Retrospective assessment of the effectiveness of the Milan system for reporting salivary gland cytology: A systematic review and meta-analysis of published literature.

INTRODUCTION: Fine needle aspiration (FNA) has been widely utilized in establishing the nature of salivary gland lesions and guiding the clinical management. This study aimed to determine the accuracy of FNA in detecting salivary gland neoplasms and malignancies, employing the "Milan System for Reporting Salivary Gland Cytopathology" (MSRSGC).

METHOD: A systematic search was conducted. The data on FNA and histologic diagnosis were extracted and categorized based on the MSRSGC and risk of malignancy (ROM) was calculated. The risk of publication bias and level of heterogeneity were evaluated. A mixed-effects model was used to estimate FNA accuracy. Meta-regression was conducted to assess the potential effect of different variables on FNA accuracy.

RESULTS: Ninety-two studies with a total of 16 456 FNA with surgical follow-up were included. ROM was estimated as 17%, 8%, 34%, 4%, 42%, 58%, and 91%, in nondiagnostic, nonneoplastic, atypia of undetermined significance, benign neoplasm, salivary gland neoplasm of uncertain malignant potential, suspicious for malignancy, and malignant groups, respectively. High level of heterogeneity was detected (P-value <.001). Including cases with definite FNA diagnosis of neoplasm or malignancy, summary estimates of FNA sensitivity, specificity, diagnostic odds ratio, and positive and negative likelihood ratio in detecting neoplasms and malignancies were 96.9%, 95.3%, 636.8, 20.5, and 0.03, and 80.5%, 97.9%, 189.5, 37.8, and 0.2, respectively. Meta-regression showed several variables significantly impacting FNA accuracy; however, subgroup analysis did not reduce the level of heterogeneity.

CONCLUSION: FNA can be used as a reliable diagnostic tool in the preoperative evaluation and management of salivary glands lesions. Concise of abstract is using Milan system for reporting salivary gland FNA could increase FNA reliability, facilitate communication, and improve patient care.