Radiation dose in the selection of 131I or surgical treatment for toxic thyroid adenoma

Radioiodine Therapy in Pediatric Differentiated Thyroid Cancer: Dosimetry, Clinical Care, and Future Challenges

ABSTRACT

Thyroid cancer is very rare in children. 131 I therapy after thyroidectomy is established in pediatric differentiated thyroid cancer (DTC). Pediatric DTC guideline is silent on the optimum amount of 131 I that could be safely and effectively administered to children who are more radiosensitive. Like adult DTC, children are also given 131 I therapy empirically based either on age or body weight. Pediatric DTC guideline recommends that patient-specific dosimetry is important in children. Still, due to the low incidence rate and the practical difficulties of dosimetry, it has neither been established nor adopted in routine practice. This review article aims to discuss current approaches of 131 I therapy in children and young adult patients with DTC and dosimetric data obtained by several investigators. Efforts are required to simplify dosimetric procedures and precise results, especially in determining lesion size. We prefer 3-dimensional dosimetry over planar dosimetry, where lesion size could be measured accurately. 124 I PET/CT-based dosimetry is expected to give accurate dosimetric results. The most challenging aspect is that no randomized controlled trials are available to compare the empiric 131 I therapy results versus dosimetry-based treatment outcomes in children and young adults. Suppose dosimetry-based 131 I therapy could be shown to have better outcomes, namely, successful ablation rate, better disease-free survival, and lesser treatment-emergent adverse events than empirical 131 I treatment. In that case, one can argue in favor of the former. Unfortunately, no convincing study is currently available. Thus, there is a need for a randomized control trial to settle this issue.

Efficacy and Safety of Radiofrequency Ablation for the Treatment of Autonomously Functioning Thyroid Nodules: A Long-Term Prospective Study

Objective

This study aims to evaluate the efficacy and safety of RFA in the AFTN treatment after 2 years of follow-up and to find the factors related to treatment responses through TSH level and VRR.

Materials and Methods

This long-term prospective study was conducted from September 2017 to April 2021 on 17 AFTNs treated with RFA. Clinical evaluations, thyroid function tests, thyroid scintigraphy, and ultrasonography examinations were performed at 1 month, 3 months, 6 months, and 24 months after ablation. The primary endpoint was the success rate of RFA in restoring the euthyroidism stage after 24 months of follow-ups; secondary outcomes were VRR and improvements of US parameters, clinical examinations, and complications. The Spearman rank correlation test was used to determine related factors with treatment response variables.

Results

At the 24 months after the procedure, symptom score, cosmetic score, vascularity grade, and nodule volume significantly decreased. The VRR reduced approximately 42.77%, 63.13%, 78.3%, and 95.65% after 1 month, 3 months, 6 months, and 24 months follow-up. All 17 patients were restored euthyroid state without taking ATDs. No major complications were collected. The last TSH level was significantly correlated with the age of patients (Spearman rho = −0.637, p = 0.008). The VRR was significantly correlated with age of patients (Spearman rho = 0.566, p = 0.018) and initial TSH (Spearman rho = 0.485, p = 0.048).

Conclusion

RFA was demonstrated as a safe and effective option for AFTN treatment in long-term follow-up. It can be used as an alternative treatment with encouraging results.

Large Multinodular Toxic Goiter: Is Surgery Always Necessary?

Patients suffering from multinodular toxic goiter (MNTG) are candidates to thyroidectomy or radioiodine 131I (131I) therapy. Thyroidectomy may be preferable especially when the volume of hyperfunctioning tissue is so large that a single administration of 131I is unlikely to cure the patient in terms of nodule's volume reduction and thyroid function. We describe the case of a 71-year-old man suffering from thyrotoxic state for the presence of two large hyperfunctioning thyroid nodules. As the patient refused surgery, at first we administered 600 MBq dose of 131I, which was unable to solve hyperthyroidism and local compressive symptoms. Then, before administering another 131I dose, the patient underwent a laser ablation treatment (LAT) in both nodules. After a significant shrinkage due to LAT, the patient received 400 MBq 131I. This procedure was able to definitely cure hyperthyroidism, to induce a significant reduction of nodules' volume, and to render the patient asymptomatic for compressive symptoms. This case demonstrates that 131I preceded by LAT represents a valid alternative strategy to surgery, even in the presence of two large coexistent hot nodules.

