Most large studies suggest that no single blood type is “cancer‑proof,” but type O generally shows the lowest overall risk in several cancers, while type A tends to show a slightly higher risk. However, the differences are modest, and lifestyle and environment matter far more than ABO type for your real‑world cancer risk.

Quick Scoop

  • Some cohort and review studies report that non‑A blood groups (especially O and sometimes B) have a slightly lower risk of several cancers compared with type A.
  • For pancreatic cancer specifically, people with type O have the lowest observed risk, while A, B, and AB show higher relative risks.
  • In one long‑term cohort of Chinese men, blood type B had the lowest overall cancer risk and a lower risk of stomach, colorectal, and bladder cancers compared with type A, but results may not generalize to everyone.
  • A 2013 systematic review concluded that blood group A is associated with an increased risk of cancer overall, while blood group O is associated with decreased risk, again with relatively small effect sizes.

What blood type looks “lowest risk”?

When people ask “what blood type has the lowest risk of cancer,” the most consistent pattern across different papers is:

  • Type O :
    • Often linked with a lower risk of several solid tumors, including pancreatic cancer, when compared to A, B, or AB.
* Some reviews summarize this as O having a generally lower overall cancer risk than A.
  • Type B :
    • In at least one large cohort, B showed the lowest overall cancer risk and lower risk for gastrointestinal and bladder cancers than A.
* However, this finding is population‑specific and not universally replicated.

Because of this, many researchers cautiously describe O (and in some contexts B) as being associated with a slightly lower cancer risk than A, rather than naming a single “safest” type for everyone.

Why blood type is only a small piece

Even where links exist, ABO blood type shifts risk by a relatively small percentage compared with big drivers like:

  • Smoking, alcohol, obesity, chronic infections, and environmental exposures.
  • Family history and inherited cancer‑predisposition genes (for example BRCA1/2) that have far larger effects than ABO type.

Clinicians therefore do not use ABO blood type alone to guide cancer screening or prevention, because it explains only a small fraction of overall risk.

Practical takeaways (regardless of blood type)

For anyone worried about “what blood type has the lowest risk of cancer,” the most useful focus is on modifiable habits:

  • Don’t smoke and limit alcohol.
  • Maintain a healthy weight and stay physically active most days.
  • Eat a diet rich in fruits, vegetables, fiber, and limited processed meats.
  • Keep up with age‑appropriate screenings (mammograms, colonoscopy, Pap/HPV testing, etc.) and recommended vaccines (like HPV and hepatitis B).

In short, type O (and in some data B) may have a slightly lower cancer risk than A, but the gap is small, and everyday choices and screening have a much bigger impact than blood type.

Information gathered from public forums or data available on the internet and portrayed here.