Endocrine Abstracts

Objective: Propensity score matching (PSM) was used to study whether male patients with differentiated thyroid cancer (DTC) were the risk factors for prognosis after ¹³¹I treatment.

Methods: 1677 patients with DTC who underwent total thyroidectomy and received ¹³¹I treatment were divided into male group (n= 546) and female group (n= 1131). The PSM method was adopted to process all the data to reduce the influence of data bias and confounding variables. Independent sample T test and Mann-Whitney U test were used for all continuous variables, χ² test was used for all classified variables. Univariate and multivariate logistic regression were used to analyze the risk factors affecting prognosis, and a receiver operating characteristic (ROC) curve was used to analyze the relationship between sTg level and poor prognosis.

Results: Before PSM, the proportion of male patients with poor prognosis was significantly higher than that of female patients (21.2%(116/546) vs 14.0%(158/1131), χ² = 17.53, P= 0.001). After PSM, there was no difference in the proportion of poor prognosis between male and female groups (19.9%(107/537) vs 15.6%(84/537), χ² = 5.43, P=0.143). Multivariate logistic regression analysis showed that male (odds radio (OR) = 1.439 (95%CI: 1.016~2.038), P=0.040), high T stage (T3, T4 stage)(OR=1.816 (95%CI: 1.273~2.590), P=0.001), N1b stage (OR = 1.766 (95% CI: 1.233~2.530), P= 0.002), M1 stage (OR = 9.833 (95%CI: 3.190~30.309), P<0.001) and sTg level (OR = 1.035 (95%CI: 1.029~1.042), P<0.001) were risk factors for poor prognosis before PSM, while high T stage (T3, T4 stage)(OR = 1.870 (95%CI: 1.212~2.886), P= 0.005), M1 stage (OR = 8.993 (95%CI: 2.434~33.225), P= 0.001), high sTg level (OR = 1.040 (95%CI: 1.030~1.049), P<0.001) were still risk factors, and male (OR = 1.383 (95%CI: 0.912~2.096), P= 0.127) were no longer risk factors for poor prognosis after PSM. ROC curve analysis showed that the cut-off value of sTg was 10.25 μg/l, with the sensitivity of 81.0%(222/274) and the specificity of 84.2%(1173/1393). ConclusionsAfter reduction of selection bias by PSM, males are no longer a risk factor for prognosis after ¹³¹I treatment of DTC. In addition, high T stage (T3, T4 stage), M1 stage and sTg ≥ 10.25 μg/l were risk factors for poor prognosis. Key words Differentiated thyroid cancer; ¹³¹I treatment; Propensity Score-Matching; Gender; Risk factors; Prognosis