OBJECTIVES: Salivary gland tumors present a diagnostic challenge, with preoperative false-negative results frequently leading to an unexpected diagnosis of malignancy after parotidectomy. This study was conducted to explore the clinical utility of preoperative core needle biopsy (CNB) in diagnosing malignancies before primary parotidectomy and to assess the prognostic implications of CNB for parotid gland cancers. METHODS: This retrospective cohort study included 615 patients who underwent preoperative CNB and parotidectomy for primary parotid tumors from 2003 to 2023 at a tertiary referral hospital. Among these patients, 102 who were diagnosed with primary parotid malignancy following parotidectomy were examined regarding survival outcomes. Disease-free survival (DFS) and predictive factors were assessed through univariable and multivariable analyses. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy of CNB were determined. These metrics were then compared to those of a separate cohort of 547 patients who underwent ultrasound-guided fine needle aspiration (FNA) and parotidectomy within the same timeframe. RESULTS: In the CNB group, the 5-year predicted DFS was 86.9% (95% CI, 79.2%-95.3%). Multivariable analysis identified male sex (hazard ratio [HR], 8.48
95% CI, 1.05-68.76) and a CNB finding of malignancy (HR, 8.20
95% CI, 1.01-66.15) as factors significantly associated with decreased DFS. CNB demonstrated significantly higher sensitivity (89.0%
95% CI, 81.2%-94.4%) and NPV (97.6%
95% CI, 95.7%-98.8%) compared to FNA, which had a sensitivity of 45.2% (95% CI, 33.5%-57.3%) and an NPV of 90.8% (95% CI, 87.7%-93.3%). CONCLUSION: Preoperative CNB may be predictive of parotid cancer prognosis. Patients receiving a diagnosis of malignancy on preoperative CNB demonstrated a worse prognosis compared to those with a "less-than-malignant" diagnosis. Additionally, CNB exhibited higher sensitivity than FNA in identifying malignancies of the parotid gland.