IMPORTANCE Approximately 20% of thyroid nodules display indeterminate cytology. Molecular testing can refine the risk of malignancy and reduce the need for diagnostic hemithyroidectomy.OBJECTIVE To compare the diagnostic performance between an RNA test (Afirma genomic sequencing classifier) and DNA-RNA test (ThyroSeq v3 multigene genomic classifier). DESIGN, SETTING, AND PARTICIPANTSThis parallel randomized clinical trial of monthly block randomization included patients in the UCLA Health system who underwent thyroid biopsy from August 2017 to January 2020 with indeterminate cytology (Bethesda System for Reporting Thyroid Cytopathology category III or IV). INTERVENTIONS Molecular testing with the RNA test or DNA-RNA test. MAIN OUTCOMES AND MEASURES Diagnostic test performance of the RNA test compared with the DNA-RNA test. The secondary outcome was comparison of test performance with prior versions of the molecular tests. RESULTS Of 2368 patients, 397 were eligible for inclusion based on indeterminate cytology, and 346 (median [interquartile range] age, 55 [44-67] years; 266 [76.9%] women) were randomized to 1 of the 2 tests. In the total cohort assessed for eligibility, 3140 thyroid nodules were assessed, and 427 (13.6%) nodules were cytologically indeterminate. The prevalence of malignancy was 20% among indeterminate nodules. The benign call rate was 53% (95% CI, 47%-61%) for the RNA test and 61% (95% CI, 53%-68%) for the DNA-RNA test. The specificities of the RNA test and DNA-RNA test were 80% (95% CI, 72%-86%) and 85% (95% CI, 77%-91%), respectively (P = .33); the positive predictive values (PPV) of the RNA test and DNA-RNA test were 53% (95% CI, 40%-67%) and 63% (95% CI, 48%-77%), respectively (P = .33). The RNA test exhibited a higher PPV compared with the prior test version (Afirma gene expression classifier) (54% [95% CI, 40%-67%] vs 38% [95% CI, 27%-48%]; P = .01). The DNA-RNA test had no statistically significant difference in PPV compared with its prior version (ThyroSeq v2 next-generation sequencing) (63% [95% CI, 48%-77%] vs 58% [95% CI, 43%-73%]; P = .75). Diagnostic thyroidectomy was avoided in 87 (51%) patients tested with the RNA test and 83 (49%) patients tested with the DNA-RNA test. Surveillance ultrasonography was available for 90 nodules, of which 85 (94%) remained stable over a median of 12 months follow-up.CONCLUSIONS AND RELEVANCE Both the RNA test and DNA-RNA test displayed high specificity and allowed 49% of patients with indeterminate nodules to avoid diagnostic surgery. Although previous trials demonstrated that the prior version of the DNA-RNA test was more specific than the prior version of the RNA test, the current molecular test techniques have no statistically significant difference in performance.

BACKGROUND: Thyroid fine-needle aspiration (FNA) plays a pivotal role in the evaluation of thyroid nodules. Up to 30% of cases are diagnosed as indeterminate by FNA, including atypia of undetermined significance, follicular lesion of undetermined significance, suspicious for a follicular neoplasm, and follicular neoplasm, with approximately two-thirds having a benign outcome. The gene expression classifier (GEC) test is a molecular test for cases with indeterminate cytology. The purpose of the current study was to examine the refining role of the GEC test within a single institution. METHODS: Retrospective analysis of all thyroid FNAs during a 20-month period after implementation of GEC was performed. Cases of indeterminate cytology with concomitant GEC testing were selected and divided further in 4 subgroups. Correlation with surgical follow-up, when available, was performed. The results were compared with previously published data from the study institution before the implementation of GEC testing. RESULTS: Among the 217 cases, there were 189 with indeterminate cytology, 42% of which were benign and 50% of which were suspicious by GEC. The excisional rate of atypia of undetermined significance-follicular lesion of undetermined significance in the pre-GEC category was 63%, which decreased to 35% in the post-GEC category, whereas the malignancy rate in the excised thyroids increased from 35% in the pre-GEC category to 47% in the post-GEC category. Similar findings also were obtained for suspicious for a follicular neoplasm-follicular neoplasm lesions. CONCLUSIONS: The strength of the GEC test appears to lie in its ability to reclassify 42% of indeterminate cytology cases as benign, thereby decreasing the number of unnecessary surgical procedures. Cancer (Cancer Cytopathol) 2016;124:100-9.

BACKGROUND: ImmunoCyt (uCyt) and UroVysion are ancillary studies that may aid in the detection of urothelial carcinoma in urine specimens. We compared ImmunoCyt and UroVysion to urine cytology in the ability to detect recurrent urothelial carcinoma. METHODS: Single voided urine samples were obtained from 100 patients who had a previous history of bladder cancer. All patients underwent cystoscopy immediately after urine sample collection. Forty‐one cystoscopically suspicious lesions were biopsied. Urine samples were divided and processed blindly and independently in 3 different laboratories for ImmunoCyt, UroVysion, and urine cytology (ThinPrep method). RESULTS: Of the 41 cystoscopically positive cases, most cystoscopy findings showed multiple tumors that were papillary and less than 1 cm. Biopsies showed many low‐grade tumors (54%). Overall sensitivity of cytology for low‐ and high‐grade urothelial cell carcinoma was 15% and 27%, whereas ImmunoCyt was 62% and 91% and UroVysion was 8% and 18%, respectively. Overall specificity of cytology was 97%, whereas ImmunoCyt was 63% and UroVysion was 90%. CONCLUSIONS: ImmunoCyt is more sensitive than either cytology or UroVysion in detecting low‐grade tumors. Both cytology and UroVysion have comparable specificity in cystoscopically negative cases. Whereas ImmunoCyt may improve the cytological detection of recurrent bladder cancer, UroVysion may be used as a confirmatory test for either cytology or ImmunoCyt. Cancer (Cancer Cytopathol) 2009. © 2009 American Cancer Society.

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ThyroSeq v2 had higher specificity than Afirma GEC and allowed more patients to avoid surgery. Long-term surveillance is necessary to assess the false-negative rate of these particular molecular tests. Further studies are required for comparison with other available molecular diagnostics and for newer tests as they are developed.