Deep brush‐based cytology in tonsils resected for benign diseases

Abstract

A fraction of oropharyngeal cancer (OPC), especially in the tonsil, is caused by human papillomavirus (HPV), mainly HPV16. Noninvasive diagnostic methods to detect precancerous lesions in the tonsil would be useful, e.g., liquid-based cytology (LBC). However, ill-characterized precancerous lesions may be hidden in the depth of the tonsillar crypts. We therefore conducted a study on HPV and tonsillar precancerous lesions to evaluate, among other things, the utility of LBC obtained by deep brushing of the resected tonsils. Two hundred non-paediatric patients (mean age: 30.3 years) who underwent tonsillectomy for infection-related conditions (69%) or other conditions (mainly obstructive sleep apnoea, 31%) were included. An ultra-sensitive Luminex bead-based platform was used to test for the DNA of 21 mucosal HPV types; 56% of slides were unsatisfactory due to low number of squamous epithelial cells or the masking effect of a large number of lymphocytes. Three patients (1.5%; 95% CI: 0.5-4.3) showed suspicious cytological findings (atypical squamous cells-cannot exclude high-grade squamous intraepithelial lesion, ASC-H) while 3 others were HPV-positive (2 for HPV16 and 1 for HPV39). None of the ASC-H patients and HPV-positive patients showed dysplasia at histological examination. The rarity of HPV infection in the tonsil conflicts with the relatively frequent detection of the virus in the mouth. In conclusion, aggressive deep brushing of tonsils, while hardly applicable in vivo, is unlikely to be a reliable method to detect precancerous lesions. The absence of OPC screening modalities places the priority on multi-purpose primary prevention strategies, i.e., HPV vaccination and reduction of smoking and drinking.