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Prognosis favorable among patients with Thy 3 nodules
Patients with a thyroid nodule of indeterminate cytology and a histology of thyroid cancer have a good prognosis overall, according to findings published in The Journal of Clinical Endocrinology & Metabolism.
In addition, a clinical risk score including results of cytology and ultrasound features is helpful for managing patients with indeterminate thyroid nodules.
In the retrospective study, researchers identified eligible participants from among 100,065 patients who underwent fine needle aspiration (FNA) for thyroid nodules at the University of Pisa Hospital, Italy. Of these patients, they selected 1,520 (mean age, 46.1 years) who underwent thyroidectomy for nodules with indeterminate cytology (Thy 3).
Follow-up was between 1 and 10 years, with visits at 3, 6 and 12 months after surgery, and annually thereafter. At each visit, the researchers measured thyroglobulin, autoantibodies to thyroglobulin (TgAb), thyroid-stimulating hormone, free thyroxine and free triiodothyronine.
Neck ultrasound was utilized to evaluate structural evidence of disease. Patients were classified as disease-free if basal serum thyroglobulin was <1 ng/mL with negative TgAb. Recurrent disease status was defined as having discernible thyroglobulin linked to the presence of remnant tissue or local recurrence, lymph node metastases or distant metastases.
The investigators found that thyroid cancer at histology was present in 371 of the 1,520 patients (24.4%), with the follicular variant of papillary cancer being the most common histotype. Of the patients with cancer, 342 were disease-free after thyroidectomy and radioiodine remnant ablation, and 29 required additional treatment due to recalcitrant disease. At the end of follow-up, only 12 of the patients with cancer had persistent disease.
At thyroid ultrasound, the nodule characteristics most associated with malignancy were atypias at cytology (P=.001), blurred nodule margins (P=.005) and spot microcalcifications (P=.003). The researchers calculated a clinical score, which consisted of cytology and ultrasound characteristics. The lowest value showed a high negative predictive value (83.9%) for malignancy and an even higher negative predictive value (99.5%) for the presence of more complicated cancer disease. Only four of the 29 patients who required treatment were assigned the lowest risk score.
According to the researchers, the prognosis for patients carrying a Thy 3 nodule is, overall, “remarkably favorable.”
“We propose a clinical risk score that has a fairly good negative predictive value in the assessment of the risk of cancer, and, more importantly, a very high [negative predictive value] in the assessment of the risk of carrying a more unwieldy cancer disease in patients with indeterminate thyroid nodules,” the researchers wrote.
Disclosure: The researchers report no relevant financial disclosures.
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Rago T. J Clin Endocrinol Metab. 2014;doi:10.1210/jc.2013-4401.