Thyroid Remnant Ablation Research Articles

Outcome of radioiodine therapy in patients with papillary thyroid carcinoma concurrent with Hashimoto′s thyroiditis

Objective To evaluate the impact of low-dose 131I therapy and high-dose 131I therapy on the clinical outcome in PTC patients coexisting with Hashimoto′s thyroiditis (HT). Methods A total of 140 non-distant metastatic PTC patients (16 males, 124 females, age range: 16-66 years) from July 2010 to December 2014 were enrolled in this retrospective study. Patients concurrent with HT (n=84, group A) were divided into low-dose group (1 110 MBq, n=56, group A1) and high-dose group (5 550 MBq, n=28, group A2) according to 131I ablation dose. Patients without HT (n=56) were enrolled as control group (group B), and received 1 110 MBq of 131I. The thyroid remnant ablation outcome was evaluated according to 131I diagnostic whole-body scan (Dx-WBS), neck ultrasonography (US), serum Tg and TgAb level 6-8 months after 131I ablation therapy. The successful ablation rates were compared by χ2 test. Kruskal-Wallis rank sum test was also used. Results There were no significant differences among the 3 groups in terms of both clinicopathological features and postoperative remnant thyroid (H: 0.203-2.944, χ2: 0.271-0.970, all P>0.05). When negative Dx-WBS and US were deemed as successful ablation criterion, complete ablation rate was found significantly more in group B (94.6%, 53/56) than that in group A1 (82.1%, 46/56; χ2=4.264, P 0.05). When combining negative sTg (sTg 0.05), and no difference was observed between group A2 (12/15) and group A1 (χ2=1.320, P>0.05). Conclusion Non-distant metastatic PTC patients coexisting with HT has undesirable 131I ablation outcome compared with those without HT, increasing 131I dose is unhelpful to enhance efficiency of remnant ablation for PTC patients with HT. Key words: Thyroid neoplasms; Hashimoto disease; Radiotherapy; Iodine radioisotopes; Treatment outcome

Iodine-131: An Effective Method for Treating Lymph Node Metastases of Differentiated Thyroid Cancer.

BackgroundThe aim of this study was to assess the efficacy of radioactive iodine-131 (131I) therapy for lymph node metastasis of differentiated thyroid cancer (DTC) and to identify influential factors using univariate and multivariate analyses to determine if identified factors influence the efficacy of treatment.Material/MethodsThis study included a retrospective review of 218 patients with histologically proven DTC in the post-operation stage. After thyroid tissue remnants were eliminated with 131I therapy, patients’ lymph node status was confirmed by ultrasound and by 131I whole body scan regarding lymph node metastasis, and then patients were treated with 131I as appropriate. The treatment efficacy was assessed and possible influencing factors were identified using univariate and multivariate analyses.ResultsThe total effective rate of 131I therapy was 88.07% (including a cure rate of 20.64% and an improvement rate of 67.43%). The non-effective rate was 11.93%. Of the total 406 lymph nodes of 218 patients, 319 lymph nodes (78.57%) were judged to be effectively cured, including 133 (32.75%) lymph nodes that were totally eliminated and 186 (45.82%) lymph nodes that shrank. Eighty-seven (21.43%) of the 406 lymph nodes had no obvious change. No lymph nodes were found to be in a continuously enlarging state. Distant metastasis, size of lymph node, human serum thyroglobulin (HTG) level, and condition of thyroid remnants ablation were identified as the independent factors influencing the efficacy of treatment using univariate and multivariate analyses.ConclusionsThe use of 131I is a promising treatment for lymph node metastasis of DCT. Distant metastasis, size of lymph nodes, HTG level, and condition of thyroid remnant ablation were independent factors influencing the treatment efficacy.

