Post-treatment Hypothyroidism Research Articles

Predictive factors for the outcome of radioiodine therapy in patients with benign thyroid diseases.

Radioiodine therapy (RIT) of benign thyroid diseases is an established therapy. This study aimed to identify factors predictive for outcome in patients with non-toxic goiter (NTG), unifocal (UFA), multifocal (MUFA) or diffuse autonomy (DISA) and Graves' disease (GD). Retrospective analysis of 205 patients with benign thyroid disease (54 NTG, 46 MUFA, 24 DISA, 26 UFA, 55 GD) who underwent RIT. Follow up time was 12 months for determining treatment outcome. The type of disease was predictive for volume reduction after 12 months (NTS 66%, DISA 67%, MUFA 58%, UFA 51%, GD 71%, p<0.001) and post-treatment hypothyroidism (NTS 48%, DISA 33%, MUFA 15%, UFA 15%, p=0.006). Initial volume, intra-therapeutic uptake and intra-therapeutic half-life were independent prognostic factors for volume reduction 12 months after RIT. In patients with NTG, UFA, MUFA, DISA post-treatment hypothyroidism was significantly correlated with extent of volume reduction 12 months after RIT, achieved dose, higher pre-therapeutic TSH values and younger age. Two different strategies for pre-therapeutic dosimetry used in MUFA showed no differences regarding the therapeutic outcome. In GD, effective half-life, initial volume and Graves' ophthalmopathy were predictive for treatment failure. Reduction of thyroid volume and the percentage of hypothyroid patients one year after RIT was primarily dependent on the type of disease. In MUFA and DISA we could identify volume reduction after 3 months as a reliable predictor for hypothyroidism while in patients with GD a short intra-therapeutic half-life, a large pre-therapeutic volume and active Graves' ophtalmopathy were relevant predictors for treatment failure suggesting an intensified follow-up scheme in these patients.

Review: Improving quality of life in patients with differentiated thyroid cancer.

Well differentiated thyroid cancer is a common malignancy diagnosed in young patients. The prognosis tends to be excellent, so years of survivorship is expected with low risk disease. When making treatment decisions, physicians should consider long-term quality of life outcomes when guiding patients. The implications for treating indolent, slow growing tumors are immense and warrant careful consideration for the functioning years ahead. Surgery is the standard of care for most patients, however for a subset of patients, active surveillance is appropriate. For those wishing to treat their cancer in a more active way, novel remote access approaches have emerged to avoid a cervical incision. In the era of "doing less", options have further expanded to include minimally invasive approaches, such as radiofrequency ablation that avoids an incision, time off work, a general anesthetic, and the possibility of post-treatment hypothyroidism. In this narrative review, we examine the health related quality of life effects that surgery has on patients with thyroid cancer, including some of the newer innovations that have been developed to address patient concerns. We also review the impact that less aggressive treatment has on patient care and overall wellbeing in terms of active surveillance, reduced doses of radioactive iodine (RAI) treatment, or minimally invasive techniques such as radiofrequency ablation (RFA) for low risk thyroid disease.

Risk of post-treatment hypothyroidism in paediatric neuroblastoma

Searchable abstracts of presentations at key conferences in endocrinology ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

Survivorship Care Plans Improve the Identification of Post-radiation Hypothyroidism After Head and Neck Cancer Treatment.

