Anaplastic thyroid carcinoma in Argentina: real-world diagnostic lags and treatment barriers

Anaplastic thyroid carcinoma (ATC) is an aggressive malignancy with high mortality. Approximately 50% harbor the BRAF V600E mutation, for which dabrafenib-trametinib (DT) has been associated with improved survival (OS). Prompt diagnosis and access to molecular testing and targeted therapy are critical for outcomes. We evaluated diagnostic and therapeutic barriers in ATC patients treated in Buenos Aires, Argentina.

This retrospective multicenter cohort study included 48 ATC patients from 11 centers in Buenos Aires (2019-2025). Initial diagnostic methods (IDMs) included fine-needle aspiration cytology (FNAC), core needle biopsy (CNB), surgical biopsy, or unsuspected diagnosis after thyroidectomy. We assessed diagnostic delay, BRAF testing, DT access, and OS.

Median time from symptom onset to diagnosis was 3.16 months (IQR: 2-5.5). FNAC was the most frequent IDM (62%), but confirmed ATC in only 30%. Unsuspected ATC diagnosed in surgical specimens accounted for 29% of cases. BRAF testing was performed in 70% of patients, with 59% positivity, and a median turnaround of 7.5 days (IQR 4-29) from collection to result. Median time from diagnosis to DT initiation was 39 days (IQR 22-70). Only 40% of eligible BRAF-positive patients received DT. Median OS was 3.23 months (IQR 1.4-11.5). In an exploratory unadjusted analysis, DT-treated patients had longer OS (8.6 vs. 3.61 months; p = 0.037). Unsuspected ATC diagnosed after thyroidectomy and surgery were associated with longer OS.

Diagnostic delays and barriers to molecular testing and targeted therapy remain substantial. Optimizing diagnostic pathways, prioritizing representative tissue sampling, and improving timely access to molecular testing and DT may enable earlier treatment and better outcomes.