Application of ultrasensitive thyroglobulin assays in the follow-up of differentiated thyroid carcinoma

DTC is the most common endocrine carcinoma and its routine treatment consists of total thyroidectomy and 131I thyroid remnant ablation. Currently, standard follow-up for DTC comprises Tg measurement and neck ultrasound as well as an additional radioiodine scan when indicated. As thyroid cells are assumed to be the only source of Tg in serum, circulating Tg serves as an excellent marker of persistent or recurrent disease in DTC follow-up. With the development of highly sensitive Tg assays, now it is possible to detect very low Tg concentrations which reflect minimal amounts of thyroid tissue without the need for TSH stimulation. This review is to introduce clinical implications of highly sensitive Tg assays. Key words: Thyroid neoplasms; Thyroglobulin; Trends

Low- and high-dose radioiodine therapy for low-/intermediate-risk differentiated thyroid cancer: a preliminary clinical trial.

To compare the ablation results, therapeutic responses and adverse reactions between a low dose (1.1GBq) or high dose (3.7GBq) of 131I in low-/intermediate-risk differentiated thyroid cancer (DTC) patients. The factors influencing the ablation result and therapeutic response were also analyzed. The researchers used a random number table to randomly assign the enrolled patients to the low-dose group or high-dose group at a 1:1 ratio, and assessment of ablation result, therapeutic response, and adverse reactionsevaluated6±3months after therapy. A total of 140 patients were enrolled in the study through October 2014-June 2015. Until February 2016, 132 patients completed the trial. 99 patients were re-examined under thyroid-stimulating hormone (TSH) stimulation 3-9months after 131I therapy. For the low-dose and high-dose groups, the success rates of ablation were 52.7% (29/55) and 59.1% (26/44), respectively. The ablation results did not differ significantly between the two groups (P=0.548). One hundred and thirty two patients were re-examined 2-9months after 131I therapy. The low-dose group had an excellent response rate of~80% (53/66), an indeterminate response rate of~20% (13/66), and no cases with a biochemical incomplete response. The high-dose group had an excellent response rate of~85% (56/66), an indeterminate response rate of~11% (7/66), and a biochemical incomplete response rate of~4% (3/66). No significant differences in the therapeutic response were observed between the two groups (P=0.087). Patients in stage N1b had a significantly lower success rate of ablation than those in stage N0 (P=0.000). The success rate of ablation increased significantly with lower thyroglobulin (Tg) levels (P=0.000). A pre-treatment Tg level was significantly associated with a higher excellent response rate (P=0.002). Pre-treatment-stimulated Tg of 0.47 and 3.09μg/L were identified as cut-off values for predicting the ablation result and therapeutic response, respectively. The incidences of adverse reactions were 18% (12/66) and 39% (26/66) in the low-dose and high-dose groups, respectively, and this difference between the two groups was significant (P=0.007). The result of thyroid remnant ablation and the response to therapy did not differ significantly between the two groups. The low-dose group had a lower incidence of adverse reactions than the high-dose group. N1b and pre-treatment-stimulated Tg were factors influencing the ablation result, whereas pre-treatment-stimulated Tg was a factor influencing the therapeutic response. Pre-treatment-stimulated Tg of 0.47 and 3.09μg/L were identified as cut-off values for predicting the ablation result and therapeutic response, respectively. The study protocol was approved by the Clinical Trials and Biomedical Ethics Committee of our hospital and registered on the Chinese Clinical Trial Registry under the registration number ChiCTR-IOR-15006139.

Differentiated thyroid carcinoma: Incremental diagnostic value of 131I SPECT/CT over planar whole body scan after radioiodine therapy.