Survivorship care programs (SCPs) educate patients on post-treatment side-effects, which may lead to earlier identification and mitigation of their impact. This study assessed the impact of SCP on identification and management of post-treatment hypothyroidism in a head and neck cancer population and evaluated socio-demographic factors in the effectiveness of SCPs. A retrospective analysis was performed of sociodemographic and clinical characteristics of patients with head and neck cancer treated with radiation therapy between January 2011 and January 2019 at a large community cancer institution. Development of hypothyroidism was defined as elevated thyroid-stimulating hormone (TSH) or initiation of supplementation post-treatment. Cumulative incidence of hypothyroidism was analyzed with Gray's method. Of 608 patients, 483 (79%) had post-treatment TSH surveillance. A total of 203 (42%) of those patients developed hypothyroidism; 53 (11%) patients completed SCPs. The median follow-up was 1.4 (interquartile range=0.7-2.6) years with a median time until diagnosis of hypothyroidism of 1.2 (interquartile range=0.7-2.1) years. The median time to diagnosis was 12.0 months with SCP versus 14.2 months without. Race and insurance status were not associated with differences in thyroid surveillance. Patients with laryngeal cancer were at greatest risk of developing hypothyroidism (hazard ratio=1.92, confidence interval=1.44-2.56; p<0.077). Cumulative incidence of post-treatment hypothyroidism was higher in patients managed with SCP, 65.4% at 4 years, compared to those without (49.0%). Receipt of SCP was independently associated with an increased incidence of hypothyroidism detection (hazard ratio=1.51, confidence interval=1.04-2.20; p=0.030). In our experience, SCP utilization was independently associated with a diagnosis of hypothyroidism. This study supports implementation of a survivorship program for identification and management of post-treatment sequelae.

Radioactive iodine dose and survival in cats with hyperthyroidism (2015-2020).

Radioactive iodine (131I) is the preferred treatment for feline hyperthyroidism but neither the optimal 131I dose nor consistent predictors of post-treatment azotaemia have been determined. The aims of the study were to evaluate the relationships between: (1) 131I dose and survival; and (2) pretreatment and post-treatment serum creatinine concentration. Medical records of hyperthyroid cats treated with 131I at a single referral hospital were reviewed. Information regarding signalment, body weight, pretreatment and post-treatment serum total thyroxine concentration (TT4), serum creatinine concentration, 131I dose and survival were determined. Multivariable Cox proportional hazards analysis was used to identify variables associated with survival. Multivariable linear regression analysis was used to identify variables associated with post-treatment serum creatinine concentration. One hundred and ninety-eight (79 male, 119 female) cats were treated for hyperthyroidism with 131I (median dose 138 MBq; interquartile range 92-168). Median survival time was 1153 days (range 16-1871). Post-treatment serum creatinine (P <0.001) and age (P = 0.049) were significantly associated with survival. Every 10 µmol/l increase in post-treatment serum creatinine concentration and every year increase in age was associated with a 1.07-fold (confidence interval [CI] 1.04-1.11) and 1.17-fold (CI 1.00-1.37) increase in the daily hazard of death, respectively. Pretreatment serum creatinine concentration was directly, and post-treatment serum TT4 concentration was inversely, associated with post-treatment serum creatinine concentration. Every 1 μmol/l increase in pretreatment serum creatinine concentration was associated with an increase in post-treatment serum creatinine concentration of 0.7 μmol/l (SE 0.17; P <0.001). Conversely, every 1 nmol/l decrease in post-treatment serum TT4 concentration was associated with a 1.2 μmol/l (SE 0.61; P <0.001) increase in post-treatment serum creatinine concentration. Post-treatment serum TT4 concentration was associated with post-treatment azotaemia, which was associated with survival. Although 131I dose was not directly associated with survival, dosing strategies that minimise post-treatment hypothyroidism and azotaemia could improve patient survival.

Microwave ablation of autonomously functioning thyroid nodules: a comparative study with radioactive iodine therapy on the functional treatment success.

