Prognostic Model for Ultrasound Assessment of Malignancy Risk of Thyroid Nodules

Issue: 3/2017

Author: 1 Nonchev, Boyan Iv., 2 Danev, Vladimir Hr. , 1Argatska, Antoaneta V., 1 Miteva, Maria
J., 3 Mateva, Nonka G., 1 Orbetzova, Maria M.Author: Boyadzhieva, Mila B.1 , Hadzhieva, Elitsa G.1 , Hristozov, Kiril H.1 , Georgieva-Hristova, Darina K.2

1 Second Department of Internal Diseases, Clinic/Section of Endocrinology, Faculty of Medicine, Medical University, Plovdiv
2 Department of General and Clinical Pathology, Faculty of Medicine, Medical University, Plovdiv
3 Department of Medical Informatics, Biostatistics and e-learning, Faculty of Public Health, Medical University, Plovdiv

Abstract:
Current guidelines for the diagnosis and treatment of thyroid nodules recommend that the description of the sonographic appearance be focused on the risk of malignancy. The differences in sensitivity and specificity of each ultrasound characteristic prompt further investigation.

Aim: To investigate the correlation between the ultrasound and cytomorphological characteristics of the thyroid nodules and to suggest a prognostic model for the malignancy risk based on sonographic criteria. Patients and methods: 270 patients (male − 21 / female − 249), mean age 48,89±0,77 (range 20-83 years) with thyroid lesion referred for FNAB between 2012 and 2014 were included in the study. Ultrasonographic neck examination and FNAB were performed in all patients. A total of 329 nodules were biopsied. Based on the biopsy report some patients were referred for surgical treatment.

Results: Histological evidence consistent with thyroid carcinoma was found in 28 patients. There was no difference between the volume of benign and malignant nodules (2,69±0,33 ml vs 1,25±0,47 ml, Р>0,05). An increased incidence of malignant nodules in the isthmus (22,7%) compared to the right and left lobe (7,8% and 7,1%, respectively) (Р=0,046) was found. Univariate analysis of sonographic characteristics confirmed the prognostic significance for high malignancy risk of the following findings: solid structure, hypoechogenicity, marked hypoechogenicity, taller-than-wider shape, irregular margins, microcalcifications and posterior shadowing. The estimated significant factors were included in a multifactorial logistic regression model.

Conclusion: Applying contemporary statistical methods for multivariate analysis contributes to a more precise assessment of individual risk. The proper selection of diagnostic tools and the correct interpretation of their results contribute to the early detection of malignant nodules and referral for surgical treatment. On the other hand, a number of “unnecessary” surgical interventions could be avoided after a comprehensive evaluation of the thyroid nodular lesions.

Key words: thyroid nodule, thyroid carcinoma, thyroid ultrasound, fine-needle aspiration biopsy

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