Nomogram for selecting thyroid nodules for ultrasound-guided fine-needle aspiration biopsy based on a quantification of risk of malignancy

Background Our aim through this study was to develop a statistical tool to quantify risk of malignancy in thyroid nodules based on clinical, biochemical, and ultrasound features, which could be used to select which nodules require ultrasound-guided fine-needle aspiration. Methods Clinical records, biochemical profiles, pathology reports, and ultrasound images were reviewed. Multivariate logistic regression was used to rank variables in their ability to predict malignancy. Results In all, 190 nodules were reviewed. The final diagnoses were papillary carcinoma in 105 patients (66%), other carcinoma in 8 patients (5%), and benign thyroid pathology in 45 patients (29%). After exclusions, 182 nodules remained for analysis on a per nodule basis. The 8 variables with highest predictive value were: age; thyroid-stimulating hormone; and ultrasound size, shape, echo texture, calcification, margin, and vascularity. The nomogram had a concordance index of 75%. Conclusion We produced a nomogram able to accurately predict the need to perform ultrasound-guided fine-needle aspiration on a thyroid nodule based on biochemical, clinical, and ultrasound features.