Appendix Table 2.
Breast Cancer Incidence Rates by CAD Use, Stratified by Mammography Use in the Previous 24 Months and Whether Previous Mammography Was CAD or Non-CAD*
| Breast Cancer Diagnosis Within 1 y, by Previous Mammography Stratum |
Non-CAD |
CAD |
Adjusted OR (95% CI)† |
P Value | ||
|---|---|---|---|---|---|---|
| Breast Cancer Cases, n |
Incidence Rate‡ |
Breast Cancer Cases, n |
Incidence Rate‡ |
|||
| Non-CAD mammography 9–24 mo previous (n = 243 604) | ||||||
| Any breast cancer | 18 978 | 6.86 | 4411 | 7.45 | 1.10 (1.06–1.14) | <0.001 |
| Invasive breast cancer§ | 14 708 | 5.32 | 3347 | 5.65 | 1.08 (1.04–1.13) | <0.001 |
| Stage I invasive | 9280 | 3.36 | 2254 | 3.81 | 1.15 (1.09–1.21) | <0.001 |
| Stages II–IV invasive | 4518 | 1.63 | 902 | 1.52 | 0.97 (0.90–1.05) | 0.47 |
| DCIS | 4270 | 1.54 | 1064 | 1.80 | 1.16 (1.08–1.25) | <0.001 |
| CAD mammography 9–24 mo previous (n = 61 537) | ||||||
| Any breast cancer | 367 | 6.70 | 6084 | 6.77 | 0.99 (0.88–1.12) | 0.85 |
| Invasive breast cancer§ | 288 | 5.26 | 4606 | 5.13 | 0.94 (0.82–1.08) | 0.39 |
| Stage I invasive | 167 | 3.05 | 3030 | 3.37 | 1.03 (0.87–1.22) | 0.72 |
| Stages II–IV invasive | 100 | 1.83 | 1345 | 1.50 | 0.84 (0.67–1.05) | 0.118 |
| DCIS | 79 | 1.44 | 1478 | 1.64 | 1.16 (0.91–1.48) | 0.24 |
| No mammography in previous 24 mo (n = 104 318) | ||||||
| Any breast cancer | 12 372 | 11.90 | 4723 | 12.58 | 1.00 (0.96–1.05) | 0.96 |
| Invasive breast cancer§ | 10 093 | 9.71 | 3656 | 9.74 | 0.95 (0.90–0.99) | 0.029 |
| Stage I invasive | 5606 | 5.39 | 2144 | 5.71 | 1.01 (0.95–1.08) | 0.73 |
| Stages II–IV invasive | 3653 | 3.51 | 1241 | 3.31 | 0.86 (0.80–0.93) | <0.001 |
| DCIS | 2279 | 2.19 | 1067 | 2.84 | 1.25 (1.14–1.37) | <0.001 |
CAD = computer-aided detection; DCIS = ductal carcinoma in situ; OR = odds ratio.
Mammograms for women without breast cancer (from the SEER [Surveillance, Epidemiology and End Results]–Medicare 5% noncancer sample) are weighted by a factor of 20 so that the analysis represents the entire population of fee-for-service Medicare enrollees having screening mammography (weighted: 5 656 860 screening mammograms, including 46 361 done within 1 y of breast cancer diagnosis).
Adjusted for age, race or ethnicity, rural vs. urban residence, median income of elderly residents within the same ZIP code, presence of stable and unstable comorbid conditions, digital vs. film mammography, year of examination, and SEER region. Owing to missing covariate or outcome data, 35 531 mammograms (8.7% of total) from 13 136 women (8.3% of total) were excluded from adjusted analyses (unweighted: 373 928 mammograms from 144 022 women).
Incidence per 1000 women-years.
Incidence rates for overall invasive cancer include both staged and unstaged cancer.