Screening Mammography: Debates, Guidelines, Issues
• Qualified Recommendation: Screening mammography should be performed annually between ages 45 and 54 years.
• Qualified Recommendation: Women should have the opportunity to undergo annual screening mammography between ages 40 and 44 years.
• Qualified Recommendation: Women aged 55 and older should transition to biennial screening mammography but they should have the opportunity to continue annual screening.
• Qualified Recommendation: Women should continue screening mammography until they no longer have a life expectancy of at least 10 years.
The updated American Cancer Society screening mammography guideline therefore continues to support availability of annual screening mammography for average-risk women beginning at age 40 years and continuing for as long as life expectancy supports the benefit of undergoing treatment for a screen-detected breast cancer. However, in acknowledging the increasing risk of breast cancer with age and the increased prevalence of biologically favorable breast cancers among older versus younger women, the Society stresses that screening mammography is a must by the time a woman reaches age 45, and that she can safely consider transitioning from annual to biennial screening at age 55.
Other components of the updated guideline:
While the mammography component of the breast cancer screening guidelines have provoked the most substantial discussion, they have also addressed other screening practices, and these are summarized as follows:
• Qualified Recommendation: Clinical breast examination is not recommended for breast cancer screening among average-risk women at any age.
• Not addressed in the update, and therefore not changed from prior American Cancer Society recommendation: Breast self-examination is not recommended for average-risk women at any age.
Additional issues in the screening mammography debate
While the American Cancer Society and other organizations attempt to synthesize and interpret the existing data regarding the benefits and risks of various screening practices, clinicians must also consider several public health issues when deciding upon their own screening recommendation practices:
• Disparities and variation in breast cancer patterns associated with racial/ethnic identity: Although white American women have historically had higher population-based incidence rates of breast cancer, compared with African American women, incidence rates have risen among African Americans, and 2012 data indicate comparable rates for both groups. Furthermore, breast cancer outcome disparities have worsened, with breast cancer mortality rates 42% higher for African Americans (CA Cancer J Clin. 2015 Oct 29. doi: 10.3322/caac.21320 [Epub ahead of print]). African American women have a twofold higher population-based incidence rate of the biologically more aggressive triple-negative breast cancers at all ages, and the rates among African American women in their forties is higher than those among white American women in their fifties (Cancer. 2011;117[12]:2747-53; J Natl Cancer Inst. 2015;107[6]: djv048). Prevalence of breast cancer in the premenopausal age range is also higher among African American patients. Delayed initiation of breast cancer screening, and more prolonged intervals between screenings is therefore likely to have a disproportionate impact on the breast cancer burden of the African American population.
• Demographics of the American female population: While overall population-based incidence rates of breast cancer have been stable among American women younger than age 45 years, U.S. Census data reveal 10 million more women in the 20-45 years age range for 2010, compared with 1980. The absolute number of breast cancer patients belonging to this young age category has therefore increased (JAMA Oncol. 2015;1[7]:877-8).
• Scenarios that are not relevant for routine screening recommendations: Clinicians must continue to aggressively counsel patients regarding the importance of overall breast health awareness. The development of a new breast mass, inflammatory skin changes, and/or bloody nipple discharge should prompt immediate medical attention regardless of the result and timing of the most recent mammogram. Furthermore, women facing increased risk of breast cancer because of family history, chest wall irradiation in adolescence/early adulthood, and high-risk breast biopsy pathology (atypia, lobular carcinoma in situ) are candidates for more intense surveillance such as breast MRI in addition to mammography. The most appropriate management of women with increased risk based upon mammographic density remains unclear. Lastly but extremely importantly, American-based breast cancer screening recommendations do not apply to low- and middle-income countries where screening mammography is not widely available. Clinical breast examination and breast self-examination may play a different role in the breast cancer burden of these populations.
Dr. Newman is an ACS Fellow, Director of the Breast Oncology Program, Multi-Hospital Henry Ford Health System, Detroit, and founding Medical Director, Henry Ford Health System International Center for the Study of Breast Cancer Subtypes. Dr. Newman has acted as a volunteer advisor to the American Cancer Society.
