Background: The management of indeterminate thyroid nodules (Bethesda III/IV) has evolved with molecular testing, aiming to reduce unnecessary surgeries. However, the comparative effectiveness of different platforms in influencing surgical decision-making remains unclear. This systematic review and meta-analysis evaluate the impact of molecular testing on surgical avoidance rates. Methods: A systematic literature search was conducted across eight electronic databases, including Embase, PubMed, and Cochrane Library, from January 2019 to December 2024, following PRISMA guidelines to encompass most recent advancements in the last 5 years. Studies evaluating Afirma Gene Expression Classifier (GEC), Afirma Genomic Sequencing Classifier (GSC), ThyroSeq V2, ThyroSeq V3, and ThyGenX/ThyraMIR were included. The primary outcome was surgical avoidance, analyzed using a random-effects model. Results: Thirty-one studies comprising 4464 indeterminate thyroid nodules met inclusion criteria. Pooled surgical avoidance rates varied across platforms: ThyroSeq V2 (50.3%, 95% CI: 20.8–79.6%), ThyroSeq V3 (62.5%, 95% CI: 54.8–70.0%), Afirma GEC (58.8%, 95% CI: 43.6–73.1%), Afirma GSC (50.6%, 95% CI: 34.3–66.8%), and ThyGenX/ThyraMIR (68.6%, 95% CI: 63.1–73.9%). ThyGenX/ThyraMIR had the highest surgical avoidance rate and lowest heterogeneity (I² = 51.2%), while ThyroSeq showed improvement from V2 to V3. Conclusions: Molecular testing reduces unnecessary thyroid surgeries, with avoidance rates ranging from 50.3% to 68.6%. While ThyGenX/ThyraMIR showed the highest avoidance rate, its limited representation warrants cautious interpretation. Standardized protocols are needed to optimize clinical application. Further prospective studies should compare platforms and assess long-term outcomes and cost-effectiveness.

Background: A BRAF V600E mutation in papillary thyroid cancer (PTC) has been shown to be associated with aggressive behavior. Nevertheless, not all BRAF V600E PTCs behave aggressively. Allele frequency (AF) is the number of mutated molecules divided by the total number of wild-type molecules at a specific location in the genome. The relationship between BRAF V600E AF and the histopathological features of thyroid malignancies is not well understood. We hypothesized that the BRAF V600E AF will correlate directly with aggressive histopathological behavior. The aim of this study was to examine this relationship. Methods: A retrospective chart review was performed for patients treated for BRAF V600E thyroid malignancies from 2019 to 2022 at McGill University tertiary care hospitals (n = 317). Patients with BRAF V600E-positive malignancies that included information on AF were included (n = 44). The correlation between AF and tumor histopathological features was analyzed. Results: Out of the 44 nodules with a BRAF V600E mutation, those with aggressive features of PTC had a mean AF of 25.8%, which was significantly higher than the non-aggressive group with a mean AF of 10.25% (p = 0.020). Additionally, there was a statistically significant difference in mean AF between patients with a positive sentinel LN (29%) and those with a negative sentinel LN (17.8%) (p = 0.021). Classical PTC was present in 29.5% (13/44) of nodules, with a mean AF of 15.6%. The tall cell subtype was found in 64% (28/44) of nodules, with a mean AF of 23%. Solid and hobnail subtypes were less common in this study, and there was no statistically significant relationship between AF and histopathological subtypes (p = 0.107). Nodules smaller than 1cm had a mean AF of 13.3%, while nodules ranging from 1 2cm had a mean AF of 20.6%, and those larger than 2cm had a mean AF of 27.7%. However, no statistical difference was observed between AF and nodule size (p = 0.160). Conclusion: In this study, BRAF V600E mutations in conjunction with AF help to determine whether thyroid malignancies will display aggressive behavior. This pre-operative finding can help thyroid specialists to determine the extent of thyroidectomy and whether lymph node dissection is required.

We thank the commenter for their interest in our systematic review and meta-analysis evaluating the impact of molecular testing on surgical decision-making in indeterminate thyroid nodules