Evaluation of integrin αvβ3-targeted imaging for predicting disease progression in patients with high-risk differentiated thyroid cancer (using 99mTc-3PRGD2)

Abstract

Background: High-risk differentiated thyroid cancer (DTC) needs effective early prediction tools to improving clinical management and prognosis. This cohort study aimed to investigate the prognostic impact of 99mTc-PEG4-E[PEG4-c(RGDfK)]2 (99mTc-3PRGD2) SPECT/CT in high-risk DTC patients after initial radioactive iodine (RAI) therapy. Methods: Thirty-three patients with high-risk DTC were prospectively recruited; all patients underwent total thyroidectomy and received 99mTc-3PRGD2 SPECT/CT before RAI ablation. Follow-up was done with serological and imaging studies. The correlation between 99mTc-3PRGD2 avidity and remission rate for initial RAI therapy was evaluated using logistic regression analysis. The prognostic value of 99mTc-3PRGD2 SPECT/CT was evaluated by Kaplan-Meier curve and Cox regression analysis. Results: 99mTc-3PRGD2 avidity was significantly correlated with the efficacy of initial RAI ablation and an effective predictor for non-remission in high-risk DTC (OR = 9.36; 95% CI = 1.10–79.83; P = 0.041). 99mTc-3PRGD2 avidity was associated with poor prognosis in patients with high-risk DTC and an independent prognostic factor for shorter progression-free survival (PFS) (HR = 9.47; 95% CI = 1.08–83.20; P = 0.043). Survival analysis, which was performed between DTC patients with concordant (131I positive/99mTc-3PRGD2 positive) and discordant (131I negative/99mTc-3PRGD2 positive) lesions, indicated that patients with concordant lesions had significantly better PFS than those with discordant lesions (P = 0.022). Moreover, compared with repeated RAI, additional surgery or targeted therapy with multikinase inhibitors could lead to a higher rate of remission in 99mTc-3PRGD2-positive patients with progressive disease. Conclusions: 99mTc-3PRGD2 SPECT/CT is a useful modality in predicting progression of the disease after initial RAI and guiding further treatment in high-risk DTC patients.