DynaMed Plus Quiz: Breast cancer screening

Screening for breast cancer refers to any test performed on a woman without current signs or symptoms of breast cancer, with the goal to detect disease as early as possible. Possible features of ductal carcinoma in situ on a screening mammogram include linearly arranged pleomorphic calcifications.

A 2011 diagnostic case-control study compared screening mammograms conducted on 19,078 women one year after treatment with 55,315 matched controls, looking for ductal carcinoma in situ, stage 1 breast cancer, or stage 2 breast cancer.

According to this study, which one of the following was true regarding recurrent breast cancer?

A. There was a lower rate of cancer, as compared to the control group.

B. There was no significant increase in the number of abnormal mammograms, as compared to the control group.

C. The incidence of ductal carcinoma in situ is significantly higher than for invasive cancer.

D. There is a significant difference between ipsilateral vs. contralateral detection.

DynaMed Plus answer

Based on a study by Houssami and colleagues published in the Feb. 23, 2011, issue of JAMA, all of the above statements are false except C, which reflects that the study found a significantly greater incidence of ductal carcinoma in situ (78.7% [95% CI, 71.4% to 84.5%]) than invasive cancer (61.1% [95% CI, 56.6% to 65.4%]) (P<0.001). According to the study, screening mammography in women with a history of early-stage breast cancer has a low to moderate detection rate for recurrent cancer in the first five years after breast cancer treatment. The DynaMed Plus evidence summary for this question is online.

Screening is controversial for women 40 to 49 years of age:

• The United States Preventive Services Task Force (USPSTF) and the American College of Physicians (ACP) recommend against routine screening but recommend screening every two years if requested by an informed patient (USPSTF Grade C).
• The National Comprehensive Cancer Network (NCCN) and the American College of Obstetricians and Gynecologists (ACOG) recommend annual mammography screening beginning at age 40 years (NCCN Category 1).
• The American Cancer Society (ACS) recommends annual regular mammography beginning at age 45 (Strong recommendation), with an option to begin annual screening at age 40 (Qualified recommendation).

For women ages 50 to 74, screening is universally recommended with differences in frequency:

• The USPSTF and ACP recommend screening mammography every two to three years.
• NCCN and ACOG recommend annual screening (NCCN Category 1).
• ACS recommends annual mammography screening for women aged 50 to 54 years, with transition to biennial at age 55 years and an option for continued annual screening (ACS Qualified recommendation).

For women ages 75 years and older, screening is generally not recommended, although the USPSTF and NCCN state that the evidence in this age group is inconclusive. The ACS recommends continued screening as long as overall health is good and life expectancy is 10 years or greater (ACS Qualified recommendation).

Mammography remains the screening test of choice. However, for diagnosing women with mammographic abnormality or family history of breast cancer, several studies found that the addition of three-dimensional digital breast tomosynthesis may result in higher specificity and may decrease recall rate (except in women with mostly fat tissue) and increase cancer detection rate (except in women with extremely dense breast tissue) compared to two-dimensional digital mammography alone for diagnosing breast cancer.

The DynaMed Plus topic on mammography for breast cancer screening is online.