The objective of this study was to compare the efficiency of microwave ablation (MWA) and radioactive iodine (RAI) in the treatment of toxic adenoma (TA), and to investigate the functional treatment success of the used modalities for its remission. Treatment outcomes- thyroid hormone levels and nodule characteristics- of 30 patients (23:7 F:M; 52.77 ± 11.13 years) treated by MWA were compared with the those of 35 patients (24:11 F:M; 61.43 ± 12.60 years) treated by RAI. The baseline characteristics of TAs, which are gender and pre volume, were analogous and did not show any statistical significance (p > 0.05). Thyroid hormone levels of patients treated with two different methods were measured after 9 months, and the obtained results were compared. Although there was no statistically significant difference in the nodule volume (p > 0.05), there was a greater volume reduction rate (VRR%) in the group treated with MWA rather than RAI (p < 0.05) at the end of the follow-up. In the MWA group, there was a higher increase in FT3 than in the RAI group (p < 0.05). Furthermore, no statistically significant difference in TSH (p = 0.124) and FT4 (p = 0.144) levels of the patients as treatment outcomes was observed. The therapeutic success was accomplished in 18/30 (60%) of the MWA group and in 24/35 (68.6%) of the RAI group. Therapeutic success of MWA and RAI did not show any statistically significant difference (p = 0.471). However, the development of hypothyroidism in 7 of 35 patients treated with RAI was observed. On the other hand, no case of post-treatment hypothyroidism was observed in patients treated with MWA. In this regard, MWA could be a great alternative to RAI due to its advantages in terms of non-exposure to radiation and lower risk of post-treatment hypothyroidism.

Does Levothyroxine Administration Before and During Head and Neck Radiation Therapy Prevent Post-Treatment Hypothyroidism?

Clinical ThyroidologyVol. 32, No. 10 HypothyroidismDoes Levothyroxine Administration Before and During Head and Neck Radiation Therapy Prevent Post-Treatment Hypothyroidism?Charles H. EmersonCharles H. EmersonDivision of Endocrinology and Metabolism, Department of Medicine; University of Massachusetts School of Medicine, Worcester, Massachusetts, U.S.A.Search for more papers by this authorPublished Online:6 Oct 2020https://doi.org/10.1089/ct.2020;32.461-463AboutSectionsView articleView Full TextPDF/EPUB Permissions & CitationsPermissionsDownload CitationsTrack CitationsAdd to favorites Back To Publication ShareShare onFacebookTwitterLinked InRedditEmail View articleFiguresReferencesRelatedDetails Volume 32Issue 10Oct 2020 InformationCopyright 2020 American Thyroid Association, Inc.To cite this article:Charles H. Emerson.Does Levothyroxine Administration Before and During Head and Neck Radiation Therapy Prevent Post-Treatment Hypothyroidism?.Clinical Thyroidology.Oct 2020.461-463.http://doi.org/10.1089/ct.2020;32.461-463Published in Volume: 32 Issue 10: October 6, 2020PDF download

The impact of socioeconomic factors and survivorship on radiation induced hypothyroidism in a single institution cohort study.

e24065 Background: To determine factors associated with the development of post-treatment hypothyroidism (HY) in the head and neck (HN) population as well as evaluate the impact of socio-economic factors and survivorship program. Methods: We collected demographics, insurance coverage, disease staging, treatment characteristics, and details of thyroid function measurement as well as supplementation for all HN oncology patients (n = 608) who presented between January 2011 and January 2019 at Levine Cancer Institute, Charlotte, North Carolina. Insurance was categorized as Government (Medicaid or Medicare), Private, or Uninsured. Patient malignancies were grouped as oropharynx, oral cavity, larynx/hypopharynx, nasopharynx, nasal cavity/sinus, or primary salivary gland. Thyroid function was evaluated by use of laboratory thyroid stimulating hormone (TSH) values. Timing of thyroid supplementation was standardized to start of treatment. Details of thyroid hormone supplementation was collected. Data was analyzed with Chi-square and ANOVA methods, using SAS 9.4 (Cary, NC). Results: 483 patients (79%) had post treatment surveillance with TSH. The patients (n = 125, 21%) with no identifiable thyroid surveillance did not have any racial or socioeconomic disparities identified. Caucasian and African American thyroid surveillance rates were similar at 79% and 81%, respectively. There was no difference based on insurance: Government 81%, Uninsured 81%, and Private 76%. Of patients with thyroid surveillance, 203 (42%) developed post-treatment HY. The mean and median time frame until HY identification was 544 days and 450 days, respectively. A mean and median dose of thyroid hormone supplementation of 75 mcg of levothyroxine. Most patients had lower rates of thyroid dysfunction with TSH levels between 5-10. Fewer African Americans (24%) developed HY than Caucasians (47%). Patients with laryngeal cancer were at greatest risk to develop HY (57%), followed by oropharynx (40%) and oral cavity (40%). Staging did not demonstrate a significant difference between development of HY. Conclusions: This study is the largest cohort of HN patients to be evaluated for post HN treatment induced HY. Oncology team providers and primary care physicians should be aware of the significant rates of HY. In our institution we identified a consistency of care provided regardless of socioeconomic and racial factors.

