lasted more than 12 years but slowly faded. Five years leaves a margin for a missed lesion; 10 years is reasonable only after an exam you know was complete, well prepped, and high quality. If polyps are found, what they were sets the next exam, often 3 to 5 years (US Multi-Society Task Force).
4. Don't go shorter, and don't add stool tests. Among 1,256 people rescoped about 5 years after a clean exam, none had cancer and 1.3% had an advanced polyp. Colonoscopy every 1 to 3 years, which some longevity doctors advise, adds bleeding, perforation, and sedation risk for almost no yield, and no study shows that stool tests between normal colonoscopies help.

Guideline minimum: the USPSTF grades screening A for 50–75, B for 45–49, and C (individual decision) for 76–85, with any test in the table below and colonoscopy every 10 years; the ACS also starts at 45. If you will not have a colonoscopy, a yearly FIT or a stool DNA test every 3 years is far better than nothing.

The Shield blood test caught 83% of cancers but only 13% of advanced precancerous polyps, so it does much less to prevent cancer than colonoscopy or stool tests. The ACS calls blood tests "not preferred", for people who will not do anything else, and the USPSTF's 2021 recommendation does not include them. Medicare covers it every 3 years; the cash price is $1,495 (2026). It beats no screening Moderate.

Any positive stool, blood, or CT test needs a colonoscopy, and the benefit depends on it. Medicare now counts the colonoscopy after a positive stool test as part of screening, and many private plans do too; confirm with yours before you test.

Colonoscopy causes serious bleeding in about 15 and perforation in about 3 per 10,000 screening procedures. In the NordICC trial, people merely invited to colonoscopy had 18% less colorectal cancer over 10 years, though only 42% went.

Higher risk. A parent, sibling, or child with colorectal cancer or advanced polyps, inflammatory bowel disease, a hereditary syndrome, or past abdominal radiation can mean colonoscopy only, earlier and more often. Ask for a schedule based on your relative's age at diagnosis.

Breast cancer#

Mammography reduces breast cancer deaths in trials Strong. Per 1,000 women, starting at 40 rather than 50 averts about 1.3 more breast cancer deaths (1.8 for Black women, whose death rate is about 40% higher), at the cost of about 1,376 false positives and 14 overdiagnosed cancers over a lifetime of screening. Standard 2D and 3D mammography (tomosynthesis) are both fine.

The optimal plan follows the American College of Radiology (ACR) and the Society of Breast Imaging: a mammogram every year from 40, which finds smaller tumors and causes fewer interval cancers than every 2 years, at the cost of more callbacks.

Dense breasts hide cancers and raise risk. Since September 10, 2024, every US mammography report must say whether yours are dense. In the Dutch DENSE trial, offering MRI to women with extremely dense breasts halved interval cancers (cancers found between screens), from 5.0 to 2.5 per 1,000 Moderate, with about 80 false positives per 1,000 MRIs. Its effect on deaths is unknown, so supplemental MRI is a reasonable bet, not a proven one; expect some benign biopsies, and check coverage first.

Cervical cancer#

Cervical screening Strong and the HPV vaccine together could nearly eliminate this cancer. Here the optimal plan, the American Cancer Society's, tests less than the USPSTF: a primary HPV test every 5 years from 25 to 65. Most HPV infections clear on their own within a year or two, so early Pap tests mostly find changes that would have gone away, and the USPSTF found that testing more often than every 5 years with an HPV test adds tests and colposcopies without substantially improving benefit.

Sources: USPSTF 2018, USPSTF draft, ACS.

Self-collection. In May 2024 the FDA approved HPV tests on samples you collect yourself in a clinic, and in May 2025 it authorized the first at-home kit, the Teal Wand, which matched clinician collection in a validation study. A positive result still needs an in-person exam. After a hysterectomy that removed the cervix for reasons other than cancer or precancer, screening can stop.

Lung cancer#

Annual low-dose CT (LDCT) of heavy smokers cut lung cancer deaths 20% in the US National Lung Screening Trial and 24% in men in the NELSON trial Strong.