The purpose of this prospective study was to determine the incremental diagnostic value of single photon emission computed tomography/computed tomography with iodine-131 over planar whole body scan in the staging of patients with differentiated thyroid carcinoma. A total of 365 patients (270 female, 95 male) with differentiated thyroid carcinoma were treated with radioiodine therapy for thyroid remnant ablation with radical intent after thyroidectomy between January 2013 and November 2014. In addition to planar whole body scan, single photon emission computed tomography/computed tomography of neck and chest were performed. Each radioactive focus at whole body scan was classified as positive or equivocal with respect of specific territories: thyroid bed, cervical lymph nodes and distant metastases.Whole-body scan detected focal uptake in 353 patients and no uptake in 12. The location was considered equivocal in 100. Single photon emission computed tomography/computed tomography detected focal uptake in 356 patients and no uptake in nine. In three patients with negative wholebody scan, single photon emission computed tomography/computed tomography provided information about residual activity in the thyroid bed. By single photon emission computed tomography/computed tomography the location was equivocal in 18 patients only. Single photon emission computed tomography/computed tomography was helpful in 82 out of 100 patients with equivocal findings by whole body scan allowing a correct identification of the uptake sites. In a great number of equivocal whole body scan, due to high remnant activity, single photon emission computed tomography/computed tomography was able to differentiate between thyroid remnant and lymph nodes uptake. In 22 out of 100 patients with doubtful whole body scan, single photon emission computed tomography/computed tomography correctly identified nodal or distant metastases, and in 2/100 patients, focal uptake classified as metastatic by whole body scan was reclassified as para-physiological by single photon emission computed tomography/computed tomography. The TNM classification changed in 13 out of 22 patients. Single photon emission computed tomography/computed tomography improves detection and localization of the iodine-131 uptake after thyroidectomy in patients with differentiated thyroid carcinoma and it is more accurate than whole body scan to evaluate lymph nodes and to identify and characterize distant metastases. Single photon emission computed tomography/computed tomography aids assessment of lower/upper stage in a significant number of patients with differentiated thyroid carcinoma and it can affect therapy decision-making and patient management.

Parameters Influencing Curative Effect of 131I Therapy on Pediatric Differentiated Thyroid Carcinoma: A Retrospective Study.

BACKGROUND This study aimed to investigate the parameters influencing the effectiveness of first 131I thyroid remnant ablation and then 131I treatment of metastatic lesions in children and adolescents with differentiated thyroid carcinoma (DTC). MATERIAL AND METHODS A total of 88 children and adolescents with DTC were divided into 2 groups: 56 in the complete-ablation group and 32 in the incomplete-ablation group for the first 131I ablation; 32 in the incomplete-ablation group were further divided: 19 in the complete-remission group and 13 in the incomplete-remission group for subsequent 131I treatment of metastatic lesions. Influential parameters were analyzed using t test, t' test, rank-sum test, χ2-test, and Fisher exact test, and logistic regression analysis was performed. Radioactive iodine uptake (RAIU), lymph node metastases, and pulmonary metastases were selected as influential parameters. RESULTS After logistic regression analysis, RAIU, only lymph node metastases, and pulmonary metastasis were significantly associated with the complete-ablation rate. High levels of RAIU and serum thyroglobulin (Tg) were not conducive to disease remission after subsequent 131I treatment of metastatic lesions. The remission rate of patients with pulmonary metastasis was lower than the rate of patients with lymph node metastases or no metastases. CONCLUSIONS Results demonstrated that a high remission rate is associated with low postoperative RAIU and Tg. Lymph node metastasis and pulmonary metastasis reduce the complete-remission rate of first 131I ablation therapy. Pulmonary metastasis reduces the remission rate of subsequent 131I treatment. Also, 131I treatment for pediatric DTC with pulmonary metastasis achieved progression-free survival.

