In several countries, increased incidence of squamous cell carcinoma (SCC) of the tongue in young adults has been suspected during the last decades. Some reports indicate a lower survival rate for young patients compared to older patients. In other reports, there has not been any considerable difference in survival when comparing young adults to older patients, whereas some authors have shown better survival for young adults. This disease is rare in young adults, and early reports were based on comparable small numbers and selected patients. Our aim was first to perform a population-based study to determine if an increased incidence in SCC of the tongue could be verified in a larger population comprising the Scandinavian countries Denmark, Finland, Sweden and Norway. A second aim was to determine survival rates for young adults compared to older patients. The material was based on the annual cancer incidence and survival reports from the Scandinavian cancer registries. The study period was 1960 -1994. During that period, 5,024 SCCs of the tongue were reported. Of these, 276 (5.5%) were young adults (20 -39 years). The incidence increased at all ages except for women 65-79 years old. The increase was most pronounced in young adults: 0.06 -0.32 for men and 0.03-0.19 for women, counted by 100,000 person-years. Relative survival was significantly better for young adults compared to older patients.

After a median follow-up time of 22 months (range 0-36 months), 30 recurrences, 2 SPT, 12 lost to follow-up and 21 deaths before recurrence or SPT were observed. Tumour stage was associated with both a higher risk of recurrence/SPT and of DICD. In univariate analysis, patients with tonsillar carcinoma had a significantly higher risk of recurrence/SPT than patients with carcinoma at other sites, but there was no difference according to site in multivariate analyses. High alcohol consumption was associated with a higher risk of recurrence/SPT, but not of DICD. There was no increased risk of recurrence/SPT related to smoking, but there was an association between smoking and DICD. High-risk HPV-positive cases had a higher risk of recurrence/SPT, but a lower risk of DICD compared with high-risk HPV-negative cases. This seemingly higher risk should be interpreted by taking the competing risk of DICD into account.

In all, 12 280 cases were reported, of which 673 were diagnosed in patients aged 20-39 years. The trend of an increase persisted after 1994 in both sexes and all three age groups except in young males.

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