Enhancing the efficacy of 131I therapy in non-toxic multinodular goitre with appropriate use of methimazole: an analysis of randomized controlled study

PurposeIt is possible to raise the rate of the uptake of 131I in the thyroid gland (RAIU) by increasing the endogenous TSH level through appropriate use of methimazole (MMI) prior to 131I therapy. The purpose of this paper is to assess the impact of pre treatment with MMI on the efficacy of 131I therapy in non-toxic multinodular goitre (NMG).MethodsThirty-one patients with NMG received 131I treatment in order to reduce the volume of the thyroid (TVR). Those in group 1 (n = 16) were administered 10 mg of methimazole for 6 weeks. Four days after its discontinuation, they received 131I. Patients in group 2 (n = 15) were given a placebo instead of MMI. The therapeutic activity of 131I was constant (800 MBq) and was repeated every 6 months. Treatment was discontinued when TVR reached <40 ml.ResultsIn group 1, RAIU increased approximately twofold. Ten patients from group 2 and four patients from group 1 received further doses of 131I. The median of time until TVR decreased below 40 ml was 9 months [6–12 months] and 18 months [14–22 months] in group 2. At 2 years after the 131I therapy, the occurrence of hypothyroidism did not differ significantly (36% in group 1 and 33% in group2, p = 0.074).ConclusionsRadioiodine treatment of NMG preceded with appropriate application of MMI is efficient thanks to increased RAIU, shorter period of treatment, and lower frequency of 131I administration, without an increase in the incidence of post-treatment hypothyroidism.

Comparison between radioiodine therapy and single-session radiofrequency ablation of autonomously functioning thyroid nodules: A retrospective study.

To compare the efficacy of Radioiodine (RI) and Radiofrequency ablation (RFA) in the treatment of autonomously functioning thyroid nodules (AFTNs). End-points: nodule volume reduction (NVR) and thyroid function normalization. Twenty-two patients (2:20M:F; 51.9±13.9years) affected by 25 AFTNs, treated by RFA were retrospectively compared with 25 patients (8:17M:F; 57.2±12.8years) affected by a single AFTN treated by RI. Both group showed analogous characteristics as to age, gender, toxic/pretoxic phase and pretreatment nodule volume (calculated by the ellipsoid formula). Thyroid hormone levels and autoimmune thyroid profile were assessed before treatment. A fixed RI activity of 555MBq (15mCi) was administered. RFA was performed with an 18G, single-tipped electrode, by the "modified moving shot technique." Thyroid hormones were assessed and the nodule post-treatment volume calculated 12months after treatment. No statistical difference was found between the post-treatment NVR by comparing RI and RFA (P=0.69). The volume reduction rates were 68.4±28.9% and 76.4±16.9% after RI and RFA, respectively. As to the thyroid function, 5/25 patients developed clinical hypothyroidism after RI. After RFA, all the 22 patients silenced their AFTN and normalized the thyroid hormones. Subclinical hypothyroidism was recorded in two patients after both RI and RFA. Thus, the functional therapeutic success, defined as the restoration of euthyroidism, was achieved in 18/25 (72%) patients treated by RI and in 20/22 (90.9%) treated by RFA. No statistical difference in NVR was found between RI and RFA. All patients responded to RI but 5/25 were "over-treated" developing hypothyroidism. RFA was effective in all patients with no case of post-treatment clinical hypothyroidism. No radiation exposure and lower risk of post-treatment hypothyroidism might make RFA the favourite option especially for young patients.

