Repeat Fine-Needle Aspiration Detects Thyroid Cancer in Less than 1% Cases
Repeat fine-needle aspiration following a nondiagnostic result detected malignancy in less than 1% of cases, according to findings reported in the September issue of Radiology. The authors suggest that ultrasound followup may be more appropriate than repeat fine-needle aspiration in patients with initially nondiagnostic results from thyroid nodule biopsy.
“Current guidelines generally advise repeat biopsy of non-diagnostic thyroid biopsies or even surgery until a diagnosis is obtained. Our research suggests that this approach may be too aggressive. The likelihood of a false-positive FNA was much higher than a true positive FNA, putting patients through unnecessary surgery,” said senior author Michael D. Beland, MD, Associate Professor of Diagnostic Imaging at The Warren Alpert Medical School of Brown University, and Director of the Ultrasound Department at Rhode Island Hospital, Providence, RI.
“In most cases, a non-diagnostic FNA should be considered a very reassuring finding, particularly in younger patients,” Dr. Beland said. “Follow-up ultrasound rather than repeating the FNA may be more appropriate unless the appearance of the nodule is very suspicious or the patient is at high risk for thyroid cancer,” he said.
Retrospective Chart Review
The researchers reviewed medical records from 393 cases of single nodule biopsy performed between 2004 to 2012 that were nondiagnostic and had adequate cytologic, surgical, or ultrasound followup.
During followup, 9 cases of malignancy were detected on repeat fine-needle aspiration (n=2; 0.5%) or surgical examination (n=7; 1.8%). Overall, 336 of the 393 nodules underwent repeat fine-needle aspiration, which showed suspicious or malignancy in 18 nodules (5.4%) prompting surgical removal and evaluation and leading to a diagnosis of 2 malignancies (0.6%). Repeat biopsies had a false-positive rate of 4.9%.
Men and Older Patients Are at Higher Risk for Malignancy
The odds of malignancy were significantly higher in men than women (odds ratio, 4.2; P=0.045) and increased with each 1-cm increase in anteroposterior, minimum, and mean nodule diameter (1.78, 2.10, and 1.96, respectively). Median age was significantly older in patients who developed malignancies (64 years) than in those without malignancies (55.4 years).
Ultrasound Followup Recommended
“Only 2 of the 18 repeat FNAs of nodules that were interpreted as suspicious for malignancy were found to be actually malignant at surgical pathologic examination,” Edward G. Grant, MD, noted in a commentary in the September issue of Clinical Thyroidology.
“This and the overall results, therefore, suggest that an initial appropriately performed biopsy with nondiagnostic results can be a reassuring indication of benignity and that imaging follow-up rather than repeat FNA or surgery should be recommended,” noted Dr. Grant, Professor and Chairman of Radiology at Keck School of Medicine, University of Southern California, Los Angeles. “In addition, two thirds (6 of 9) of the detected malignancies were papillary cancers. Given their indolent clinical course, a ‘delay’ in diagnosis caused by follow-up ultrasound rather than immediate repeat FNA is probably clinically irrelevant,” he said.
“No cancers were found in patients younger than 47 years old, and the risk of malignancy increased with advancing age,” Dr. Grant wrote. “The authors, therefore, propose that patients younger than 47 years of age can be treated conservatively following nondiagnostic FNA results (again, with serial ultrasound rather than with repeat biopsy),” he noted.
October 24, 2014