Absorbed dose estimation to family members of patients treated with radioiodine for thyroid cancer

Introduction Thyroid remnant ablation with radioiodine is a well-established treatment for patients with Differentiated Thyroid Carcinoma (DTC) following thyroidectomy. After 3–4 days of hospitalization, these patients return home, presenting a possible radiation hazard to their family members. Purpose This work aims at estimating the radiation burden to the cohabitants of DTC patients treated with radioiodine, after hospital release. Materials and methods 724 patients (183/541 men/women) suffering from DTC were treated with radioiodine activities ranging from 1850 to 9250MBq. Thyroid Hormone Withdrawal (THW) was applied in 305 patients (42.1%), whereas 419 (57.9%) patients were prepared with recombinant human TSH (rhTSH). Radioiodine T eff was calculated from dose rate measurements at 1 and 2 m from the patients, performed at regular time intervals throughout their hospitalization. All patients were discharged 3–4 days post-treatment and were provided with written and oral instructions about radiation protection precautions. Patients were grouped according to their family status and radiation doses to their cohabitants were estimated based on appropriate exposure scenarios. Results Mean radioiodine T eff was 15.3 h (range 1.9–37.5 h). T eff in the rhTSH group was lower than the THW group (14.5 h and 17.1 h respectively, p〈0.05). Mean absorbed doses to all family members were estimated to be well below the corresponding dose constraints. Maximum dose to any child was slightly above 0.5 mSv, whereas maximum dose to any non-relative co-traveller was Conclusion Provided necessary precautions are followed, radiation burden to the family members of DTC patients treated with radioiodine following thyroidectomy can be kept lower than the corresponding dose constraints.

Reappraisal of the indication for radioiodine thyroid ablation in differentiated thyroid cancer patients.

Radioactive iodine therapy is administered to patients with differentiated thyroid cancer (DTC) for eradication of thyroid remnant after total thyroidectomy or, in patients with metastatic disease, for curative or palliative treatment. In past years, thyroid remnant ablation was indicated in almost every patient with a diagnosis of DTC. Nowadays, careful revision of patients' outcome has introduced the concept of risk-based selection of patients candidate to thyroid remnant ablation. The present review aims to underline the indications for thyroid remnant ablation and to address methodologies to be employed.

Outcome of Well-Differentiated Thyroid Carcinoma Patients Receiving a Cumulative Doses of ? 600 mCi (22GBq) of I-131

Background: There is no maximum limit for cumulative dose of I-131 for persistent disease in well-differentiated thyroid carcinoma (DTC) patients. However, most remissions are obtained with cumulative activity equal to or lower than 600 mCi (22 GBq). On the other hand a significantly increased risk of leukemia and secondary cancers has been reported with high cumulative dose of I-131 (? 600 mCi). Above this cumulative activity further radioiodine therapy should be taken on an individualized basis.Objective: The aim of the study was to see the outcome of patients with well differentiated thyroid carcinoma receiving a cumulative doses (CDs) of ? 600 mCi I-131.Patient and Method: A retrospective study of 72 patients with DTC receiving a CDs of ?600 mCi I-131 in the National Institute of Nuclear Medicine and Allied Sciences (NINMAS), Dhaka during the period of January 1994 up to December 2007 was carried out. Initially all patients were treated by thyroidectomy followed by radioiodine therapy as adjusted by standard protocol. The mean period of follow up was 8.9 ± 6 years. From the medical files, age, gender, histopathological variant, thyroid remnant and radio ablation doses, follow up data were recorded. Age was further categorized as <45 and ?45 years. Thyroid bed remnant was designated as significant if the thyroid bed uptake was ?5% after surgery. Dose was categorized in ?5 dose and > 5 doses to find its association with status on last follow up. Disease free (DF) was established as: undetectable or suppressed serum Tg levels <2.0 ng/mL and stimulated serum Tg level <10 ng/mL, two consecutive negative whole body scans.Results: A total of 38 patients had papillary carcinoma, eight had follicular variant of papillary carcinoma and 26 had follicular carcinoma. Age range at diagnosis was nine to 72 years. There were 22 males and 50 females giving a M: F ratio of about 1:2. Among the 72 patients 25 patients had lymph node metastases, eight had lung metastases and 20 had bone metastases at presentation. Twenty-one patients died during the whole observation period and 20 of them were cancer related. Two patients developed second malignancy.Conclusion: DTC patients with follicular variant, ? 45 years of age, having bone metastasis and significant thyroid remnant have less favourable outcome in spite of high cumulative doses of radioiodine. DTC patients with higher TNM stage and bone metastasis require higher and more radioiodine doses.Bangladesh J. Nuclear Med. 17(2): 114-119, July 2014

Is radioiodine administration in patients with papillary thyroid multifocal microcarcinoma unnecessary?

