Optimization of serum thyroglobulin measured at different time points for prognostic evaluation in differentiated thyroid carcinoma patients

Abstract

Although serum thyroglobulin (Tg) is a reliable differentiated thyroid carcinoma (DTC) prognostic marker, its cutoff values can be affected by TSH stimulation status. Serum Tg prognostic values measured at different time points before and after radioactive iodine (RAI) therapy prepared with recombinant human TSH (rhTSH) in DTC patients, were investigated. This study included 160 DTC patients who underwent surgery followed by rhTSH-aided RAI therapy. Their serum Tg levels were measured 7 days before (D-7Tg), on the day of (D0Tg), and 2 days after (D2Tg) the RAI therapy. For response evaluation, the patients were classified into 2 groups: acceptable response and non-acceptable response (non-AR). Optimal Tg level cutoff values measured at different time points were evaluated for persistent or recurrent disease (PRD) prediction, as well as therapeutic response. Multivariate analysis showed that D-7Tg, D0Tg, and D2Tg significantly predicted non-AR ( P < .05, for all). Optimal Tg level cutoff values for non-AR prediction were 0.6, 2.6, and 3.7 ng/mL for D-7Tg, D0Tg, and D2Tg, respectively. Cox regression analysis showed that Tg levels were significantly associated with PRD free survival with D-7Tg, D0Tg, and D2Tg cutoff values of 0.8, 4.0, and 6.0 ng/mL, respectively (D-7Tg, P = .010; D0Tg, P = .005; D2Tg, P = .011). Serum Tg levels measured at the different time points could predict PRD free survival as well as therapeutic response with different cutoff values in DTC patients who underwent rhTSH-aided RAI therapy.

Only peak thyroglobulin concentration on day 1 and 3 of rhTSH-aided RAI adjuvant treatment has prognostic implications in differentiated thyroid cancer

“…Some studies demonstrated that Tg measurement after rhTSH stimulation and therapeutic RAI application is of prognostic significance [ 9 , 11 , 13 , 22 ]. Melo et al [ 11 ] reported the prognostic value of Tg5 (i.e., measurement 5 days after first rhTSH injection) in predicting disease status 1 year post-ablation.…”

“…The difference between the above-mentioned cutoff values of Tg5 was explained by the presence or absence of prophylactic neck dissection and by surgeon experience in total thyroidectomy. Also recently, Mutstudy et al [ 13 ] showed that Tg levels measured two days after RAI therapy have prognostic significance. ROC curve analysis showed an optimal Tg cutoff value of 3.7 ng/mL, which was confirmed as an independent prognostic factor in multivariate analysis.…”

“…It would seem reasonable to have the same approach during RAI treatment, however, Tg released due to thyrocyte RAI damage may confound interpretation of the results [16]. Some studies demonstrated that Tg measurement after rhTSH stimulation and therapeutic RAI application is of prognostic significance [9,11,13,22]. Melo et al [11] reported the prognostic value of Tg5 (i.e., measurement 5 days after first rhTSH injection) in predicting disease status 1 year post-ablation.…”

“…In contrast, data on optimal measurement times and on the prognostic value of the Tg level after recombinant human TSH (rhTSH) stimulation are rather limited [9][10][11][12]. Only one report has compared measurements taken at different points around the time of rhTSH stimulation [13]. In diagnostic settings, the highest prognostic value of Tg measurement is 5 days after the first rhTSH injection [14,15].…”

Editorial: Recent advances in papillary thyroid carcinoma: diagnosis and predictive factors

“…Radioactive iodine resistant (RAIR) cases with metastatic disease are analyzed according to thyroglobulin and TSH change speed in the manuscript by Meng et al. Although the concept has been raised in previous reports and is considered by some authors as an important criterion to determine radioactive iodine-resistant malignancies ( 5 ), they construct a nomogram based on Thyroglobulin stimulated (Ts) differences at ablation and first recurrence: Ts1-Ts2: ΔTgs, as well as Thyroid Stimulant Hormone levels at same periods: TSHs1-TSH2= ΔTSHs. A ratio ΔTgs/ΔTSHs considering these two differences ≤1.5 as well as older age predicts rapid progression of the disease for these patients, which makes closer monitoring imperative, along with considering early administration of TKI agents.…”