Assessing the risk of false-negative fine-needle aspiration cytology and of incidental cancer in nodular goiter

Abstract

Objective: In cases of multinodular goiter with negative cytologic result, reasonable management options include surgical treatment, simple follow-up, or more recently introduced conservative therapies such as laser or radiofrequency ablation, and recombinant human thyroid-stimulating hormone-augmented radioiodine. For patients who are eligible for follow-up or nonsurgical treatments, the possibility that they may have an undiagnosed malignancy (false-negative [FN]-fine-needle aspiration cytology [FNAC] result or incidental thyroid cancer [ITC]) should be considered. The aim of our study was to assess the risk of malignancy in patients known to have presumably benign thyroid disease.

Methods: Surgical series of patients who underwent total thyroidectomy for benign disease between 2000 and 2010 at two Italian centers were reviewed. Patients with any preoperative suspicion of malignancy were excluded.

Results: Histologic examination revealed that 84 of 970 (8.6%) thyroidectomized patients had malignancy (5% ITC and 3.6% FN-FNAC), with 89.8% of ITCs having a diameter <10 mm, and 65.7% of FN-FNAC cancers having a diameter >30 mm. Sixty-seven thyroid malignancy patients (79.8%) had stage I disease (American Joint Committee on Cancer criteria). The risk of FN-FNAC increases with increasing size of the nodule, while the risk of ITC increases as nodule size decreases.

Conclusion: The risk of malignancy in presumably benign thyroid disease cannot be overlooked, but can be minimized through skillfully performed ultrasonography (US) examination and FNAC. Once a patient with multinodular goiter is referred for follow-up or nonsurgical therapy, careful US surveillance is mandatory.