Writings
One in Eight Cancers Is an Infection. You Can Test For It.
Originally published on Substack.
I’m a cardiologist. I’m writing about cancer because the most important number I read this week has nothing to do with hearts.
2.3 million.
That’s how many new cancers in 2024 were caused by infections, according to IARC’s new analysis in The Lancet Oncology. It’s 12% of every new cancer on Earth. The word the authors use is attributable, which means remove the microbe and most of those tumors never happen.
Five agents did almost all of it:
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H. pylori: ~760,000 (mostly stomach)
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HPV: ~750,000 (cervix, anus, throat, and more)
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Hepatitis B: ~360,000 (liver)
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Epstein-Barr: ~260,000 (nasopharynx, Hodgkin lymphoma, some stomach)
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Hepatitis C: ~160,000 (liver)
Here is the comparison that stopped me. Lung cancer is about 11% of new U.S. cancer cases, and we built a fifty-year national campaign around it. Infection’s share of new cancers worldwide is the same size, and we treat it like weather.
This is the part that should make you angry
None of this requires a breakthrough. The tools exist today.
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Scotland: women vaccinated against HPV at 12-13 have shown no invasive cervical cancers in more than a decade of follow-up.
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Australia: after the 2007 national program, HPV prevalence in vaccine-eligible people fell about 90%. In 2021 there wasn’t one documented cervical cancer in Australian women under 25, the first time in data going back to 1982.
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Hepatitis C: we don’t “manage” it anymore. Direct-acting antivirals cure it. We still lose 160,000 people a year to HCV-linked cancers because of missed diagnoses and paperwork.
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H. pylori: a breath test, a course of treatment, and a test to confirm it worked. Eradication cuts gastric cancer incidence by roughly a third.
Some of the dying is optional. That’s what makes this number so hard to read.
Why it still doesn’t feel like news
Cancer branding is stuck in the 1970s: the infusion chair, the genomic panel, the moonshot. A two-week antibiotic course doesn’t get a ribbon. A teenager’s HPV shot doesn’t get a TED Talk. A hepatitis B series in infancy never trends.
We also taught people that cancer is non-communicable. Some of it is communicable. You can catch the cause, and you can interrupt it.
Your five-minute action list
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Stomach: If you’ve had ulcers, unexplained indigestion, or a family history of stomach cancer, or you grew up somewhere H. pylori is common, ask for a urea breath test or stool antigen. If it’s positive, treat it, then test for cure. Resistance has wrecked the old regimens, so don’t assume the first round worked.
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Your kids: HPV and hepatitis B vaccines prevent cancers decades later. Boys too. Throat and anal cancers don’t care about the culture war.
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Your blood: Born in a high-hepatitis-B region? Had transfusions or injection exposure in an earlier era? Never been screened for hepatitis C? Get the labs. HCV is curable and HBV is suppressible. Waiting isn’t stoicism.
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Your screening: Vaccinated women still need cervical screening. The countries erasing cervical cancer used both.
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Your group chat: Send this to one person who would never think to ask.
The heart clock
I live on the heart clock, where the warning comes years before the event. A man’s erections fade two to four years before his chest pain, because the smaller arteries narrow first. It’s a memo from the vascular system, and most men never bring it up.
Infection-driven cancer is the same memo at planetary scale. The signal arrived decades ago, and we keep treating the late organ.
I’ll keep writing about GLP-1s and the next generation of heart drugs. They will change obesity and heart failure. They won’t vaccinate a twelve-year-old or eradicate a stomach bacterium. Longevity isn’t one miracle molecule. It’s refusing to die of the boring things.
One in eight new cancers last year had a name you can culture, vaccinate against, or treat.
Share this with the one person you want around in twenty years.
Live longer. Live wiser. Come walk with me.
— Afshine Emrani, MD FACC
Education only, not personal medical advice. Decisions belong with your clinician.
Source: Rumgay H, et al. Global burden of cancer attributable to infections in 2024. Lancet Oncol. 2026;27:1237-1248.
