Prolonged Survival in Anaplastic Thyroid Cancer: Insights From Multi-Modal Treatment

Anaplastic thyroid cancer (ATC) is a rare and aggressive malignancy with limited treatment options and a poor prognosis. This study evaluates the outcomes of patients with locally advanced or metastatic ATC treated at two tertiary centres, focusing on the efficacy of pembrolizumab and lenvatinib, and the impact of BRAF status.

A retrospective review of 16 ATC patients treated between January 2018 and June 2024 at two tertiary Australian hospitals was conducted. Pathological confirmation was required for inclusion. Clinical data, including treatment regimens, response rates assessed by Response Evaluation Criteria in Solid Tumours version 1.1 (RECIST 1.1), progression-free survival (PFS), and overall survival (OS), were analysed.

Fifteen out of 16 patients (94%) had metastatic disease. Five patients (31%) had a BRAFV600E mutation, with four receiving first-line (1L) dabrafenib/trametinib, achieving a 75% (3/4) objective response rate. Eleven patients (50%) were BRAF wildtype, and eight received pembrolizumab and lenvatinib as both 1L and second-line (2L) settings, with an objective response rate of 75% (6/8) in both 1L and 2L settings, including three complete responses. Programmed death-ligand 1 tumour proportional score ≥50% was found in 64% (9/14) of patients, correlating with better outcomes. Median time on treatment for the pembrolizumab and lenvatinib group was not reached, with the longest survival exceeding 12 months at the time of data cut-off.

This case series highlights promising outcomes with systemic treatment options in ATC, but the analysis is limited by a small sample size, emphasising the need for further research and collaboration to improve clinical outcomes.