Received Radioactive Iodine Treatment Research Articles

Comparison of Radioactive Iodine Activities in Terms of Short- and Long-term Results in Ablation Therapy in Patients with Low-risk Differentiated Thyroid Cancer.

The aim of this study was to compare the treatment responses after ablation with 30-50 mCi radioactive iodine (RAI) and 100 mCi RAI in patients with differentiated thyroid cancer (DTC) who were in the low-risk group according to 2015 American Thyroid Associations Classification (ATA 2015) criteria. Between February 2016 and August 2018, 100 patients who received RAI treatment in our clinic after total thyroidectomy and who were in the low-risk group DTC were included in this retrospective study. These patients were divided into 2 groups: low-activity (30-50 mCi) (group 1) and high-activity (100 mCi) (group 2). While 54 patients were treated with low activity, 46 patients received high activity RAI. The 2 groups were compared according to the 1st- and 3rd-year treatment response status. According to the first-year follow-up, 15 patients were accepted as indeterminate response and 85 patients as excellent response. Three (5.5%) of the patients who were accepted as indeterminate response were in group 1 and 12 (26%) were in group 2. According to the third year follow-up, 1 patient in group 1 and 3 patients in group 2 were accepted as indeterminate response. No biochemical incomplete response or recurrent disease was detected. In the chi-square analysis performed to investigate the relationship between the first-year treatment response and RAI activities, a significant relationship was found (p=0.004). In the Mann-Whitney U test performed to investigate the parameters that may be effective in the treatment response, only the preablative serum thyroglobulin value was shown to have a significant difference between the two groups (p=0.01). In the long-term follow-up of the patients, based on the third year treatment response data, chi-square analysis was performed to evaluate the two groups in terms of treatment responses, and no statistically significant relationship was found (p=0.73). Ablation with 30-50 mCi can be safely applied in DTC patients who are in the ATA 2015 low-risk group and are planned for RAI ablation treatment.

Predictors of Hypothyroidism Following Empirical Dose Radioiodine in Toxic Thyroid Nodules: Real-Life Experience

ObjectiveWe aimed to determine the factors predicting hypothyroidism after radioactive iodine (RAI) treatment in patients with toxic adenoma and toxic multinodular goiter. MethodsWe retrospectively collected the data of 237 patients with toxic multinodular goiter or toxic adenoma who had consecutively received RAI treatment between 2014 and 2020 at 2 medical centers. Patients who received the second RAI treatment and whose medical records could not be accessed were excluded from the study. Finally, 133 patients were included in the study. RAI was administered at an empirical dose of 15 or 20 mCi. ResultsThe median age of the 133 participants was 69 years (interquartile range, 62-75 years), and 64.7% of the participants were women. A total of 42.1% of the patients had toxic adenoma, whereas 57.9% of patients had toxic multinodular goiter. The median follow-up was 24 months (interquartile range, 11-38 months). During the follow-up, 61.7% of patients became euthyroid, 30.8% developed hypothyroidism, and 7.5% remained hyperthyroid. The median month of hypothyroidism onset was 4 months (interquartile range, 2-9 months). Regression analysis revealed 2 factors that could predict hypothyroidism: thyroid-stimulating hormone (odds ratio, 2.548; 95% CI, 1.042-6.231; P = .04) and thyroid volume (odds ratio, 0.930; 95% CI, 0.885-0.978; P = .005). ConclusionOverall, 30.8% of the cases developed hypothyroidism after the RAI treatment. Approximately 78% of hypothyroidism developed within the first 10 months. The risk of hypothyroidism was higher in patients with higher thyroid-stimulating hormone and smaller thyroid volume.

Surgical Risk Prediction for Nasolacrimal Duct Obstruction in Radioactive Iodine-Treated Thyroid Cancer: A Nationwide Cohort Study.

