The range and demographics of salivary gland tumours diagnosed in a UK population

Epithelial Salivary Gland Tumors in Two Distant Geographical Locations, Finland (Helsinki and Oulu) and Israel (Tel Aviv): A 10-Year Retrospective Comparative Study of 2,218 Cases

“…The present results on malignant SGTs in minor salivary glands in TAU is in accordance with the data reported in other 2005 WHO-based studies, in which the frequency of malignant SGTs in the minor glands ranged from about 55% (Sri Lanka and southern Iran) [9,21] to 62% (China) [24]. In the remaining two relevant studies (from the UK and Turkey), the frequency of these tumors was about 40% [22,23], but that figure is still higher than the values from the Finnish centers. The differences in the incidence of malignant SGTs between Israel and Finland and other geographical regions appear to strengthen the influence of geographical factors and their impact on the distribution of these tumors.…”

“…This is in line with the present study. However, one institution-based report has shown that basal cell adenoma and canalicular adenoma may present slightly more frequently than Warthin tumor [23]. The major reason for this may be that there was a high number of SGTs of the minor salivary glands in that series, and Warthin tumors are extremely rare in minor salivary glands.…”

“…Earlier single-center studies that were also based on the 2005 WHO classification have reported these two tumors as being the most common malignant SGTs, but the order differed: one study found an equal frequency of these tumors [24], two studies found ACC to be more common [21,22], and the other two studies, including one from the UK, found mucoepidermoid carcinoma to be more common [9,23]. Before 2005, the frequency of mucoepidermoid carcinoma among British patients was much lower than the worldwide range [1], with a predominance of ACC [10,28].…”

“…This was the first study that compared the data on SGTs from two remote geographic locations by examiners who collated data strictly according to the 2005 WHO classification [1]. Other studies similarly reporting epidemiologic data on SGTs provided data accumulated within individual centers and described their results in comparison with studies carried out according to earlier WHO classification systems [9,[21][22][23][24]. The main findings of this research were the differences in the annual incidence of the SGTs (highest in Helsinki, lower in Oulu, and lowest in TAU), in the frequency of the malignant forms of SGT (two-to three-fold higher in TAU than in the Finnish centers), and in the frequency of malignant SGTs in the minor glands versus the parotid gland (higher in TAU compared to the Finnish centers).…”

“…These differences can be partially explained by the difficulty that sometimes arises in differentiating tumors that originate from the mucosal glands of the floor of the mouth from those originating within the submandibular glands, thereby artificially inflating the number of one of the two sites [23]. The incidence of SGTs in the minor salivary glands was considerably higher in TAU (34%) compared to Helsinki (11%) and Oulu (4%).…”