Effect of Breast Augmentation on the Accuracy of Mammography and Cancer Characteristics

Context: Breast augmentation is not associated with an increased risk of breast cancer; however, implants may interfere with the detection of breast cancer thereby delaying cancer diagnosis in women with augmentation. Objective: To determine whether mammography accuracy and tumor characteristics are different for women with and without augmentation. Design, Setting, and Participants: A prospective cohort of 137 women with augmentation and 685 women without augmentation diagnosed with breast cancer between January 1, 1995, and October 15, 2002, matched (1:5) by age, race/ethnicity, previous mammography screening, and mammography registry, and 10533 women with augmentation and 974915 women without augmentation and without breast cancer among 7 mammography registries in Denver, Colo; Lebanon, NH; Albuquerque, NM; Chapel Hill, NC; San Francisco, Calif; Seattle, Wash; and Burlington, Vt. Main Outcome Measures: Comparison between women with and without augmentation of mammography performance measures and cancer characteristics, including invasive carcinoma or ductal carcinoma in situ, tumor stage, nodal status, size, grade, and estrogen-receptor status. Results: Among asymptomatic women, the sensitivity of screening mammography based on the final assessment was lower in women with breast augmentation vs women without (45.0% [95% confidence interval {CI}, 29.3%-61.5%] vs 66.8% [95% CI, 60.4%-72.8%]; P=.008), and specificity was slightly higher in women with augmentation (97.7% [95% CI, 97.4%-98.0%] vs 96. 7% [95% CI, 96.6%-96.7%]; P<.001). Among symptomatic women, both sensitivity and specificity were lower for women with augmentation compared with women without but these differences were not significant. Tumors were of similar stage, size, estrogen-receptor status, and nodal status but tended to be lower grade (P=.052) for women with breast augmentation vs without. Conclusions: Breast augmentation decreases the sensitivity of screening mammography among asymptomatic women but does not increase the false-positive rate. Despite the lower accuracy of mammography in women with augmentation, the prognostic characteristics of tumors are not influenced by augmentation.