Background: To estimate the incident risk of surgical intervention for nasolacrimal duct obstruction after radioactive iodine (RAI) treatment and elucidate the high-risk group of patients with thyroid cancer (TC). Methods: This is a nationwide, population-based cohort study using data from the Korean National Health Claims database. Among the entire South Korean population aged between 20 and 80 years from 2007 to 2019, all patients with TC were included. Among all TC patients, a cohort was established by classifying it into the RAI and non-RAI groups according to whether RAI treatment was performed during the recruitment period. A log-rank analysis was used to evaluate the risk of nasolacrimal duct obstruction surgery in the RAI group compared with that in the non-RAI group. The Cox proportional hazards regression analysis was performed to calculate the adjusted hazard ratio (HR). The analysis was performed stratified by the age group, sex, frequency of RAI treatment, and cumulative dose of 131I. Results: Among 55,371 TC patients, who received RAI treatment, 515 (0.93%) underwent nasolacrimal duct obstruction surgeries, and among 56,950 TC patients, who did not receive RAI treatment, 72 (0.13%) underwent the surgeries. The average timing of incident nasolacrimal duct obstruction surgery was 3.8 ± 2.1 years after the first exposure to RAI. The incidence rate of nasolacrimal duct obstruction surgery was 104.04/100,000 person-years in the RAI group. There was a significantly higher risk of nasolacrimal duct obstruction surgery (HR 7.50 [confidence interval, CI: 5.86-9.60], p < 0.001) in the RAI group than in the non-RAI group. The risks significantly increased in the high-dose group (HR 14.15 [CI: 10.88-18.39]) and those younger than 50 years (HR 15.54 [CI: 9.76-24.72]). Conclusion: We quantified the risk of RAI-induced nasolacrimal duct obstruction surgery through a long-term follow-up of 9 years, which may contribute to estimating the general health care burden related to RAI treatment for TC patients in a practical setting. Great attention should be paid to its risk in patients younger than 50 years, especially in those treated with high doses.

The Effect of Radioactive Iodine Therapy on Ovarian Function and Fertility in Female Thyroid Cancer Patients: A Systematic Review and Meta-Analysis.

Introduction: Thyroid cancer is one of the most common carcinomas diagnosed in adolescents and young adults, with a rapidly rising incidence for the past three decades. Surgery is the standard treatment for patients with differentiated thyroid carcinoma (DTC), and when indicated, followed by radioactive iodine (RAI) treatment. The aim of this study was to evaluate the possible effects of RAI therapy on ovarian function and fertility in women. Methods: The PubMed, Embase, and Web of Science databases were systematically searched up to January 2020. In addition, a meta-analyses were performed for anti-Mullerian hormone (AMH) levels after RAI, comparison of AMH levels prior and 1 year after RAI, and pregnancy rates in patient with thyroid cancer receiving RAI compared with patients with thyroid cancer who did not receive RAI. Results: A total of 36 studies were eligible for full-text screening and 22 studies were included. The majority of the studies had a retrospective design. Menstrual irregularities were present in the first year after RAI in 12% and up to 31% of the patients. Approximately 8-16% of the patients experienced amenorrhea in the first year after RAI. Women who received RAI treatment (median dose 3700 MBq [range 1110-40,700 MBq]); had menopause at a slightly younger age compared with women who did not receive RAI treatment, 49.5 and 51 years, respectively (p < 0.001). Pooled AMH of the seven studies reporting AMH concentrations after RAI was 1.79 ng/mL. Of these, four studies reported AMH concentrations prior and 1 year after RAI. The mean difference was 1.50 ng/mL, which was significant. Finally, meta-analysis showed that patients undergoing RAI were not at a decreased risk of becoming pregnant. Conclusions: Most of the studies indicate that RAI therapy for DTC is not associated with a long-term decrease in pregnancy rates although meta-analyses show a significant decrease in AMH levels after RAI therapy. Prospective studies are needed to confirm these results. We recommend counseling patients about the possible effects of 131I and incorporate today's knowledge in multidisciplinary counseling.

Effects of radioactive iodine treatment on cardiovascular disease in thyroid cancer patients: a nationwide cohort study.