Large multinodular goiter--outpatient radioiodine treatment.

131-I treatment of nodular, especially nontoxic, goitre is still reserved mainly for elderly patients, whose numerous concomitant diseases disqualify them from surgery. Therapy often involves isolation and is available only in selected centres, which may be located far from some patients' places of residence, which is inconvenient for elderly people. The aim of the study was to assess the effectiveness of outpatient fractionated 131-I treatment of patients with large nodular goitres, as well as to evaluate complications and the factors affecting treatment results. The study included 35 patients with a large nodular goitre. Thyroid volume and treatment results were evaluated using US and CT neck examination. Mean thyroid volume prior to treatment was 104.36 mL (range 36.23-301.09 mL). An average administered 131-I activity was 1806 MBq (range 800-4000). The average reduction of goitre volume was 43.18% (range -17.23-89.66%). Final treatment results correlated with the thyroid size reduction obtained three months after treatment (r = 0.74; p = 0.001). Symptoms of transient hyperthyroidism were observed in 8.57% of patients, in 5.4% Graves disease was induced (including severe Graves' orbitopathy in 2.7%), and in 2.86% TRAb increase without development of hyperthyroidism was observed. The treatment results were not influenced by initial thyroid volume (r = -0.01; p = 0.95). An increase in thyroid volume during the treatment was reported in 20% of patients, with a mean increase of 22.3% (range 0.63-55.03%). Post-treatment hypothyroidism was diagnosed in 42.9% of patients. One patient was diagnosed with salivary gland damage. Fractionated 131-I treatment of large nodular goitres is an effective method, the results of which are comparable to those obtained from the administration of one-time high doses of radioiodine.

Thyroid stimulating hormone suppression post-therapy in patients with Graves' disease: a systematic review of pathophysiology and clinical data.

Post-treatment hypothyroidism is common in Graves' disease, and clinical guidelines recommend monitoring for it; however, thyroid stimulating hormone (TSH) can remain suppressed in these patients following treatment. The objectives of this study were to explore the proposed pathophysiology behind the phenomenon of post-therapy TSH suppression and to systematically review existing clinical data on post-therapy TSH suppression in patients with Graves' disease. A systematic literature search was performed using EMBASE and PubMed databases, with several combinations of MeSH terms. Bibliography mining was also done on relevant articles to be as inclusive as possible. A total of 18 articles described possible mechanisms for post-therapy TSH suppression. Several of the studies demonstrate evidence of thyrotroph atrophy and hypothesize that this contributes to the ongoing suppression. TSH receptors have been identified in folliculo-stellate cells of the pituitary as well as astroglial cells of the hypothalamus, mediating paracrine feedback. A few studies have demonstrated inverse correlation between autoantibody titres and TSH levels, suggestive of their role in mediating ongoing TSH suppression in patients with Graves' disease. In addition, five studies were identified that provided clinical data on the duration of TSH suppression. Combined data show that 45.5% of patients recover TSH by 3 months after treatment, increasing to 69.3% by 6 months, and plateauing to 73.8% by 12 months (p>0.0001). Sub-analysis also shows that for patients who are TBII negative, 80.7% recover their TSH by 6 months compared with only 58.7% in those who are TBII positive (p= 0.003). Clinical data suggests that TSH recovery is most likely to occur within the first 6 months after treatment, with recovery plateauing at approximately 70% of patients, suggesting that reliance on this assay for monitoring can be very misleading. Furthermore, TBII positivity is associated with lower likelihood of TSH recovery. Pathophysiology behind suppressed TSH involves not only anatomical but also autoimmune mechanisms.

