The incidence of tonsillar cancer in Sweden is increasing.
CONCLUSIONS
The incidence of tonsillar cancer in Sweden is increasing, particularly among men. Risk factors other than smoking may have contributed to the observed secular trend in men. In women, however, smoking can be a part of the explanation. Further studies to look at changes in other environmental factors, such as human papilloma virus (HPV) infection, are clearly warranted.


OBJECTIVE
Head and neck cancer is related to smoking habits and smoking has decreased substantially during the last 30 years in Sweden. However, there is suspicion that the incidence of tonsillar cancer has increased in the last 30 years as it has in the USA and Finland, in spite of reduced prevalence of known risk factors. The time trends of oral and oropharygeal cancer have been studied in Sweden, but not tonsillar cancer specifically.


METHODS
We used the Swedish Cancer Registry to assess the secular trend of incidence of tonsillar cancer in Sweden since 1960. For comparison we investigated the incidence of other oral cancers and lung cancer, which are also smoking-related. The prevalence of smoking was investigated for reference. Age-standardized incidence rates were calculated and linear regression was used to evaluate secular trends.


RESULTS
The incidence of tonsillar cancer increased by 2.6% per year in men and 1.1% in women. No similar increase was seen in the other oral cancers. For lung cancer there was a decrease in the incidence in men, but in women the incidence is still increasing.
Hammarstedt
Lalle
L
Department of Oto-Rhino-Laryngology, Head and Neck Surgery, Karolinska University Hospital, Sweden. lalle.hammarstedt@karolinska.se
Dahlstrand
Hanna
H
Lindquist
David
D
Onelöv
Liselotte
L
Ryott
Michael
M
Luo
Juhua
J
Dalianis
Tina
T
Ye
Weimin
W
Munck-Wikland
Eva
E
D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D015994:Incidence; D008175:Lung Neoplasms / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009062:Mouth Neoplasms / Q000453:epidemiology; D012042:Registries; D017678:Sex Distribution; D012907:Smoking / Q000453:epidemiology / Q000639:trends; D013548:Sweden / Q000453:epidemiology; D014067:Tonsillar Neoplasms / Q000453:epidemiology*