Description Na %
Head and Neck cancer subtype
Head and Neck
Oral cavity
Larynx
Oral cavity and Oropharynx
Oropharynx
Tongue
Larynx and Hypopharynx
Oral cavity and Pharynx
Pharynx
Hypopharynx
Oral cavity, Oropharynx and Larynx
Tonsil
31
14
12
7
5
4
3
2
1
1
1
1
37.8
17.1
14.6
8.5
6.1
4.9
3.7
2.4
1.2
1.2
1.2
1.2
Country of study
Europe
USA and Canada
Asia
Australia and New Zealand
Africa
South America		 47
22
10
3
1
1		 57.3
26.8
12.2
3.7
1.2
1.2
Gender
Both males and females
Male only
Not reported
71
5
6
86.6
6.1
7.3
Study Design (as reported by the authors)
Cross sectional
Prospective
Retrospective
Retrospective chart review
Pilot
Cohort
Case-Control
Case Series
Follow up
Survey
Univariate and correlational descriptive
Study design not reported in methods
22
15
6
3
2
2
1
1
1
1
1
27
26.8
18.3
7.3
3.7
2.4
2.4
1.2
1.2
1.2
1.2
1.2
32.9
Year of publication
1981 - 1984
1985 - 1990
1991 - 1999
2000 - 2005
2006 - 2011
3
0
10
31
38		 3.7
0.0
12.2
37.8
46.3
Sample size
Minimum, Maximum
Median (IQR)		 13, 1761
80 (44, 154)

aNumbers do not always add up to total (n = 82), because of multiple values.