The 26 percent figure is a relative risk increase, and on its own it can be misleading without knowing the starting point.

In the original trial, breast cancer incidence went from about 30 per 10,000 women per year on placebo to about 38 per 10,000 on combined hormone therapy, an absolute increase of 8 cases per 10,000 women per year, or less than one additional case per 1,000 women per year. Both the relative and absolute numbers are true and come from the same data; quoting only the relative number inflates the alarm, and quoting only the absolute number can minimize a real signal. A responsible answer gives both.

What to know about this answer

There is no real scientific disagreement about the arithmetic here; the only disagreement is a communication one, over which framing (relative or absolute) should lead when the finding is reported to the public.

What the research shows, and which source each finding rests on

The 2002 WHI breast cancer result was hazard ratio 1.26, with an absolute excess of 8 additional invasive breast cancers per 10,000 women per year of use.

B[1]

The correct absolute framing places placebo incidence at roughly 30 per 10,000 women per year and combined-therapy incidence at about 38 per 10,000, less than one additional case per 1,000 women per year.

B[1]

Relative-risk-only reporting, quoting an increased breast cancer risk percentage without the base rate, is identified as the single most durable distortion of the WHI finding.

B[1]

Where the real disagreement is

Each position is shown with its own sources. A position listed here is not necessarily the accepted view.

absolute risk framing should always accompany relative risk

clinicians across the corpus, including Sharon Malone and Mary Claire Haver

Both describe the same underlying arithmetic, moving from about 4 to 5 cases (or 30 to 38 per 10,000) rather than leading with the 26 percent figure alone, because the relative number by itself does not convey how rare the underlying event is.

B[1]

What would settle it: This is not an open empirical question; it is a matter of following standard practice for communicating risk, which is to report both the relative and absolute numbers together.

What is really going on here

  1. Tell me my risk in absolute numbers, per 1,000 or per 10,000 women like me per year, not just as a percentage increase.
  2. Is the risk being discussed incidence (diagnosis) or death?

Questions for your doctor

  1. Can you give me my personal risk in absolute numbers, not just a percentage?
  2. How does this absolute number compare to other everyday risks I already accept?
  3. Does this number change meaningfully based on how long I'd be on hormone therapy?

Questions with no answer yet

If both the relative and absolute framings of this number are equally true, why does the debate over which one to lead with keep recurring instead of settling into standard practice?

Not directly studied yet

No research does not mean it does not work, and it does not mean it works. It means nobody has tested it yet.

What is known: This is a communication question rather than an open scientific one; the underlying arithmetic, roughly 30 versus 38 cases per 10,000 women per year, is not disputed by either side of the broader hormone therapy debate.

What would test it: A study of patient comprehension comparing relative-only, absolute-only, and combined risk framings could show which approach patients actually understand best.

Does presenting both the relative and absolute numbers together actually change what patients decide, compared with presenting only one?

Not directly studied yet

No research does not mean it does not work, and it does not mean it works. It means nobody has tested it yet.

What is known: No study specific to hormone therapy counseling has tested whether dual framing changes patient decisions or comprehension compared with single framing, even though this is standard advice among clinicians referenced in this database.

What would test it: A patient-comprehension or decision-making study comparing different risk-communication formats specifically in the hormone therapy counseling context.

Sources

  1. 1.Risks and benefits of estrogen plus progestin in healthy postmenopausal women: principal results From the Women's Health Initiative randomized controlled trial.Writing Group for the WHI Investigators (Rossouw JE et al.), JAMA 2002 · Randomised trial

The letter grades the type of study behind a claim, not the answer itself.

This page is general information based on published research and public sources. It is not medical advice and not a personal assessment, and it does not replace a conversation with your doctor. Peritale is a wellness product, not a medical device, and is not intended to diagnose, treat, cure or prevent any disease. For any medical question, speak with a licensed clinician.

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