Markedly elevated serum preoperative thyroglobulin predicts radioiodine-refractory thyroid cancer

Background Repeated radiotherapy brings limited benefits and significant side effects for differentiated thyroid cancer patients (DTC) with radioiodine refractory (RAIR). However, the prognostic role of preoperative thyroglobulin (pre-Tg) in predicting RAIR is unclear. Methods In the present study, data were retrospectively reviewed from 5173 patients who underwent radiotherapy in the Jiangyuan Hospital from January 2006 to December 2020. Results A total of 1,102 patients with or without repeated radiotherapy were compared (repeated vs. single radiotherapy; n = 199 vs. n = 903). Pre-Tg was significantly elevated in patients with repeated radiotherapy. After the classification of RAIR (non-RAIR, n = 786 vs. RAIR, n = 90), elevated pre-Tg was also correlated with RAIR after univariate and multivariate analyses. According to the receiver operating characteristic curve analysis, elevated pre-Tg well predicted RAIR (AUC = 0.76, CI: 0.71-0.82, p < 0.0001). To control the selection bias, the propensity score matching was used. Pre-Tg level was found to be an independent predictor of RAIR (p < 0.001, HR = 7.25, CI: 2.55-20.62). Conclusion Our results indicate that markedly elevated pre-Tg level can be served as an independent predictor of RAIR-DTC, which can guide a more precise treatment strategy and/or an active surveillance during surgery and follow-ups.