Recombinant Thyrotropin vs Levothyroxine Withdrawal in 131I Therapy of N1 Thyroid Cancer: A Large Matched Cohort Study (ThyrNod).

CONTEXT: Recombinant human thyrotropin (rhTSH) has been shown to be an effective stimulation method for radioactive iodine (RAI) therapy in differentiated thyroid cancer, including in those with nodal metastases (N1 DTC). OBJECTIVES: To demonstrate the noninferiority of rhTSH vs thyroid hormone withdrawal (THW) in preparation to RAI regarding disease status at the first evaluation in the real-life setting in patients with N1 DTC. DESIGN: This was a French multicenter retrospective study. Groups were matched according to age (<45/≥45 years), number of N1 nodes (≤5/>5 lymph nodes), and stage (pT1-T2/pT3). RESULTS: The cohort consisted of 404 patients pT1-T3/N1/M0 DTC treated with rhTSH (n = 205) or THW (n = 199). Pathological characteristics and initially administrated RAI activities (3.27 ± 1.00 GBq) were similar between the two groups. At first evaluation (6 to 18 months post-RAI), disease-free status was defined by thyroglobulin levels below threshold and a normal ultrasound. Disease-free rate was not inferior in the rhTSH group (75.1%) compared with the THW group (71.9%). The observed difference between the success rates was 3.3% (-6.6 to 13.0); rhTSH was therefore considered noninferior to THW because the upper limit of this interval was <15%. At the last evaluation (29.7 ± 20.7 months for rhTSH; 36.7 ± 23.8 months for THW), 83.5% (rhTSH) and 81.5% (THW) of patients achieved a complete response. This result was not influenced by any of the known prognostic factors. CONCLUSIONS: A preparation for initial RAI treatment with rhTSH was noninferior to that with THW in our series of pT1-T3/N1/M0-DTC on disease-free status outcomes at the first evaluation and after 3 years.

Tyrosine kinase inhibitor treatments in patients with metastatic thyroid carcinomas: a retrospective study of the TUTHYREF network.

OBJECTIVE: Tyrosine kinase inhibitors (TKIs) are used to treat patients with advanced thyroid cancers. We retrospectively investigated the efficacy of TKIs administered outside of clinical trials in metastatic sites or locally advanced thyroid cancer patients from five French oncology centers. DESIGN AND METHODS: THERE WERE 62 PATIENTS (37 MEN, MEAN AGE: 61 years) treated with sorafenib (62%), sunitinib (22%), and vandetanib (16%) outside of clinical trials; 22 had papillary, five had follicular, five had Hürthle cell, 13 had poorly differentiated, and 17 had medullary thyroid carcinoma (MTC). Thirty-three, 25, and four patients were treated with one, two, and three lines of TKIs respectively. Primary endpoints were objective tumor response rate and progression-free survival (PFS). Sequential treatments and tumor response according to metastatic sites were secondary endpoints. RESULTS: Among the 39 sorafenib and 12 sunitinib treatments in differentiated thyroid carcinoma (DTC) patients, partial response (PR) rate was 15 and 8% respectively. In the 11 MTC patients treated with vandetanib, 36% had PR. Median PFS was similar in second-line compared with first-line sorafenib or sunitinib therapy (6.7 vs 7.0 months) in DTC patients, but there was no PR with second- and third-line treatments. Bone and pleural lesions were the most refractory sites to treatment. CONCLUSIONS: This is the largest retrospective study evaluating TKI therapies outside of clinical trials. DTC patients treated with second-line therapy had stable disease as best response, but had a similar median PFS compared with the first-line treatment.