The thyroglobulin to TSH ratio to predict successful ablation after iodine therapy in papillary thyroid carcinoma

Introduction: In recent years, thyroidectomy and radioactive iodine remnant ablation and thyroid-stimulating hormone suppression therapy with thyroxine have emerged as the optimal treatment for differentiated thyroid cancer. The aim of the study was to analyze the sTg/TSH ratio to predict the value of successful ablation and also to evaluate whether this ratio can be used as a suitable predictor and compared with stimulated thyroglobulin (sTg).Methods: We investigated patients who underwent total thyroidectomy for DTC, with or without neck lymph node dissection, from ۲۰۱۵ to ۲۰۲۴. The administered dose was determined by experienced nuclear medicine physician based on thyroid remnant status and the presence of distant metastases Four to six months after I-۱۳۱ treatment, all patients underwent follow-up assessments. Successful ablation was defined as the absence of detectable lesions on diagnostic iodine scan, neck ultrasound, Tg levels below ۱ ng/mL and negative TgAb results.Results: Of the total ۱۵۴, ۱۱۵ patients (۷۴.۷%) achieved successful ablation, while ۳۹ patients (۲۵.۳%) had unsuccessful ablation. Primary tumor size, multifocality and cervical lymph node involvement were associated with a higher rate of failure to successful ablation (P = ۰.۰۰۴). Patients were classified based on a Tg cutoff of ۲.۲۵ ng/mL. At sTg levels greater than ۲.۲۵ ng/mL, the chance of successful ablation decreased by ۸۹% (OR=۰.۱۱). At a Tg/TSH ratio cutoff of ۰.۰۴۶, patients with ratios below this value had a success rate of ۷۰.۴%, which was statistically significant compared to those with higher ratios (P < ۰.۰۰۱).Conclusion: The present study showed that both sTg and sTg/TSH ratio can predict ablation outcome in the PTC patients. With the equal specificity (۷۰.۴ %), the sensitivity of sTg/TSH ratio (۸۲ %) is slightly higher than sTg (۷۹.۵%) as a better predictor of the efficacy of RAI treatment and successful ablation.

کلیدواژه ها:

Differentiated thyroid carcinoma ، Serum thyroglobulin ، Radioactive iodine therapy ، Thyroid remnant ablation