The Relative Risk of Cancer in Sonographically Detected Thyroid Nodules with Calcifications

Yang, Yoon Soo; Lim, Hyun Sil; Kim, Yon Woo; Oh, Jeong Ki; Hong, Ki Hwan

Abstract

BACKGROUND AND OBJECTIVES
The aim of this retrospective study was to evaluate the significance of sonographically detected thyroid calcifications in the diagnosis of thyroid cancer. SUBJECTS AND METHOD: Two hundred ninety-one patients with thyroid disease, including 75 with thyroid cancer and 54 with calcified thyroid nodule, were reviewed during the period of January 2001 to May 2003. Each patient underwent preoperative high resolution sonography to evaluate the thyroid gland for the presence of calcifications. RESULTS: The highest incidence of calcification was found in thyroid cancer (36%), followed by multinodular goiter (20%), follicular adenoma (13%), and single nodular goiter (3%). The incidence of cancer was significantly higher in calcified nodules (50%) than in noncalcified nodules in the entire group (20%) (p<0.001), with a relative risk of 3.9. In the group of solitary thyroid nodules, the incidence of cancer in the calcified nodules (56%) was higher than that in the nodules without calcification (21%) (p=0.002). In the group of multiple thyroid nodules, the incidence of cancer in the calcified nodules (47%) was higher than that in the nodules without calcification (19%) (p=0.001). The relative risk in presence of calcification was 4.6 in the solitary nodules and 3.7 in the multiple nodules. Compared with multiple noncalcified thyroid nodules, the solitary calcified nodules demonstrated a relative risk of 5.2. In patients younger and older than 40 years, the relative risk in the presence of calcification was about the same, around 4. CONCLUSION: The detection of thyroid calcifications by sonography is diagnostically valuable. The presence of calcifications should raise the suspicion of malignancy.