A clinical algorithm for fine-needle aspiration molecular testing effectively guides the appropriate extent of initial thyroidectomy.

OBJECTIVE: To test whether a clinical algorithm using routine cytological molecular testing (MT) promotes initial total thyroidectomy (TT) for clinically significant thyroid cancer (sTC) and/or correctly limits surgery to lobectomy when appropriate. BACKGROUND: Either TT or lobectomy is often needed to diagnose differentiated thyroid cancer. Determining the correct extent of initial thyroidectomy is challenging. METHODS: After implementing an algorithm for prospective MT of in-house fine-needle aspiration biopsy specimens, we conducted a single-institution cohort study of all patients (N = 671) with nonmalignant cytology who had thyroidectomy between October 2010 and March 2012, cytological diagnosis using 2008 Bethesda criteria, and 1 or more indications for thyroidectomy by 2009 American Thyroid Association guidelines. sTC was defined by histological differentiated thyroid cancer of 1 cm or more and/or lymph node metastasis. Cohort 2 patients did not have MT or had unevaluable results. In cohort 1, MT for a multigene mutation panel was performed for nonbenign cytology, and positive MT results indicated initial TT. RESULTS: MT guidance was associated with a higher incidence of sTC after TT (P = 0.006) and a lower rate of sTC after lobectomy (P = 0.03). Without MT results, patients with indeterminate (follicular lesion of undetermined significance/follicular or oncocytic neoplasm) cytology who received initial lobectomy were 2.5 times more likely to require 2-stage surgery for histological sTC (P < 0.001). In the 501 patients with non-sTC for whom lobectomy was the appropriate extent of surgery, lobectomy was correctly performed more often with routine preoperative MT (P = 0.001). CONCLUSIONS: Fine-needle aspiration biopsy MT for BRAF, RAS, PAX8-PPARγ, and RET-PTC expedites optimal initial surgery for differentiated thyroid cancer, facilitating succinct definitive management for patients with thyroid nodules.

Thyroid nodules (≥4 cm): can ultrasound and cytology reliably exclude cancer?

BACKGROUND: Whether a threshold nodule size should prompt diagnostic thyroidectomy remains controversial. We examined a consecutive series of patients who all had thyroidectomy for a ≥4 cm nodule to determine (1) the incidence of thyroid cancer (TC) and (2) if malignant nodules could accurately be diagnosed preoperatively by ultrasound (US), fine needle aspiration biopsy (FNAB) cytology and molecular testing. METHODS: As a prospective management strategy, 361 patients with 382 nodules ≥4 cm by preoperative US had thyroidectomy from 1/07 to 3/12. RESULTS: The incidence of a clinically significant TC within the ≥4 cm nodule was 22 % (83/382 nodules). The presence of suspicious US features did not discriminate malignant from benign nodules. Moreover, in 86 nodules ≥4 cm with no suspicious US features, the risk of TC within the nodule was 20 %. US-guided FNAB was performed for 290 nodules, and the risk of malignancy increased stepwise from 10.4 % for cytologically benign nodules, 29.6 % for cytologically indeterminate nodules and 100 % for malignant FNAB results. Molecular testing was positive in 9.3 % (10/107) of tested FNAB specimens, and all ten were histologic TC. CONCLUSIONS: In a large consecutive series in which all ≥4 cm nodules had histology and were systematically evaluated by preoperative US and US-guided FNAB, the incidence of TC within the nodule was 22 %. The false negative rate of benign cytology was 10.4 %, and the absence of suspicious US features did not reliably exclude malignancy. At minimum, thyroid lobectomy should be strongly considered for all nodules ≥4 cm.