Molecular‐derived risk of malignancy and the related positive call rate of indeterminate thyroid cytology diagnoses as quality metrics for individual cytopathologists

Abstract

BackgroundIndeterminate thyroid cytopathology diagnoses represent differing degrees of risk that are corroborated by follow‐up studies. However, traditional cytologic–histologic correlation may overestimate the risk of malignancy (ROM) because only a subset of cases undergo resection. Alternatively, some molecular tests provide probability of malignancy data to calculate the molecular‐derived risk of malignancy (MDROM) and the positive call rate (PCR). The authors investigated MDROMs and PCRs of indeterminate diagnoses for individual cytopathologists as quality metrics.MethodsThis study was approved by the Department of Pathology Quality Improvement Program. Thyroid cytopathology diagnoses and ThyroSeq v3 results were retrieved for each cytopathologist for a 2‐year period with at least 3 years of follow‐up for the atypia of undetermined significance (AUS), follicular neoplasia (FN), and follicular neoplasia, oncocytic‐type (ONC) cytopathologic diagnoses. MDROMs and PCRs were compared with reference ROMs and cytologic–histologic correlation outcomes.ResultsThe overall MDROMs (and ranges for cytopathologists) for the AUS, FN, and ONC categories were 13.4% (range, 5.8%–20.8%), 28.1% (range, 22.1%–36.7%), and 27.0% (range, 19.5%–41.5%), respectively, and most individual cytopathologists' MDROMs were within reference ROM ranges. However, PCRs more effectively parsed the differences in cytopathologists' ROM performance. Although the overall PCRs were not significantly different across cytopathologists (p = .06), the AUS PCRs were quite different (p = .002). By cytologic–histologic correlation, six of 55 resected cases (10.9%) were falsely negative, and there were no false‐positive cases.ConclusionsMDROMs and PCRs evaluate concordance with reference ROMs and with one another and provide individual feedback, which potentially facilitates quality improvement.

Exploring the atypia of undetermined significance: Malignant ratio, ThyroSeq v3 positive call rate, molecular‐derived risk of malignancy, and risk of malignancy as possible quality metric tools in thyroid cytology

“…5 We also analyzed the relationship between the AUS:M ratio and TSV3 PCR, using the framework established by Cibas et al 20 for ASCUS:SIL ratios and high-risk HPV positivity rates in gynecologic cytology. Moreover, we examined the relationship between the AUS:M ratio and MDROM, using the MDROM as a surrogate of the ROM, as highlighted by Ohori et al 23 Additionally, we investigated the relationship between the AUS:M ratio and ROM.…”

“…Correlation of AUS rates with MT results has been put forward as a QA metric tool to attain the target rate of 10%. 9,21,22 Furthermore, Ohori et al 23 recently demonstrated that the MDROM could be used as a feedback tool to provide potential strategies for practice improvement.…”

“…5 Moreover, integrating AUS rates with molecular test (MT) results has been put forward as a QA metric to attain the target rate of 10%. 9,21,22 Furthermore, Ohori et al 23 recently demonstrated that the molecular-derived risk of malignancy (MDROM) could be used as a feedback tool to provide potential strategies for practice improvement. However, considering that many laboratories may not have access to molecular testing or may use different molecular platforms, using the ROM as a metric could be more practical in such settings.…”