BackgroundRadioactive iodine (RAI) treatment is a standard treatment in differentiated thyroid cancer (TC). However, its adverse effects on cardiovascular diseases (CVDs) have not been clearly elucidated.MethodsIn this retrospective cohort study based on the Korean National Health Insurance Service-National Health Screening Cohort (2002–2015), we analyzed 4,845 patients with TC with a median follow-up of 66 months. We evaluated and compared the risk of CVD between patients treated with and without RAI therapy. The primary CVD outcome was defined as a composite of ischemic stroke (IS), ischemic heart disease (IHD), hemorrhagic stroke (HS), or heart failure (HF).ResultsOverall, 2,533 patients (52.3%) received RAI treatment with a median cumulative dosage of 103 mCi [interquartile range (IQR), 40–162 mCi]. The incidence of the primary CVD outcome in patients who did not receive RAI therapy and those who did was 17.32 [95% confidence interval (CI), 15.07–19.90] and 13.96 (95% CI, 12.17–16.01) per 1,000 person-years, respectively, indicating an adjusted hazard ratio (HR) of 0.87 (95% CI, 0.71–1.07) after multivariate adjustments for variable confounding factors. The risks of IS (HR, 0.83; 95% CI, 0.51–1.34), IHD (HR, 0.90; 95% CI, 0.71–1.13), HS (HR 1.01; 95% CI, 0.49–2.09), and HF (HR 0.89; 95% CI, 0.49–1.63) were comparable between the patients who received RAI therapy and those who did not. There was no cumulative dose-dependent risk for CVD in TC patients who received RAI treatment.ConclusionsRAI treatment is a prevalent and crucial treatment for TC, and has been used in more than half of TC patients in Korea from 2004 to 2015. This study found no significant between-group difference for the CVD risk in patients with TC who received RAI treatment and those who did not, giving further evidence to allay concerns related to the adverse effects of RAI.

Short-term bone marrow suppression in differentiated thyroid cancer patients after radioactive iodine treatment.

After thyroidectomy in differentiated thyroid cancer (DTC), radioactive iodine (RAI) treatment is often used for remnant ablation. However, RAI treatment has been associated with bone marrow suppression, and leukopenia, anemia, and thrombocytopenia may occur after a single RAI administration. In this study, we examined the change in complete blood counts at 1 week after RAI administration; this is less well studied. A group of 189 DTC patients who received RAI treatment and underwent blood tests before and after treatment, were included. Peripheral blood counts at baseline were compared to those obtained at 1 week, 1-6 months, and 6-12 months after RAI treatment in order to test for bone marrow suppression. At 1 week after RAI treatment, there was a significant decrease in the white blood cell count (WBC, 5.8 ± 1.6 × 109/L vs. 5.4 ± 1.5 × 109/L, p < 0.001) and hemoglobin level (Hb, 13.5 ± 1.7 g/dL vs. 13.3 ± 1.4 g/dL, p = 0.001). The WBC decrease was mostly due to lymphocyte counts (2.2 ± 0.6 × 109/L vs. 1.6 ± 0.5 × 109/L, p < 0.001), with no decrease in the neutrophil count. Although not significantly changed at 1 week, platelets counts were altered within 6 months (265 ± 69 × 109/L vs. 239 ± 53 × 109/L, p < 0.001). The decline in the WBC count recovered within 6 months; lymphocyte and platelet counts recovered within 12 months. In conclusion, RAI treatment after a thyroidectomy was associated with a statistically significant but temporary decline in WBC counts and Hb levels at 1 week. Physicians treating DTC patients should not decrease usage of moderate dose RAI treatments.

Changes in the pulmonary function test after radioactive iodine treatment in patients with pulmonary metastases of differentiated thyroid cancer.

ObjectivePulmonary function test (PFT) is a useful tool for an objective assessment of respiratory function. Impaired pulmonary function is critical for the survival and quality of life in patients with pulmonary metastases of solid cancers including thyroid cancer. This study aimed to evaluate clinical factors associated with severely impaired pulmonary function by serial assessment with PFT in patients with pulmonary metastasis of differentiated thyroid cancer (DTC) who received radioactive iodine treatment (RAIT).PatientsThis retrospective study enrolled 31 patients who underwent serial PFTs before and after RAIT for pulmonary metastasis of DTC. We evaluated the risk factors for severe impairment of pulmonary function.ResultsThe median age of the patients was 44.1 years and 18 of them were female patients. Severe impairment of pulmonary function was observed in five patients (16%) after a median of three RAITs (cumulative I-131 activity = 20.4 GBq). These patients were older and more frequently had mild impairment of baseline pulmonary function, respiratory symptoms, or progressive disease compared with patients with stable pulmonary function. Neither cumulative dose nor number of RAIT was associated with decreased pulmonary function. Coexisting pulmonary diseases, presence of respiratory symptoms, and metastatic disease progression were significantly associated with severe decrease in forced vital capacity during follow-up (p =.047, p =.011, and p =.021, respectively).ConclusionsPulmonary function was severely impaired during follow-up in some patients with pulmonary metastasis of DTC after a high-dose RAITs. Neither the number of RAIT nor the cumulative I-131 activity was associated with decreased pulmonary function. Serial PFT might be considered for some high-risk patients during follow-up.