Radioactive iodine therapy for hyperthyroidism: Our experience

Context: Radioactive iodine (RAI) therapy for hyperthyroidism is safe and definitive, although, post-treatment hypothyroidism and the need for life-long thyroxine are to be expected. The optimal dose of I-131 for hyperthyroidism is still debated. Aims: The aim of this study is to evaluate the response rate of hyperthyroidism to RAI treatment, optimum effective dose, effect of pre-treatment with anti-thyroid medications, ophthalmopathy, and hypothyroidism incidence post RAI therapy. Subjects and Methods: A prospective study was conducted in a tertiary care center to look at the therapeutic practice of use of RAI in the treatment of hyperthyroidism, to determine whether the expected or desired therapeutic outcome is achieved. Seventy consecutive subjects of hyperthyroidism, treated with RAI were followed-up. Results: Grave's disease was the most common cause of hyperthyroidism. The dose of RAI ranged from 4 mCi to 17.5 mCi. Over 95% cure rate achieved with RAI dose 4-7 mCi. Hypothyroidism occurred in 52.17% cases with this dose. Goiter size significantly decreased with RAI therapy. No deterioration of eye signs observed with RAI therapy. Pre-treatment with anti-thyroid drugs had no influence on outcome. Conclusions: RAI treatment is an effective modality for definitive treatment of hyperthyroidism with long-term cure approaching 95%. Its efficacy, safety and low cost made it the preferred definitive treatment for most patients with hyperthyroidism.

Thyrotoxicosis with Post-Treatment Hypothyroidism in a Patient with Acute Suppurative Thyroiditis Due to Porphyromonas

Acute suppurative thyroiditis (AST) is a rare, life-threatening thyroid infection characterized by a tender neck mass and fever. As these features are shared with self-limited subacute thyroiditis (SAT), it is important to differentiate between the two disorders. We report a case of AST in a 21-year-old woman who presented with steadily worsening throat pain for 3 weeks, a tender left neck mass, and thyrotoxicosis. She was initially given prednisone for treatment of presumed SAT but then it acutely worsened. Fine needle aspiration yielded pus on gross examination, and she required intubation and emergent surgical drainage to maintain her airway. Culture of the abscess isolated Streptococcus F and Porphyromonas, a gram-negative intracellular anaerobe not previously reported to cause AST. She improved quickly after surgery, developed transient hypothyroidism that did not require treatment with thyroid hormone, and is currently euthyroid. An abnormal piriform sinus fistula was identified on the left using an esophagram. AST may be difficult to clinically differentiate from SAT. Fine needle aspiration revealing pus, culture yielding bacteria or fungi, abscess on ultrasonography and computed tomography, and left-sided predominance are important in the diagnosis of AST. AST should be considered in any patient with SAT who does not rapidly improve following institution of steroids. Further, the presence of thyrotoxicosis does not eliminate AST as an initial diagnosis.

Prediction of post-treatment hypothyroidism using changes in thyroid volume after radioactive iodine therapy in adolescent patients with Graves' disease.

BackgroundThe goal of iodine-131 therapy for pediatric Graves' disease is to induce hypothyroidism. However, changes in post-treatment thyroid volume have not been investigated in pediatric and/or adolescent patients.ObjectiveThe aim of this retrospective study was to examine whether changes in thyroid volume predict post-treatment hypothyroidism in adolescent Graves' disease patients.Patients and MethodsWe used ultrasonography to examine changes in thyroid volume, and also assessed thyroid functions, at 0, 1, 3, 5, 8 and 12 months after iodine-131 treatment in 49 adolescents ranging in age from 12 to 19 years retrospectively. Based on thyroid function outcome at 12 months, patients were divided into two groups: 29 patients with overt hypothyroidism requiring levothyroxine replacement and 20 without overt hypothyroidism. We compared changes in post-radioiodine thyroid volume between the two groups.ResultsAbout 90% of patients whose thyroid volume at 3 months after iodine-131 administration was less than 50% of the original volume were hypothyroid by one year after treatment (positive predictive value 88%, sensitivity 75.9%, specificity 85.0%).ConclusionsWe believe ultrasonographic measurement of thyroid volume at 3 months after iodine-131 to be clinically useful for predicting post-treatment hypothyroidism in adolescent Graves' disease patients.