Laser ablation and 131-iodine: a 24-month pilot study of combined treatment for large toxic nodular goiter

CONTEXT

It is normally recognized that the preferred treatment in large toxic thyroid nodules should be thyroidectomy.

OBJECTIVE

The aim of the study was to assess the efficacy of combined laser ablation treatment (LAT) and radioiodine 131 (131I) treatment of large thyroid toxic nodules with respect to rapidity of control of local symptoms, of hyperthyroidism, and of reduction of administered 131I activity in patients at refusal or with contraindications to surgery.

DESIGN AND SETTING

We conducted a pilot study at a single center specializing in thyroid care.

PATIENTS

Fifteen patients were treated with LAT, followed by 131I (group A), and a series of matched consecutive patients were treated by 131I only (group B).

INTERVENTION(S)

Laser energy was delivered with an output power of 3 W (1800 J per fiber per treatment) through two 75-mm, 21-gauge spinal needles. Radioiodine activity was calculated to deliver 200 Gy to the hyperfunctioning nodule.

MAIN OUTCOME MEASURE(S)

Thyroid function, thyroid peroxidase antibody, thyroglobulin antibody, ultrasound, and local symptoms were measured at baseline and up to 24 months.

RESULTS

Nodule volume reduction at 24 months was: 71.3 ± 13.4 vs 47.4 ± 5.5%, group A (LAT+131I) vs group B (131I), respectively; P < .001). In group A (LAT+131I), a reduction in radioiodine-administered activity was obtained (-21.1 ± 8.1%). Local symptom score demonstrated a more rapid reduction in group A (LAT+131I). In three cases, no 131I treatment was needed after LAT.

CONCLUSIONS

In this pilot study, combined LAT/131I treatment induced faster and greater improvement of local and systemic symptoms compared to 131I only. This approach seems a possible alternative to thyroidectomy in patients at refusal of surgery.

Influence of iodine-131 dose on the outcome of hyperthyroidism in children

OBJECTIVES

Iodine-131 is an effective treatment for Graves' hyperthyroidism in children and adults. Yet the responses to treatment as related to iodine-131 dose in children are not well-defined. The objective of this study was to examine the relationship between the dose of iodine-131 in children with hyperthyroidism and thyroid status 1 year after treatment.

METHODS

We examined the outcome of iodine-131 treatment in children and adolescents with Graves' disease, as related to dose. Three iodine-131 doses were compared: 72 to 108 Gy (80-120 microCi/g), 180 to 225 Gy (200-250 microCi/g), and 270 to 364 Gy (300-405 microCi/g) in 31 patients ranging in age from 7 to 18 years old. Thyroid status was assessed >1 year after therapy.

RESULTS

We found that doses of 100 Gy (110 microCi/g), 200 Gy (220 microCi/g), and 300 Gy (330 microCi/g) resulted in hypothyroidism in 50%, 70%, and 95% of treated individuals, respectively. These data show that to insure ablation of thyroid tissue doses, >270 Gy (300 microCi/g) is needed, especially when the thyroid is large.