Radioactive iodine ablation does not prevent recurrences in patients with papillary thyroid microcarcinoma

Although papillary thyroid microcarcinoma (PTMC) has a favourable long-term prognosis, disease recurrence after initial treatment remains a problem and controversy exists regarding the role of radioactive iodine (RAI) ablation in PTMC. We performed this study to evaluate the effect of RAI ablation on disease recurrence in patients with PTMC. Between 1994 and 2004, 2579 patients underwent thyroid surgery for thyroid cancer at Samsung Medical Center. Among these patients, 704 patients with PTMC presumed disease-free after initial treatment were followed up for disease recurrence (median, 64 months; range, 1-185 months). Patients with PTMC with microscopic extrathyroidal extension, cervical lymph node metastases or multifocality were considered to be in the intermediate-risk group for recurrence. Disease recurrence was found in six patients at a median of 29 months (range, 10-70 months) after initial treatment; all six patients with recurrent tumours had received RAI treatment after total thyroidectomy. Disease-related mortality was not observed, even after recurrence. Based on a Cox regression model considering the standardized inverse probability of treatment weight (IPTW) within each propensity score stratum of patients with a similar likelihood of having received RAI ablation, the likelihood ratio for recurrence did not differ between the RAI ablation group and no RAI group (P = 0·17). When we performed a subgroup analysis considering only patients with PTMC at intermediate-risk for recurrence, RAI ablation again did not have a significant effect on recurrence (P = 0·79). Radioactive iodine ablation after total thyroidectomy in low- and intermediate-risk patients with PTMC did not prevent recurrent tumours. Future randomized, controlled, multicenter prospective trials involving a larger sample of patients followed-up for a longer duration are warranted to confirm our findings.

Evidence for Higher Success Rates and Successful Treatment Earlier in Graves' Disease with Higher Radioactive Iodine Doses

Graves' disease is commonly treated with curative intent using radioactive iodine (RAI). While higher doses have been shown to increase success rates, more evidence is needed. Further, very few studies assess the time to treatment success without the need for antithyroid drugs after a single dose of RAI within the first year post-dose, despite earlier success being an important treatment objective. We aimed to evaluate the outcome of different RAI doses in terms of success rates and time to achieve this success (eu- or hypothyroidism). We hypothesized that higher doses would not only increase success rates, but bring about successful treatment earlier.We retrospectively analyzed the medical records of all patients diagnosed with Graves' disease between 1994 and 2009. Details of RAI treatment and outcomes thereof were documented. In our analysis, we divided the patients who received RAI treatment into three groups according to the dose received: I (≤15 mCi); II (16-20 mCi); III (≥21 mCi).There were 498 patients diagnosed with Graves' disease. However, 105 were either lost to follow-up or still undergoing treatment. Of the remaining 393, there were 258 who received RAI treatment. The average initial dose was 21.42±6.5 mCi and overall success rate was 86%. Success rates were 74%, 85%, and 89% (p<0.05), while average time to successful treatment was 8.1, 4.6, and 2.9 months, respectively (p<0.001), for groups I, II, and III. When 20 mCi was given empirically, 85% obtained successful treatment; most of these within 3 months (mean 3.9; mode and median 3 months).This study provides additional evidence that success post-treatment correlates with administered dose and shows clearly, for the first time, that successful treatment is achieved earlier with higher doses. This knowledge is relevant to all clinicians managing Graves' disease as it can be taken into consideration when discussing treatment plans with patients.

