Table 2. Stage distribution according to screening frequency and time from last screening to cancer diagnosis.
| Variables | Matched dataset (n=9,424) | Un-matched dataset (n=18,388) | |||||
|---|---|---|---|---|---|---|---|
| Diagnosed with CIS | Diagnosed at higher stages* | Total | Diagnosed with CIS | Diagnosed at higher stages* | Total | ||
| Screening frequency | |||||||
| Never | 2,581 (43.28) | 2,131 (61.57) | 4,712 (50.00) | 2,819 (24.16) | 2,284 (33.98) | 5,103 (27.75) | |
| Once | 1,885 (31.61) | 713 (20.60) | 2,598 (27.57) | 3,527 (30.23) | 1,903 (28.31) | 5,430 (29.53) | |
| Twice | 826 (13.85) | 297 (8.58) | 1,123 (11.92) | 2,234 (19.15) | 1,078 (16.04) | 3,312 (18.01) | |
| Three times or more | 671 (11.27) | 320 (9.25) | 991 (10.51) | 1,282 (26.45) | 666 (21.68) | 1,948 (24.71) | |
| Time from last screening to cancer diagnosis | |||||||
| Never | 2,581 (27.39) | 2,131 (22.61) | 4,712 (50.00) | 2,819 (15.33) | 2,284 (12.42) | 5,103 (27.75) | |
| ≤11 mo | 2,484 (26.36) | 847 (8.99) | 3,331 (35.35) | 6,539 (35.56) | 2,848 (15.49) | 9,387 (51.05) | |
| 12–23 mo | 458 (4.86) | 145 (1.54) | 603 (6.40) | 1,046 (5.69) | 507 (2.76) | 1,553 (8.45) | |
| 24–35 mo | 196 (2.08) | 93 (0.99) | 289 (3.07) | 500 (2.72) | 282 (1.53) | 782 (4.25) | |
| ≥36 mo | 244 (2.59) | 245 (2.60) | 489 (5.19) | 762 (6.53) | 801 (11.92) | 1,563 (8.50) | |
| Total | 5,963 (63.27) | 3,461 (36.73) | 9,424 (100) | 11,666 (63.44) | 6,722 (36.56) | 18,388 (100) | |
Values are presented as number (%).
CIS, carcinoma in situ.
*Higher stages include localized, regional, and distant stage.