Multinodular goitre: 'much more to it than simply iodine deficiency'

For over a century, multinodular goitre (MNG) has been looked upon as the simple consequence of iodine deficiency. This view is now no longer tenable. Indeed, many characteristics of MNG do not fit with the iodine deficiency concept. For example, nodular goitre is a frequent disease even in those countries where the population is never exposed to iodine shortage. Moreover, neither multinodularity, nor the proverbial heterogeneity of growth and function or the autonomous, thyroid stimulating hormone (TSH)-independent growth of many goitres are compatible with the iodine deficiency concept, let alone subclinical or overt thyrotoxicosis which often complicates the course of a MNG. Recent investigations have led to the conclusion that MNGs are true benign neoplasias that are due to the high intrinsic growth potential of a variable, genetically predetermined fraction of all thyrocytes. Gross and heritable metabolic and functional differences between the individual thyrocytes, from which new follicles are generated during goitrogenesis, are the cause of the often spectacular functional and structural heterogeneity of MNG. Superimposed iodine deficiency changes the epidemiology, but not the basic mechanisms of goitrogenesis. These new pathogenetic concepts have a profound impact on the clinical management of MNG.

Radioiodine and percutaneous ethanol injection in the treatment of large toxic thyroid nodule: a long-term study

Surgery is generally recommended for large thyroid toxic nodules (TTNs). When surgery is not applicable, both radioactive iodine (RAI) and percutaneous ethanol injection (PEI) are alternative treatments. In this retrospective study, the long-term efficacy of nonsurgical treatments was evaluated in 43 patients with TTN, selected on the basis of presence of hyperthyroidism and a fairly large nodule (3- and 4-cm in diameter) completely inhibiting controlateral lobe captation during scintigraphy. Twenty-one patients were treated by RAI (administered dose 670+/-160 MBq; range 555-925) and twenty-two were treated by PEI (6+/-1 sessions; range 5-9). FT4, FT3, thyrotropin (TSH), and nodule volume were assessed before and at fixed intervals after treatment. Median follow-up was 36 months (range, 12-84). Compared to baseline values, with both therapies, serum FT4, FT3, and nodule volume were decreased (p < 0.01) and serum TSH was increased (p < 0.01), after 3 months and during the entire follow-up. Nodule volume reduction percentage was 66.8+/-22.0 and 78.4+/-18.0, in the RAI- and PEI-treated groups, respectively. At the end of follow-up, 34 patients were euthyroid (16 RAI- and 18 PEI-treated). Four RAI-treated patients (19%) showed slightly high TSH levels (4.2-5.3 mU/L), whereas three PEI-treated patients (13.6%) still had suppressed TSH levels, although being clinically asymptomatic. One RAI-treated patient (4.8%) showed overt hypothyroidism during the follow-up period and was then treated with L-thyroxin. One patient (4.6%), who was initially cured by PEI, became newly hyperthyroid during the follow-up period. Both treatments were well-tolerated. In conclusion, both of these nonsurgical treatments are effective and may be chosen also for relatively large TTNs. Specifically, RAI seems to be more effective for treating hyperthyroidism but has minimal sequelae of subclinical or clinical hypothyroidism, while, after PEI treatment the possibility of stable subclinical hyperthyroidism or hyperthyroidism relapse should be taken into account.

Systemic radiation therapy with unsealed radionuclides

Systemic unsealed radiation therapy is achieved when a radioactive substance is administered orally or parenterally and that material is concentrated in an organ or site for sufficient time to deliver a therapeutic dose of radiation. The radioactive material usually emits beta particles. In general, there is intense local radiation of the abnormal tissues, and normal organs, which do not trap the radioactive material, are exposed to a small radiation dose. The most frequent treatments involve radioiodine (131)I for hyperthyroidism and differentiated thyroid cancer. Other applications include treatment of painful skeletal metastases, polycythemia vera, malignant cysts, and neuroendocrine tumors. The treatments are usually well tolerated and not associated with long-term effects, such as cancer or infertility.

