Table 2.
Yearly incidence rates of cervical cancer after completed negative follow-up results of histologically confirmed cervical intraepithelial neoplasia (CIN) and after normal primary smear test results
| Interval (years) after primary smear test | CIN with completed negative follow-up test results | Normal primary smear test results | |||||
|---|---|---|---|---|---|---|---|
| Woman years | No of cases | Incidence per 100 000 woman years (95% CI) | Woman years | No of cases | Incidence per 100 000 woman years (95% CI) | ||
| 0 to 1 | 76 | 0 | 0 (0 to 4853.8) | 5 442 539 | 252 | 4.6 (4.1 to 5.2) | |
| 1 to 2 | 3376 | 0 | 0 (0 to 109.3) | 4 829 887 | 194 | 4.0 (3.5 to 4.6) | |
| 2 to 3 | 9541 | 2 | 21.0 (2.5 to 75.7) | 4 158 762 | 194 | 4.7 (4.0 to 5.4) | |
| 3 to 4 | 11 358 | 3 | 26.4 (5.4 to 77.2) | 3 277 698 | 213 | 6.5 (5.7 to 7.4) | |
| 4 to 5 | 10 115 | 3 | 29.7 (6.1 to 86.7) | 2 451 794 | 226 | 9.2 (8.1 to 10.5) | |
| 5 to 6 | 7135 | 5 | 70.1 (22.8 to 163.5) | 1 433 680 | 221 | 15.4 (13.4 to 17.6) | |
| 6 to 7 | 5399 | 4 | 74.1 (20.2 to 189.7) | 1 081 698 | 111 | 10.3 (8.4 to 12.4) | |
| 7 to 8 | 4372 | 1 | 22.9 (0.6 to 127.4) | 916 117 | 85 | 9.3 (7.4 to 11.5) | |
| 8 to 9 | 3272 | 2 | 61.1 (7.4 to 220.8) | 776 855 | 57 | 7.3 (5.6 to 9.5) | |
| 9 to 10 | 2311 | 0 | 0 (0 to 159.6) | 651 666 | 60 | 9.2 (7.0 to 11.9) | |
| Total* | 56 956 | 20 | 35.1 (21.4 to 54.2) | 25 020 697 | 1613 | 6.4 (6.1 to 6.8) | |
*Total hazard ratio comparing incidence rates of cervical cancer 35.1 per 100 000 woman years at risk and 6.4 per 100 000 woman years at risk, corrected for year in follow-up, was 4.2 (95% confidence interval 2.7 to 6.5; table 3).