Evaluation of integrin α(v)β(3)-targeted imaging for predicting disease progression in patients with high-risk differentiated thyroid cancer (using (99m)Tc-3PRGD(2))

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 (99m)Tc-PEG(4)-E[PEG(4)-c(RGDfK)](2) ((99m)Tc-3PRGD(2)) 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 (99m)Tc-3PRGD(2) SPECT/CT before RAI ablation. Follow-up was done with serological and imaging studies. The correlation between (99m)Tc-3PRGD(2) avidity and remission rate for initial RAI therapy was evaluated using logistic regression analysis. The prognostic value of (99m)Tc-3PRGD(2) SPECT/CT was evaluated by Kaplan-Meier curve and Cox regression analysis. RESULTS: (99m)Tc-3PRGD(2) 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). (99m)Tc-3PRGD(2) 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 ((131)I positive/(99m)Tc-3PRGD(2) positive) and discordant ((131)I negative/(99m)Tc-3PRGD(2) 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 (99m)Tc-3PRGD(2)-positive patients with progressive disease. CONCLUSIONS: (99m)Tc-3PRGD(2) SPECT/CT is a useful modality in predicting progression of the disease after initial RAI and guiding further treatment in high-risk DTC patients.