Therapeutic options in the management of toxic and nontoxic nodular goiter

Nodular goiter is present in 500 to 600 million people and is usually secondary to endemic iodine deficiency. Despite adequate iodine intake, 4% to 6% of American adults are goitrous. Sporadic nodular goiter ensues from the natural heterogeneity of thyroid follicular cells, which, when amplified by yet unidentified trophic stimuli, results in episodes of proliferating, rapidly dividing micronodules. The initial small diffuse goiter evolves into a multinodular goiter (MNG) with 1 or more dominant nodules that may or may not be autonomous. An autonomous functioning thyroid adenoma (AFTA) usually possesses a somatic gain-of-function mutation of the thyrotropin (TSH) receptor associated with rapid growth, hemorrhagic necrosis, and reparative fibrosis that accentuate goiter nodularity. Diagnostic evaluation consists of patient history and physical examination, serum TSH determination, free thyroxine and free triiodothyronine measurements, and imaging studies assessing goiter function, size, and anatomy. If treatment is required, L-thyroxine, thionamides, surgery, radioiodine (I-131), and percutaneous ethanol injection (PEI) are effective in selected patients. In euthyroid patients, L-thyroxine reduces goiter size in some patients, but continued therapy is required to prevent regrowth. Thionamides control the hyperthyroidism of toxic nodular goiter in preparation for more definitive therapy, but are rarely used long term. Surgery and I-131 are most commonly selected for definitive therapy for the toxic AFTA, and the toxic or euthyroid MNG, but PEI is effective in selected toxic AFTAs.

Percutaneous ethanol injection of large autonomous hyperfunctioning thyroid nodules

PURPOSE

To verify the effectiveness of percutaneous ethanol injection (PEI) in the treatment of large (>30-mL) hyperfunctioning thyroid nodules.

MATERIALS AND METHODS

Twelve patients (eight women, four men; age range, 26-76 years) with a large hyperfunctioning thyroid nodule (volume range, 33-90 mL; mean, 46.08 mL) underwent PEI treatment under ultrasonographic (US) guidance. US was used to calculate the volume of the nodules and to assess the diffusion of the ethanol in the lesions during the procedure. When incomplete necrosis of the nodule was depicted at scintigraphy performed 3 months after treatment, additional PEI sessions were performed.

RESULTS

Four to 11 PEI sessions (mean, seven) were performed in each patient, with an injection of 3-14 mL of 99.8% ethanol per session (total amount of ethanol per patient, 30-108 mL; mean, 48.5 mL). At scintigraphy after treatment in all patients, recovery of extranodular uptake, absence of uptake in the nodule, and normalization of thyroid-stimulating hormone (thyrotropin) levels were observed. In all patients, US showed volume reductions of 30%-50% after 3 months and 40%-80% after 6-9 months. Side effects were self-limiting in all patients. During the 6-48-month follow-up, no recurrence was observed.

CONCLUSION

PEI is an effective and safe technique for the treatment of large hyperfunctioning thyroid nodules.

Toxic nodular goiter. Toxic adenoma and toxic multinodular goiter

Solitary toxic adenoma and toxic multinodular goiter are very common forms of thyrotoxicosis around the world. Advances in molecular biology and genetics have led to new insights into the pathogenesis of these disorders. Current theories on autonomy in the thyroid are discussed in this article. The therapeutic roles of surgery, radioiodine ablation, and percutaneous ethanol administration also are reviewed.

Treatment of hyperthyroidism with radioactive iodine

Treatment of hyperthyroidism with RAI has been performed for more than a half century with efficacy and safety. For its optimal use, the physician must employ appropriate patient selection criteria and clinical judgment concerning pretreatment patient preparation. The dose of the 131I needed remains an area of uncertainty and debate; thus far, it has not been possible to resolve the trade-off between efficient definitive cure of hyperthyroidism and the high incidence of post-therapy hypothyroidism. Early side effects are uncommon and readily manageable. Other than the need for long-term monitoring and, in most cases, lifelong L-T4 treatment, late adverse consequences of this treatment remain only conjectural. The available follow-up studies support the current majority opinion of North American thyroid specialists that RAI treatment is an excellent choice for most hyperthyroid patients.

