Screening Mammography in Women with a Personal History of Breast Cancer

Women with a personal history of breast cancer (PHBC) are at risk of developing second breast cancers. The second cancers can be ipsilateral (in-breast recurrence or new ipsilateral cancer) or contralateral. The risk of a second breast cancer is estimated to be 5.4 to 6.6 per 1000 woman-years. It is thought that women with a PHBC may benefit from early detection of second breast cancers; however, evidence of the benefit of screening is from nonrandomized studies and extrapolation of benefit from randomized population mammography screening trials. Researchers recently conducted a study to assess the accuracy and outcomes of screening mammography and the factors associated with screening outcomes in women with a PHBC. Results were reported in the Journal of the American Medical Association [2011;305(8):790-799].

The study utilized data on a cohort of women with a PHBC, mammogram matched to non-PHBC women, who received screening mammograms through facilities affiliated with the National Cancer Institute’s Breast Cancer Surveillance Consortium (BCSC). Registries for the facilities affiliated with the BCSC collect demographic and mammography data from women receiving screening mammograms. The current study identified screening mammograms from 1996 to 2007.

During the study period, there were 58,870 screening mammograms in 19,078 women with a PHBC and 58,870 matched screening examinations in 55,315 women without a PHBC. The women were matched on breast density, age group, and mammography registry and year. Analysis found that compared with matched non-PHBC screens, a higher proportion of screening mammograms from PHBC women was associated with a family history of breast cancer (23.2% vs 17.6%), postmenopausal status (91.6% vs 87.5%; P<.001), history of breast plastic surgery (6.9% vs 0.8%; P<.001), and receipt of mammography between 9 and 14 months since the previous screen (82.7% vs 43.1%; P<.001). Women with a PHBC had 655 second cancers compared with women without PHBC (499 invasive, 156 ductal carcinoma in situ), who had 342 cancers (285 invasive, 57 ductal carcinoma in situ) within a year of screening mammography.

There was a significant difference in the proportion of women with ductal carcinoma in situ among women with a PHBC compared with women without a PHBC (23.8% vs 16.7%; P=.009). Screening accuracy and outcomes in women with a PHBC compared with non-PHBC women were cancer rates of 10.5 per 1000 screens (95% confidence interval [CI], 9.7-11.3) versus 5.8 per 1000 screens (95% CI, 5.2-6.4); cancer detection rate of 6.8 per 1000 screens (95% CI, 6.2-7.5) versus 4.4 per 1000 screens (95% CI, 3.9-5.0); interval cancer rate of 3.6 per 1000 screens (95% CI, 3.2-4.1) versus 1.4 per 1000 screens (95% CI, 1.1-1.7); sensitivity 65.4% (95% CI, 61.5%-69.0%) versus 76.5% (95% CI, 71.7%-80.7%); specificity 98.3% (95% CI, 98.2%-98.4%) versus 99.0% (95% CI, 98.9%-99.1%); and abnormal mammogram results in 2.3% (95% CI, 2.2%-2.5%) versus 1.4% (95% CI, 1.3%-1.5%), respectively (P<.001 for all comparisons). Screening sensitivity in women with a PHBC for detection of in situ cancer was higher (78.7%; 95% CI, 71.4%-84.5%) than invasive cancer (61.1%; 95% CI, 56.6%-65.4%; P<.001). Sensitivity in PHBC women was also lower in the initial 5 years (60.2%; 95% CI, 54.7%-65.5%) than after 5 years following the first cancer (70.8%; 95% CI, 65.4%-75.6%; P=.006); it was similar for detection of ipsilateral cancer and contralateral cancer. In women with a PHBC and non-PHBC women, screen-detected and interval cancers were predominantly early stage.

The researchers summarized by noting that “mammography screening in PHBC women detects early-stage second breast cancers but has lower sensitivity and higher interval cancer rate, despite more evaluation and higher underlying cancer rate, relative to that in non-PHBC women.”