Table 2. Risk of multiple primary cancers among EC survivors stratified by histology.
| Multiple primary cancer site | SCC | AC | P | ||||
|---|---|---|---|---|---|---|---|
| No. of observed | SIR | 95% CI | No. of observed | SIR | 95% CI | ||
| No. of patients | 14,540 | – | – | 23,909 | – | – | – |
| No. of person—years | 23,101.62 | – | – | 44,809.91 | – | – | – |
| All site | 913 | 2.28 | 2.13–2.43 | 1,272 | 1.57 | 1.48–1.65 | <0.001 |
| Oral cavity and pharynx | 153 | 16.54 | 14.03–19.38 | 31 | 1.38 | 0.94–1.96 | <0.001 |
| Esophagus | 49 | 10.02 | 7.41–13.25 | 103 | 8.81 | 7.19–10.68 | 0.660 |
| Stomach | 61 | 7.58 | 5.80–9.74 | 131 | 9.29 | 7.76–11.02 | 0.528 |
| Small intestine | 7 | 3.58 | 1.44–7.37 | 18 | 4.95 | 2.94–7.83 | 0.533 |
| Colon and rectum | 52 | 1.25 | 0.93–1.64 | 124 | 1.61 | 1.34–1.92 | 0.220 |
| Liver | 23 | 3.24 | 2.05–4.86 | 30 | 2.14 | 1.44–3.05 | 0.148 |
| Pancreas | 16 | 1.32 | 0.75–2.14 | 43 | 1.89 | 1.37–2.55 | 0.271 |
| Larynx | 40 | 10.34 | 7.39–14.08 | 11 | 1.28 | 0.64–2.30 | <0.001 |
| Lung and bronchus | 229 | 3.63 | 3.17–4.13 | 221 | 1.81 | 1.58–2.06 | <0.001 |
| Breast | 35 | 1.06 | 0.74–1.48 | 26 | 1.08 | 0.71–1.59 | <0.001 |
| Brain | 0 | – | – | 3 | 0.36 | 0.07–1.05 | 0.997 |
| Kidney | 31 | 2.52 | 1.71–3.58 | 90 | 3.31 | 2.66–4.07 | 0.055 |
| Myeloma | 5 | 0.73 | 0.24–1.70 | 4 | 0.34 | 0.09–0.86 | 0.185 |
| Non-hodgkin lymphoma | 21 | 1.35 | 0.83–2.06 | 49 | 1.41 | 1.04–1.86 | 0.488 |
| Hodgkin lymphoma | 0 | – | – | 4 | 2.11 | 0.58–5.41 | 0.315 |
| Thyroid | 7 | 1.77 | 0.71–3.64 | 27 | 3.69 | 2.43–5.37 | 0.107 |
| Leukemia | 14 | 1.33 | 0.73–2.23 | 34 | 1.41 | 0.98–1.98 | 0.487 |
| Prostate | 74 | 0.83 | 0.65–1.04 | 154 | 0.72 | 0.61–0.84 | 0.639 |
| Ovary | 3 | 0.90 | 0.18–2.62 | 2 | 0.84 | 0.10–3.05 | 0.240 |
P values comparing SIR for esophageal SCC versus esophageal AC survivors were calculated using Poisson regression. SCC, squamous cell carcinoma; AC, adenocarcinoma; EC, esophageal cancer; SIR, standardized incidence ratio; CI, confident interval.