Sources: ACS, USPSTF. A pack-year is a pack a day for a year. The ACS dropped the 15-year cutoff because risk stays high for decades after quitting, so if you quit 20 years ago, ask for the scan anyway. Pair screening with help to quit; radiation dose is covered in Scans and imaging.

Never-smokers should not get screening CT, even with a family history, outside a study: the benefit is unproven Weak and overdiagnosis is real. In a Taiwanese study of 12,011 never-smokers, 17.4% of first scans were positive and only 14% of positives were cancer. Across Taiwan, as CT screening spread among women who mostly never smoked, early-stage lung cancer diagnoses rose more than sixfold while late-stage cancers did not fall, the signature of overdiagnosis. For never-smokers, test your home for radon; see Avoiding harm.

Prostate cancer#

PSA screening is a real trade-off Mixed, and two changes have tilted it toward benefit since the 2018 USPSTF advice. Using MRI to decide who needs a biopsy halved diagnoses of harmless cancers (0.6% vs 1.2%) in the Swedish GÖTEBORG-2 trial of 17,980 men, and active surveillance (monitoring instead of immediate treatment) now spares many men with low-grade cancer surgery or radiation.

The optimal plan Moderate follows the American Urological Association's 2023 guideline at its earliest ages and uses your own numbers to set the pace:

1. Baseline PSA by 45, or at 40 if you are at higher risk: Black men, BRCA2 and other germline carriers, and men with a strong family history. A mid-40s PSA is unusually informative: in a Swedish cohort followed for decades, 44% of prostate cancer deaths occurred in men whose PSA at 45–49 was in the top tenth (1.6 ng/mL or more), while men below the median (0.68 ng/mL) had a 15-year metastasis risk of 0.09%.
2. Repeat by result, as the AUA endorses: under 1 ng/mL, every 2 to 4 years; 1 to 3 ng/mL, every 1 to 2 years. At 60, a PSA of 1 or less carries a 0.5% risk of metastasis by 85, so many such men can stop.
3. If PSA is raised or rising, repeat it, then get a prostate MRI before any biopsy. In the PRECISION trial, MRI first found significant cancer in 38% vs 26% of men and cut insignificant diagnoses by 13 percentage points. A secondary blood test such as the Prostate Health Index, 4Kscore, or Stockholm3 can decide who needs the MRI; Stockholm3 meant about a third fewer MRIs than PSA alone, with the same detection.
4. From 70, decide with your doctor, based on your PSA history and health.

Optimal is not maximal: a biopsy triggered by PSA alone, without an MRI first, adds harm, and a rectal exam has low accuracy as a screening test. Guideline minimum: the USPSTF (2018, grade C) leaves it to an individual decision for men 55 to 69 and advises against it at 70 and older; it found screening prevents about 1.3 prostate cancer deaths and 3 metastatic cancers per 1,000 men over 13 years, while 20–50% of screen-detected cancers are overdiagnosed. Its update has no draft as of October 2026.

Skin cancer#

The optimal plan Weak is a monthly self-check for everyone; a full-skin exam by a dermatologist every 2 years from 40 if you have light skin; and a yearly exam, starting younger, if you have had skin cancer, have a close relative with melanoma, many or atypical moles, fair skin with a history of blistering sunburns, or a weakened immune system. The trade-off is overdiagnosis: US melanoma diagnoses have climbed far faster than melanoma deaths. Guideline minimum: the USPSTF found evidence insufficient to recommend for or against routine clinician skin exams (2023), excluding people with a personal or family history of skin cancer. Details are in Eyes, ears, teeth, and skin.

Liver cancer#

Liver cancer surveillance is for people with liver disease: ultrasound, with or without the blood marker AFP, every 6 months for cirrhosis of any cause and some chronic hepatitis B, per the American Association for the Study of Liver Diseases Moderate. Fatty liver disease is covered in Metabolic health.

Cancers without routine screening#

The ovarian trial holds a lesson for every new test: screening found more early cancers and 24.5% fewer stage IV cancers, yet no fewer women died. Earlier detection is not the same as saving lives.

