甲状腺乳頭癌における術前甲状腺ホルモン感受性状態の再発予後意義

The relationship between thyroid hormone sensitivity and the risk of recurrence in patients with papillary thyroid carcinoma (PTC) has not been thoroughly investigated, and it remains unclear whether factors such as TSH suppression efficacy or underlying autoimmune mechanisms mediate this association. The primary objective of the present study was to examine the complex interrelationships among thyroid hormone sensitivity indices and their collective utility as biomarkers for predicting recurrence.

This study retrospectively analyzed a cohort of 196 patients who underwent initial surgical resection and received a pathological confirmation of PTC between January 2015 and July 2016. Logistic regression analysis was employed to evaluate the potential association of thyroid hormone sensitivity indices-specifically, the thyrotropin index (TSHI) and thyrotroph T4 resistance index (TT4RI)-with PTC recurrence, as well as to assess their predictive utility.

In patients with papillary thyroid carcinoma (PTC), multivariate logistic regression identified both TSHI ≥ 3.6 and TT4RI ≥ 54.2 as independent prognostic factors associated with reduced recurrence risk (TSHI: OR = 0.107,95%CI : 0.012-0.948, P = 0.045; TT4RI: OR = 0.158,95%CI : 0.026-0.529, P = 0.005). Furthermore, net reclassification improvement (NRI) and integrated discrimination improvement (IDI) analyses revealed that the inclusion of thyroid hormone sensitivity indices significantly enhanced the predictive accuracy for recurrence events (TSHI: NRI = 0.292,95%CI:-0.001-0.602, P = 0.064; IDI = 0.032, 95%CI : 0.013-0.051, P = 0.001; TT4RI: NRI = 0.663,95%CI : 0.376-0.951, P < 0.001; IDI = 0.053, 95%CI : 0.025-0.082, P < 0.001). Finally, receiver operating characteristic (ROC) curve analysis demonstrated that the combination of TSHI and TT4RI yielded superior predictive performance, with an area under the curve (AUC) of 0.790 (P < 0.001), significantly outperforming either index alone.

In conclusion, thyroid hormone resistance, indicated by elevated TSHI and TT4RI, represents an independent protective factor against recurrence in PTC. The integration of these indices significantly improves recurrence prediction, with their combination offering superior discriminative ability, highlighting their collective utility as clinically relevant biomarkers for optimizing postoperative surveillance and management strategies in PTC.