Association between thyroid nodule size and malignancy rate

Abstract

Introduction The diagnostic performance of ultrasound-fine needle aspiration to identify thyroid nodules harbouring malignancy remains variable. The aim of this study was to determine thyroid nodule size and cytological classification as predictors of malignancy risk. Materials and methods We conducted a retrospective cohort analysis at an academic hospital involving 499 consecutive patients who underwent thyroid surgery between 2004 and 2015. Results A total of 503 thyroid nodules (499 patients, 84% female; mean age 50.8 years, standard deviation, SD, 15.4 years) were analysed. Of these, 19.5% were malignant. The mean (± SD) nodule size was 3.28 ± 1.63 cm and 3.27 ± 1.54 cm for benign and malignant nodules, respectively. The odds of malignancy for thyroid nodules less than 3.0 cm was similar to those for nodules of 3.0 cm or greater (0.26 compared with 0.29; p=0.77). Overall, the sensitivity and specificity of fine-needle aspiration in this cohort were 71.4% and 100%, respectively. The overall false negative rate was 5.4%. When the cut-off of 3.0 cm was used, the false negative rate in thyroid nodules less than 3.0 cm was 0% compared with 7.0% in nodules of 3.0 cm or greater. Thus, class (p<0.01) but not nodule size (p=0.49), was associated with higher malignancy risk. Conclusions Our results suggest that thyroid nodule size did not accurately predict the risk of thyroid malignancy irrespective of fine-needle aspiration cytology. Routine diagnostic thyroid lobectomy solely owing to thyroid nodule size of 3.0 cm or greater is currently not justified.

Predictors of Malignancy in Thyroid Nodules

“…These results agree with Jinih et al [28] who reported that, their results suggested that, nodule size is not accurately predict the risk of thyroid malignancy irrespective of the results of FNAC.…”

Unenhanced magnetic resonance imaging of papillary thyroid carcinoma with emphasis on diffusion kurtosis imaging

“…In some studies, thyroid nodule size was found to be inversely related to malignancy risk, as larger nodules have lower malignancy rates (31,32). However, this has been contested by other studies (33,34). The 2015 ATA guideline and 2017 ACR Thyroid Imaging Reporting and Data System (TI-RADS) recommend diagnostic fine-needle aspiration (FNA) of the thyroid nodule based on nodule size and features of high-risk imaging on ultrasound, such as microcalcification, nodule hypoechogenicity, solid component, irregular margin, and a taller-than-wide shape (7,9).…”

Incidence of Microcarcinoma and Non-Microcarcinoma in Ultrasound-Found Thyroid Nodules

“…Though some studies found that malignant risk is associated with nodule size, for example, a series of observational studies have found that thyroid cancers over 4 cm were associated with more aggressive behavior whereas tumors smaller than 1.5 cm had a good overall prognosis [12,13,14]. However, some other researches indicated no correlation between size and risk [15,16]. A recent study found that the impact of nodule size on the malignancy risk differed according to the ultrasound pattern.…”

“…More ultrasound-found nodules were diagnosed as carcinoma by histology examinations [136 (11.2%) nodules found by ultrasound vs 68 (3.9%) by palpation, x 2 =59.737, p=0.000], and 88 (64.7%) nodules found by ultrasound were non-microcarcinoma. Among the malignant nodules con rmed by histopathology, a higher proportion of microcarcinoma was detected in ultrasound-found nodules [35.3% (48/136) vs 16.2% (11/68), x 2 =8.183, p=0.004].…”