Are cancers of the salivary gland increasing?
T Zheng, TR Holford, Y Chen, B Ward, W Liu, J Flannery and P Boyle Yale School of Medicine, Yale Cancer Center, New Haven, CT 06520-8034, USA. BACKGROUND: Recent studies indicate that cancers of the salivary gland are increasing, and the factors responsible for the increase are unknown. Artefactual changes, such as shift in classifying cancers of the floor of the mouth to cancers of the salivary gland, could affect the time trend for salivary gland cancer. METHODS: The current study examined the time trends for cancers of the salivary gland and for cancers of the floor of the mouth and lower gum by using Connecticut Tumor Registry data for the time period 1935-1992. A regression model was used to identify the components of birth cohort, period and age as determinants of the observed time trend. RESULTS: Cancers of the salivary gland have recently increased in Connecticut, with a relative risk of 1.48 (95% CI: 1.06-2.08) for females in 1990-1992 compared to 1980-1984, and a comparable r
