Background: Anaplastic thyroid cancer (ATC) is an aggressive form of thyroid cancer with poor overall survival (OS). The ideal treatment for ATC is not clear and benefits of targeted molecular agents/immunotherapy is not well established. Multimodality treatment (MMT) may reduce locoregional tumor progression (LTP) and improve OS when compared to treatment with palliative intention (TPI). Expanding MMT with targeted therapy/immunotherapy may further improve OS. This study aims to compare survival outcomes and morbidity between ATC patients treated with MMT and TPI. Additionally, the effect of MMT +/- targeted therapy/immunotherapy on OS in ATC was assessed.
Methods: We performed a retrospective (1979-2018) cohort study of ATC patients within a single tertiary hospital referral centre. Patients were assigned to either TPI or MMT following MDT discussion and their own preference. The primary outcome measure was LTP. Secondary outcome measures were one-year OS and major treatment related morbidity defined as grade IV events.
Results: 67 patients had sufficient follow-up data for inclusion. Disease was staged: Stage IVA (n=1), IVB (n=31) or IVC (n=34) ATC. Patients were treated with MMT (n=33) or TPI (n=34). LTP was lower (p=0.02) in patients receiving MMT (46%) when compared to TPI (74%). MMT increased one-year OS to 43% compared to 0% in TPI (p<0.0001). There was no difference in major complications between the MMT (15%) or TPI (23%) cohort(p=0.54). A combination of MMT, targeted therapy and/or immunotherapy (n=5) increased one-year survival in Stage IVC ATC to 60%, compared to 33% or 0% in patients receiving MMT without targeted therapy and/or immunotherapy (n=11) or PI (n=18) respectively (p < 0.0001).
Conclusion: MMT reduces LTP and improves OS in selected ATC patients without increasing morbidity. The addition of targeted molecular therapy or immunotherapy to multimodality treatment protocols is associated with improved OS in ATC patients.