Table 2.
Treatment characteristics (n = 84).
| Characteristic | Nr. (% or Range) | Site of Solitary Plasmacytoma | ||
|---|---|---|---|---|
| Extramedullary | Bone | p-value | ||
| Type of surgery | <0.001 | |||
| Resection | 20 (24%) | 15 (50%) | 5 (9%) | |
| Biopsy | 64 (76%) | 15 (50%) | 49 (91%) | |
| Systemic therapy | 0.004 | |||
| Yes | 28 (33%) | 4 (13%) | 24 (44%) | |
| No | 56 (67%) | 26 (87%) | 30 (56%) | |
| Timing of systemic therapy | ||||
| Prior to RT alone | 5/28 (18%) | 2/4 (50%) | 3/24 (12%) | <0.001 |
| Adjuvant alone | 21/28 (75%) | 0/4 (0%) | 21/24 (88%) | |
| Both | 2 (7%) | 2/4 (50%) | 0/24 (0%) | |
| Radiation parameters | ||||
| Med. radiation dose (range), Gy | 42 (30–59.4) | 50 (36–59.4) | 40 (30–59.4) | <0.001 |
| Radiation doses | <0.001 | |||
| ≤40 Gy | 44 (53%) | 3 (10%) | 41 (76%) | |
| >40–50 Gy | 22 (26%) | 16 (53%) | 6 (11%) | |
| >50 Gy | 18 (21%) | 11 (37%) | 7 (13%) | |
| Med. fraction dose (range), Gy | 2 (1.8–3) | 2 (1.8–3) | 2 (1.8–2) | 0.03 |
| Follow-up, m | 46 (2–154) | 40 (2–154) | 52 (2–149) | 0.4 |
| Follow-up, IQR | 53 | 48 | 55 | |
| RT technique | 0.02 | |||
| Proton therapy | 4 (5%) | 4 (13%) | 0 | |
| IMRT | 64 (76%) | 22 (74%) | 42 (78%) | |
| 3D-CRT | 16 (19%) | 4 (13%) | 12 (22%) | |
| Response to RT | 0.7 | |||
| Yes | 81 (96%) | 29 (97%) | 52 (96%) | |
| No | 3 (4%) | 1 (3%) | 2 (4%) | |
| Type of response | <0.001 | |||
| CR | 39/81 (48%) | 25/29 (86%) | 14/52 (27%) | |
| PR | 8/81 (10%) | 4/29 (14%) | 4/52 (8%) | |
| SD | 34/81 (42%) | 0 | 34/52 (65%) | |
| Relapse | 0.7 | |||
| Yes | 29 (35%) | 9 (30%) | 20 (37%) | |
| No | 55 (65%) | 21 (70%) | 34 (63%) | |
| Pattern of relapse | 0.6 | |||
| Local | 8 (10%) | 3/30 (10%) | 5/54 (9%) | |
| Multiple myeloma | 21 (25%) | 6/30 (20%) | 15/54 (28%) | |
Med: median; m: month; Gy: gray; RT: radiotherapy; IQR: interquartile range; CRT: 3-dimention conventional radiotherapy; IMRT: intensity-modulated radiotherapy; CR: complete response; PR: partial response; SD: stable disease.