Distribution and Frequency of Salivary Gland Tumours: An International Multicenter Study.

BACKGROUND: Salivary gland tumours (SGT) are a relatively rare group of neoplasms with a wide range of histopathological appearance and clinical features. To date, most of the epidemiological studies on salivary gland tumours are limited for a variety of reason including being out of date, extrapolated from either a single centre or country studies, or investigating either major or minor glands only. METHODS: This study aimed to mitigate these shortcomings by analysing epidemiological data including demographic, anatomical location and histological diagnoses of SGT from multiple centres across the world. The analysed data included age, gender, location and histological diagnosis from fifteen centres covering the majority of the world health organisation (WHO) geographical regions between 2006 and 2019. RESULTS: A total of 5739 cases were analysed including 65% benign and 35% malignant tumours. A slight female predilection (54%) and peak incidence between the fourth and seventh decade for both benign and malignant tumours was observed. The majority (68%) of the SGT presented in major and 32% in the minor glands. The parotid gland was the most common location (70%) for benign and minor glands (47%) for malignant tumours. Pleomorphic adenoma (70%), and Warthin's tumour (17%), were the most common benign tumours whereas mucoepidermoid carcinoma (26%) and adenoid cystic carcinoma (17%) were the most frequent malignant tumours. CONCLUSIONS: This multicentre investigation presents the largest cohort study to date analysing salivary gland tumour data from tertiary centres scattered across the globe. These findings should serve as a baseline for future studies evaluating the epidemiological landscape of these tumours.

Diagnosis of parotid gland tumours with Contrast-Enhanced Ultrasound: a systematic review and meta-analysis.

AIM: Contrast-enhanced ultrasound (CEUS) appears to be a promising application for the diagnosis of parotid gland tumours. We aimed to systematically review and meta-analyse the ability of CEUS in distinguishing benign from malignant parotid gland tumours. MATERIAL AND METHODS: PubMed was searched for relevant studies. Data on area under time intensity curve (AUC) in arbitrary unit (AU), and mean transit time (MTT) in seconds (sec) were analysed using the Cochrane Review Manager Software. RESULTS: Nine studies met the eligibility criteria comprising a total number of 498 parotid gland tumours (benign, number (n)=423; malignant, n=75). Descriptive evaluation of parotid gland tumours following CEUS administration showed overlap characteristics in benign and malignancies. Two publications assessed AUC and MTT in 72 and 60 parotid gland tumours, respectively. AUC was significantly lower in benign compared to malignant tumours following contrast administration (AUC, mean difference (MD) -266.77 AU, 95% confidence intervals (CI) -433.22, -100.33, p=0.002). No significant different in MTT between benign and malignant tumours (p=0.12). Heterogeneity was statistically significant in AUC (p=0.04) and MTT (p<0.00001). CONCLUSION: Descriptive evaluation of parotid gland tumours showed overlap CEUS characteristics. Perfusion related CEUS parameters analysis is promising in differentiating benign parotid tumours from malignancies.