Novel recombinant human thyroid-stimulating hormone in aiding postoperative assessment of patients with differentiated thyroid cancer-phase I/II study.

PURPOSE: Thyroid hormone withdrawal (THW) inevitably induced hypothyroidism in patients with differentiated thyroid cancer (DTC), and we aimed to evaluate the safety and efficacy of a novel recombinant human thyroid-stimulating hormone (rhTSH, ZGrhTSH) as an alternative of THW in China. METHODS: Totally, 64 DTC patients were enrolled with 24 in the dose-escalation cohort equally grouped into 0.9 mg × 1 day, 0.9 mg × 2 day, 1.8 mg × 1 day, and 1.8 mg × 2 day dosage, and 40 further enrolled into 0.9 mg × 2 day dose-expansion cohort. All patients underwent both ZGrhTSH phase and levothyroxine (L-T4) withdrawal phase for self-comparison in terms of TSH levels, the radioactive iodine (RAI) uptake, stimulated thyroglobulin level, and the quality of life (QoL). RESULTS: In ZGrhTSH phase, no major serious adverse events were observed, and mild symptoms of headache were observed in 6.3%, lethargy in 4.7%, and asthenia in 3.1% of the patients, and mostly resolved spontaneously within 2 days. Concordant RAI uptake was noticed in 89.1% (57/64) of the patients between ZGrhTSH and L-T4 withdrawal phases. The concordant thyroglobulin level with a cut-off of 1 µg/L was noticed in 84.7% (50/59) of the patients without the interference of anti-thyroglobulin antibody. The QoL was far better during ZGrhTSH phase than L-T4 withdrawal phase, with lower Billewicz (- 51.30 ± 4.70 vs. - 39.10 ± 16.61, P < 0.001) and POMS (91.70 ± 16.70 vs. 100.40 ± 22.11, P = 0.011) scores which indicate the lower the better. Serum TSH level rose from basal 0.11 ± 0.12 mU/L to a peak of 122.11 ± 42.44 mU/L 24 h after the last dose of ZGrhTSH. In L-T4 withdrawal phase, a median of 23 days after L-T4 withdrawal was needed, with the mean TSH level of 82.20 ± 31.37 mU/L. The half-life for ZGrhTSH clearance was about 20 h. CONCLUSION: The ZGrhTSH held the promise to be a safe and effective modality in facilitating RAI uptake and serum thyroglobulin stimulation, with better QoL of patients with DTC compared with L-T4 withdrawal.

Effect of BRAFV600E and TERT Promoter Mutations on Thyroglobulin Response in Patients With Distant-Metastatic Differentiated Thyroid Cancer.

OBJECTIVE: To assess the impact of serine/threonine-protein kinase B-Raf (BRAF) V600E and telomerase reverse transcriptase (TERT) promoter mutations in patients with distant-metastatic differentiated thyroid cancer (DM-DTC) based on thyroglobulin (Tg) response to radioactive iodine (RAI) therapy. METHODS: The BRAFV600E and TERT mutations in primary tumors or metastatic lymph nodes of 114 patients with DM-DTC were retrospectively examined. RAI avidity was evaluated using a posttreatment iodine-131 whole-body scan. The Tg response was dynamically assessed at a median follow-up period of 56.50 months (interquartile range, 28.43-97.98 months). RESULTS: BRAFV600E was detected in 38.6% of cases, the TERT mutation in 21.1% of cases, and both the BRAFV600E and TERT mutations in 14.9% of cases. Patients with both the mutations tended to be older at diagnosis (P < .001) and less multifocal (P = .011) and have more aggressive histologic subtypes (P = .011) and a higher Ki-67 index (P = .003). Patients with neither mutation tended to be have more RAI avidity than those with either the BRAFV600E mutation alone or both the mutations (P = .001 and .001, respectively). Patients with both the mutations exhibited a more unfavorable Tg response than those without both the mutations and those with the BRAFV600E mutation alone (P = .001 and .013, respectively). The Tg progression-free survival was shorter in patients with the TERT mutation alone than in those with neither mutation (P = .021), and it tended to be shorter when it coexisted with the BRAFV600E mutation (P < .001); however, no significant difference was observed between those with the BRAFV600E mutation alone and those with neither mutation (P = .890). CONCLUSION: The coexistence of the BRAFV600E and TERT promoter mutations synergistically induce the loss of RAI avidity and leads to an undesirable Tg response in patients with DM-DTC. The TERT promoter mutation appears to affect Tg response more than the BRAFV600E mutation.

Response to Surgery Assessments for Sparing Radioiodine Remnant Ablation in Intermediate-Risk Papillary Thyroid Cancer.

CONTEXT: Using response to surgery when tailoring radioiodine (RAI) therapy for papillary thyroid cancer (PTC) is valued but lacks prospective validation. OBJECTIVE: To spare RAI thyroid remnant ablation among patients with intermediate-risk PTCs using 3-tiered assessments with response to surgery highlighted, in addition to the risk of the recurrence stratification and TNM staging. METHODS: Patients with no evidence of disease (NED) identified as excellent response (ER) or indeterminate response (IDR) to surgery were spared from RAI thyroid remnant ablation after informed consent and prospectively enrolled under active surveillance. Those involved in other trials or without sufficient follow-up data were excluded. Dynamic responses were followed and compared longitudinally. The main outcome measures were NED presenting as durable ER or IDR for over 12 months. RESULTS: Of the enrolled 215 patients, 47.4% (102/215) ER and 52.6% (113/215) IDR were identified regarding RAI decision-making. After a median of 23.6 (interquartile range 13.8-31.6) months, the share of ER increased to 82.8% (178/215) and IDR decreased to 16.3% (35/215), with 85 patients shifting from IDR to ER over time, only 0.5% (1/215) structural incomplete response and 0.5% (1/215) biochemical incomplete response observed. Successful remnant ablation was observed in 27.7% (26/94) of the patients completing 2 diagnostic whole-body scans after a median interval of 13.0 months, indicating a theranostic effect. In the 173 patients followed for over 12 months, the NED rate did not differ between ER and IDR subgroups (100% vs 97.9%, P = .20). CONCLUSION: Through the 3-tiered assessments with response to surgery highlighted, postoperative ER and IDR spared from RAI remnant ablation may indicate similar favorable responses in intermediate-risk patients with PTC during 23.6 months of follow-up.

Identification of Radioactive Iodine Refractory Differentiated Thyroid Cancer.

Most differentiated thyroid cancer (DTC) patients have an excellent prognosis. However, about one-third of DTC patients with recurrent or metastatic disease lose the hallmark of specific iodine uptake initially or gradually and acquire radioactive iodine-refractory DTC (RAIR-DTC) with poor prognosis. Due to the potentially severe complications from unnecessarily repeated RAI therapy and encouraging progress of multiple targeted drugs for advanced RAIR-DTC patients, it has become crucial to identify RAIR-DTC early. In this review, we focus on the progress and controversies regarding the defining of RAIR-DTC, further with subsistent approaches and promising molecular nuclear medicine imaging in identifying RAIR-DTC, which may shed light on the proper management methodsof such patients.