The Impact of Thyroid Cancer and Post-Surgical Radioactive Iodine Treatment on the Lives of Thyroid Cancer Survivors: A Qualitative Study

BackgroundAdjuvant treatment with radioactive iodine (RAI) is often considered in the treatment of well-differentiated thyroid carcinoma (WDTC). We explored the recollections of thyroid cancer survivors on the diagnosis of WDTC, adjuvant radioactive iodine (RAI) treatment, and decision-making related to RAI treatment. Participants provided recommendations for healthcare providers on counseling future patients on adjuvant RAI treatment.MethodsWe conducted three focus group sessions, including WDTC survivors recruited from two Canadian academic hospitals. Participants had a prior history of WDTC that was completely resected at primary surgery and had been offered adjuvant RAI treatment. Open-ended questions were used to generate discussion in the groups. Saturation of major themes was achieved among the groups.FindingsThere were 16 participants in the study, twelve of whom were women (75%). All but one participant had received RAI treatment (94%). Participants reported that a thyroid cancer diagnosis was life-changing, resulting in feelings of fear and uncertainty. Some participants felt dismissed as not having a serious disease. Some participants reported receiving conflicting messages from healthcare providers on the appropriateness of adjuvant RAI treatment or insufficient information. If RAI-related side effects occurred, their presence was not legitimized by some healthcare providers.ConclusionsThe diagnosis and treatment of thyroid cancer significantly impacts the lives of survivors. Fear and uncertainty related to a cancer diagnosis, feelings of the diagnosis being dismissed as not serious, conflicting messages about adjuvant RAI treatment, and treatment-related side effects, have been raised as important concerns by thyroid cancer survivors.

Cost Savings of Patients With a MACIS Score Lower Than 6 When Radioactive Iodine Is Not Given

To assess the cost savings if the current policy of treating patients with a MACIS (metastases, age, completeness of resection, invasion, and size) score lower than 6 using radioactive iodine (RAI) was changed to reflect the findings of recent studies. Retrospective medical record review. Mount Sinai Hospital, Toronto, Ontario. Between January 1, 2002, and July 1, 2005, 199 consecutive patients with a MACIS score lower than 6 who received RAI treatment after total thyroidectomy. Patient demographics were analyzed. Costs for the dose of RAI, hospital stay, and health insurance claims were included in the calculations. For 199 consecutive patients, the cost for sodium iodide 131 treatment totaled Can$161 588, and the required 2-day stay in isolation totaled Can$764 558. The overall cost to the health care system was Can$934 106, which translates into approximately Can$4694 per patient. By following the recommendations of recent evidence-based studies and by ceasing to treat patients with a MACIS score lower than 6 after total thyroidectomy using RAI, cost savings can be accrued for health care systems involved in the treatment of thyroid cancer. Alternate strategies, such as treating patients who need RAI therapy on an outpatient basis and reducing the dose of RAI, can lower costs as well.

Is it useful to routinely biopsy hot nodules in iodine deficient areas?

Incidence of nodular thyroid disease as well as that of functioning thyroid nodules (FTN) increases dramatically in iodine deficient (ID) areas. Cancer is extremely rare in FTN; thus, some do not routinely biopsy and treat them with radioactive iodine (RAI) straight away or follow-up. The outcome of 296 patients followed or treated at our institution for solitary or multiple FTN were retrospectively evaluated. Hospital records of 224 female, 72 male patients, with a mean +/- SD age of 54.9 +/- 12.4 yr and followed for 22 (0-156) months were examined. 175 patients had solitary, 121 had multiple hot or warm nodules. 230 (77.7%) of the patients received RAI treatment. 402 fine needle aspiration biopsies (FNABs) were performed on 260 patients and on 343 FTN (381 benign and 21 suspicious diagnoses). Eleven of the patients were operated for suspicious FNAB results and 10 were followed-up. Only one nodule turned out to be malignant. Malignancy is extremely rare in functioning thyroid nodules (0.34%) and some of malignant cases could be predicted by their suspicious clinical features. Routine practice of treating FTN with RAI therapy is reasonable in clinically low-risk patients. FNAB is reserved for cases with suspicious clinical features, resulting in fewer surgeries and reduced cost.