Utilizing the McGill Thyroid Nodule Score to compare between hemithyroidectomy cases who required completion thyroidectomy and cases of hemithyroidectomy alone.

Objectives: This study aims to evaluate whether the McGill Thyroid Nodule Score (MTNS) accurately helps to decide the extent of surgery (hemithyroidectomy versus total thyroidectomy) based on the malignancy risk and to assess whether its use lowers the rate of completion thyroidectomy in cases of indeterminate thyroid nodules.

Methods: We performed a retrospective cohort study comparing MTNS results of patients undergoing hemithyroidectomy in King Abdulaziz Medical City, NGHA, Jeddah from the period of January 2013 to December 2017. We divided the cases into hemithyroidectomy who required completion and hemithyroidectomy who did not need completion surgery. The pre-operative indeterminate FNA biopsy subgroup comprised of Bethesda type III (atypia of undetermined significance/follicular lesion of undetermined significance) and Bethesda type IV (follicular neoplasm/suspicious for a follicular neoplasm/Hurthle cell neoplasm). Post-operative histopathology was divided into benign or malignant groups.

Results: Of the 501 patient charts reviewed, 111 (22.2%) had an indeterminate FNA biopsy. 97 (87.4%) patients were females and 14 (12.6%) were males. In the hemithyroidectomy group, the pre-operative mean of the MTNS was 6.65, while in the completion thyroidectomy the mean was 11.47. The median MTNS was 7 (32% risk of malignancy) for the hemithyroidectomy group and 11 (63% risk of malignancy) for the completion thyroidectomy group (p < 0.001).

Conclusions: Based on the MTNS the risk of malignancy in cases of hemithyroidectomy who required completion surgery was significantly higher than those who underwent hemithyroidectomy only. The MTNS can be of value to thyroid surgeon in the pre-operative decision-making when dealing with an indeterminate thyroid nodule on FNA biopsy.