Endocrine Abstracts

Therapeutic strategy for the management of radioiodine-refractory differentiated thyroid cancer (rrDTC) and advanced medullary thyroid cancer (MTC) had changed with the introduction of the multityrosine-kinase-inhibitors (MKI) sorafenib&lenvatinib and vandetanib&cabozantinib respectively. Only recently, the market approval of pralsetinib (FDA) and selpercatinib (FDA and EMA) as first highly selective RET(rearranged during transfection)- inhibitors have expanded the therapeutic landscape of thyroid cancer treatment. Here, we evaluated clinical characteristics, therapy regimes and efficacy of 77 rr(P)DTC (18 PTC, 22 FTC, 38 PDTC) and 59 advanced MTC patients upon TKI treatment (in total: 136 pts.) in a single tertiary reference centre. In the subset of (P)DTC patients the median age at diagnosis was 59 years (DTC: 59 years (29-79 years); PDTC 58 (29-79 years)). The median age at initialisation of the first TKI was 63 years. 75 patients were treated with lenvatinib and 48 patients were treated with sorafenib. Lenvatinib was first line option in 63 patients and sorafenib in 11 patients. One patient received pazopanib (PFS: 14 months) as first line therapy. The median PFS for lenvatinib was 18 months and three months for sorafenib. Upon responders, median PFS was 23 and eight months respectively, and 22 and 14 months when applied as first line option. To date, a total of four patients received cabozantinib as third line treatment. The median PFS for this subsets was not calculated. The subgroup of MTC patients included 51 sporadic patients and four with multiple endocrine neoplasia (MEN2a: two patients; MEN2b: two patients). The median age at diagnosis was 50 (15-90) years. The median age at initialisation of the first TKI was 56 years (22-90 years). Fifty patients were treated with vandetanib and 14 were treated with cabozantinib. Eleven patients received pralsetinib and selpercatinib was administered in 8 patients during their course of disease. Pazopanib and sunitinib were applied in two patients as an individualised treatment concept. Vandetanib was first line treatment option in 47 patients and cabozantinib only in two patients. Median PFS in vandetanib was 30 months and 12 in cabozantib respectively. To date, therapy with pralsetinib (5/11) and selpercatinib (5/8) is ongoing in five patients respectively. In conclusion, TKI therapy in advanced thyroid cancer appears to be effective in a real-world scenario.