SUMMARY OF THE STUDY
A total of 2749 thyroid nodules in 2552 patients underwent ultrasound-guided biopsy between January 2015 and December 2015 at a single South Korean institution. Using the recorded ultrasound features, such as composition, echogenicity, margin, calcification, and shape, the nodules were classified according to the 2015 ATA five-group risk ranking system. Of all 2749 thyroid nodules, 964 nodules in 915 patients measured between 1 and 2 cm. Among these, 147 nodules were surgically removed, and 590 nodules that were not excised had benign or cancer results on biopsy; these two groups were included in the study. Of the total of 737 thyroid nodules in 723 patients, 162 (22%) were cancerous and 575 (78%) were benign. The average age of the patients was 51 years, and the average size of the nodules was 14 mm.
Using the ATA five-group ranking system, the cancer rate was 58% in group A/high suspicion, 6.5% in group B/ intermediate, 2.1% in group C/low and 1.3 % in group D/very low. Since there was no statistical difference between the cancer rates of the low/C and very low/D risk groups, the authors proposed to combine these two groups in one category in a modified four-group stratification system. Biopsy of nodules 2 cm or larger was proposed for the revised low suspicion group.
When comparing their diagnostic performance, the modified four-group system performed better overall than the five-group ATA system. With the revised 4-group ranking system, a larger number of unnecessary biopsies in benign nodules could be avoided.
WHAT ARE THE IMPLICATIONS OF THIS STUDY?
This is one of the first large series to validate that the 2015 ATA risk assessment system for thyroid nodules measuring between 1 and 2 cm effectively differentiates nodules with high, intermediate, and low risk of cancer based on their ultrasound appearance. The proposed modified four-group risk stratification system is easier to use and suggests that fewer nodules should undergo biopsy; however, it needs further confirmation in other studies.
— Alina Gavrila, MD, MMSC
ATA THYROID BROCHURE LINKS
Thyroid Nodules: https://www.thyroid.org/thyroid-nodules/
Fine Needle Aspiration Biopsy of Thyroid Nodules: https://www.thyroid.org/fna-thyroid-nodules/