Radioiodine Remnant Ablation In Patients Research Articles

Sufficiency of a Single Negative Thyroglobulin Standard for Judging the Success of Ablation in Low- and Intermediate-risk Differentiated Thyroid Cancer: A Retrospective Study.

We investigated how reduced successful ablation criteria may be used to evaluate radioiodine remnant ablation in patients with low- and intermediate-differentiated thyroid carcinoma (DTC). Overall, 254 low- and intermediate-risk patients with DTC were categorized into three groups (positive, weak, positive, and negative) on the basis of a visual study of thyroid imaging performed before postoperative iodine treatment. Semi-quantitative analysis parameters were incorporated into the positive Tc-99m pertechnetate scanning to further examine the clinical use of thyroid imaging. We investigated the value of successful judgment criteria and the influencing factors of radioiodine ablation. At the same time, the predictive value of thyroglobulin (Tg) for radioiodine treatment and the overall clinical efficacy were assessed. A total of 250 (98.43%) patients were identified as having functional thyroid tissue residue on the Tx-whole-body scan, and 137 (53.94%) patients had positive Tc-99m pertechnetate scans using semi-quantitative analysis. The single Tg standard could not substitute the double standard (χ! !=22.042, p<0.001) for patients with residual thyroid weight by a semiquantitative analysis. However, the semi-quantitative analysis revealed no association between 99mTcO4-thyroid scan and ablation treatment using semi-quantitative analysis; only preablation sTg levels were related with success in the multivariate logistic regression analysis, with a cut-off value of 2.88 ng/mL. The pre-ablation stimulated Tg level was also the primary factor of satisfactory response following follow-up with an optimal cut-off of 6.506 ng/mL. Even in low- and intermediate-risk patients with DTC, a single negative Tg standard also requires receiving some restrictions in the evaluation of ablation success and is inadequate. Conventional 99mTcO4 thyroid imaging combined with a quantitative analysis program can improve the clinical practice of single negative Tg standard.

Clinical Outcomes after Early and Delayed Radioiodine Remnant Ablation in Patients with Low-Risk Papillary Thyroid Carcinoma: Propensity Score Matching Analysis.

BackgroundThe clinical outcomes of delayed radioiodine remnant ablation (RRA) therapy in patients with low-risk papillary thyroid carcinoma (PTC) are unclear. We aimed to evaluate the clinical impact of the interval between total thyroidectomy (TT) and RRA therapy in patients with low-risk PTC.MethodsWe included 526 patients who underwent TT and RRA for low-risk PTC with a primary tumor size of >1 cm between 2000 and 2012. Patients were divided into the early (<90 days) and the delayed (≥90 days) RRA groups based on the interval between TT and RRA. The results of diagnostic whole-body scan (DxWBS), ongoing risk stratification (ORS; response to therapy), and disease-free survival (DFS) were evaluated before and after propensity score matching (PSM).ResultsAmong the 526 patients, 75 (14.3%) patients underwent delayed RRA; they had more cervical lymph node metastasis and received a higher RRA dose than those who underwent early RRA. The median follow-up period was 9.1 years after initial therapy, and the structural recurrence rate was 1.9%. In DxWBS, 60 patients had focal iodine uptake limited in operative bed, with no significant difference between groups. According to ORS, 78%, 20%, 1%, and 1% patients were classified into excellent, indeterminate, biochemical incomplete, and structural incomplete response groups, respectively. There was no significant difference in ORS or DFS between groups before and after PSM.ConclusionThe timing of the first RRA had no clinical impact in patients with low-risk PTC. Thus, the clinical decision for RRA can be determined >3 months after TT considering other prognostic factors.

Radioiodine Uptake and Thyroglobulin-Guided Radioiodine Remnant Ablation in Patients with Differentiated Thyroid Cancer: A Prospective, Randomized, Open-Label, Controlled Trial.

Radioiodine (131I) remnant ablation (RRA) has become a key step in the postoperative treatment of differentiated thyroid cancer (DTC). However, inadequate or excessive 131I is common using fixed activities. This study was designed to explore the feasibility of radioiodine uptake and thyroglobulin (RAIU-Tg)-guided RRA. A total of 277 patients were randomized to the RAIU-Tg-based activity group or a fixed activity of 3.7 GBq group at a ratio of 4:1. The RAIU-Tg-based activity was established based on four levels of RAIU (≤2%, 2-5%, 5-15%, and >15%) and Tg levels (≤2, 2-5, 5-10, and >10 ng/mL). Based on this, 131I activities of 1.1, 1.85, 3.7, and 5.55 GBq were administered. If the levels for RAIU and Tg were not in the same category, the higher activity determined by either RAIU or Tg was administered. Successful RRA was defined as negative diagnostic whole-body scan and Tg <1 ng/mL (anti-Tg antibody negative) or negative diagnostic whole-body scan (anti-Tg antibody positive) under thyrotropin stimulation six months or more post RRA. There was no statistically significant difference in baseline characteristics between the RAIU-Tg-based activity group (n = 207) and the fixed activity group (n = 58). The activity of 131I used in the RAIU-Tg-based activity group (3.26 ± 1.54 GBq) was significantly lower than that used in the fixed activity group (p < 0.0001), whereas the rate of successful RRA in the RAIU-Tg-based activity group was significantly higher than the rate in the fixed activity group (94.2% vs. 70.7%; p < 0.0001). The rates of successful RRA in the four subgroups of the RAIU-Tg-based activity group were comparable (p = 0.543). Although there was no statistically significant difference in the incidence of total/short-term adverse effects between the RAIU-Tg-based activity group and the fixed activity group, a significantly lower incidence of intermediate adverse effects, which predominantly consisted of xerostomia, was reported in the RAIU-Tg-based activity group. Compared to a fixed activity of 3.7 GBq, RAIU-Tg-guided dosimetry can improve the success rate and decrease the incidence of intermediate side effects of RRA in postoperative patients with DTC.

