Core-Needle Biopsy May Predict Prognosis Preoperatively in Parotid Cancer

Background: Salivary gland tumors are challenging to diagnose, and preoperative false-negative results often lead to unexpected malignancy diagnosis after parotidectomy. This study aimed to investigate the clinical utility of preoperative core needle biopsy (CNB) diagnosis in patients undergoing primary parotidectomy and its prognostic implications for parotid gland cancers.

Methods: We conducted a retrospective cohort study involving 615 patients who underwent preoperative CNB and parotidectomy for primary parotid tumors from 2003 to 2023 at a tertiary referral hospital. Of these, 102 patients diagnosed with primary parotid malignancy post-parotidectomy were analyzed for survival outcomes. DFS and predictive factors were assessed through univariable and multivariable analyses. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy of CNB were calculated and compared to that of another cohort of 547 patients undergoing ultrasound-guided fine-needle aspiration (FNA) and parotidectomy during the same period.

Results: In the CNB group, the 5-year predicted DFS was 86.9% (95% CI, 79.2%-95.3%). Multivariable analysis identified male sex (HR, 8.48; 95% CI, 1.05-68.76) and "malignant on CNB" (HR, 8.20; 95% CI, 1.01-66.15) were 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 (sensitivity 45.2% [95% CI, 33.5%-57.3%]; NPV 90.8% [95% CI, 87.7%-93.3%]).

Conclusion: Preoperative CNB may predict the prognosis of parotid cancer. Patients with a preoperative "malignant" diagnosis on CNB had a poorer prognosis compared to those with a "less-than-malignant" diagnosis. CNB also exhibited greater sensitivity than FNA in detecting parotid gland malignancies.