Table 3.

Prognosis of early breast cancer by age group, subtypes, and ethnicity

Classification		Versus age <40 (reference)	Adjusted hazard ratio	95% CI	P-value
HR+/HER2−	SEER-White	Age 40-49	0.65	0.57-0.76	<0.001
		Age ≥50	2.36	2.08-2.67	<0.001
	SEER-Asian	Age 40-49	0.71	0.30-1.71	0.45
		Age ≥50	3.49	1.64-7.42	0.001
	ABCCG-Asian	Age 40-49	0.62	0.48-0.80	<0.001
		Age ≥50	1.29	1.04-1.61	0.02
HR+/HER2+	SEER-White	Age 40-49	1.01	0.72-1.41	0.96
		Age ≥50	3.93	2.96-5.21	<0.001
	SEER-Asian	Age 40-49	0.91	0.08-10.03	0.94
		Age ≥50	6.82	0.93-49.80	0.06
	ABCCG-Asian	Age 40-49	0.87	0.51-1.50	0.62
		Age ≥50	1.96	1.22-3.16	0.01
HR–/HER2+	SEER-White	Age 40-49	1.36	0.91-2.04	0.13
		Age ≥50	3.23	2.27-4.60	<0.001
	SEER-Asian	Age 40-49	0.69	0.17-2.84	0.61
		Age ≥50	1.10	0.33-3.63	0.88
	ABCCG-Asian	Age 40-49	0.92	0.57-1.49	0.74
		Age ≥50	1.01	0.66-1.55	0.96
Triple-negative	SEER-White	Age 40-49	0.99	0.85-1.16	0.92
		Age ≥50	1.64	1.43-1.87	<0.001
	SEER-Asian	Age 40-49	0.65	0.31-1.35	0.25
		Age ≥50	0.94	0.51-1.74	0.85
	ABCCG-Asian	Age 40-49	0.85	0.65-1.11	0.22
		Age ≥50	0.82	0.65-1.04	0.10

Adjusted with age, histologic grade, T stage, N stage, HR status, HER2 status, and study centers.

ABCCG, Asian Breast Cancer Cooperative Group; CI, confidence interval; HER2, human epidermal growth factor receptor 2; HR, hormone receptor; SEER, Surveillance, Epidemiology, and End Results Program.