Association between iodine intake and treatment outcomes of radioiodine remnant ablation in patients with papillary thyroid cancer

Objective To evaluate the association between iodine intake and treatment outcomes of radioiodine remnant ablation in patients with papillary thyroid cancer (PTC), and to investigate the determinants related to the ablation efficacy. Methods A total of 95 PTC patients (28 males, 67 females; average age 39.8 years) without distant metastases from January 2013 to May 2014 were enrolled in this retrospective study. All patients underwent total thyroidectomy and 2-4 weeks of low iodine diet (LID) before initial 131I therapy. Patients were divided into 3 groups according to urinary iodine excretion (UIE): moderate-severe iodine deficiency group (0<UIE<50 μg/L, n=30), mild iodine deficiency group (50 μg/L≤UIE<100 μg/L, n=26), adequate iodine group (100 μg/L≤UIE<300 μg/L, n=39). Patients were followed up for 3-6 months after radioiodine ablation, successful ablation was defined as no visible uptake in the thyroid bed on diagnostic 131I whole body scan and Tg level <2 μg/L (with negative TgAb), or no visible uptake in thyroid bed on posttreatment 131I whole body scan. χ2 test, two-sample t test, Mann-Whitney u test and logistic regression analysis were performed. Results In all, 84.2%(80/95)of patients were successfully ablated. The successful rates in the three iodine intake groups were 96.7%(29/30), 84.6%(22/26) and 74.4%(29/39), respectively, with significant difference (χ2=7.374, P<0.05). Univariate analysis revealed that UIE, pre-treatment TSH, pre-treatment Tg and the amount of remnant thyroid tissue at ablation affected ablation efficacy (χ2=7.374, t=2.037, z=-2.966, χ2=4.144, all P<0.05). Logistic regression showed that the level of pre-treatment Tg (P<0.05) and iodine intake (P<0.05) were independent factors of ablation efficacy. Conclusion Iodine intake before 131I remnant ablation is one of the important factors affecting treatment outcomes. Thyroid remnant could be more successfully ablated if reasonable LID protocols be adopted according to the iodine nutritional status before treatment. Key words: Thyroid neoplasms; Surgery, operative; Radiotherapy; Iodine radioisotopes

Role of Recombinant Human Thyrotropin (rhTSH) in the Treatment of Well-Differentiated Thyroid Cancer

Since the introduction of radioiodine (RAI) for treatment of well-differentiated thyroid cancer (DTC) more than 50years ago, prolonged periods of hypothyroidism were routinely used as part of the treatment regimen. Recombinant human TSH (rhTSH) was introduced in the 1990s as a tool to elevate the serum TSH without the need for thyroid hormone withdrawal and symptomatic hypothyroidism. After being initially approved as a diagnostic tool for use in RAI scanning and stimulated thyroglobulin testing, rhTSH was approved as an adjunct to RAI remnant ablation in patients without distant metastases in Europe in 2005 and in the US in 2007. Following successful use of rhTSH for diagnostic purposes, it has been extensively studied for use with therapeutic doses of RAI in the setting of RAI remnant ablation and is now an integral part of DCT therapy. The use of rhTSH in clinical practice in the last decade was coupled with the growing interest in an individualized, risk-stratified approach to the management of patients with DCT. While traditional treatment for DTC included surgery and RAI therapy for all patients, many more recent studies demonstrated the value of selective use of RAI only in patients who will probably benefit from treatment. This manuscript reviews the evolving role of rhTSH in the current risk adapted climate of thyroid cancer management with particular emphasis on the use of rhTSH as an aid to RAI therapy.

Radiation doses to cohabitants of patients undergoing radioiodine ablation for thyroid cancer

The drive to reduce hospital stay after radioiodine remnant ablation in patients with thyroid cancer may increase the risk of radiation exposure to family members. The aim of this study was to evaluate the key determinants of dose exposure to familial members, with particular reference to the degree of adherence to current radiation safety guidelines. All participants prospectively received our standard departmental oral and written safety instructions, with a mandatory 3-day restriction period. The postmicturition radiation levels of treated patients were measured (at 1-m distance) at the time of discharge using a portable radiometer. The radiation exposure of cohabitants was assessed with an optically stimulated luminescence-based personal dosimeter during the 3 days after hospital discharge. A questionnaire was used to assess the adherence of relatives/cohabitants to radiation safety guidelines. A total of 38 patients with thyroid cancer and 48 household members were included. At 48 h post therapy, the patient's median emission at 1-m distance was 13.4 μSv/h. The mean cumulative cohabitant exposure was 102 μSv (<50-1000). A positive correlation between cohabitant radiation exposure and the radiation level of the patient was observed (P=0.016). This correlation was absent when the recommended guidelines were followed (P=0.56). Only 17 household members (35.4%) strictly followed the recommended guidelines, but dose exposures exceeded 0.3 mSv in only four cases, in which a mean of between 5.8 and 9.5 h were spent in close proximity to the patient in the first 3 days, including sleeping with treated patients in half of the cases. Despite poor compliance with safety guidelines, a short-stay protocol respects current legislation, and is applicable to most patients treated with 3.7 GBq for radioiodine remnant ablation.

Perspective: The Case Against Radioiodine Remnant Ablation in Patients with Well-Differentiated Thyroid Carcinoma

We take issue with the stance that postoperative radioiodine remnant ablation should be applied ubiquitously as adjuvant therapy in patients with well-differentiated thyroid carcinoma. In this article, we state the reasons that we believe a compelling case can be made against ablation in most patients.