Head and neck cancer incidence trends in young Americans, 1973-1997, with a special analysis for tongue cancer.

OBJECTIVE: To examine the temporal changes in head and neck cancer in young adults in the United States.
METHODS: Using the cancer surveillance database from the National Cancer Institute Surveillance, Epidemiology, and End Results (SEER) Program, we calculated age-adjusted incidence rates for head and neck cancers. Using the joinpoint regression model, we described tongue cancer incidence trends and established the statistical significance of temporal changes. We also compared changes in 5-year survival rates for tongue cancer.
RESULTS: From 1973 to 1997, there were 63 409 patients with head and neck cancer in the 9 SEER registries. Of these, 3339 patients were younger than 40 years. The incidence of head and neck cancer remained stable in groups older than 40 years comparing the 1973-1984 and 1985-1997 data. In contrast, tongue cancer in adults younger than 40 years increased approximately 60% during the same period. We detected a significant increase until 1985, the estimated annual percentage change being 6.7% (95% confidence interval, 2.7%-10.8%; P<.001). After 1985, incidence rates stopped rising but remained steadily high. The change in tongue cancer incidence rates for young adults was related to birth cohorts between 1938 and 1948. The absolute increase in 5-year survival for tongue cancer ranged from 11.7% (<40 years old) to 6.6% (40-64 years old) between 1973-1984 and 1985-1997, with the most significant improvement occurring in young Americans with regional or distant disease (27% and 21%, respectively).
CONCLUSIONS: A sharp increasing trend in tongue cancer in young Americans may be attributed to persons born after 1938. The reason for the increase is uncertain. Improved survival rates in young patients suggest the emergence of a distinct disease process that is apparent in white but not black populations.