Table 2. Baseline clinical characteristics.
| Baseline characteristics | Overall (n=840) | CPCs absent (n=678) | CPCs present (n=162) | P-value |
|---|---|---|---|---|
| Median age at transplant (range), years | 61.1 (24.4–76.1) | 61.4 (24.4–76.1) | 59.9 (32.2–73.8) | 0.068 |
| Males (%) | 59.6 | 61.2 | 53.1 | 0.060 |
| ISS stage, n (%) | 0.004 | |||
| Stage I | 161 (19.2) | 143 (21.1) | 18 (11.1) | |
| Stage II | 313 (37.3) | 257 (37.9) | 56 (34.6) | |
| Stage III | 204 (24.3) | 156 (23.0) | 48 (29.6) | |
| Missing | 162 (19.3) | 122 (18.0) | 40 (24.7) | |
| Median time from diagnosis to transplant (range), months | 6.1 (1.3–11.9) | 6.1 (1.3–11.9) | 6.3 (2.4–11.9) | 0.215 |
| FISH cytogeneticsa, n (%) | 0.001 | |||
| High risk | 191 (22.7) | 138 (20.4) | 53 (32.7) | |
| Standard risk | 551 (65.6) | 453 (66.8) | 98 (60.5) | |
| Missing | 98 (11.7) | 87 (12.8) | 11 (6.8) | |
| Pre-transplant response, n (%) | <0.001 | |||
| CR | 136 (16.2) | 128 (18.9) | 8 (4.9) | |
| VGPR | 221 (26.3) | 193 (28.5) | 28 (17.3) | |
| PR | 346 (41.2) | 284 (41.9) | 62 (38.3) | |
| MR or SD | 93 (11.1) | 57 (8.4) | 36 (22.2) | |
| PD | 44 (5.2) | 16 (2.4) | 28 (17.3) | |
| Induction regimen | ||||
| PI-based only, n (%) | 297 (35.4) | 255 (37.6) | 42 (25.9) | 0.004 |
| IMiD-based only, n (%) | 256 (30.5) | 206 (30.4) | 50 (30.9) | 0.905 |
| PI- and IMiD-based, n (%) | 277 (33.0) | 211 (31.1) | 66 (40.7) | 0.021 |
| Melphalan dose, n (%) | 0.938 | |||
| Full | 740 (88.1) | 597 (88.1) | 143 (88.3) | |
| Reduced | 100 (11.9) | 81 (11.9) | 19 (11.7) | |
| Post-transplant maintenance or consolidation, n (%) | 321 (38.2) | 262 (38.6) | 59 (36.4) | 0.600 |
Abbreviations: CPC, circulating plasma cell; CR, complete response; FISH, fluorescence in situ hybridization; IMiD, immunomodulator; ISS, International staging system; MR, minimal response; PD, progressive disease; PI, proteasome inhibitor; PR, partial response; SD, stable disease; VGPR, very good partial response.
a
High-risk FISH cytogenetics was defined by t(4;14), del(17p), t(14;16), t(14;20) and +1q.