Table 2. Standardized incidence ratios (SIRs) and 95% confidence intervals (CIs) for gastrointestinal cancers in appendectomy patients with different discharge diagnoses.
| All appendectomy cohort | Appendicitis | Other diagnoses | ||||
|---|---|---|---|---|---|---|
| Observed cases* | SIR (95% CI)§ | Observed cases* | SIR (95% CI)§ | Observed cases* | SIR (95% CI)§ | |
| Esophageal cancer, all | 255 | 1.00 (0.88–1.13) | 153 | 0.93 (0.79–1.09) | 102 | 1.14 (0.93–1.38) |
| Esophageal adenocarcinoma | 118 | 1.32 (1.09–1.58) | 79 | 1.25 (0.99–1.55) | 39 | 1.50 (1.07–2.05) |
| Esophageal squamous-cell carcinoma | 114 | 0.79 (0.65–0.95) | 62 | 0.71 (0.54–0.91) | 52 | 0.92 (0.69–1.21) |
| Gastric cancer, all | 831 | 1.00 (0.93–1.07) | 496 | 1.01 (0.92–1.10) | 335 | 0.98 (0.87–1.09) |
| Non-cardia gastric cancer | 685 | 0.99 (0.92–1.07) | 393 | 0.99 (0.90–1.10) | 292 | 0.99 (0.88–1.11) |
| Cardia cancer | 146 | 1.06 (0.89–1.25) | 103 | 1.11 (0.91–1.35) | 43 | 0.95 (0.69–1.28) |
| Colon cancer, all | 2473 | 1.03 (0.99–1.07) | 1373 | 1.00 (0.95–1.06) | 1100 | 0.98 (0.92–1.04) |
| Right-sided colon cancer | 1282 | 1.04 (0.99–1.10 | 693 | 1.05 (0.97–1.13) | 589 | 1.04 (0.95–1.12) |
| Left-sided colon cancer | 860 | 0.96 (0.90–1.03) | 498 | 0.99 (0.91–1.08) | 362 | 0.92 (0.83–1.02) |
| Rectal cancer | 1280 | 0.98 (0.93–1.04) | 712 | 0.94 (0.87–1.01) | 568 | 0.94 (0.87–1.01) |
*The first year of observation and corresponding events were excluded.
§ Observed to expected number of cancer cases, based on age- (5-year strata), calendar year- (5-year strata) and sex-specific incidence data in the total Swedish population. Ninety-five percent CIs of SIRs were calculated by assuming that observed cancer occurrence followed a Poisson distribution.