SummaryRadioiodine (RAI) has played a crucial role in differentiated thyroid cancer treatment for more than 60years. However, the use of RAI administration in patients with papillary thyroid microcarcinoma (even multifocal) is now being widely discussed and often not recommended. In accordance with European consensus, and contrary to the American Thyroid Association (ATA) guidelines, we recently performed RAI thyroid remnant ablation in a patient with differentiated papillary multifocal microcarcinoma. The post-therapeutic whole-body scan and SPECT/CT revealed the real and unexpected extent of disease, with metastases to upper mediastinal lymph nodes. This finding led to the patient’s upstaging from stage I to stage IVa according to the American Joint Committee on Cancer/International Union Against Cancer criteria.Learning points131I is a combined beta–gamma emitter, thus allowing not only residual thyroid tissue ablation but also metastatic tissue imaging.RAI remnant ablation omission also means post-treatment whole-body scan omission, which may lead to disease underestimation, due to incorrect nodal and metastatic staging.RAI should be considered also in “low-risk” patients, especially when the lymph node involvement is not reliably documented.Lower administered RAI activity (30mCi, 1.1GBq) may be a workable compromise in low-risk patients, not indicated for RAI remnant ablation according to ATA guidelines.

Evaluation of ablation of thyroid remnants with 1850 MBq iodine-131 in 67 patients with thyroid cancer.

Radioiodine remnant ablation (RRA) is used to destroy residual normal thyroid tissue after total thyroidectomy in differentiated thyroid carcinoma (DTC) patients. As 1850-MBq RRA is routinely performed at our facility, we evaluated the outcomes. Sixty-seven DTC patients without macroscopic residual lesions after total thyroidectomy were evaluated. Thyroglobulin (Tg) was measured 2-3 months before RRA with thyroxin administration (pretreatment); just before ablation after a 3-week iodine intake restriction with thyroxin withdrawal (THW) (N.=16) or recombinant human thyroid-stimulating hormone (rhTSH) stimulation (N.=51); and 3 months after RRA, after a 2-week iodine intake restriction and 3-week THW (N.=57) or rhTSH stimulation (N.=10). All patients received 131I (1850 MBq) treatment followed by 131I scintigraphy about 8 days later (8.18±0.91) and 131I scintigraphy (185 MBq) after the dosage 24 hours later 3months after RRA. Initial RRA goal was defined as negatively visible uptake in 131I thyroid bed (VUT) and a Tg level of <2 ng/mL 3 months after RRA. Rest 60 patients whose TSH levels were below 0.5 µIU/mL of all 67 patients were evaluated. Negatively VUT on 3 months after RRA was shown in 56 out of 60 patients (93.3%). Initial RRA goal was achieved in 21 (42.0%) of 50 patients, excluding 3 patients whose Tg levels 3 months after RRA were not measured and 7 patients with anti-Tg antibodies. Pretreatment Tg levels (P=0.0003) was significant predictive factor for Initial RRA goal on multivariate logistic regression analysis. RRA with 1850 MBq is effective by visual diagnosis, about 40% of all intermediate or high-risk DTC patients achieved initial RRA goals by both visual and Tg levels diagnosis.

放射性ヨウ素内用療法（アブレーション）の適応

放射性ヨウ素内用療法（アブレーション）の適応

Treatment and outcome of 32 patients with distant metastases of Hürthle cell thyroid carcinoma: a single-institution experience.