Dose distribution in the thyroid gland following radiation therapy of breast cancer-a retrospective study

PurposeTo relate the development of post-treatment hypothyroidism with the dose distribution within the thyroid gland in breast cancer (BC) patients treated with loco-regional radiotherapy (RT).Methods and materialsIn two groups of BC patients postoperatively irradiated by computer tomography (CT)-based RT, the individual dose distributions in the thyroid gland were compared with each other; Cases developed post-treatment hypothyroidism after multimodal treatment including 4-field RT technique. Matched patients in Controls remained free for hypothyroidism. Based on each patient's dose volume histogram (DVH) the volume percentages of the thyroid absorbing respectively 20, 30, 40 and 50 Gy were then estimated (V20, V30, V40 and V50) together with the individual mean thyroid dose over the whole gland (MeanTotGy). The mean and median thyroid dose for the included patients was about 30 Gy, subsequently the total volume of the thyroid gland (VolTotGy) and the absolute volumes (cm3) receiving respectively < 30 Gy and ≥ 30 Gy were calculated (Vol < 30 and Vol ≥ 30) and analyzed.ResultsNo statistically significant inter-group differences were found between V20, V30, V40 and V50Gy or the median of MeanTotGy. The median VolTotGy in Controls was 2.3 times above VolTotGy in Cases (ρ = 0.003), with large inter-individual variations in both groups. The volume of the thyroid gland receiving < 30 Gy in Controls was almost 2.5 times greater than the comparable figure in Cases.ConclusionsWe concluded that in patients with small thyroid glands after loco-radiotherapy of BC, the risk of post-treatment hypothyroidism depends on the volume of the thyroid gland.

Hypothyroidism After Radiotherapy for Nasopharyngeal Cancer Patients

The aim of this study was to determine the long-term incidence and possible predictive factors for posttreatment hypothyroidism in nasopharyngeal carcinoma (NPC) patients after radiotherapy. Four hundred and eight sequential NPC patients who had received regular annual thyroid hormone surveys prospectively after radiotherapy were included in this study. Median patient age was 47.3 years, and 286 patients were male. Thyroid function was prospectively evaluated by measuring thyroid-stimulating hormone (TSH) and serum free thyroxine (FT4) levels. Low FT4 levels indicated clinical hypothyroidism in this study. With a median follow-up of 4.3 years (range, 0.54-19.7 years), the incidence of low FT4 level was 5.3%, 9.0%, and 19.1% at 3, 5, and 10 years after radiotherapy, respectively. Hypothyroidism was more common with early T stage (p = 0.044), female sex (p = 0.037), and three-dimensional conformal therapy with the altered fractionation technique (p = 0.005) after univariate analysis. N stage, chemotherapy, reirradiation, and neck electron boost did not affect the incidence of hypothyroidism. Younger age and conformal therapy were significant factors that determined clinical hypothyroidism after multivariate analysis. Overall, patients presented with a low FT4 level about 1 year after presenting with an elevated TSH level. Among our study group of NPC patients, 19.1% experienced clinical hypothyroidism by 10 years after treatment. Younger age and conformal therapy increased the risk of hypothyroidism. We suggest routine evaluation of thyroid function in NPC patients after radiotherapy. The impact of pituitary injury should be also considered.

