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Original Investigation
Less Is More
April 20, 2020

Effect of a Mammography Screening Decision Aid for Women 75 Years and Older: A Cluster Randomized Clinical Trial

Author Affiliations
  • 1Division of General Medicine, Department of Medicine, Harvard Medical School, Beth Israel Deaconess Medical Center, Boston, Massachusetts
  • 2Division of Geriatric Medicine, Department of Medicine, The University of North Carolina at Chapel Hill
  • 3Department of Family Medicine, The University of North Carolina at Chapel Hill
  • 4Ariadne Labs, Boston, Massachusetts
  • 5Division of General Internal Medicine, Department of Medicine, University of Colorado School of Medicine, Aurora
  • 6Adult and Child Consortium for Outcomes Research and Delivery Science, University of Colorado, Aurora
  • 7Department of Population Health, University of Utah School of Medicine, Salt Lake City
  • 8Informatics, Decision-Enhancement and Analytic Sciences Center, Health Services Research & Development, US Department of Veterans Affairs, Salt Lake City, Utah
  • 9Division of General Internal Medicine and Primary Care, Department of Medicine, Harvard Medical School, Brigham and Women’s Hospital, Boston, Massachusetts
JAMA Intern Med. 2020;180(6):831-842. doi:10.1001/jamainternmed.2020.0440
Key Points

Question  How does use of a workbook mammography screening decision aid (DA) for women 75 years and older affect their screening decisions?

Findings  In this cluster randomized clinical trial of 546 women aged 75 to 89 years, receipt of the decision aid before a visit with their clinician led to women 75 years and older being more knowledgeable about mammography screening, having more discussions with their primary care physician about screening, and fewer women being screened.

Meaning  Use of a mammography screening decision aid may help women 75 years and older make more informed decisions about mammography screening and, as a result, may reduce overscreening.


Importance  Guidelines recommend that women 75 years and older be informed of the benefits and harms of mammography before screening.

Objective  To test the effects of receipt of a paper-based mammography screening decision aid (DA) for women 75 years and older on their screening decisions.

Design, Setting, and Participants  A cluster randomized clinical trial with clinician as the unit of randomization. All analyses were completed on an intent-to-treat basis. The setting was 11 primary care practices in Massachusetts or North Carolina. Of 1247 eligible women reached, 546 aged 75 to 89 years without breast cancer or dementia who had a mammogram within 24 months but not within 6 months and saw 1 of 137 clinicians (herein referred to as PCPs) from November 3, 2014, to January 26, 2017, participated. A research assistant (RA) administered a previsit questionnaire on each participant’s health, breast cancer risk factors, sociodemographic characteristics, and screening intentions. After the visit, the RA administered a postvisit questionnaire on screening intentions and knowledge.

Interventions  Receipt of the DA (DA arm) or a home safety (HS) pamphlet (control arm) before a PCP visit.

Main Outcomes and Measures  Participants were followed up for 18 months for receipt of mammography screening (primary outcome). To examine the effects of the DA, marginal logistic regression models were fit using generalized estimating equations to allow for clustering by PCP. Adjusted probabilities and risk differences were estimated to account for clustering by PCP.

Results  Of 546 women in the study, 283 (51.8%) received the DA. Patients in each arm were well matched; their mean (SD) age was 79.8 (3.7) years, 428 (78.4%) were non-Hispanic white, 321 (of 543 [59.1%]) had completed college, and 192 (35.2%) had less than a 10-year life expectancy. After 18 months, 9.1% (95% CI, 1.2%-16.9%) fewer women in the DA arm than in the control arm had undergone mammography screening (51.3% vs 60.4%; adjusted risk ratio, 0.84; 95% CI, 0.75-0.95; P = .006). Women in the DA arm were more likely than those in the control arm to rate their screening intentions lower from previsit to postvisit (69 of 283 [adjusted %, 24.5%] vs 47 of 263 [adjusted %, 15.3%]), to be more knowledgeable about the benefits and harms of screening (86 [adjusted %, 25.5%] vs 32 [adjusted %, 11.7%]), and to have a documented discussion about mammography with their PCP (146 [adjusted %, 47.4%] vs 111 [adjusted %, 38.9%]). Almost all women in the DA arm (94.9%) would recommend the DA.

Conclusions and Relevance  Providing women 75 years and older with a mammography screening DA before a PCP visit helps them make more informed screening decisions and leads to fewer women choosing to be screened, suggesting that the DA may help reduce overscreening.

Trial Registration  ClinicalTrials.gov Identifier: NCT02198690

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    1 Comment for this article
    Women need all the facts, to make informed decisions
    Paula Gordon, MD, FRCPC | University of British Columbia
    The authors have shown their bias, shared by the authors of the commentary: They regarded the decision aid to be successful because 9% fewer women received mammography screenings in the decision aid group. It’s possible that the decision aid (DA) was incomplete, and withheld important information.

    They did not disclose the contents of the DA, either in the article or in the supplemental material. But they stated that they did not tell women their estimated life expectancy. Given the importance of a given woman’s life expectancy on shared decision-making, it casts doubt on the value of the DA. A
    woman in North America who lives to age 75 years has an average life expectancy of 12–14 additional years. Had the women in the study known this, perhaps they would have decided to continue screening.

    Based on the references cited, the authors based the data in the article and in the DA on only the randomized trials of mammography done from the 1960’s to the early 1990’s, using mammography equipment that was primitive, by today’s standards. They did not incorporate the data from more recent observational studies using modern equipment.

    Coldman et al showed 40% mortality reduction overall. Tabar et al showed 47% mortality reduction 20 years after diagnosis, but 60% mortality reduction in the first 10 years after diagnosis: arguably a more relevant number when informing women 75 and older. If this information had been included, more women may have chosen to continue screening.

    The DA apparently did not include information about the benefits of early detection, other than mortality reduction. Surely women value lumpectomy rather than mastectomy for the sake of faster recovery, if not cosmesis. And unlike mortality reduction, which may take years to benefit a woman with newly diagnosed breast cancer, the benefit of less surgery is immediate.

    Drs. Elmore and Ngo-Metzger presented modeling based on the performance of screening in younger women. But screening performs better in older women. If the correct inputs had been used in the model, the benefits would probably have been shown to outweigh the harms.

    Destounis showed that screening mammograms in women aged 75 years and older showed a substantial cancer detection rate. Most tumors were low stage, intermediate to high grade, and invasive. And most women did have surgery

    Overdiagnosis has been discussed widely in the literature, but is only relevant if it leads to overtreatment. And treatment is determined by surgeons and oncologists. If a women is known to not be a candidate for treatment, she should not be screened. But if she is, and a small cancer if found, she may still be offered hormone therapy or excision with local anesthesia to slow/stop the progression to less treatable disease. If we trust our colleagues to not over-treat cancer, then we can continue screening older healthy women, with the potential to find early cancers that can be treated less aggressively, and improve women’s quality of life.

    Women should be encouraged to make an informed decision. If decision aids are are to be used, they must be factual and not withhold important information, such as a woman’s life expectancy. For women in 2020 to decide the value of screening, they should be provided with contemporary data on women who do attend screening with modern equipment, not 30-60 year old trial data using obsolete equipment, affected by non-compliance and contamination. Only when women have all these facts, will they be in a position to make decisions that fit their personal values.
    CONFLICT OF INTEREST: I earn some of my income from reading screening mammograms