BackgroundIt is generally believed that patients with Hürthle cell thyroid carcinoma (HCTC) have a poor prognosis. Furthermore, distant metastases represent the most frequent cause of thyroid cancer-related death of patients with HCTC. The aim of this study was to report the treatment and outcomes of patients with distant metastases.MethodsAltogether 108 patients were treated for HCTC from 1972 to 2011 in our tertiary center and 32 patients (19 females, 13 males; median age 64.5 years) had either initially proven metastatic disease (N = 12) or distant progression of HCTC after initial treatment (N = 20). Patients with metastases were followed for 1–226 (median 77) months. Data were collected on the patients’ gender and age, extent of their disease, morphologic characteristics, therapy, outcome, and survival rate. Statistical correlation between possible prognostic factors and cause-specific survival from time of detection of metastases was analyzed by univariate analysis and log-rank test.ResultsThe most common were lung metastases, followed by bone, mediastinum, kidney, and liver in 24, 8, 2, 1, and 1 case, respectively. Total thyroidectomy, lobectomy, subtotal thyroidectomy and neck dissection were performed in 19, 10, 3, and 7 patients, respectively. Radioiodine (RAI) ablation of thyroid remnant was performed in 30 patients, while 20 of them had RAI therapy (median 4 times). RAI uptake in metastases was present in 16 patients and ranged from 0.05 % to 12 %. Chemotherapy was used in 13 patients and external beam radiotherapy in 19 patients. Locoregional control of disease was achieved in 19/21 (90 %) cases who succumbed due to HCTC. Estimated 10-year disease-specific survival for all patients was 60 %. 10-year disease-specific survival for patients with pulmonary metastases and other sites metastases was 60 % and 62 %, respectively. 10-year disease-specific survival for patients with single organ and multiple organ metastases was 52 %, and 100 %, respectively. Estimated median disease-specific survival after the diagnosis of metastatic disease for all patients was 77 months. The median disease-specific survival after the diagnosis of metastatic disease for patients with pulmonary metastases and other sites metastases was 72 and 138 months, respectively.ConclusionsTen-year disease-specific survival for all patients with metastatic Hürthle cell thyroid carcinoma, patients with pulmonary metastases and bone metastases was 60 %, 60 % and 68 %, respectively.

Recombinant Human Thyroid Stimulating Hormone versus Thyroid Hormone Withdrawal for Radioactive Iodine Treatment of Differentiated Thyroid Cancer with Nodal Metastatic Disease.

Introduction. Recombinant human thyroid stimulating hormone (rhTSH) is approved for preparation of thyroid remnant ablation with radioactive iodine (RAI) in low risk patients with well differentiated thyroid cancer (DTC). We studied the safety and efficacy of rhTSH preparation for RAI treatment of thyroid cancer patients with nodal metastatic disease. Methods. A retrospective analysis was performed on 108 patients with histopathologically confirmed nodal metastatic DTC, treated with initial RAI between January 1, 2000, and December 31, 2007. Within this selected group, 31 and 42 patients were prepared for initial and all subsequent RAI treatments by either thyroid hormone withdrawal (THW) or rhTSH protocols and were followed up for at least 3 years. Results. The response to initial treatment, classified as excellent, acceptable, or incomplete, was not different between the rhTSH group (57%, 21%, and 21%, resp.) and the THW group (39%, 13%, and 48%, resp.; P = 0.052). There was no significant difference in the final clinical outcome between the groups. The rhTSH group received significantly fewer additional doses of RAI than the THW group (P = 0.03). Conclusion. In patients with nodal-positive DTC, preparation for RAI with rhTSH is a safe and efficacious alternative to THW protocol.

Short-Term Side Effects after Radioiodine Treatment in Patients with Differentiated Thyroid Cancer.

