Table 3. The incidence of major secondary primary cancer in aspirin users and non-aspirin users among HNSCC patients identified during 2000–2011.

	Aspirin user (N = 3576)		Non-aspirin user (N = 14667)
Cancer Type	Event	Ratea	Event	Ratea	HR (95% CI)b	P
Head and neck cancer	9	0.69	21	0.66	1.44 (0.62–3.37)	0.39
Esophagus cancer	33	2.54	162	5.10	0.60 (0.41–0.90)	0.01
Stomach cancer	4	0.31	25	0.79	0.27 (0.08–0.87)	0.03
Colorectal cancer	16	1.23	46	1.45	0.59 (0.31–1.11)	0.10
Liver cancer	28	2.15	82	2.58	0.67 (0.42–1.08)	0.10
Lung cancer	37	2.84	118	3.71	0.71 (0.18–1.07)	0.10
Bladder cancer	6	0.46	9	0.28	0.83 (0.26–2.62)	0.83

^a Rate: Incidence rate per 1000 person-year

^b Adjusted for age, sex, urbanization, coronary heart disease, hypertension, diabetes, atrial fibrillation, heart failure, hyperlipidemia, chronic kidney disease, and medicines use of COX2, and statins.