Purpose: To study whether male sex is a risk factor for prognosis in patients with differentiated thyroid cancer after 131I treatment using the propensity score matching (PSM) method.
Methods: From April 2016 to October 2021, 1948 postoperative differentiated thyroid cancer patients aged 43 (interquartile range: 34, 54) years who received 131I treatment were retrospectively enrolled and divided into male (n = 645) and female groups (n = 1303). The PSM method was adopted to process all data to reduce the influence of data bias and confounding variables. The Mann-Whitney U test and χ2 test were used for data analysis. Multivariate logistic regression was used to analyze the risk factors affecting prognosis, and the receiver operating characteristic curve was used to analyze the relationship between stimulated thyroglobulin (sTg) level, 131I dose, and poor prognosis.
Results: Before PSM, the proportion of male patients with poor prognosis was significantly higher than that of female patients. After PSM, there was no difference in the proportion of poor prognosis between male and female groups. Multivariate logistic regression analysis showed that male sex; high T stage, N1b stage, and M1 stage; high sTg level; and high 131I dose were risk factors for poor prognosis before PSM. After PSM, high T stage, M1 stage, high sTg level, and 131I dose were still risk factors but male sex was no longer a risk factor for poor prognosis.
Conclusions: After the reduction of selection bias by PSM, male sex was no longer a risk factor for prognosis after 131I treatment of differentiated thyroid cancer. In addition, high T stage (T3 + T4 stage), M1 stage, sTg ≥10.15 ng/mL, and 131I dose ≥260 mCi were risk factors for poor prognosis.
Keywords: 131I treatment; differentiated thyroid cancer; prognosis; propensity score matching; risk factors; sex.
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