SIR stratified according to cumulative cyclophosphamide and rituximab doses*
| Cumulative dose (g) | Patients (n) | N observed malignancies | SIR (95% CI)† | SIR p Value† | RR (95% CI)† | RR p Value† |
|---|---|---|---|---|---|---|
| Cyclophosphamide | ||||||
| 0 | 89 | 8 | 1.37 (0.59 to 2.70) | 0.47 | 1 (reference) | |
| 0.1–20 | 207 | 31 | 1.91 (1.30 to 2.71) | 0.001 | 1.39 (0.63 to 3.50) | 0.52 |
| 20–108 | 16 | 5 | 5.06 (1.64 to 11.82) | 0.007 | 3.69 (0.95 to 12.78) | 0.06 |
| Rituximab | ||||||
| 0 | 167 | 34 | 2.86 (1.98 to 3.99) | <0.001 | 1 (reference) | |
| 0.1–6 | 70 | 7 | 1.41 (0.57 to 2.90) | 0.47 | 0.49 (0.18 to 1.13) | 0.11 |
| 6–18 | 83 | 3 | 0.45 (0.09 to 1.32) | 0.10 | 0.16 (0.03 to 0.50) | <0.001 |
*SIR is the ratio of the observed to expected malignancies adjusted for sex, age (per 5-year age group) and calendar time period (per 1-year calendar time period). SIR represents the malignancy risk compared with the general population, and the RR represents the malignancy risk compared with the reference group.
†Calculated by exact Poisson regression analysis.
RR, relative risk; SIR, standardised incidence ratio.