What to Ask Before Your Next Mammogram

“Questions for Your Doctor” — the second in the series

I was on a train when I read Marc Girardot’s essay on mammograms. Halfway through, I messaged my wife: “Did you know that a mammogram is an X-ray?” She replied instantly: Yes. I could feel her eyes rolling. An hour later I messaged again: “Did you know that a mammogram is the equivalent of 100 X-rays?” This time she was quiet.

That gap — between what women think they know and what they were never actually told — is what this document is about.

Mammography screening delivers ionising radiation to compressed breast tissue, generates false positives in up to 60% of women over ten years, and has never been shown to reduce all-cause mortality in any randomised trial. Peter Gøtzsche, whose Cochrane reviews represent the most comprehensive independent assessment of the evidence, found that for every 2,000 women screened over ten years, approximately 10 healthy women will be overdiagnosed and treated unnecessarily — surgery, radiation, sometimes chemotherapy — for conditions that would never have threatened their lives. Approximately 200 more will experience false positive results leading to callbacks, biopsies, and weeks of anxiety for what turns out to be nothing.

The screening invitation doesn’t mention any of this. It presents the mammogram as something every woman does — a responsible act of self-care. It is not informed consent. The information that should precede the appointment almost never does.

Mammogram Screening: Questions for Your Doctor contains ten questions designed to change that.

Eight questions address the mammogram itself — its radiation dose, accuracy for your breast density, false positive rate, the mortality evidence, overdiagnosis, compression risks, and alternatives like thermography, ultrasound, and MRI. Two questions address DCIS (ductal carcinoma in situ), the most common downstream finding from mammography — a diagnosis that was virtually unknown before screening was introduced, and one where 75–90% of untreated cases never progress to invasive cancer.

Each question is followed by a Key Fact and two paragraphs of context drawn from the published evidence. A cascade guide at the front identifies which questions matter most depending on where you are: called for a routine mammogram, called back after a positive result, told you have DCIS, or considering alternatives. A one-page Quick Reference at the back is designed to be printed and taken to the appointment.

Here is one of the ten questions, with its Key Fact:

Question 4. What is the evidence that routine mammography screening actually reduces my overall risk of dying?

Key Fact: No randomised trial has shown that mammography screening reduces all-cause mortality. The best evidence shows women who are screened have about the same chance of dying as those who aren’t.

The full document — including two paragraphs of context for each question, the cascade guide, and the printable Quick Reference — is available for download below.

The evidence is drawn from Breast Cancer: What They Didn’t Tell You, which compiles research from Peter Gøtzsche, Dr Jeff Barke, H. Gilbert Welch, and multiple randomised controlled trials spanning 25 years of follow-up. Every statistic in the document traces back to a named source.

If you or someone you know has an appointment coming up, print the Quick Reference page and take it with you.

The series so far, and what’s coming next:

1. The PSA Test (available now)

2. Mammogram Screening (available now)

3. Colonoscopy (in development)

4. The Childhood Vaccine Visit (in development)

5. Statin Prescription (in development)

If there is a screening test, a prescription, or a procedure where you needed the right questions before you walked into the room, put it in the comments. The next topics will come from what you need most.

The Questions for Your Doctor series is available exclusively to paid subscribers.

Mammogram Screening: Questions for Your Doctor is available for download below.