Multi-cancer blood tests#

Multi-cancer early detection (MCED) tests look for tumor DNA in the blood. Most read the chemical tags (methylation patterns) on circulating DNA, which differ between cancer and normal tissue, so they can flag a "cancer signal" and guess its organ of origin. The appeal is that many deadly cancers, such as pancreatic, ovarian, and stomach cancer, have no screening test at all.

Galleri: the evidence#

Galleri, from Grail, screens for more than 50 cancer types and costs $699 online or $599 through a provider as of October 2026. It needs a prescription and may be HSA or FSA eligible.

What the numbers mean. About 4 in 10 positives are false alarms followed by scans, and the test catches about 4 in 10 cancers overall, far fewer early ones, so a negative result does not mean you are cancer-free.

NHS-Galleri matters most because it was randomized. Galleri quadrupled screen-detected cancers, but stage III diagnoses rose as stage IV fell, so late-stage cancers overall did not drop. Grail stresses the stage IV reduction; the BMJ reported the trial failed its main aim. Both are accurate. Whether fewer stage IV cancers means fewer deaths is unanswered.

FDA status. Grail applied for approval in January 2026. On September 23, 2026, an FDA advisory panel voted 7 to 2 that benefits outweigh risks (6 to 4 on effectiveness) for adults 50 and older, alongside standard screening. As of late October 2026 the FDA had not announced a decision.

Other multi-cancer tests#

The National Cancer Institute's Vanguard study is enrolling up to 24,000 people aged 45 to 75 to test Shield MCD and Avantect, a pilot for a trial of whether MCED testing reduces deaths. That answer is years away.

The case for and against#

Overall the evidence is Mixed: these tests find cancer, but the one randomized trial did not show the benefit it was designed to show.

If you decide to test#

This is an optional extra, a reasonable choice if you can absorb the cost and the occasional false alarm. If you choose it:

• Be up to date on the screening above first, and keep doing all of it; the manufacturers agree.
• Test once a year from 50, the interval and age its maker suggests; start earlier only with a strong reason such as a high-risk family history.
• Arrange follow-up first: who will order the CT or PET-CT if it is positive, and how you will pay.
• Read a negative as "no signal found," not "no cancer," and keep reporting symptoms.
• Don't use it to investigate symptoms; see a doctor.
• Revisit the decision each year as trial results, FDA status, and prices change.

Full-body MRI: the deep dive#

Companies such as Prenuvo and Ezra sell an hour or less in an MRI scanner as a way to "see everything" and catch cancer early. Radiologists, who read these scans for a living, are among the loudest skeptics.

What a whole-body MRI shows#

MRI uses a strong magnet and radio waves, with no ionizing radiation, to image soft tissue. A whole-body MRI strings together fast scans of the head, neck, chest, abdomen, pelvis, and often the spine. Commercial protocols range from about 22 minutes for head to pelvis to 50 to 65 minutes for the fullest packages.

Most rely on diffusion-weighted imaging (DWI), which highlights densely packed tumor cells. Screening scans usually skip intravenous contrast dye, which, with a protocol not tuned to any one organ, gives lower sensitivity and specificity than a targeted diagnostic MRI, according to the Canadian Association of Radiologists.

Companies and prices#

These are list prices from company websites in October 2026. All are self-pay. The IRS lets you count an electronic body scan as a medical expense, and companies say scans may be HSA or FSA eligible.

Check what is covered. A head-to-pelvis scan without the chest is a different product from one with it, though both are sold as "full-body."

What the studies show#

There are no randomized trials of whole-body MRI screening in average-risk adults and no data on deaths. Cohort studies report what the scans find, and several systematic reviews pool them.

Follow-up adds up. In a German population study, 32% of 2,969 people scanned were told of a potentially relevant finding, and their outpatient costs over the next two years ran 11.6% higher than in similar unscanned people. Among 21,651 people scanned at a commercial provider, 7.0% had a pancreatic cyst; most never become cancer, but many trigger years of repeat scans. A 2026 evidence review for Canadian family doctors summed it up as many findings, little benefit.