Efficacy of low doses of radioiodine in the treatment of autonomous thyroid nodules: importance of dose/area ratio

Radioiodine (131I) represents an interesting alternative to surgery in the treatment of autonomously functioning thyroid nodules (AFTN), but leads to a significant incidence of hypothyroidism when high doses are used. Over 4 years, we have treated 40 patients (hyperthyroid [Plummer's disease]: 6, single hot nodules with undetectable thyrotropin [TSH] and normal serum free thyroxine [FT4]: 34), 34 single hot nodules with undetectable thyrotropin TSH and normal serum free thyroxine [FT4] with 131I. The dose level was neither related to the concentration of FT4 nor to the iodine uptake on thyroid scintigram. Retrospectively we measured the nodule's area on the scan and calculated the dose/area ratio (DAR). Three months after treatment, 30 patients were euthyroid, 9 were still hyperthyroid, and 1 was hypothyroid. The mean DAR of the euthyroid patients was twofold higher than for the hyperthyroid subjects (1.4 +/- 0.8 vs. 0.7 +/- 0.3 mCi/cm2; p = .003) and one-half the DAR for the hypothyroid patient (2.82 mCi/cm2). Twenty of the 30 euthyroid patients had received a dose higher than 1 mCi/cm2 and 7 of 9 hyperthyroid patients had received a dose lower than 1 mCi/cm2. (chi2 = 12.9; p = .02). The initial values of T4, TSH, and dose level of patients who were euthyroid or hyperthyroid at 3 months were not different. These data suggest that the efficacy of 131I for treating AFTN depends on the DAR, rather than the initial T4 value or the 131I uptake. A DAR between 1 and 1.5 mCi/cm2 seems to be optimal and avoids hypothyroidism.

Resolution of hyperthyroidism in a pregnant woman with toxic thyroid nodule by percutaneous ethanol injection

Overt hyperthyroidism was found in a 35-year-old pregnant woman at the 13th week of gestation who was referred to us for tachycardia, tremors, and weight loss. Clinical signs, symptoms, and laboratory findings led to the diagnosis of toxic thyroid nodule. She was treated with ultrasound guided percutaneous ethanol injection (PEI) and, after 2 weeks of treatment, the woman was completely euthyroid. These findings suggest that during pregnancy PEI appears to be a rapid and safe therapy for toxic nodular goiter and an effective alternative to the administration of antithyroid drugs.

Radioiodine-associated thyroid cancers

Numerous investigations document that exposure to low dose external therapeutic radiation leads to the development of benign and malignant thyroid neoplasms. There is considerable controversy, however, concerning whether radioactive iodine (131I) causes thyroid cancer. The aim of this investigation was to examine our experience and that in the literature related to this problem. From 1982 to March 1993 seven of 373 patients (1.9%) with thyroid cancer who were treated by one surgeon had a history of treatment with radioactive iodine for Graves' disease and toxic nodular goiter. Sixty-five patients have previously been reported in the literature from 1957 to present. Our patients (five women, two men) ranged in age from 26 to 80 years (mean 57 years). The interval between the exposure to the internal radiation and development of cancer ranged from 3 to 29 years (mean 11.4 years), and the mean age at the time of 131I treatment was 45 years (18-76 years). The therapeutic dose of 131I was 5 to 100 mCi (mean 25.3 mCi) in our patients. Two of our patients received 131I twice. The age of patients reported in the literature at the time of 131I treatment ranged from 7 to 74 years (mean 48 years). The mean therapeutic dose of 131I was 20.6 mCi (1.25-180.0 mCi) and the latent period was documented for a mean 8.7 years (0.25-28.0 years) in these patients. Three of 29 patients in the literature received 131I twice. Fine-needle aspiration cytology of thyroid nodules was positive for cancer in six of our patients (86%).(ABSTRACT TRUNCATED AT 250 WORDS)

Percutaneous ethanol injection treatment of autonomously functioning single thyroid nodules: optimization of treatment and short term outcome

