A Systematic Review and Meta-Analysis of the Diagnostic Accuracy of Fine-Needle Aspiration Cytology for Parotid Gland Lesions

Abstract

The clinical usefulness of fine-needle aspiration cytology (FNAC) for the diagnosis of parotid gland lesions is controversial. Many accuracy studies have been published, but the literature has not been adequately summarized. We identified 64 studies on the diagnosis of malignancy (6,169 cases) and 7 studies on the diagnosis of neoplasia (795 cases). The diagnosis of neoplasia (area under the summary receiver operating characteristic [AUSROC] curve, 0.99; 95% confidence interval [CI], 0.97-1.00) had higher accuracy than the diagnosis of malignancy (AUSROC, 0.96; 95% CI, 0.94-0.97). Several sources of bias were identified that could affect study estimates. Studies on the diagnosis of malignancy showed significant heterogeneity (P < .001). The subgroups of American, French, and Turkish studies showed greater homogeneity, but the accuracy of these subgroups was not significantly different from that of the remaining subgroup. It is not possible to provide a general guideline on the clinical usefulness of FNAC for parotid gland lesions owing to the variability in study results. There is a need to improve the quality of reporting and to improve study designs to remove or assess the impact of bias.

Comparison of Fine-Needle Aspiration and Core Needle Biopsy under Ultrasonographic Guidance for Detecting Malignancy and for the Tissue-Specific Diagnosis of Salivary Gland Tumors

“…However, the authors stated that a direct comparison of FNA and CNB was not possible because of an unexpected significant heterogeneity in the findings of studies regarding FNA, and they concluded that CNB could be reserved for special clinical settings, such as cases that were not diagnosed with FNA, given the theoretic drawbacks of CNB, such as facial nerve damage or use of local anesthesia. 1,14 Our present data demonstrate that USCNB can be safely performed because none of our 282 patients experienced facial nerve injury, and it has a significantly higher diagnostic accuracy for malignant salivary gland tumors. Another disadvantage of USCNB is that it uses larger bore needles compared with USFNA, which might increase the potential risk for tumor seeding along the needle tract.…”

“…This lower diagnostic accuracy could have resulted from the histologic diversity of the salivary gland tumors and could suggest that cytologic examination alone is not sufficient for diagnosing malignant tumors of the salivary glands, thus necessitating a larger specimen with preserved histologic architecture. Schmidt et al 1,14 tried to compare the diagnostic performances of FNA and CNB for detecting malignant salivary gland tumors in 2 separate meta-analyses. However, the authors stated that a direct comparison of FNA and CNB was not possible because of an unexpected significant heterogeneity in the findings of studies regarding FNA, and they concluded that CNB could be reserved for special clinical settings, such as cases that were not diagnosed with FNA, given the theoretic drawbacks of CNB, such as facial nerve damage or use of local anesthesia.…”

“…Fineneedle aspiration (FNA) is a well-accepted and widely used technique for the preoperative diagnosis of salivary gland masses, showing an average specificity for detecting malignant tumors among these masses of up to 96% with little variation from study to study. 1,2 Remarkable variation is seen in the sensitivity of FNA, however, which ranges from 33% to 100%, with an average of 79%. [1][2][3][4][5][6][7] A recently published meta-analysis has suggested the influence of verification bias on the reported diagnostic accuracies of FNA, leading to an underestimation of its sensitivity and overestimation of its specificity in previous articles.…”

“…1,2 Remarkable variation is seen in the sensitivity of FNA, however, which ranges from 33% to 100%, with an average of 79%. [1][2][3][4][5][6][7] A recently published meta-analysis has suggested the influence of verification bias on the reported diagnostic accuracies of FNA, leading to an underestimation of its sensitivity and overestimation of its specificity in previous articles. 8 In addition to verification bias, differences in test conditions have a major effect on the diagnostic performance of FNA.…”

“…The authors of that study could not reach a definitive conclusion, however, due to the significant heterogeneity regarding FNA findings in the literature, even with a systematic review. 1,14 Therefore, a study with a large series that considers different test conditions and minimizes any verification bias is still required for comparing the diagnostic performance of FNA and CNB and ultimately suggesting some clinical guidelines. Accordingly, we designed our current retrospective study to evaluate the diagnostic performance of FNA and CNB, both performed under US guidance, for detecting malignancy and undertaking tissue-specific diagnoses of salivary gland tumors in a large series of patients in our tertiary hospital.…”