Oral Presentation ESA-SRB-AOTA 2019

Real-world experience with lenvatinib for radioactive iodine refractory differentiated thyroid carcinoma with analyses of prognostic biomarkers for survival outcomes: Korean multicenter study (#169)

Eyun Song 1 , Mijin Kim 2 , Eui Young Kim 3 , Bo Hyun Kim 2 , Dong Yeob Shin 4 , Ho-Cheol Kang 5 , Byeong-Cheol Ahn 6 , Won Bae Kim 1 , Young Kee Shong 1 , Min Ji Jeon 1 , Dong Jun Lim 7
  1. Asan Medical Center,University of Ulsan College of Medicine, Seoul, Korea
  2. Pusan National University Hospital, Busan
  3. Dongnam Institute of Radiological and Medical Sciences Cancer Center, Busan
  4. Severance Hospital, Yonsei University College of Medicine, Seoul
  5. Chonnam national university hwasun hospital, Chonnam
  6. Kyoungpook national university hospital, Kyoungpook
  7. Seoul St. Mary’s Hospital, The Catholic University of Korea, Seoul

Background: Lenvatinib is the latest addition to the treatment options for radioactive iodine (RAI)-refractory differentiated thyroid carcinoma (DTC). This study assessed the efficacy of lenvatinib in real-world practice and identified prognostic biomarkers for survival outcomes.

Methods: A multicenter cohort study was conducted in 43 patients receiving lenvatinib, as 1st-line or 2nd-line after sorafenib, for RAI-refractory DTC. Progression-free survival (PFS) was evaluated according to various clinical factors including thyroglobulin doubling time (TgDT), tumor volume DT (TVDT), and tumor growth slope (TGS, slope of tumor change rate).

Results: Thirty-two patients were previously treated with sorafenib. Patients were treated with lenvatinib for 14 months (median) and the median starting dose was 20 mg with reduction to a maintenance dose of 10mg during follow-up. The median PFS was 21.8 months and median OS was not reached. Disease control rate was 97.7% with time to the first objective response of 3.8 months. The PFS according to previous sorafenib treatment, metastatic sites, or maintenance dose did not exhibit any difference. However, TGS measured before (TGSpre) and after (TGSpost) the initiation of lenvatinib were associated with PFS (TGSpre p=0.003;TGSpost p=0.036). Other factors associated with PFS were the sum of the largest diameters of target lesions (p=0.043) and TgDT (p=0.024). However, TVDT calculated before (TVDTpre) and after (TVDTpost) lenvatinib treatment did not portend any impact on PFS (p=0.923 and p=0.966, respectively). Withdrawal of lenvatinib occurred in 21 patients with 7 patients due to lenvatinib-induced adverse events (AEs). AEs of any grade were reported in all patients and AEs of grade 3-4 occurred in 13.9%. The most common AE was hypertension.

Conclusions: Our results support the efficacy of lenvatinib for patients with RAI-refractory DTCs. Measuring the TgDT and TGS can assist in predicting the clinical outcomes in these patients. Although AEs occur frequently, most of them were manageable.