Twenty-five patients with solitary autonomous thyroid nodules (15 nontoxic, 10 toxic) received percutaneous ethanol injection treatment (PEIT) under sonographic guidance in 4-7 sessions (1-2 weekly). To test different doses, smaller nodules (volume less than 15 mL) were given 0.75-2.8 mL ethanol/mL nodular tissue while larger nodules received 0.5-1 mL/mL. Except for 1 patient who developed hyperpyrexia, no relevant adverse effects were observed. A slight, asymptomatic increase in serum thyroid hormone levels was observed in both groups during the treatment. Three months after treatment, a biochemical and clinical remission of hyperthyroidism was observed in 8 of 10 patients with toxic nodules. A significant increase of TSH level was seen in both groups (p less than 0.01). Significant shrinkage of volume (p less than 0.001) as well as structural alterations of nodules were consistently recorded at sonography. A linear relationship (r = 0.98; p less than 0.0001) between pretreatment volume and volume reduction was found both for large and small nodules, thus suggesting that even limited ethanol doses may be therapeutically effective. A recovery of extranodular parenchyma activity at scintiscan occurred in 16 (64%) of 25 patients. These data confirm that PEIT is effective in obtaining functional ablation and in inducing remission of hyperthyroidism. Adverse effects are infrequent. In spite of the small patient sample, a 0.5-1 mL ethanol dose per each mL of tissue appears as effective as larger doses and seems appropriate for treatment.

Percutaneous ethanol injection treatment of autonomous thyroid adenoma: hormonal and clinical evaluation

OBJECTIVE

We have evaluated the efficacy of percutaneous ethanol injection as an alternative to surgery and iodine-131 treatment in solitary autonomous thyroid adenoma.

DESIGN

Percutaneous ethanol injection (0.5-2.8 ml ethanol/ml nodular tissue) was performed under sonographic guidance in 3-5 (1-2 weekly) sessions; a 7.5 MHz linear real-time scanner (Toshiba, mod. 32B) was used for sonographic studies. The thyroid hormone profile was assessed during treatment and for the next 6 months.

PATIENTS

Fifty-six patients (40 females, 16 males, mean age 46 +/- SD 9 years; 30 pretoxic, 26 toxic) were included in the study: their pretreatment technetium-99 m thyroid scan showed a single hot nodule with total suppression of extranodular tissue in 45 and near-total suppression in 11.

MEASUREMENTS

Thyroid hormones, antithyroglobulin and antiperoxidase antibodies were measured by specific radioimmunoassay, while thyrotrophin was evaluated by ultrasensitive immunoradiometric assay.

RESULTS

Apart from a case of transient pyrexia, no relevant adverse effects were observed. A slight thyroid hormone increase was seen in both groups immediately following a treatment. Six months after therapy a biochemical and clinical remission of hyperthyroidism was observed in 18 out of 22 toxic patients (81.8%); a significant increase of TSH levels was seen in both groups (P less than 0.01). With follow-up, significant volume shrinkage (P less than 0.001) as well as structural alterations of the nodule were consistently recorded at sonography; a linear relationship (r = 0.98; P less than 0.0001) between pretreatment volume and volume reduction was found. At scintiscan, functional activity of extranodular parenchyma was found in 40 out of 56 patients (71.4%), 16/26 (61.5%) in the hyperthyroid group, 24/30 (80.0%) in the pretoxic group.

CONCLUSIONS

These data confirm that percutaneous ethanol injection is effective in obtaining functional ablation and in inducing remission of hyperthyroidism, when present; adverse effects seem infrequent.

Radiation dose assessments in radioiodine (131I) therapy. 1. The necessity for in vivo quantitation and dosimetry in the treatment of carcinoma of the thyroid

In order to destroy thyroid cancer metastases by radioiodine an average tissue dose of 80-300 Gy is needed. Such high doses can be expected, following the administration of the conventional 5.5 GBq of 131I, only if both the percentage uptake per gram in the target tissue and the effective half life of the radioiodine in it are higher than well-defined threshold values, and if every dimension of the tissue exceeds several millimeters. The fulfillment of such favourable conditions in actual clinical cases can only be confirmed by in vivo quantitation of the absorbed dose achieved as a result of the administration of radioiodine.

