Index date: date of histological diagnosis of OS or ES	Osteosarcoma VTE % (95% CI)	Ewing sarcoma VTE % (95% CI)	Osteosarcoma MB % (95% CI)	Ewing sarcoma MB % (95% CI)
3 months	5.2 (3.5–7.3)	1.8 (0.50–4.8)	1.2 (0.48–2.4)	0
6 months	6.7 (4.8–9.1)	1.8 (0.50–4.8)	2.3 (1.3–3.9)	0.61 (0.06–3.1)
9 months	7.5 (5.4–10)	4.2 (1.9–8.1)	2.5 (1.4–4.1)	0.61 (0.06–3.1)
12 months	8.3 (6.1–11)	6.1 (3.1–10)	3.3 (2.0–5.1)	1.2 (0.24–4.0)
24 months	8.8 (6.6–11)	6.7 (3.5–11)	4.0 (2.6–6.0)	2.5 (0.81–5.8)

OS: osteosarcoma; ES: Ewing sarcoma; VTE: venous thromboembolism; MB: major bleeding; CI: confidence interval

Adjusted cumulative incidence: cumulative incidence adjusted for competing risk of death (following the CICR method).