Breast density notification

Dr. Wilkinson’s commentary, “Breast density notification: Are family doctors prepared to counsel patients on risks and management?,” outlines why and how she believes family physicians should counsel women on breast density.[1] While I agree with Dr. Wilkinson that family physicians need to be prepared to counsel women with denser breasts, the counselling she suggests appears not to take into account all the available evidence.

Dr. Wilkinson asserts that women with dense breasts have an increased risk of breast cancer and therefore need additional screening. She is correct that dense breasts increase the risk of breast cancer diagnosis, [2] but shouldn’t screening decisions be based on the ability to reduce mortality and morbidity. rather than the risk of diagnosis? A diagnosis of cancer is not relevant if it will never cause any harm. For instance, for prostate cancer males have an increased risk, and screening will diagnose more prostate cancer. Yet, screening is not recommended as it is unlikely to improve mortality and is associated with substantial harm. [3]

Based on current evidence, more intensive screening of women with dense breasts may be comparable to screening for prostate cancer. The majority of large observational studies suggest that dense breasts are not associated with an increase in breast cancer mortality, [4-11] only three Swedish studies suggest an association. [12-14] Moreover, while a combination of mammography and sonography or yearly mammograms increase the diagnosis of breast cancer for women with dense breasts, there is a lack of evidence about whether it improves survival. [15-17] There is, however, evidence that this additional screening may be harmful because of false positives, overdiagnosis, and mental health sequelae. [17-19]

Having had patients, friends, and family members heartbreakingly pass away from breast cancer, I would wholeheartedly support increased screening if the evidence supported it, but the current evidence is equivocal. It is important that women be informed of the nuance between the risk of diagnosis and the risk of mortality and the evidence for both the benefit and harm of additional screening. The 9-point checklist Dr. Wilkinson provides for “shared decision-making” is unlikely to accomplish this. The updated Canadian Task Force on Preventative Health Care recommendations, expected in 2024, will hopefully provide a more balanced approach.

1. Wilkinson AN. Breast density notification: Are family doctors prepared to counsel patients on risks and management? Can Fam Physician. 2023;69(11):748-750.
2. Bodewes FTH, van Asselt AA, Dorrius MD, Greuter MJW, de Bock GH. Mammographic breast density and the risk of breast cancer: A systematic review and meta-analysis. The Breast 2022;66:62-68.
3. Bell N, Gorber SC, Shane A, Joffres M, Singh H, Dickinson J et al. Canadian Task Force on Preventive Health Care. Recommendations on screening for prostate cancer with the prostate-specific antigen test. CMAJ 2014;186(16):1225-34.
4. Porter GJ, Evans AJ, Cornford EJ, Burrell HC, James JJ, Lee AH, et al. Influence of mammographic parenchymal pattern in screening-detected and interval invasive breast cancers on pathologic features, mammographic features, and patient survival. AJR Am J. Roentgenol. 2007;188(3):676-83.
5. Gierach GL, Ichikawa L, Kerlikowske K, Brinton LA, Farhat GN, Vacek PM, et al. Relationship between mammographic density and breast cancer death in the Breast Cancer Surveillance Consortium. J Natl Cancer Inst. 2012;104(16):1218-27.
6. Zhang S, Ivy JS, Diehl KM, Yankaskas BC. The association of breast density with breast cancer mortality in African American and white women screened in community practice. Breast Cancer Res Treat. 2013;137(1):273-83.
7. Maskarinec G, Pagano IS, Little MA, Conroy SM, Park SY, Kolonel LN. Mammographic density as a predictor of breast cancer survival: the Multiethnic Cohort. Breast Cancer Res 2013;15(1):R7.
8. Hwang KT, Chu AJ, Kim J, Lee JY, Chang JH, Oh S, et al. Prognostic Influence of Preoperative Mammographic Breast Density in Operable Invasive Female Breast Cancer. Sci Rep. 2018;8(1):16075.
9. van der Waal D, Verbeek ALM, Broeders MJM. Breast density and breast cancer-specific survival by detection mode. BMC Cancer 2018;18(1):386.
10. Heindl F, Fasching PA, Hein A, Hack CC, Heusinger K, Gass P, et al. Mammographic density and prognosis in primary breast cancer patients. Breast 2021;59:51-7.
11. Pizzato M, Carioli G, Rosso S, Zanetti R, La Vecchia C. Mammographic breast density and survival in women with invasive breast cancer. Cancer Causes & Control 2022;33(9):1207-13.
12. Chiu SY, Duffy S, Yen AM, Tabár L, Smith RA, Chen HH. Effect of baseline breast density on breast cancer incidence, stage, mortality, and screening parameters: 25-year follow-up of a Swedish mammographic screening. Cancer Epidemiol Biomarkers Prev. 2010 May;19(5):1219-28.
13. Olsson Å, Sartor H, Borgquist S, Zackrisson S, Manjer J. Breast density and mode of detection in relation to breast cancer specific survival: a cohort study. BMC Cancer 2014;28;14:229.
14. Eriksson L, Czene K, Rosenberg LU, Törnberg S, Humphreys K, Hall P. Mammographic density and survival in interval breast cancers. Breast Cancer Res 2013;15(3):R48.
15. Glechner A, Wagner G, Mitus JW, Teufer B, Klerings I, Böck N, et al. Mammography in combination with breast ultrasonography versus mammography for breast cancer screening in women at average risk. Cochrane Database Syst Rev 2023;3(3):CD009632.
16. Seely JM, Peddle SE, Yang H, Chiarelli AM, McCallum M, Narasimhan G. Breast Density and Risk of Interval Cancers: The Effect of Annual Versus Biennial Screening Mammography Policies in Canada. Can Assoc Radiol J 2022;73(1):90-100.
17. Kerlikowske K, Zhu W, Hubbard RA, Geller B, Dittus K, Braithwaite D., et al. Breast Cancer Surveillance Consortium. Outcomes of screening mammography by frequency, breast density, and postmenopausal hormone therapy. JAMA Intern Med 2013;173(9):807-16.
18. Hayse B, Lannin DR. Supplemental ultrasound screening for women with dense breasts. Ann Intern Med 2015;162(11):801-2.
19. Brodersen J, Siersma VD. Long-term psychosocial consequences of false-positive screening mammography. Ann Fam Med 2013;11(2):106-15.