Molecular analysis using SalvGlandDx improves risk of malignancy estimation and diagnosis of salivary gland cytopathology: An exploratory multicenter study

Abstract

Background: Diagnosis of salivary gland neoplasms is challenging, especially on cytological specimens acquired by fine-needle aspiration. The recently implemented standardized Milan system for reporting salivary gland cytopathology provides an estimated risk of malignancy (ROM); yet, for two of the categories, the diagnosis of the lesion remains unclear. However, a precise diagnosis is desirable for optimal patient management, including planning of surgery and imaging procedures. Methods: Cytological specimens (n = 106) were subjected to molecular analysis using the SalvGlandDx panel. The risk of malignancy was calculated for each detected alteration based on the diagnosis of the resection specimen. By taking into account the molecular alterations, their associated ROM, the clinical and cytological features, and the current literature, the Milan category was evaluated. Results: Of n = 63 technically valid cases, 76% revealed a molecular alteration. A total of 94% of these molecularly altered cases could be assigned to a different Milan category when additionally taking molecular results into account. In only 2% of the salivary gland neoplasms of uncertain malignant potential, in which a molecular alteration was detected, the classification remained salivary gland neoplasms of uncertain malignant potential. Conclusion: Molecular analysis of cytological specimens provides a benefit in classifying salivary gland neoplasms on fine-needle aspiration. It can improve the ROM estimation and thus help to assign cases of formerly unknown malignant potential to clearly benign or malignant categories.