Aim: Ultrasound-guided Fine Needle Aspiration Biopsy (USg-FNAB) is the most accurate modality for distinguishing malignant or possibly malignant from benign thyroid nodules. However, a certain amount of specimens turn out to be non-diagnostic or inadequate. Several factors contribute to this outcome such as the examiners experience, characteristics of the nodule and patients compliance. Understanding these factors could contribute to reduction of non-diagnostic results.
Methods: All nodules examined by USg-FNAB between Jan 2014 and Nov 2015 at the thyroid clinic of our department were reviewed (n=682 patients with 987 nodules). Patient demographic characteristics (sex and age), nodule characteristics (size, location, previous FNAB) and the experience of the examiner were recorded.
Results: The only factor that exhibited a significant positive association with non-diagnostic cytology on USg-FNA was the age of the patient (P < 0.01). Nodule size was marginally negatively associated (P=0.054). No other factor emerged as a predictor of non-diagnostic cytology.
Conclusions: The present study indicates that patient age is a prognostic factor for non-diagnostic cytology on USg-FNA. This might be attributed to the fact that older patients usually present with nodules baring morphologic characteristics such as cystic composition and peripheral calcifications that are associated with non-diagnostic cytology. On the other hand, the marginally negative association with nodule size, seems justified by the fact that small nodules are technically more difficult to biopsy. It is of note that the examiners experience has not emerged as a prognostic factor, possibly due to the fact that nodules which are not easily accessible are usually biopsied by more experienced staff.
20 - 23 May 2017
European Society of Endocrinology