Breast Cancer Screening

Carolyn J. Crandall, MD, MS, on ACP’s Breast Cancer Screening Recommendations

The American College of Physicians (ACP) issued a guidance statement on breast cancer screening in women with average risk in April 2019 – just 2 days shy of its Internal Medicine Meeting in Philadelphia, Pennsylvania.1 Their new recommendations include:

  • Women aged 50 to 74 years with average risk are recommended to undergo screening via mammography biennially.
  • Clinicians are recommended to discuss whether to screen for breast cancer with mammography before age 50 years, as well as the benefits and harms of screening, among average-risk women aged 40 to 49 years. The authors of the guideline noted that, in the majority of women aged 40 to 49 years, the potential harms of screening outweigh the benefits.
  • Clinicians are recommended to discontinue screening in average-risk women aged 75 years or older or in women with a life expectancy of 10 years or less.
  • In average-risk women of all ages, clinical breast examination is not recommended as a modality of breast cancer screening.

These recommendations mirror those of the American Cancer Society, American Society of Breast Surgeons, and US Preventive Services Task Force. However, they differ from guidelines issued by organizations such as the American College of Obstetricians and Gynecologists, which recommend starting screening at age 40 years in average-risk women.2

In an interview with Consultant360, Carolyn J. Crandall, MD, MS, from the David Geffen School of Medicine at UCLA, shared insight on conflicting screening guidelines, the benefits and harms of screening, and translating the ACP’s new guidance statement into practice. She discussed this topic in-depth at the ACP Internal Medicine Meeting.3

Consultant360: Why do many guidelines conflict on whether breast cancer screening via mammography should begin at age 40 years vs age 50 years in average-risk women?

Dr Crandall: Guidelines issued by various organizations differ for several reasons, including:

  • How each organization weighs the tradeoffs between the benefits of reducing breast cancer mortality and the potential harms of screening mammography, such as false positive test results, overdiagnosis, and overtreatment.
  • How heavily these organizations emphasize and/or rely on observational or modeling data.
  • There is low certainty about how much screening mammography benefits women in the first place.

C360: What are the benefits and harms of initiating screening at age 40 years vs age 50 years in average-risk women?

Dr Crandall: Screening mammography does not provide a significant decrease in breast cancer deaths for women aged 40 to 49 years who are screened over the course of 10 years.4 We have to weigh that information against the known harms, which include increased risk of receiving a false positive test result after 10 years of screening beginning at age 40 years. In this age group, this risk is approximately 42% for biennial screening and 61% with annual screening.5

C360: The ACP’s guidance statement did not recommend clinical breast examination alone as a modality of breast cancer screening in average-risk women, citing no demonstrated benefits and some potential harms. Was this surprising?

Dr Crandall: Internists who are not focused on women’s health may be surprised to hear that data suggest there were no demonstrated benefits, but definite potential harms, associated with using the clinical breast examination to screen for breast cancer (either alone or in combination with screening mammography) in average-risk women. Key points to discuss with patients are that there was no mortality benefit of adding clinical breast examination to mammography, and yet there were many additional false positive test results per case of breast cancer detected when clinical breast examination was added to mammography.

C360: For future screening guidelines, what will be the goal going forward for unaddressed challenges such as the effects of magnetic resonance imaging, ultrasound, and digital breast tomosynthesis on morbidity, mortality, and quality of life, as well as the effects of adjunctive imaging in women with dense breasts?

Dr Crandall: Clinicians have to become very comfortable in shared decision-making discussions with women. While we may be tempted to use these additional modalities, it would be premature to do so without any information regarding how to balance the risks and benefits.  We need to first determine that information. We do not yet know the effects of those adjunctive techniques on mortality, morbidity, or quality of life.

Carolyn J. Crandall, MD, MS, is an internal medicine physician and professor of medicine in the Division of General Internal Medicine and Health Services Research at the David Geffen School of Medicine at University of California, Los Angeles.

—Christina Vogt


1. Qaseem A, Lin JS, Mustafa RA, Horwitch CA, Wilt TJ; Clinical Guidelines Committee of the American College of Physicians. Screening for breast cancer in average-risk women: a guidance statement from the American College of Physicians. Ann Intern Med. 2019;170(8):547-560. doi:10.7326/M18-2147.

2. ACOG practice bulletin: clinical management guidelines for obstetrician-gynecologists. The American College of Obstetricians and Gynecologists. 2017;179.

3. Crandall CJ. Clinical Guidelines: Breast cancer, depression, hematuria, pelvic exam. ACP Internal Medicine Meeting 2019; April 11, 2019; Philadelphia, PA.

4. Nelson HD, Fu R, Cantor A, Pappas M, Daeges M, Humphrey L. Effectiveness of breast cancer screening: systematic review and meta-analysis to update the 2009 US Preventive Services Task Force recommendation. Ann Intern Med. 2016;164(4):244-55. doi:10.7326/M15-0969.

5. Hubbard RA, Kerlikowske K, Flowers CI, Yankaskas BC, Zhu W, Miglioretti DL. Cumulative Probability of false-positive recall or biopsy recommendation after 10 years of screening mammography: a cohort study. Ann Intern Med. 2011; 155(8):481-492. doi:10.7326/0003-4819-155-8-201110180-00004.