Comparing Aspiration and Non-aspiration Fine Needle Techniques in Cytodiagnosis of Thyroid Nodules

Abstract

Background: Nodular goitre remains a problem of enormous magnitude with an estimated prevalence of 19 to 35% worldwide. Of all thyroid nodules 5-10% are cancerous and require surgery. By identifying the benign ones unnecessary surgery, the associated morbidity and associated costs could be avoided. Fine needle cytology is recommended as the initial evaluation of thyroid nodules. Its main limitations are inadequate cellular harvest and indeterminate results. Aspiration (FNA) and non-aspiration (FNNA) techniques were evaluated in this study for purposes of judging which technique is better for cellular harvest. In providing the standard amount of follicular cells for cytodiagnosis (SAFC). Methods: In a cross-sectional comparative descriptive study, 100 thyroid nodules were categorized by their widest diameter into <1cm, 1-4 cm and >4cm. Both FNA and FNNA were performed on each nodule (randomly assigned). After Papanicolaou and Diff-Quik staining, the follicular cells harvested were quantitatively analyzed for the SAFC by a cytopathologist blinded to the biopsy technique used and compared using Wilcoxon signed Ranks test and McNamara’s test statistic. Ethical approval was secured. Results: The patients’ age range was 19 to 70 yrs (mean 43yrs) and 95.5% were females. Regarding the provision of the SAFC: FNNA had a higher mean cell count than FNA (108 Vs 63), p= 0.001; FNNA was superior to FNA, OR= 6.5, p<0.01; and there was no significant difference between the nodules of diameter >4 cm and 1-4 cm, using FNNA or FNA. Conclusion: The findings suggest that with regard to the provision of the standard amount of follicular cells for cytodiagnosis of thyroid nodules, FNNA is superior to FNA technique. There is no statistically significant association with the diameter of the thyroid nodule biopsied. FNNA technique is less technically challenging and does not require a syringe holder.