Table 1. Baseline characteristics of radiation-induced sarcomas (cases) and sporadic sarcoma (controls).
| Variable | RIS (n=98) | Controls (n=239) | Total (n=337) | P-value |
|---|---|---|---|---|
| Gender | ||||
| Female | 72 (73%) | 117 (49%) | 189 (56%) | <0.001 |
| Male | 26 (27%) | 122 (51%) | 148 (44%) | |
| Age at sarcoma diagnosis (years) | ||||
| <60 | 51 (52%) | 124 (52%) | 175 (52%) | 0.979 |
| ⩾60 | 47 (48%) | 115 (48%) | 162 (48%) | |
| Time period of diagnosis | ||||
| Before 1990 | 19 (19%) | 65 (27%) | 84 (25%) | 0.294 |
| 1990–1999 | 35 (36%) | 82 (34%) | 117 (35%) | |
| From 2000 | 44 (45%) | 92 (39%) | 136 (40%) | |
| Histological diagnosis a | ||||
| Angiosarcoma | 12 (12%) | 18 (7%) | 30 (9%) | 0.637 |
| MFH | 41 (42%) | 97 (41%) | 138 (41%) | |
| Osteosarcoma | 26 (27%) | 76 (32%) | 102 (30%) | |
| MPNST | 7 (7%) | 20 (8%) | 27 (8%) | |
| Leiomyosarcoma | 12 (12%) | 28 (12%) | 40 (12%) | |
| Tumour size | ||||
| <5 cm | 25 (26%) | 41 (17%) | 66 (20%) | 0.065 |
| ⩾5 cm | 70 (74%) | 195 (83%) | 265 (80%) | |
| Unknown | 3 | 3 | 6 | |
| Tumour necrosis | ||||
| Yes | 64 (69%) | 149 (62%) | 213 (67%) | 0.729 |
| No | 29 (31%) | 74 (31%) | 103 (33%) | |
| Unknown | 5 | 16 | 21 | |
| Bone or soft tissue/viscera | ||||
| Bone | 29 (31%) | 81 (33%) | 110 (33%) | 0.595 |
| Soft tissue/viscera | 65 (69%) | 158 (67%) | 223 (67%) | |
| Unknown | 4 | 0 | 4 | |
| Site b | ||||
| Extremity/trunk wall | 39 (40%) | 184 (77%) | 223 (66%) | <0.001 |
| Head/abdomen/axial/thoracic | 59 (60%) | 55 (23%) | 114 (34%) | |
| Metastases at diagnosis | ||||
| Yes | 20 (20%) | 39 (16%) | 59 (18%) | 0.370 |
| No | 78 (80%) | 200 (84%) | 278 (82%) | |
| Chemotherapy | ||||
| Yes | 37 (38%) | 106 (45%) | 143 (43%) | 0.257 |
| No | 60 (62%) | 130 (55%) | 190 (57%) | |
| Unknown | 1 | 3 | 4 | |
| Radiotherapy | ||||
| Yes | 22 (22%) | 78 (33%) | 100 (30%) | 0.046 |
| No | 76 (78%) | 155 (67%) | 231 (70%) | |
| Unknown | 6 | 6 | ||
| Surgery | ||||
| Yes | 70 (71%) | 215 (90%) | 285 (85%) | <0.001 |
| No | 28 (29%) | 24 (10%) | 52 (15%) | |
| Complete surgical remission (operated patients only, n=70) | ||||
| Yes | 45 (64%) | 165 (77%) | 210 (74%) | 0.034 |
| No | 25 (36%) | 49 (23%) | 74 (26%) | |
| Unknown | 1 | 1 | ||
| Complete surgical remission (all patients) c | ||||
| Yes | 45 (46%) | 165 (69%) | 210 (62%) | <0.001 |
| No | 53 (54%) | 73 (31%) | 126 (38%) | |
| Unknown | 1 | 1 | ||
| Surgery and radiotherapy | ||||
| Yes | 15 (15%) | 67 (29%) | 82 (25%) | 0.01 |
| No | 83 (85%) | 166 (71%) | 249 (75%) | |
| Unknown | 6 | 6 | ||
| Local recurrences | ||||
| Yes | 29 (41%) | 37 (17%) | 66 (23%) | <0.001 |
| No | 41 (59%) | 178 (83%) | 219 (77%) | |
| No surgery | 28 | 24 | 52 | |
Abbreviations: MFH=malignant fibrous histiocytoma; MPNST=malignant peripheral nerve sheath tumour; RIS=radiation-induced sarcoma.
a
Localisation of the RIS: all angiosarcomas and MPNST were localised in soft tissue. In all 68% of the MFH, 92% of the LMS and 27% of the OS were localised in soft tissue.
b
(1) Extremities (bone and soft tissue) + trunk wall (soft tissue including the axillary region and groin). (2) Head and neck (bone and soft tissue), intrathoracic and intraabdominal (soft tissue and viscera), and axial skeleton including the scapula, clavicle, ribs and pelvic bones.
c
Complete surgical remission also includes patients not operated.