Table 2.
Association of oral leukoplakia with risk of oral cavity cancer compared with the KPNC population, 1997–2012
| Anatomic site | Overall |
<12 mo after leukoplakia diagnosis |
≥12 mo after leukoplakia diagnosis |
|||
|---|---|---|---|---|---|---|
| No. observed | SIR (95% CI)* | No. observed | SIR (95% CI)* | No. observed | SIR (95% CI)* | |
| All oral cavity cancers | 161 | 40.8 (34.8 to 47.6) | 73 | 103.3 (81.0 to 129.9) | 88 | 27.2 (21.8 to 33.5) |
| Lip | 9 | 11.3 (5.2 to 21.4) | 3 | 22.1 (4.6 to 64.5) | 6 | 9.3 (3.4 to 20.2) |
| Tongue | 112 | 99.6 (82.0 to 119.9) | 47 | 267.9 (196.8 to 356.2) | 65 | 69.1 (53.3 to 88.1) |
| Gingiva | 5 | 32.3 (10.5 to 75.3) | 2 | 85.8 (10.4 to 309.8) | 3 | 23.2 (4.8 to 67.8) |
| Floor of mouth | 13 | 61.5 (32.7 to 105.1) | 11 | 306.3 (152.9 to 548.0) | 2 | 11.6 (1.4 to 41.7) |
| Palate | 9 | 43.2 (19.8 to 82.0) | 3 | 86.5 (17.8 to 252.8) | 6 | 35.2 (12.9 to 76.5) |
| Other mouth | 13 | 60.9 (32.4 to 104.1) | 7 | 223.8 (90.0 to 461.1) | 6 | 33.4 (12.3 to 72.7) |
*
SIRs and exact 95% Poisson confidence intervals for the comparison of oral cavity cancer incidence between patients with oral leukoplakia (n = 4886) vs the entire KPNC population. SIRs were adjusted for age, sex, and calendar year. CI = confidence interval; KPNC = Kaiser Permanente Northern California; SIR = standardized incidence ratio.