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
