Table 1. The Distribution of Different Clinicopathological Features from the 188 Primary OPSCC Cases Between 2008 and 2014.

	Time period							Overall	Statistical significance (2008–2013)
	2008–2009	2009–2010	2010–2011	2011–2012	2012–2013	2013–2014	2014.1–4
Patient/tumor data
No. of patients	15	29	29	27	35	40	13	188
HPV Negative	14	27	28	25	31	30	11	166	NS
HPV Positive	1	2	1	2	4	10	2	22
Age at diagnosis, y
Mean	57	58	60.	58	57	59	59	58	NS
Median	57	55	59	57	56	58	58	58
Sex
Male	13	27	24	24	31	39	10	168	NS
Female	2	2	5	3	4	1	3	20
Tumor site
Base of tongue	7	8	12	14	14	12	7	74	NS
Oropharynx (not further specified)	3	11	8	5	9	14	4	54
Soft palate	5	9	8	6	11	10	1	50
Tonsil	0	1	1	2	1	4	1	10
aSmoking
Smoker	10	22	14	15	21	26	8	116	NS
Nonsmoker	4	7	13	6	14	13	5	62
Unknown	1	0	2	6	0	1	0	10
bAlcohol consumption
Drinker	6	14	11	14	20	17	7	89	NS
Nondrinker	8	15	16	7	15	22	6	89
Unknown	1	0	2	6	0	1	0	10
Pathological grades
1	2	4	4	2	5	1	1	19	NS
2	11	18	18	20	26	28	10	131
3	2	7	7	5	4	11	2	38
Nodal stage
Negative	6	17	17	12	17	27	7	103	NS
Positive	9	12	12	15	18	13	6	85
Clinical stage
I~II	4	16	16	12	16	26	6	96	NS
III~IV	11	13	13	15	19	14	7	92

NS, Not Significant

^aFormer/current smokers were defined as at least one pack-year history of smoking.

^bPositive alcohol use was defined as current alcohol use of more than one drink per day for one year (12 ounces of beer with 5% alcohol, five ounces of wine with 12–15% alcohol, or one ounce of liquor with 45–60% alcohol). All other patients were classified as negative alcohol users.