Background: Fine needle aspiration (FNA) is commonly used in the study of neoplastic lesions of the parotid gland, however controversy exists regarding its diagnostic accuracy.
Objective: To evaluate the performance of FNA biopsy as compared to open surgical biopsy in the diagnosis of carcinoma of the parotid gland.
Material and method: Forty-six patients with parotid masses from 7 health centres in Bucaramanga, Colombia were identified and included in the study. All patients underwent FNA and open surgical biopsy, with the latter considered the diagnostic gold standard. The FNA and final surgical histopathology were interpreted as either positive or negative for malignancy by pathologists blinded to the FNA outcome. Only standard histological stains were used. The data were compared in a contingency table and analyzed statistically to determine the accuracy of FNA to predict the surgical pathology according to standard measures.
Results: The mean age of patients was 52 +/- 16 years old and 59 % were female. Using FNA, 18 % of the initial diagnoses were found to be erroneous at final pathology. FNA had a sensitivity of 0.54, a specificity of 0.90, a PPV of 0.70, an NPV of 0.83, an LR+ of 5.92, an LR of 0.5, and kappa of 0.48 in the identification of parotid gland carcinoma from referral population with a disease prevalence of 28.3 %.
Conclusions: In line with other previous studies, FNA biopsy alone was unreliable to diagnose parotid gland carcinoma. Its low sensitivity and LR indicates its limitations as a screening test; in addition its low kappa shows a modest correlation to the eventual diagnosis. Therefore, further critical examination of techniques and interpretation of parotid FNA are recommended. The development of new methods allowing a valid and precise diagnosis of this pathology and that, like the FNA, have low cost and ease of application is recommended.