Clinical, cytological and ultrasonographic features of incidental thyroid cancer in a hospital‐based study in vietnam

INTRODUCTION: Thyroid nodules are common diseases of the endocrine system, with a 5% prevalence rate in the general population. This study aimed to identify prevalence, clinical, cytological and ultrasonographic features of incidental thyroid cancer and its associated factors in Vietnam. METHODS: This cross‐sectional descriptive study consisted of 208 patients with incidental thyroid nodules detected by ultrasound at the Endocrinology Department, Bach Mai Hospital, Hanoi, Vietnam between November 2019 and August 2020. Clinical information, sonography characteristics of thyroid nodules, results of fine‐needle aspiration biopsy (FNAB), postoperative pathology and lymph node metastasis were collected. A multiple logistic regression model was used to estimate factors associated with thyroid cancer. RESULTS: A total of 272 thyroid nodules (from 208 participants) were included in this study. The mean age was 47.2 ± 12.0 (years). The rate of incidental thyroid cancer patients detected was 17.3%. Nodules <1 cm in size were significantly more prevalent for malignant nodules. The size of more than half of thyroid cancer nodules was 0.50–0.99 cm. Postoperative pathology of all nodules with Bethesda V and VI was papillary thyroid cancer which was consistent with cytological results. 33.3% of thyroid cancer patients have lymph node metastasis. The regression model showed that thyroid cancer was more likely to occur at a younger age (≤ 45 years vs. >45 years, OR 2.8; 95% CI: 1.3–6.1), taller‐than‐wide nodules (OR 6.8; 95% CI: 2.3–20.2) and hypo‐echoic nodules (OR 5.2; 95% CI: 1.7–15.9). CONCLUSION: The study showed that the prevalence of incidental thyroid cancers was 17.3%, of which 100% was papillary carcinoma. People under the age of 45 and the presence of ultrasound characteristics, such as taller‐than‐wide and hypoechoic nodules increased risk for malignancy.