Patient and Disease Characteristics Before Radioimmunotherapy
| Characteristic | All patients (n = 38) | 131I-Tositumomab (n = 18) | 90Y-Ibritumomab tiuxetan (n = 20) | P* |
|---|---|---|---|---|
| Age at radioimmunotherapy (y) | 0.07 | |||
| Median | 64 | 60 | 67 | |
| Range | 40–80 | 41–78 | 40–80 | |
| Age > 60 y (n) | 24 (63%) | 9 (50%) | 15 (75%) | 0.18 |
| Male sex (n) | 25 (66%) | 13 (72%) | 12 (60%) | 0.51 |
| Histology at radioimmunotherapy (n) | 1.00 | |||
| Indolent | 27 (71%) | 13 (72%) | 14 (70%) | |
| Aggressive | 11 (29%) | 5 (28%) | 6 (30%) | |
| Transformed from original histology (n) | 1.00 | |||
| Yes | 6 (16%) | 3 (17%) | 3 (15%) | |
| No | 32 (84%) | 15 (83%) | 17 (85%) | |
| Stage at radioimmunotherapy (n) | 1.00 | |||
| I–II | 8 (21%) | 4 (22%) | 4 (20%) | |
| III–IV | 30 (79%) | 14 (78%) | 16 (80%) | |
| IPI score† (n) | 0.28 | |||
| 0–2 | 14 (47%) | 10 (56%) | 4 (33%) | |
| 3–5 | 16 (53%) | 8 (44%) | 8 (67%) | |
| Prior treatment regimens (n) | ||||
| Median | 3 | 3 | 2 | |
| Range | 1–8 | 1–8 | 1–7 | |
| Prior treatment with rituximab (n) | 37 (97%) | 17 (94%) | 20 (100%) | 0.47 |
| Prior treatment with fludarabine (n) | 10 (26%) | 5 (28%) | 5 (25%) | 1.00 |
| Normal LDH (118–273 mg/dL) at radioimmunotherapy‡ (n) | 18 (58%) | 9 (60%) | 9 (56%) | 1.00 |
| Bone marrow involvement at radioimmunotherapy§ (n) | 8 (22%) | 4 (22%) | 4 (21%) | 1.00 |
| Prior bone marrow transplantation (n) | 4 (11%) | 3 (17%) | 1 (5%) | 0.33 |
| Prior radiation therapy (n) | 8 (21%) | 6 (33%) | 2 (10%) | 0.12 |
| Full-dose treatment‖ (n) | 26 (68%) | 12 (67%) | 14 (70%) | 1.00 |