Table 3.
Standardized incidence ratio (SIR) of second primary rectal cancer (SPRC).
| NRT | EBRT | EBRT–BRT | |||||||
|---|---|---|---|---|---|---|---|---|---|
| Observed | SIR | 95% CI | Observed | SIR | 95% CI | Observed | SIR | 95% CI | |
| Total | 979 | 0.85# | 0.80–0.91 | 325 | 1.22# | 1.09–1.36 | 187 | 1.85# | 1.60–2.14 |
| Age at diagnosis (years) | |||||||||
| 20–59 | 82 | 1.12 | 0.89–1.40 | 8 | 1.21 | 0.52–2.38 | 18 | 3.00# | 1.78–4.74 |
| 60–74 | 365 | 0.78# | 0.7–0.87 | 97 | 1.23 | 1.00–1.50 | 70 | 1.77# | 1.38–2.24 |
| 75+ | 532 | 0.88# | 0.81–0.96 | 220 | 1.21# | 1.06–1.38 | 99 | 1.79# | 1.45–2.18 |
| Gender | |||||||||
| Male | 632 | 0.80# | 0.74–0.87 | 236 | 1.15# | 1.01–1.31 | 91 | 1.63# | 1.32–2.01 |
| Female | 347 | 0.97 | 0.87–1.08 | 89 | 1.43# | 1.15–1.76 | 96 | 2.12# | 1.72–2.59 |
| Race | |||||||||
| White | 837 | 0.83# | 0.78–0.89 | 267 | 1.24# | 1.10–1.40 | 152 | 1.87# | 1.59–2.20 |
| Black | 74 | 0.96 | 0.75–1.21 | 31 | 1.02 | 0.69–1.44 | 19 | 1.49 | 0.90–2.33 |
| Other | 68 | 1.23 | 0.96–1.56 | 27 | 1.29 | 0.85–1.87 | 16 | 2.35# | 1.34–3.82 |
| Latency | |||||||||
| 60–119 months | 509 | 0.88# | 0.8–0.96 | 163 | 1.04 | 0.88–1.21 | 63 | 1.22 | 0.94–1.56 |
| 120–239 months | 385 | 0.84# | 0.76–0.92 | 135 | 1.39# | 1.16–1.64 | 95 | 2.33# | 1.89–2.85 |
| 240+ months | 85 | 0.81 | 0.65–1.00 | 27 | 2.14# | 1.41–3.12 | 29 | 3.42# | 2.29–4.91 |
| Year | |||||||||
| 1975–1984 | 18 | 0.85 | 0.51–1.35 | 2 | 0.51 | 0.06–1.84 | 1 | 0.50 | 0.01–2.80 |
| 1985–1994 | 132 | 0.92 | 0.77–1.09 | 28 | 1.20 | 0.80–1.74 | 21 | 1.68# | 1.04–2.57 |
| 1995–2004 | 271 | 0.92 | 0.81–1.03 | 62 | 1.13 | 0.87–1.45 | 35 | 1.67# | 1.16–2.32 |
| 2005+ | 558 | 0.82# | 0.75–0.89 | 233 | 1.26# | 1.10–1.43 | 130 | 1.99# | 1.66–2.36 |
| Site | |||||||||
| Cervix | 49 | 1.22 | 0.90–1.62 | 19 | 2.94# | 1.77–4.60 | 49 | 2.44# | 1.80–3.22 |
| Corpus uteri | 211 | 1.00 | 0.87–1.14 | 65 | 1.27 | 0.98–1.62 | 47 | 1.87# | 1.38–2.49 |
| Ovary | 42 | 1.21 | 0.87–1.64 | 2 | 0.89 | 0.11–3.22 | 0 | 0 | 0–100.45 |
| Prostate | 359 | 0.75# | 0.67–0.83 | 220 | 1.13 | 0.99–1.29 | 91 | 1.63# | 1.32–2.01 |
| Bladder | 318 | 0.84# | 0.75–0.94 | 19 | 1.45 | 0.87–2.26 | 0 | 0 | 0–174.55 |
SIR, standardized incidence ratios; CI, confidence interval; NRT, no radiation therapy; EBRT, external beam radiation therapy; EBRT–BRT, combination of external beam with brachytherapy.
#p < 0.05.