Table 29a: Breast cancer screening with mammography for ages 40–49

Introduction: Mammography in women ages 40 to 49 saves lives, but the benefit for these younger women is less than in older women. Five of the eight randomized controlled trials that included women ages 40-49 showed mammography increased survival. A meta-analysis that combined the results from most of these studies found that mammography reduced the risk of death from breast cancer [1].

A recent review of 117 studies found that while mammography reduces breast cancer mortality in women ages 40-49, the risk of false positive results is quite high [2]. Most major organizations, including Susan G. Komen for the Cure®, the American Cancer Society and the National Cancer Institute, feel that the modest survival benefits of mammography in women ages 40 to 49 outweigh the risks of false positive results. They all recommend regular mammograms for all women aged 40 to 49.

The U.S. Preventive Services Task Force no longer recommends routine mammography for women ages 40 to 49 [3]. Instead, the Task Force encourages women ages 40 to 49 to make informed decisions about when to start mammography screening [3]. Likewise, the American College of Physicians recommends that mammography decisions for women ages 40-49 be based on a woman’s breast cancer risk profile as well as her own preferences after understanding the potential benefits and harms of screening mammography [4]. For more on mammography in women ages 40-49, visit the Early Detection & Screening chapter. 

There has been a controversy on the benefits of mammography for women of any age. In 2000, the authors of a report reviewing the trials on mammography called into question the methods of some of these studies. They concluded that the evidence pointed to mammography having no benefit [5]. However, when researchers revisited these trials in response to the report, they concluded that while there were some problems with the trials, the evidence as a whole still shows that mammography reduces mortality [1.6].

Study selection criteria: Available randomized controlled trials.

Table note: Relative risk above 1 indicates increased risk. Relative risk below 1 indicates decreased risk.

*The combined relative risk for the two studies deemed optimal in their methodology was 1.33 (0.92-1.92).

References

1. Humphrey LL, Helfand M, Chan BKS, et al. Breast cancer screening: a summary of the evidence for the U.S. Preventive Services Task Force. Annals of Internal Medicine 137(5): 347-367, 2002.
2. Armstrong K, Moye E, Williams S, Berlin JA, Reynolds EE. Screening mammography in women 40 to 49 years of age: a systematic review for the American College of Physicians. Ann Intern Med. 146(7):516-26, 2007.
3. U.S. Preventive Services Task Force. Screening for breast cancer: U.S. Preventive Services Task Force recommendation statement. Ann Intern Med. 151(10):716-726, 2009.
4. Qaseem A, Snow V, Sherif K, Aronson M, Weiss KB, Owens DK for the Clinical Efficacy Assessment Subcommittee of the American College of Physicians. Screening mammography for women 40 to 49 years of age: a clinical practice guideline from the American College of Physicians. Ann Intern Med. 146(7):511-5, 2007.
5. Gotzsche PC and Olsen O. Is screening for breast cancer with mammography justifiable? Lancet. 355: 129-134, 2000.
6. Gotzshe PC, Nielsen M. Screening for breast cancer with mammography. Cochrane Database Syst Rev. 18;(4):CD001877, 2006.
7. Moss SM, Cuckle H, Evans A, et al. for the Trial Management Group. Effect of mammographic screening from age 40 years on breast cancer mortality at 10 years' follow-up: a randomised controlled trial. Lancet. 368(9552):2053-60, 2006.
8. Miller AB, To T, Baines CJ, et al. The Canadian National Breast Screening Study-1: Breast cancer mortality after 11 to 16 years of follow-up. Annals of Internal Medicine 137(5, Part 1): 305-315, 2002.
9. Bjurstam N, Björneld L, Warwick J, et al. The Gothenburg Breast Screening Trial. Cancer. 97(10):2387-96, 2003.
10. Alexander FE, Anderson TJ, Brown HK, et al. 14 years of follow-up from the Edinburgh randomised trial of breast-cancer screening. Lancet. 353(9168):1903-8, 1999.
11. Kerlikowske K, Grady D, Rubin SM, et al: Efficacy of screening mammography: A meta-analysis. JAMA 273:149-154, 1995.

Updated 11/19/09