Appendix Table A1.

Cox model for event-free survival (timed from diagnostic biopsy) for ‘registration cohort’ patients (N = 1531)—complete-case analysis with no imputed data.

Characteristic	N	EFS events	Adjusted HR (95% CI)	p-value	Overall p-value
Pulmonary metastases
No metastasesa	1349	516	1.00	n/a	<0.001
Metastases	182	124	2.39 (1.96–2.93)	<0.001
Non-pulmonary metastases
No metastasesa	1485	609	1.00	n/a	<0.001
Metastases	46	31	1.97 (1.35–2.88)	<0.001
Site of the tumour
Other limb site	1276	499	1.00	n/a	<0.001
Proximal femur/humerus	199	105	1.42 (1.13–1.77)	<0.001
Axial skeleton	56	36	1.59 (1.12–2.28)	0.010
WHO classification of sarcoma at diagnosis
Conventional: chondroblastic	252	123	1.00	n/a	<0.001
Conventional: osteoblastic	943	403	0.89 (0.72–1.09)	0.256
Conventional: other	235	82	0.71 (0.54–0.95)	0.021
Telangiectatic	74	23	0.58 (0.37–0.91)	0.017
Small cell	7	3	1.15 (0.36–3.65)	0.811
High-grade surface	20	6	0.56 (0.25–1.29)	0.171
Age
Child	466	172	1.00	n/a	0.004
Adolescent	742	323	1.29 (1.07–1.56)	0.008
Adult	323	145	1.33 (1.06–1.66)	0.015
Gender
Female	639	251	1.00	n/a	0.015
Male	892	389	1.18 (1.01–1.39)	0.043
Relative tumour volumeb
Small (<1/3 of involved bone)	851	307	1.00	n/a	<0.001
Large (≥1/3 of involved bone)	680	333	1.35 (1.14–1.59)	<0.001
Pathological fracture at diagnosis
No	1343	558	1.00	n/a	0.457
Yes	188	82	1.00 (0.79–1.28)	0.992
Surgical margins achievedc
Wide/Radical	1295	532	1.00	n/a	0.019
Marginal	214	94	1.02 (0.79–1.31)	0.872
Intralesional	22	14	1.41 (0.81–2.46)	0.226

CI, confidence interval; EFS, event-free survival; HR, hazard ratio; WHO, World Health Organisation.

^aincludes possible metastases.

^bas reported with no imputed data.

^cas reported by the pathologist. Note: 336 missing values on relative tumour volume not imputed (as shown in Table 3 in main text, for comparison).