Does Size Matter? Evaluation of malignancy rate differences between small and large thyroid follicular neoplasms.
OBJECTIVE
To determine if there is a significant difference in the malignancy rates of thyroid follicular neoplasms, based on lesion size.


METHODS
Retrospective study.


METHODS
Tertiary care institution.


METHODS
We retrospectively reviewed charts from patients with a thyroid fine-needle biopsy diagnosis of "follicular neoplasm," who subsequently had thyroidectomy, from 2000 to 2005 at our institution. The size of the lesion was determined from pathology reports or preoperative sonograms. We divided the patients into "large nodule" and "small nodule" groups, based on the median size.


METHODS
Malignancy rate difference between thyroid follicular neoplasms in large nodule and small nodule size groups.


RESULTS
One hundred seventeen patients were included. The median size was 2.2 cm; thus, our small nodule group included lesions < or = 2.2 cm with a malignancy rate of 16.7%. The large nodule group included lesions > 2.2 cm with a malignancy rate of 26.3%. Chi-square analysis showed no statistically significant difference between the groups (p = .20). A receiver operating characteristic (ROC) curve was generated, and all cutoff values of tumour size did not lie far from the line of no discrimination. The area under the ROC curve was 0.52 (95% confidence interval = 0.38-0.66), indicating that the use of increasing tumour size as a diagnostic tool may be worse than chance.


CONCLUSIONS
There was no statistical difference in the malignancy rates of follicular neoplasms observed in the small nodule and large nodule groups. Our ROC curve also indicated that tumour size cannot be used to predict malignancy.
Tibbo
Jamie J
JJ
Department of Otolaryngology-Head and Neck Surgery, University of Ottawa, Ottawa, Ontario.
Corsten
Martin J
MJ
D018263:Adenocarcinoma, Follicular / Q000473:pathology*; D044963:Biopsy, Fine-Needle; D005260:Female; D006801:Humans; D008297:Male; D012372:ROC Curve; D012189:Retrospective Studies; D013964:Thyroid Neoplasms / Q000473:pathology*