The role of thyroid sonographic malignancy risk features, when fine needle aspiration biopsy result turns to be indeterminate

16.05.2022

Agnieszka Kotecka-Blicharz1, Marcela Krzempek2, Alexander Jorge Cortez2,  Małgorzata Oczko-Wojciechowska3, Agnieszka Czarniecka4, Ewa Nożyńska5, Ewa Chmielik5,  Barbara Jarząb1, Jolanta Krajewska1

1 Department of Nuclear Medicine and Endocrine Oncology, Maria Sklodowska-Curie National Research Institute of Oncology, Gliwice Branch, Poland
2 Department of Biostatistics and Bioinformatics, Maria Sklodowska-Curie National Research Institute of Oncology, Gliwice Branch, Poland
3 Department of Genetic and Molecular Diagnostics of Cancer, M. Sklodowska-Curie National Research Institute of Oncology, Gliwice Branch,  Poland
4 The Oncologic and Reconstructive Surgery Clinic, Maria Sklodowska-Curie National Research Institute of Oncology, Gliwice Branch, Poland
5 Tumor Pathology Department, Maria Sklodowska-Curie National Research Institute of Oncology, Gliwice Branch, Poland

Introduction: Although the role of the thyroid ultrasound is well established in the initial thyroid nodule work up, it is still equivocal whether the thyroid ultrasound pattern could have an impact on refining malignancy risk after an indeterminate cytopathology result. We aim to assess the possible supportive role of the thyroid nodule ultrasound malignancy risk features listed in the Polish guidelines when a biopsy result is indeterminate.

Material and methods: We retrospectively reviewed thyroid ultrasound scans from 175 adult patients with thyroid nodules and indeterminate cytopathology results, who underwent thyroid surgery. Sonographic malignancy risk features were reported in accordance with the guidelines of the Polish National Societies Diagnostics and Treatment of Thyroid Carcinoma and included the following: solid structure, hypoechogenicity, microcalcifications, taller than wide shape, irregular margins, features of extrathyroidal expansion, suspicious cervical lymph nodes.

Results: The malignancy risk in relevant cytological categories, estimated on the basis of histological verification, was 10.9% for Bethesda III category, 12.1% for Bethesda IV, and 71.4% for Bethesda V. The predominant type of thyroid malignancy was papillary thyroid carcinoma (79%). Thyroid nodules sonographic malignancy risk features provided high specificity but low sensitivity in selected groups of indeterminate thyroid nodules. Microcalcifications was the only characteristic that solely had a clinically relevant positive likelihood ratio (> 10) to suggest malignancy in the analysed cohort, but it was not observed in thyroid nodules eventually verified as follicular thyroid carcinoma. An accumulation of more than one sonographic risk feature yielded significant increase in malignancy risk only in Bethesda V category thyroid nodules.

Conclusions: The impact of sonographic malignancy risk features on refining post-biopsy probability of thyroid cancer in thyroid nodule with indeterminate cytopathology, may be inadequate to sort patients (without any doubt) between those who require thyroid surgery and those who only require surveillance. There is an urgent need to search for new tools in the diagnostics of indeterminate thyroid nodules and to standardize thyroid ultrasound reports.

Keywords: indeterminate thyroid nodule; thyroid nodule; Bethesda system; thyroid ultrasonography; fine needle aspiration biopsy

Full publication in Endokrynologia Polska »