Table 1.
Estimated Likelihood of Malignancy in a Thyroid Nodule with Indeterminate Cytology and Recommended Management
| Bethesda cytologic category | Ancillary testing | Estimatedarisk of malignancy; range (median) | Recommendation | |
|---|---|---|---|---|
| III (AUS/FLUS) | None | 6–48% (14%) | Repeat FNA, ancillary testing, or diagnostic lobectomy | |
| GECb (reported prevalence 24%) | Suspicious | 38% | Diagnostic lobectomy | |
| Benign | 5% | Active surveillance | ||
| 7-gene MTc (reported prevalence 14%) | Positive | 88% | Oncologic thyroidectomy | |
| Negative | 6% | Active surveillance or diagnostic lobectomy | ||
| IV (FN/FL) | None | 14–34% (25%) | Ancillary testing or diagnostic lobectomy | |
| GECb (reported prevalence 25%) | Suspicious | 37% | Diagnostic lobectomy | |
| Benign | 6% | Active surveillance | ||
| 7-gene MTc (reported prevalence 27%) | Positive | 87% | Oncologic thyroidectomy | |
| Negative | 14% | Diagnostic lobectomy | ||
| ThyroSeq2.0 paneld (reported prevalence 27%) | Positive | 87% | Oncologic thyroidectomy | |
| Negative | 5% | Observation | ||
| V (SMC) | None | 53–87% (70%) | Ancillary testing or oncologic thyroidectomy | |
| GECb (reported prevalence 62%) | Suspicious | 76% | Oncologic thyroidectomy | |
| Benign | 15% | Diagnostic lobectomy | ||
| 7-gene MTc (reported prevalence 54%) | Positive | 95% | Oncologic thyroidectomy | |
| Negative | 28% | Diagnostic lobectomy | ||
Estimated risk based upon reported studies that used Bethesda classification. Estimates are highly dependent on the prevalence of disease in a given population. Thus, if the prevalence of malignancy in a category of indeterminate cytology is higher than disease prevalence reported in the referenced studies above, then the estimated likelihood of malignancy would be higher. Sonographic and clinical factors may also significantly affect these estimates in individual patients.
GEC, gene expression classifier, data as reported by Alexander et al. (21).
7-gene MT, seven-gene mutational panel, data as reported by Nikiforov et al. (30).
ThyroSeq2.0 panel, data as reported by Nikiforov et al. (36).