Galectin-3 Test May Decrease Unnecessary Surgical Procedures
Reported May 19, 2008
NEW YORK — May 19, 2008 — Testing potentially cancerous thyroid nodules for the presence of galectin-3 could substantially decrease the number of unnecessary surgical procedures, reported authors of a study published in the June 2008 edition of The Lancet Oncology.
Armando Bartolazzi, MD, PhD, St. Andrea Hospital, Rome, Italy, and colleagues undertook a national study to assess whether testing for galectin-3 could differentiate between benign and malignant cells, thereby preventing unnecessary surgical procedures.
They tested galectin-3 expression in 465 people scheduled for surgery to remove thyroid nodules that could not be determined by cytology as benign or malignant. Patients were enrolled in the study between June 1, 2003, and August 30, 2006. Most participants were women (76%), and the mean age was 50 years (range 21-76 y). Individuals with thyroid nodules smaller than 1 cm in diameter were not enrolled.
After the nodules were removed, the final histological results that determined whether they had been cancerous were compared with the findings from galectin-3 testing. Galectin-3 was not expressed in 331 of 465 nodules (71%); 280 (85%) of these galectin-3-negative nodules turned out to be benign; 29 (9%) were cancerous; the remaining 6% were borderline.
Of these 29 false-negatives, 8 had a different galectin-3 expression in postoperative testing, suggesting that there might have been some technical problems in the testing. The sensitivity of the test was 78% (95% confidence interval [CI], 74-82) and specificity was 93% (90-95). The positive predictive value was 82% (78-86) and negative predictive value was 91% (88-93).
“The galectin-3 method proposed here does not replace conventional [fine-needle aspiration]-cytology,” concluded the authors, “but represents a complementary diagnostic method for those follicular nodules that remain indeterminate. The correct approach for this preoperative characterisation of thyroid nodules always needs careful multidisciplinary assessment of each patient, according to published guidelines.”
SOURCE: The Lancet Oncology