Objectives. I-131 therapy for differentiated thyroid cancer (DTC) could induce adverse effects. The purpose of this study was to report and analyze symptoms after I-131 treatment within the hospitalization and present relevant medical intervention. Methods. I-131 doses ranging from 3.7 to 9.25 GBq (100–250 mCi) were administrated for thyroid remnant ablation or treating DTC metastases. 117 patients with DTC for I-131 therapy were monitored through the video and intercommunicating with standardized questionnaire at different time points after I-131 oral administration. Adverse effects were recorded and relevant clinical factors were analyzed. Results. Among all the 117 patients, 55 cases complained of neck's pain or swelling and 79 cases presented with gastrointestinal symptoms. Pain or swelling of salivary gland occurred in 15 patients, headache and vertigo in 10, insomnia in 9, vocal cord paralysis in 6, fatigue or general malaise in 6, and foreign body sensation in 5. Body numbness and urinary symptoms were observed in only 1 case, respectively. Those side effects were related with sex, pre-I-131 treatment TSH levels, frequency of I-131 therapy, and lymph node metastases. Conclusions. Short-term side effects after I-131 therapy for DTC patients varied individually; severe symptoms were not uncommon but generally did not need emergent medical intervention.

Predictivity of stimulated serum thyroglobulin and antithyroglobulin antibodies for the efficacy of thyroid remnant ablation on patients with differentiated thyroid carcinoma

Predictivity of stimulated serum thyroglobulin and antithyroglobulin antibodies for the efficacy of thyroid remnant ablation on patients with differentiated thyroid carcinoma

Regional Variation across Canadian Centers in Radioiodine Administration for Thyroid Remnant Ablation in Well-Differentiated Thyroid Cancer Diagnosed in 2000-2010.

Background. Use of radioactive iodine (RAI) ablation has been reported to vary significantly between studies. We explored variation in RAI ablation care patterns between seven thyroid cancer treatment centers in Canada. Methods. The Canadian Collaborative Network for Cancer of the Thyroid (CANNECT) is a collaborative registry to describe and analyze patterns of care for thyroid cancer. We analyzed data from seven participating centers on RAI ablation in patients diagnosed with well-differentiated (papillary and follicular) thyroid cancer between 2000 and 2010. We compared RAI ablation protocols including indications (based on TNM staging), preparation protocols, and administered dose. We excluded patients with known distant metastases at time of RAI ablation. Results. We included 3072 patients. There were no significant differences in TNM stage over time. RAI use increased in earlier years and then declined. The fraction of patients receiving RAI varied significantly between centers, ranging between 20–85% for T1, 44–100% for T2, 58–100% for T3, and 59–100% for T4. There were significant differences in the RAI doses between centers. Finally, there was major variation in the use of thyroid hormone withdrawal or rhTSH for preparation of RAI ablation. Conclusion. Our study identified significant variation in use of RAI for ablation in patients with well-differentiated thyroid cancer both between Canadian centers and over time.

Assessment of radioiodine therapy efficacy for treatment of differentiated thyroid cancer patients with pulmonary metastasis undetected by chest computed tomography.

Radioiodine therapy (RAI) has proven effective for the treatment of patients exhibiting differentiated thyroid cancer (DTC) with pulmonary metastases. However, the early detection of metastasis remains challenging, and various studies have reported variations in radioiodine treatment efficacy. The present study investigated whether RAI is an effective method for the treatment of DTC with pulmonary metastases undetected by computed tomography (CT). A retrospective study was performed, analyzing iodine-131 (131I) therapy in 21 DTC patients with lung metastases that were undetected by CT. All 21 patients were initially treated with radioiodine ablation of thyroid remnants. Routine chest CT was performed prior to 131I treatment without diagnostic radioiodine whole-body scanning (DxWBS), and post-therapeutic WBS was performed 3–5 days subsequent to oral administration of 131I. The overall effectiveness rate was 95.2% (20/21). The rates for complete response (CR), partial response and no response were 23.8 (5/21), 71.4 (15/21) and 4.8% (1/21), respectively. There were 12 patients with diffuse uptake, and the remaining 9 patients demonstrated focused and low uptake. The difference in CR rate between diffuse uptake and focused uptake patients was not statistically significant (P=0.123). A correlation was observed between thyroglobulin (Tg) levels and extrapulmonary metastases. All patients exhibited extrapulmonary metastases when Tg levels were >87.5 ng/ml (area under receiver operating characteristic curve, 1.0; P<0.001). Overall, DTC patients with lung metastases undetected by CT imaging responded well to 131I radiotherapy and demonstrated a positive prognosis. Serum Tg levels prior to 131I treatment may correlate with metastasis, and this may suggest a requirement for the performance of DxWBS prior to radiotherapy.

