Screening & monitoring · graded by use, three uses
Mammography screening for breast cancer
Breast cancer deaths, women aged 50 to 69.
At a glance
This is about breast X-rays to find cancer early. For women 50 to 69, studies found fewer deaths from breast cancer, about 8 to 21 fewer per 10,000 women over 10 years. But the best-run studies did not find a clear drop. For women in their 40s, the drop was too small to be sure of. Screening did not change how many women died from any cause. It also leads to some cancers being treated that would never have caused harm.
- What was measured
- Deaths from breast cancer, deaths from any cause and numbers of breast surgeries in women invited to breast X-ray screening.
- How big
- Over 10 years, about 8 breast cancer deaths were prevented per 10,000 women aged 50 to 59 and 21 per 10,000 women aged 60 to 69. The summary gives deaths prevented, not the two group rates.Read from the summary of PMID PubMed ID: the permanent number the US National Library of Medicine gives a published paper. Each one links to that paper's record on PubMed. 26756588.
- Who it applies to
- Women aged 50 to 69 at average risk, in trials in Sweden, the US, Canada and the UK that used imaging and treatment now outdated. Women at high inherited risk and women with breast symptoms were not the group studied.
- Safety
- Screening finds some cancers that would never have caused harm, which then get treated: screened women had more lumpectomies and mastectomies. False alarms lead to more imaging and biopsies.
- Compared with
- Women who were not invited to screening.
- Certainty
- Grade B, resting on: Meta-analyses A study that pools the numbers from several trials into one combined estimate. of randomized trials of mammography screening against no screening.
- What would change this grade
- Could rise to A with: A large randomized trial of an invitation to modern digital mammography against no invitation, with adequate randomization and concealment, cause of death adjudicated by a committee blind to allocation, run by a group independent of the original trials. Who: Women aged 50 to 69 at average risk. Measured: Breast cancer deaths adjudicated blind to allocation, with death from any cause and overdiagnosis reported. Length: At least 10 to 15 years of follow-up.
- Cost
- No price recorded yet.
- Sources
- 3 studies cited on this record, listed under Sources.
The B belongs to one of the three uses graded on this record. The other two carry their own letters.
As studied, and the trials
Nelson et al. (Ann Intern Med, 2016; PMID 26756588): breast cancer deaths 14% lower at 50 to 59 (7 trials) and 33% lower at 60 to 69 (5 trials), 8 and 21 deaths prevented per 10,000 women over 10 years. The Cochrane review dissents: the three trials it judged adequately randomized were not significant (relative risk The risk in one group expressed as a share of the risk in another. It can make a small absolute difference look large. 0.90, 0.79 to 1.02), and only the four with suboptimal randomization were (PMID 23737396). Positive pooled trials with a dissent on trial quality: B.
As studied, and the trials
Nelson et al. (PMID 26756588) pooled 9 trials in women aged 39 to 49: breast cancer deaths relative risk 0.92 (0.75 to 1.02), about 3 deaths prevented per 10,000 women over 10 years, not statistically significant Unlikely to be explained by chance alone at the threshold the study set. It says nothing about whether the difference is large enough to matter.. Tested, no clear benefit: D on Route 2 Human randomized trials have been run and did not show benefit on the stated outcome. One of the two routes to the lowest letter on EBL's scale..
As studied, and the trials
Death from any cause was not reduced: relative risk 0.99 (0.95 to 1.03) in the Cochrane review (PMID 23737396), not reduced in the Task Force review (PMID 26756588), and 0 days of lifetime gained in a pooled analysis (Bretthauer et al., 2023; PMID 37639247). Tested, no benefit: D on Route 2.
Read the grade that matches your goal. How EBL grades by use →
A letter describes the human evidence, not the product, the manufacturer, or the intervention's worth.
See the full evidence record →Mammography screening for breast cancer, graded on deaths from breast cancer in women aged 50 to 69 invited to mammography screening: what the randomized trials measured, in whom, and what they did not show.
Why this letter
Why this gradeThe reasoning, and what the grade does not cover.
Grade B on breast cancer deaths in women aged 50 to 69: pooled randomized trials find fewer deaths, 8 per 10,000 women at 50 to 59 and 21 per 10,000 at 60 to 69 over 10 years (PMID 26756588).
WHY NOT Athe three trials judged adequately randomized did not show a significant reduction (PMID 23737396), the trials are decades old, and cause of death may have been misclassified in favor of screening. Grade D, tested, on breast cancer deaths at 39 to 49, where 9 pooled trials did not show a significant reduction (PMID 26756588), and on death from any cause at every age (PMIDs 23737396, 26756588, 37639247).
WHAT THIS GRADE DOES NOT COVERtomosynthesis (3D mammography), MRI or ultrasound screening, which these trials did not test; women at high inherited risk, such as BRCA carriers; women with a breast lump or other symptoms, for whom imaging is diagnosis, not screening; and women over 74.
A grade describes the human evidence for a named use. It is not advice, and it is not a judgment on any individual prescription. How the letters are decided →
Evidence notes: randomized trial, meta-analysis
Endpoint graded: Deaths from breast cancer in women aged 50 to 69 invited to mammography screening (hard)
Last reviewed: October 2026
The trial that would change this grade.
Positive trials of this shape from independent research groups would move this entry to A.
