Comparison of Palpation-Guided Versus Ultrasound-Guided Fine-Needle Aspiration Biopsies of Thyroid Nodules in an Outpatient Endocrinology Practice

Abstract

To investigate the role of thyroid ultrasonography in our outpatient endocrine practice. We compared the efficacy of ultrasound-guided fine-needle aspiration biopsy (US-FNAB) of thyroid nodules with that of palpation-guided aspiration (P-FNAB) and determined the malignancy rates of palpable and nonpalpable nodules. All patients referred for assessment of thyroid nodular disease from October 1997 through August 2001 were included in the study. Fine-needle aspirations were performed by palpation guidance until October 1999, after which US-FNAB was exclusively performed. All thyroid examinations, ultrasound imaging, and aspiration biopsies were performed by the same endocrinologist in an office-based setting. Histopathologic and cytologic diagnoses were compared for patients who underwent thyroidectomy. A total of 376 nodules in 276 patients were aspirated during a 47-month period. P-FNAB was used on 157 nodules, and US-FNAB was performed on 219 nodules (both procedures were done on 21 nodules). For palpable thyroid nodules that were resected, the cytologic diagnostic accuracy rate was 60.9% and 80% for P-FNAB and US-FNAB, respectively. With use of ultrasound guidance, the sensitivity, positive predictive value, and negative predictive value increased significantly. In addition, the inadequate specimen rate decreased from 11.2% in the P-FNAB group to 7.1% in the US-FNAB group. Among the nodules that were not palpable, the malignancy rate was similar to that for the palpable thyroid nodules (5.1% versus 6.8%). US-FNAB improved the cytologic diagnostic accuracy, sensitivity, and positive predictive value and reduced the false-negative rate in comparison with P-FNAB. The malignancy rate for nonpalpable thyroid nodules was similar to that for palpable nodules.