EFFICACY AND PROGNOSIS IN PATIENTS WITH PAPILLARY THYROID CANCER WITH POSTOPERATIVE PREABLATIVE STIMULATED THYROGLOBULIN ABOVE 10 NG/ML AFTER INITIAL THERAPY WITH RADIOIODINE.

[OBJECTIVE] Few prognostic analyses have been conducted for papillary thyroid cancer (PTC) patients with preablative stimulated Tg >10 ng/mL. We investigated the therapeutic responses and prognosis of these patients after the initial radioiodine (RAI) therapy.

[METHODS] We retrospectively assessed 256 patients with PTC who underwent RAI remnant ablation after total thyroidectomy, and all presTg levels were >10 ng/mL. We assessed therapeutic responses and influencing factors 6-12 months after the initial RAI therapy. The Kaplan-Meier method was used to analyze progression-free survival (PFS).

[RESULTS] After initial RAI therapy, excellent (ER), indeterminate (IDR), biochemically incomplete (BIR), and structurally incomplete (SIR) responses were identified in 5.1% (13/256), 22.6% (58/256), 46.9% (120/256), and 25.4% (65/256) of the patients, respectively. Among them, incomplete response (IR [BIR+SIR]), accounting for 72.3% of the responses. Univariate and multivariate analyses showed that presTg (OR=1.047, 95% CI 1.027-1.066, p=0.000), sex (OR=3.356, 95% CI 1.613-6.986, p=0.001), and tumor size (OR=1.431, 95% CI 1.050-1.951, p=0.023) were independent risk factors for IR. ROC analysis identified presTg levels and tumor size cutoffs of 24.4 mg/mL and 2.3 cm, respectively, for predicting IR. The PFS was significantly shorter in the SIR group than in the ER, IDR, and BIR groups (p=0.020). At the last follow-up, the number of patients with SIR decreased significantly (65 to 44 cases).

[CONCLUSIONS] PresTg level, tumor size, and male sex were predictive of IR, and patients with initial SIR showed the poorest prognosis. Individualized interventions can improve the prognosis of patients with an initial SIR.