Better or Just More Sensitive?


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Data from observational studies seem to support the efficacy of DBT in breast cancer screening.11But to date, no randomized, controlled head-to-head study has been completed to definitively compare DBT and standard mammographic imaging.1The USPSTF has concluded that the current evidence base is “insufficient to assess the benefits and harms of digital breast tomosynthesis as a primary screening method for breast cancer.”12

DBT has also arrived amid — and might well renew — a longstanding debate about screening and overdiagnosis of low-risk breast cancer.13-17Each year, approximately 60,000 US women receive diagnoses of breast screening-detected low-grade ductal carcinoma in situ (DCIS), sometimes referred to as stage 0 breast cancer.18Most undergo surgical interventions. But authors of a 2015 study of 100,000 women followed for 20 yearsconcluded that surgery for low-grade DCIS did not offer a survival benefit.17

Some experts are concerned that the improved sensitivity with DBT might contribute to overdiagnosis and overtreatment of subclinical neoplasms that are unlikely to ever pose a threat to the patient.1,7That may not be an implausible concern. New imaging technologies can contribute to such problems. For example, recent decades saw neck ultrasonography-associated overdiagnosisand overtreatment of subclinical nodules as thyroid cancers.

The US National Cancer Institute and Eastern Cooperative Oncology Group (ECOG-ACRIN) Cancer Research Group’s Tomosynthesis Mammographic Imaging Screening Trial (TMIST) is to enroll 165,000 women aged 45 to 74 years to compare DBT and conventional 2D digital mammography.

Until data from that study are available for analysis, however, the risks and benefits of DBT are likely to remain an open and contentious question.


Bryant Furlowis a medical journalist based in Albuquerque, New Mexico. 


References

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2. Peppard HR, Nicholson BE, Rochman CM, Merchant JK, Mayo RC 3rd, Harvey JA. Digital breast tomosynthesis in the diagnostic setting: indications and clinical applications. Radiographics. 2015;35(4):975-990.

3. Houssami N, Miglioretti DL. Digital breast tomosynthesis: a brave new world of mammography screening. JAMA Oncol. 2016;2(6):725-727.

4. Radiation-emitting products: 2018 scorecard statistics. US Food & Drug Administration website. https://www.fda.gov/radiation-emittingproducts/mammographyqualitystandardsactandprogram/facilityscorecard/ucm595007.htm#mar. Accessed April 5, 2018.

5. Radiation-emitting products: 2017 scorecard statistics. US Food & Drug Administration website. https://www.fda.gov/Radiation-EmittingProducts/MammographyQualityStandardsActandProgram/FacilityScorecard/ucm539394.htm#mar. Accessed April 5, 2018.

6. Radiation-emitting products: 2016 scorecard statistics. US Food & Drug Administration website. http://wayback.archive-it.org/7993/20170112094133/http://www.fda.gov/Radiation-EmittingProducts/MammographyQualityStandardsActandProgram/DocumentArchives/ucm484151.htm#jun. Accessed April 5, 2018.

7. Andrews M. When you need a breast screening, should you get a 3-D mammogram? Kaiser Health News website. https://khn.org/news/when-you-need-a-breast-screening-should-you-get-a-3-d-mammogram/. Accessed April 4, 2018.

8. Svahn TM, Houssami N, Sechopoulos I, Mattsson S.Review of radiation dose estimates in digital breast tomosynthesis relative to those in two-view full-field digital mammography. Breast. 2015;24(2):93-99.

9. Gilbert FJ, Tucker L, Gillan MG, et al. TOMMY trial: A comparison of TOMosynthesis with digital MammographY in the UK NHS Breast Screening Programme. Health Technol Assess. 2015;19(4):i-xxv, 1-136.

10. Helvie MA. Digital mammography imaging: breast tomosynthesis and advanced applications. Radiol Clin North Am. 2010;48(5):917-929.

11. Poplack S. Breast tomosynthesis: clinical evidence. Radiol Clin North Am. 2017;55(3):475-492.

12. Final recommendation statement. Breast cancer: screening. US Preventive Services Task Force website. Accessed April 4, 2018.

13. Wallis MG. How do we manage overdiagnosis/overtreatment in breast screening?Clin Radiol. 2018;73(4):372-380.

14. Feinberg J, Wetstone R, Greenstein D, Borgen P. Is DCIS overrated? Cancer Treat Res. 2018;173:53-72.

15. Feig SA. Overdiagnosis of invasive breast cancer and DCIS: why do estimates vary?Breast Dis. 2014;25(3):196-201.

16. Groen EJ, Elshof LE, Visser LL, et al. Finding the balance between over- and under-treatment of ductal carcinoma in situ (DCIS). Breast. 2017;31:274-283.

17. Sagara Y, Mallory MA, Wong S, et al. Survival benefit of breast surgery for low-grade ductal carcinoma in situ: a population-based cohort study. JAMA Surg. 2015;150(8):739-745.

18. Kolata G. Doubt is raised over value of surgery for breast lesion at earliest stage. New York Times. August 20, 2015. https://www.nytimes.com/2015/08/21/health/breast-cancer-ductal-carcinoma-in-situ-study.html. Accessed April 4, 2018.