Table 4.
Summary of studies of mammographic density and risk of second breast cancers
| Results | ||||||||
|---|---|---|---|---|---|---|---|---|
|
Authors, region (year) |
Study population |
Median follow-up |
Measurement of MD |
Eventsb | Number | HR (95% CI) |
Adjustmentsa | Comments |
| Habel et al. [91], USA (2010) | 935 patients with DCIS | 8 years | Planimeter Highest versus lowest quintile of dense area |
All Ips. |
228 164 |
1.8 (1.2 to 2.9) 1.7 (1.0 to 2.9) | Age, BMI, treatment, and diagnosis year | Similar HR in subgroups of age, BMI, treatment, and menopausal status |
| Cont. | 59 | 3.0 (1.3 to 6.9) | ||||||
| Hwang et al. [93], USA (2007) | 3,274 patients with DCIS | 39 months | BI-RADS High (3 or 4) versus low (1 or 2) | All inv. | 133 | 1.4 (0.9 to 2.1) | Age and radiation treatment | No interaction of density with radiation treatment |
| Ips. inv. | 83 | 1.0 (0.6 to 1.6) | ||||||
| Cont. inv. | 52 | 3.1 (1.6 to 6.1) | ||||||
| Habel et al. [90], USA (2004) | 334 patients with DCIS | 11 years | Planimetry >75% versus <25% PMD | All | 112 | 2.8 (1.3 to 6.1) | Age, BMI, and radiation treatment | No interaction with radiation treatment or menopausal Status |
| Ips. | 80 | 3.0 (1.2 to 7.5) | ||||||
| Cont. | 28 | 3.4 (0.7 to 16.2) | ||||||
| Cil et al. [79], Canada (2009) | 335 patients with invasive breast cancer | 8 years | Wolfe score High versus low Wolfe score | Ips. inv. | 34 | 5.7 (1.6 to 20.0) | Age, menopause, and radiation treatment | Association stronger in those who did not receive radiation treatment |
| Dist. inv. | 31 | No association (HR not given) | ||||||
| Park et al. [92], USA (2008) | 136 patients with invasive breast cancer | 7.7 years | Computer- assisted >75% versus <25% PMD | Ips. inv. | 19 | 3.4 (1.6 to 7.5) | BMI | |
| Cont./Dist. inv. | 25 | No association (HR not given) | ||||||
aFactors included in the analysis of mammographic density and risk of second breast cancer. bEvents include in situ and invasive cancer unless specified as invasive (inv.). All, all second breast cancers; BI-RADS, Breast Imaging-Reporting and Data System; BMI, body mass index; CI, confidence interval; Cont., second cancer in contralateral breast; DCIS, ductal carcinoma in situ; Dist, distant metastasis; HR, hazard ratio; Ips, second cancer in ipsilateral breast; MD, mammographic density; PMD, percent mammographic density.