Appendix Table 6.
Breast Cancer Incidence Rates by CAD Use, Stratified by Mammography Use in the Previous 24 Months and Whether Mammography Was CAD or Non-CAD*
| Breast Cancer Diagnosis Within 1 y, by Mammography Type |
Non-CAD |
CAD |
Adjusted OR (95% CI)† |
P Value | ||
|---|---|---|---|---|---|---|
| Breast Cancer Cases, n |
Incidence Rate‡ |
Breast Cancer Cases, n |
Incidence Rate‡ |
|||
| Current film-screen mammography (n = 380 217) | ||||||
| Any breast cancer | 30 314 | 8.23 | 12 378 | 8.12 | 1.01 (0.98–1.04) | 0.55 |
| Invasive breast cancer§ | 23 999 | 6.51 | 9518 | 6.24 | 0.98 (0.95–1.01) | 0.126 |
| Stage I invasive | 14 379 | 3.90 | 6109 | 4.01 | 1.05 (1.01–1.09) | 0.019 |
| Stages II–IV invasive | 7944 | 2.16 | 2844 | 1.86 | 0.88 (0.84–0.93) | <0.001 |
| DCIS | 6315 | 1.71 | 2860 | 1.88 | 1.13 (1.07–1.19) | <0.001 |
| Current digital mammography (n = 29 242) | ||||||
| Any breast cancer | 1025 | 7.77 | 2644 | 8.38 | 1.07 (0.97–1.17) | 0.170 |
| Invasive breast cancer§ | 805 | 6.11 | 1948 | 6.17 | 0.98 (0.88–1.08) | 0.69 |
| Stage I invasive | 496 | 3.76 | 1226 | 3.88 | 0.98 (0.87–1.11) | 0.78 |
| Stages II–IV invasive | 242 | 1.84 | 597 | 1.89 | 1.02 (0.86–1.22) | 0.78 |
| DCIS | 220 | 1.67 | 696 | 2.21 | 1.40 (1.17–1.68) | <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 probability-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, time since previous mammogram, use of CAD on the previous examination, presence of stable and unstable comorbid conditions, digital vs. film mammography, year of examination, and SEER region. Because breast cancer is uncommon, the adjusted OR closely approximates the adjusted incidence rate ratio. 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.