Why the current trials fall short
The pooled reduction in breast cancer deaths (PMID 26756588) is not confirmed by the three adequately randomized trials in the Cochrane review (PMID 23737396), the trials are decades old, and cause of death may have been misclassified in favor of screening. A modern trial with blind cause of death adjudication showing the reduction would meet the bar for A.
ClinicalTrials.gov, the public registry run by the U.S. National Library of Medicine, lists studies that are recruiting volunteers. The link below searches it for Mammography among studies recruiting now. EBL has no relationship with any listed study and receives no payment for this link.
Search recruiting studies of Mammography on ClinicalTrials.gov
Dose, form and timing
Measured in the trials: deaths attributed to breast cancer, deaths from any cause, and numbers of breast surgeries.
Safety
Screening finds some cancers that would never have caused harm, which are then treated: in the Cochrane review, screened women had more lumpectomies and mastectomies (relative risk 1.31) and more mastectomies alone (1.20) (PMID 23737396). False-positive results lead to further imaging and biopsies.
Cautions documented in human studies. Each caution on this record, sorted by what it rests on.
- Overdiagnosis: screened women had more lumpectomies and mastectomies (relative risk 1.31) and more mastectomies alone (1.20). (PMID 23737396)
- False-positive results lead to further imaging and biopsies. (PMID 23737396)
None recorded.
None recorded.
None recorded.
Does not apply: human harm data are listed above.
Grade history
How this letter has changedLatest: No. 385 · October 2026 · First graded.
Sigmoidoscopy (A on colorectal cancer deaths, four trials pooled; Juul et al., Ann Intern Med, 2022; PMID 36215714), colonoscopy (C on colorectal cancer cases, D tested on deaths at 10 years; Bretthauer et al., N Engl J Med, 2022; PMID 36214590), mammography (B at ages 50 to 69, D tested in the 40s; Nelson et al., Ann Intern Med, 2016; PMID 26756588), low-dose CT for heavy smokers (A on lung cancer deaths; NLST, N Engl J Med, 2011; PMID 21714641; NELSON, de Koning et al., N Engl J Med, 2020; PMID 31995683), PSA (B on prostate cancer deaths; Hugosson et al., Eur Urol, 2019; PMID 30824296) and HPV testing (B on invasive cancer against the Pap test; Ronco et al., Lancet, 2014; PMID 24192252). No screening test except sigmoidoscopy significantly lengthened life in a pooled analysis of the trials (Bretthauer et al., JAMA Intern Med, 2023; PMID 37639247), and each record carries its harms. Applied the written grade definitions under the editor's standing instruction of October 2026 (Arnold Sandlow, D.C.).PMID 36215714 PMID 36214590 PMID 26756588 PMID 21714641 PMID 31995683 PMID 30824296 PMID 24192252 PMID 37639247
Every change to a letter on this site is dated and published. The full evidence log →
Sources
- Citations
- Every paper cited on this page is matched to its PubMed record on every build.
- Retractions
- None of these papers is retracted or under a journal expression of concern. PubMed is checked again on every build.
- Read against the papers
- October 2026. By the EBL editor, Arnold Sandlow, DC.
- Outside review
- Not yet done. No reviewer outside EBL has checked this record.
What each of these checks can and cannot show: evidence integrity.
Primary evidenceThree papers, each linked to its PubMed record.
Nelson et al. (Ann Intern Med, 2016; PMID 26756588), the review behind the US Preventive Services Task Force update: breast cancer deaths over 10 years, relative risk 0.92 (0.75 to 1.02) at ages 39 to 49 (9 trials; 3 deaths prevented per 10,000 women), 0.86 (0.68 to 0.97) at 50 to 59 (7 trials; 8 per 10,000), 0.67 (0.54 to 0.83) at 60 to 69 (5 trials; 21 per 10,000) and 0.80 (0.51 to 1.28) at 70 to 74; death from any cause not reduced; most trials used imaging and treatment now outdated. Gøtzsche and Jørgensen (Cochrane Database Syst Rev, 2013; PMID 23737396): 7 trials, about 600,000 women aged 39 to 74; the three with adequate randomization did not show a significant reduction in breast cancer deaths at 13 years (0.90, 0.79 to 1.02), the four with suboptimal randomization did (0.75, 0.67 to 0.83); no effect on death from any cause (0.99, 0.95 to 1.03); more lumpectomies and mastectomies in the screened groups (1.31, 1.22 to 1.42). Bretthauer et al. (JAMA Intern Med, 2023; PMID 37639247): no significant lifetime gain from mammography (0 days, -190 to 237).
Evidence Based Longevity, Inc. is owner-operated and edited by Arnold Sandlow, D.C., a California-licensed chiropractor. Evidence Based Longevity publishes in English only · Machine translations are not produced or reviewed by EBL for accuracy
How EBL searched for the trials (1 search)
The search that was run, what it returned, and what was left out and why, so the absence of evidence can be checked as well as its presence.
mammograph*[ti] AND screening[ti] AND (randomized controlled trial[pt] OR meta-analysis[pt]) AND "breast cancer mortality"[tiab]PubMed watch: does a new study change the grade? (nothing new)
No new paper matching the search behind this grade has been added to PubMed since October 2026.
Last run October 2026. A letter on EBL moves only after a logged review. A new paper never moves a letter by arriving: it is read, the answer is written here, and any change to the letter is published in the evidence log.
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