Thyroid Nodule Test Could Reduce Unnecessary Surgeries

By testing suspicious thyroid nodules using fine needle aspiration (FNA) for the presence of galectin-3--a lectin molecule that binds specific sugars--a substantial number of unnecessary surgical procedures could be eliminated, claims a new study.

Researchers at Sant'Andrea Hospital (Rome, Italy) performed an Italian national study in 465 subjects who had thyroid nodules larger than 1 cm in diameter for which malignancy could not be determined. The subjects enrolled between Jun 1, 2003 and August 30, 2006, were mostly women aged 21 to 76 years, with an average age of 50. The nodules were removed and analyzed with histological testing to determine whether they were cancerous or not. These results were compared to the results of galectin-3 tests.

The results showed that in 71% of the nodules, galectin-3 was not expressed. Of these galectin-3 negative nodules, 85% of them were, as predicted, benign, but 9% were cancerous and thus indicated potential false negatives. Of these, 28% showed different galectin-3 expression when tested post-operatively, suggesting that the false result could have been caused by technical problems in the test. The total sensitivity of the test was 78%, and specificity was 93%. The positive predictive value was 82% and the negative predictive value was 91%. The study was published in the May 19, 2008, issue of The Lancet Oncology.

"The galectin-3 method proposed here does not replace conventional FNA cytology, but represents a complementary diagnostic method for those follicular nodules that remain indeterminate. The correct approach for this preoperative characterization of thyroid nodules always needs careful multidisciplinary assessment of each patient, according to published guidelines,” concluded lead author Armando Bartolazzi, M.D., Ph.D., and colleagues of the department of pathology.

Galectin-3, (Gal-3), a member of the beta-galactoside binding lectin family, is an anti-apoptotic protein that protects T cells, macrophages, and breast carcinoma cells from death triggered by a variety of agents. It is not normally found in the cytoplasm of healthy thyroid cells; if it is abnormally present, it can block cell death, leading to the eventual development of cancer.


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