Thyroid remnant ablation in differentiated thyroid cancer: searching for the most effective radioiodine activity and stimulation strategy in a real-life scenario.

Differentiated thyroid cancer is rare, but the incidence has been increasing in the last few decades. Early treatment is based on surgery and thyroid remnant ablation (TRA) by means of radioiodine therapy. Despite radioiodine being widely used for decades, the choice of ablative activity is generally empirical and no consensus has been reached to date. The aim of our study was to compare the efficacy and safety of different radioiodine activities. In addition, we compared the ablation rate in patients treated in the hypothyroid state or after recombinant human thyroid-stimulating hormone (rhTSH) administration, retrospectively reviewing the records of 471 patients affected by differentiated thyroid cancer. Patients were subdivided into three groups on the basis of the different activities of radioiodine administered and taking into account the different approaches used to perform the therapy: thyroid hormonal withdrawal or rhTSH stimulation. The success of TRA was evaluated 12 months later. TRA was obtained in 62/79 (78.5%) in group A (1110 MBq in the hypothyroid state), 183/190 (96.3%) in group B [2220 MBq in the hypothyroid state or after rhTSH administration: 87/90 (97%) and 96/100 (96%) patients, respectively], 199/202 (98.5%) in group C [3700 MBq in hypothyroid state or after rhTSH administration: 98/100 (98%) and 101/102 (99%) patients, respectively]. Our data demonstrate that 2220 and 3700 MBq radioiodine are more effective compared with 1110 MBq in TRA, without significant differences between 2220 and 3700 MBq or between hypothyroidism and euthyroidism. We suggest rhTSH-aided TRA with 2220 MBq iodine-131, as this approach permits efficacious treatment, thereby reducing side effects, absorbed dose to body and hospital stay.

Different Radioiodine Dose for Remnant Thyroid Ablation in Patients With Differentiated Thyroid Cancer: A Meta-analysis.

Remnant thyroid ablation is crucial in the management of patients with differentiated thyroid cancer. However, the optimal dose of radioactive I for ablation is still controversial. This study aimed to compare the success rate of different activities of I for postoperative remnant ablation in randomized controlled trials (RCTs) and to determine the optimal dose. Sources were retrieved from the Cochrane Library, Medline, Embase, Scopus, and Google Scholar until March 2014. All RCTs that assessed the efficacy of different doses of I for ablation were selected. After data extraction, statistics were performed by Review Manager 5.2 software. Seventeen RCTs were considered eligible, involving 3737 patients. The overall methodological quality of the studies was good. The rate of successful remnant ablation of low versus moderate I activities (risk ratio [RR], 0.89; 95% confidence interval [CI], 0.80-1.00; P = 0.06) and moderate versus high I activities (RR, 0.94; 95% CI, 0.89-1.00; P = 0.05) showed no significant differences. However, high I activities had 11% higher successful ablation rate than low activities with an RR of 0.89 (95% CI, 0.81-0.97; P = 0.008), which was significant. We summarized all available randomized evidence to demonstrate that high dose of I was significantly better than low dose to achieve successful remnant thyroid ablation.