Radioiodine therapy in thyroid autonomy: initial results and experiences

Radioiodine therapy is an established method worldwide for treatment of hyperthyroidism. The author analyses the results of radioiodine therapy for treatment of functional autonomy performed in the Nuclear Medicine Department of Markusovszky Hospital between November 2005 and February 2007. The data of 33 patients (29 women, 4 men; age: 61.9 +/- 9.8 years) were evaluated. 23 patients with multifocal autonomy and 10 patients with unifocal autonomy were treated. Individual dosimetry was performed and the activity applied was calculated using Marinelli's formula. Patients with a complete follow-up for 6 months or more were included (mean follow-up time: 11 months). Successful elimination of functional thyroid autonomy resulting in either euthyroidism or hypothyroidism occurred in 88% of patients (29/33). The frequency of normalised TSH was 79% (26/33), the rate of post-treatment hypothyroidism was 9% (3/33) and the rate of residual hyperthyroidism was 12% (4/33). Previous treatment with antithyroid drugs had no negative influence on the success rate of radioiodine therapy. In 64% of patients (21/33) the administered activity exceeded 550 MBq, the upper limit of out-patient radioiodine therapy. The results of radioiodine therapy in the analysed patient group are coherent with the data of several large studies. According to the references, the success rate of 85-100% are satisfying and the incidence of hypothyroidism of 10-20% is acceptable.

Oxidative Stress and Enzymatic Antioxidant Status in Patients with Hypothyroidism before and after Treatment

The present study was designed to investigate the relationship between the serum levels of oxidant-antioxidant system (malondialdehyde (MDA) level, Paraoxonase (PON1) activity, nitric oxide (NO) level and superoxide dismutase (SOD) activity) and thyroid hormone status in hypothyroidism pre and posttreatment. The study group comprised 33 patients with primary hypothyroidism. 18 of these patients were reevaluated after euthyroid state i.e. at least 6 months of thyroxine replacement. The patients were compared with 26 normal healthy controls. Serum MDA level, PON1 activity, NO level and SOD activity were measured according to an enzymatic spectrophotometric method. MDA levels were found higher in patients with hypothyroidism before the treatment than the controls. MDA levels were also found to be decreased after the treatment in patients with hypothyroidism. However MDA were found still higher than the controls after the treatment. PON1 activity was found to be lower in patients pretreatment when compared to posttreatment hypothyroidism and controls. Posttreatment of hypothyroidism mean PON1 activity significantly increased compared to pretreatment level but it was still significantly lower than control level. NO level was higher in pretreatment hypothyroidism when compared to controls. SOD activity was not found different in patients before treatment when compared to controls. SOD activity was significantly higher in after treatment when compared to both pretreatment and control levels. In conclusion, increased ROS levels in hypothyroidism may result in a pro-oxidation environment, which in turn could result in decreased antioxidant PON1 activity, increased MDA and NO levels. As a result, lipid peroxidation may have a role in the pathogenesis of the atherosclerosis in hypothyroidism.

Thyroid dysfunction in laryngectomees—10 years after treatment

Hypothyroidism is 1 of the complications that follow treatment of various head and neck cancers. In the literature, reviews using different primary sites and differences in treatment modalities make comparison of post-treatment hypothyroidism not possible. The objective of this study was to evaluate the incidence of hypothyroidism in a homogenous group of patients who were treated with total laryngectomy and irradiation for laryngeal carcinoma and to assess the importance of different variables in the occurrence of hypothyroidism. A retrospective review of 147 total laryngectomy patients between 1993 and 2003 was carried out. Serum thyroxine level and free T4 levels were assessed in all patients. Hypothyroidism was classified as subclinical (increased thyroid-stimulating hormone and normal free T4 levels) and clinical (increased thyroid-stimulating hormone and decreased free T4 levels). The results showed that the overall incidence of hypothyroidism was 49% (44% subclinical and 5% clinical). Hemithyroidectomy and advanced tumor staging were risk factors for the development of hypothyroidism in these patients (p < .05) with a relative risk of 2.1 (CI 95%, 1.4-3.1) and 1.3 (CI 95%, 1.1-1.6), respectively. During follow-up, 19.9% of patients developed hypothyroidism at 3 years, 38.6% at 6 years; at 10 year follow-up, 93.3% of them had hypothyroidism. In conclusion, hypothyroidism is a frequent complication in patients treated with radiotherapy and total laryngectomy for laryngeal cancer, especially when treatment includes hemithyroidectomy. These patients should have their thyroid function evaluated periodically even 10 years after treatment.