Table 5.
Secondary malignancy and treatment factors
| Factor | Total | Event (%) | Incidence ratea) | Incidence rate ratio (95% CI) |
|---|---|---|---|---|
| Treatment | ||||
| CRT | 135 | 3 (2.2) | 1.6 | 0.163 (0.027–0.715) |
| RT | 44 | 7 (15.9) | 10.0 | |
| WB RT | ||||
| WBRT | 96 | 9 (9.4) | 6.4 | 7.208 (0.999–315.915) |
| WVRT or IFRT only | 83 | 1 (1.2) | 0.9 | |
| Total dose (Gy) | ||||
| > 50 | 105 | 9 (8.6) | 6.3 | 7.001 (0.970–306.874) |
| ≤ 50 | 74 | 1 (1.3) | 0.1 | |
| WB/WV RT dose (Gy) | ||||
| > 30 | 58 | 8 (13.8) | 9.0 | 7.375 (1.472–71.294) |
| ≤ 30 | 121 | 2 (1.6) | 0.1 | |
CI, confidence interval; CRT, radiotherapy with upfront chemotherapy; IFRT, involved-field RT; RT, radiotherapy; WB, whole brain; WV, whole ventricle.
a)
Per 10,000 person-year.