What the companies report#

• Prenuvo (company data). In a 2025 letter, three Prenuvo employees reported a 2.2% cancer detection rate, with 64% of cancers localized and 68% in organs without a standard screening test. They noted two interval breast cancers (0.2%) in 12 to 16 months, and that the full analysis has not been peer-reviewed.
• Ezra (company marketing). Ezra says its scan helped "6% of our members identify potential cancer"; "potential" means suspicious findings, not confirmed cancers.

Nobody disputes the detection rates, which match the reviews; the dispute is what they mean. Many cancers these scans find, such as small kidney tumors, low-grade prostate cancers, and small thyroid cancers, may never cause harm, and comparing detection rates with mammography misleads, because mammography has trials showing fewer deaths.

What professional bodies say#

• American College of Radiology (2023): insufficient evidence to recommend total-body screening for people without symptoms or risk factors, and no documented evidence it is cost-efficient or prolongs life.
• Canadian Association of Radiologists (2025): "opposes the use of whole-body or full-body MRI as a screening tool in asymptomatic individuals" outside evidence-based indications.
• American College of Preventive Medicine: has also called these scans unnecessary for people without symptoms.
• Abroad: the Netherlands does not permit whole-body MRI screening of healthy people, while Japan and Singapore embrace it (RSNA News, 2026).

No US guideline body recommends whole-body MRI for average-risk adults. For that use the evidence is Weak: it reliably finds things, with no evidence it improves health.

When whole-body MRI is recommended#

For a few rare inherited syndromes, whole-body MRI is standard care Moderate.

• Li-Fraumeni syndrome (TP53 variants): an American Association for Cancer Research panel recommends surveillance including annual whole-body MRI. The first scan round found cancer in 6.9% of 116 carriers at the NCI, a 2025 meta-analysis found 41 of 46 cancers at an early stage, and in Toronto five-year survival was 88.8% with surveillance vs 59.6% without (observational).
• Hereditary paraganglioma and pheochromocytoma syndromes: whole-body MRI every 2 years plus blood or urine tests.

Here the trade-off favors scanning: very high risk, many possible tumor sites, and specialists who know how to handle findings.

What it misses#

The harms#

• Cascades. Most people get at least one finding, and each can lead to more scans, biopsies, and occasionally surgery. Follow-up CT adds radiation.
• Overdiagnosis. Harmless cancers, once found, are usually treated.
• False reassurance. A clean scan is not validated as ruling out cancer, yet it can tempt people to skip colonoscopy or ignore symptoms.
• Cost. About $900 to $4,000 per scan in 2026, with follow-up billed separately.
• Contrast. When gadolinium is used, traces can remain in the body, including the brain, with no known harm.
• Anxiety. Waiting to learn what a "lesion of uncertain significance" means is a harm that falls on healthy people.

Should you get one#

For an average-risk adult, whole-body MRI is an expensive, unproven test that will probably find something, rarely finds a cancer that matters, and has not been shown to extend life. It is not part of the optimal plan. Choosing it anyway is a reasonable personal choice if you know what you are buying and treat it as an extra on top of full screening.

How to do it well#

1. Finish the optimal screening first (colonoscopy, mammography, cervical, lung, and PSA as above). The scan adds to it, never replaces it.
2. Ask who reads it. Reviewers recommend experienced oncologic radiologists and a structured 5-point scale (such as ONCO-RADS) that grades how worrying each finding is.
3. Ask about follow-up policy. Will a physician review results with you, and do they follow society guidance rather than scanning "to be safe"?
4. Get your images, not just the report. Ask for the full images (DICOM files) so future scans can be compared; comparison with a prior is often the fastest way to settle a finding.
5. Know what is covered (chest, spine, contrast), and budget for at least one follow-up scan or specialist visit.
6. Treat the first scan as a baseline, and don't repeat it yearly. No study has tested any repeat interval, and each repeat brings new incidental findings. If you repeat it, wait at least a few years, use the same provider, and have the new images compared with the old ones.

How whole-body MRI compares with other scans, including radiation doses, is covered in Scans and imaging.

Findings and warning signs#

If a scan finds something#

Symptoms you should never ignore#

Action plan#