In properly selected patients with differentiated thyroid cancer, antithyroglobulin antibodies decline after thyroidectomy and their sole presence should not be an indication for radioiodine ablation

ABSTRACT Objective Our objective was to evaluate the trend of antithyroglobulin antibodies (TgAb) during follow-up of patients with differentiated thyroid cancer (DTC) treated without RAI, as well as their role in the risk of recurrence. Subjects and methods This was a prospective, descriptive study. A total of 152 consecutive patients with DTC treated in a single institution undergoing total thyroidectomy without RAI and followed for a median of 2.3 years (0.5-10.3) were divided in two groups: TgAb(-) (n = 111) and TgAb(+) (n = 41). Patients were classified according to AJCC 7th and 8th editions, as well as to their risk of recurrence and response to treatment categories. Results Both groups, TgAb(-) and TgAb(+), were similar regarding patient and tumor characteristics. At the end of follow-up, 90 (59.2%), 57 (37.5%), 3 (2%) and 2 (1.3%) patients achieved excellent, indeterminate, biochemically incomplete and structurally incomplete response, respectively. The risk of structural recurrence was similar in both groups (TgAb[-] 0.9% vs. TgAb[+] 2.4%, p = 0.46). In the TgAb(+) group, TgAb became negative in 10 (24.4%), decreased ≥ 50% without negativization in 25 (60.9%), decreased < 50% in 4 (9.8%) and remained stable or increased in 2 (4.9%) cases. The only incomplete structural response had increasing TgAb during follow-up. Conclusions In properly selected patients with DTC, TgAb concentration immediately after total thyroidectomy should not mandate RAI ablation, and their trend during follow-up may impact the risk of recurrence.

Clinical outcomes of low and intermediate risk differentiated thyroid cancer patients treated with 30mCi for ablation or without radioactive iodine therapy

ABSTRACT Objective To retrospectively evaluate the outcomes of patients with low and intermediate risk thyroid carcinoma treated with total thyroidectomy (TT) and who did not undergo radioiodine remnant ablation (RRA) and to compare them to patients receiving low dose of iodine (30 mCi). Subjects and methods A total of 189 differentiated thyroid cancer (DTC) patients treated with TT followed by 30mCi for RRA or not, followed in two referral centers in Brazil were analyzed. Results From the 189 patients, 68.8% was ATA low-risk, 30.6% intermediate and 0.6% high risk. Eighty-seven patients underwent RRA and 102 did not. The RRA groups tended to be younger and had a higher frequency of extra-thyroidal extension (ETE). RRA did not have and impact on response to initial therapy neither in low (p = 0.24) nor in intermediate risk patients (p = 0.66). It also had no impact on final outcome and most patients had no evidence of disease (NED) at final follow-up. Recurrence/persistence of disease was found in 1.2% of RRA group and 2% in patients treated only with TT (p = 0.59). Conclusions Our study shows that in low and intermediate-risk patients, RRA with 30 mCi seems to have no major advantage over patients who did not undergo RRA regarding response to initial therapy in each risk group and also in long term outcomes.

Relationship between serum lipid profile and thyroid function after thyroid hormone withdrawal in patients with differentiated thyroid carcinoma / 中华内分泌代谢杂志

Objective To observe the relationship between serum lipid concentration profiles and thyroid function after thyroid hormone withdrawal( THW) in patients with differentiated thyroid carcinoma( DTC) .Methods Sixty-five post-operative DTC patients who prepared to receive radioiodine ablation were included in this study.Serum thyroid hormones ( TSH, FT4 , FT3 ) and lipid profile [ total cholesterol ( TC ) , triglycerides ( TG ) , low-density lipoprotein-cholesterol(LDL-C), and high-density lipoprotein-cholesterol(HDL-C)] levels were measured before and 3 weeks after THW.The relationship between serum lipid profile concentrations and thyroid hormone levels were measured.Results Before surgery, HDL-C level showed a significant positive correlation with TSH level(r=0.273, P=0.041), whereas other lipid profile did not show any significant correlation with thyroid hormones levels.Before THW, no correlation was observed between thyroid hormones and lipid profile.After 3 weeks′THW, the TC level was correlated with FT4 and FT3 levels(r were-0.321 and-0.415, respectively, both P0.05).Conclusion The serum lipid profile varies with the change of serum thyroid hormones after THW in postoperative DTC patients.

Effect of a Low Iodine Diet vs. Restricted Iodine Diet on Postsurgical Preparation for Radioiodine Ablation Therapy in Thyroid Carcinoma Patients

PURPOSE: The radioiodine ablation therapy is required for patients who underwent a total thyroidectomy. Through a comparative review of a low iodine diet (LID) and a restricted iodine diet (RID), the study aims to suggest guidelines that are suitable for the conditions of Korea. MATERIALS AND METHODS: The study was conducted with 101 patients. With 24-hour urine samples from the patients after a 2-week restricted diet and after a 4-week restricted diet, the amount of iodine in the urine was estimated. The consumed radioiodine amounts for 2 hours and 24 hours were calculated. RESULTS: This study was conducted with 47 LID patients and 54 RID patients. The amounts of iodine in urine, the 2-week case and 4-week case for each group showed no significant differences. The amounts of iodine in urine between the two groups were both included in the range of the criteria for radioiodine ablation therapy. Also, 2 hours and 24 hours radioiodine consumption measured after 4-week restrictive diet did not show statistical differences between two groups. CONCLUSION: A 2-week RID can be considered as a type of radioiodine ablation therapy after patients undergo a total thyroidectomy.

Are Medical Personnel Safe from Radiation Exposure from Patient Receiving Radioiodine Ablation Therapy? / 핵의학분자영상

Radioiodine ablation therapy has been considered to be a standard treatment for patient with differentiated thyroid cancer after total thyroidectomy. Patients may need to be hospitalized to reduce radiation exposure of other people and relatives from radioactive patients receiving radioiodine therapy. Medical staffs, nursing staffs and technologists sometimes hesitate to contact patients in radioiodine therapy ward. The purpose of this paper is to introduce radiation dosimetry, estimate radiation dose from patients and emphasize the safety of radiation exposure from patients treated with high dose radioiodine in therapy ward. The major component of radiation dose from patient is external exposure. However external radiation dose from these patients treated with typical therapeutic dose of 4 to 8 GBq have a very low risk of cancer induction compared with other various risks occurring in daily life. The typical annual radiation dose without shielding received by patient is estimated to be 5 to 10 mSv, which is comparable with 100 to 200 times effective dose received by chest PA examination. Therefore, when we should keep in mind the general principle of radiation protection, the risks of radiation exposure from patients are low and the medical personnel are considered to be safe from radiation exposure.