Incidence trends of malignant parotid gland tumors and all malignant salivary gland tumors were investigated in Sweden and in the Nordic countries.
In Sweden, 3604 salivary gland tumor cases in adults 20 years or older were identified during the period 1970-2009, of whom 2624 (73%) were malignant neoplasms of the parotid gland. The incidence of parotid gland tumors in Sweden decreased slightly during the early study period, and then remained stable for both sexes (0.9/100,000 person-years in 1970 and 0.8/100,000 person-years in 2009 for men; 0.7/100,000 person-years in both 1970 and 2009 for women).
The age-standardized incidence rate of salivary gland tumors in the whole Nordic population during the period 1970-2009 was 1.1/100,000 for men (4440 cases) and 0.9/100,000 for women (4178 cases). No increase in incidence was observed; the annual percent change was -0.1% for men and -0.2% for women.
The authors concluded that if mobile phone use were a noticeable risk factor for parotid gland tumors, some increase of the incidence rate would have been seen in the Nordic countries unless the latency period exceeds 15-20 years. The results suggest other explanations for increases in the registered incidence of parotid gland tumors observed in Israel and United Kingdom.