Solitary thyroid nodule: diagnosis and management

Thyroid nodules are common. Most are benign lesions since clinically important thyroid carcinoma is a relatively rare disease. The most sensitive and specific test for the diagnosis of thyroid cancer is fine-needle aspiration biopsy, but its diagnostic accuracy depends upon whether or not one excises all suspicious nodules, thus including them as correctly diagnosed. Nevertheless, fine-needle aspiration biopsy is the most sensitive, specific, and cost-effective test for thyroid cancer. Therapy depends upon the cause of the thyroid nodule.

Current management of the patient with autonomously functioning nodular goiter

Autonomously functioning thyroid nodules (AFTNs) are presumably independent of TSH for growth and function and appear "hot" on scintiscan because they selectively concentrate radionuclide to a greater extent than the remaining thyroid gland, which is controlled by the normal TH-TSH feedback mechanism. Such autonomously functioning tissue may occur in "patchy" areas, as a solitary nodule, or as multiple nodules (classic Plummer's disease), with the mass of hyperfunctioning tissue and the related secretion of thyroid hormones determining whether the patient is euthyroid or hyperthyroid. Important diagnostic tests include a 99mTc thyroid scan, T4 RIA, T3 uptake, FTI, TSH RIA, and occasionally T3 RIA ("T3 thyrotoxicosis"). Solitary autonomous nodules in adult patients characteristically progress slowly over many years, with toxicity rarely developing in nodules less than 2.5 cm in diameter and occurring primarily in nodules 3 cm or larger and in older patients. The decision to treat a solitary nodule depends upon the size and degree of function of the nodule and the patient's age. Surgery and radioactive iodine are effective therapies. Hyperfunctioning thyroid nodules in children and adolescents (under age 18) have a more rapidly progressive course than those in adults and should be treated by thyroid lobectomy at the time of diagnosis. Subtotal thyroidectomy is the preferred treatment for most patients with toxic multinodular goiter, because it achieves prompt control of the hyperthyroidism and removes the goiter. Radioiodine therapy and long-term antithyroid drug therapy are alternative forms of treatment for patients who are poor surgical risks or who develop recurrent hyperthyroidism following thyroid surgery.

Radioiodine treatment of solitary functioning thyroid nodules

Forty-eight patients with hyperthyroidism due to a single toxic nodule have been treated with radioiodine (131I). The mean follow-up period is 37 months. All patients were rendered euthyroid and no cases of hyperthyroidism have been observed. Forty patients required only one dose of 131I to render them euthyroid, six patients required more than one dose and two patients initially rendered euthyroid relapsed during follow-up and required further 131I treatment. It is concluded that a single fixed dose of 131I is a simple, effective treatment for a solitary toxic thyroid nodule and does not cause hypothyroidism.

Surgery for thyroid disease

Thyroidectomy is the keystone of management in most patients with thyroid cancer, and has unique advantages in many cases of hyperthyroidism. The role of thyroidectomy in these two conditions is considered, with specific discussion of indications, extent of operation, complications, and technique.

Follow-up of solitary autonomous thyroid nodules treated with 131I

We studied the long-term effects of 131I therapy for solitary autonomous thyroid nodules on the size of the nodule and on thyroid function. Twenty-three patients with autonomous thyroid adenomas that had been treated with 131I from 4 to 16.5 years earlier (mean, 8.5) were examined, and their thyroid function was tested. In 12 patients (54 per cent), the nodules were still palpable, and in 2 they had increased in size. Eight patients (36 per cent) had become hypothyroid. The incidence of hypothyroidism was not related to nodule size or the level of thyroid function before therapy with 131I or to the total dose of 131I that had been given. We conclude that 131I therapy for autonomous thyroid adenoma often causes hypothyroidism and in many cases does not eradicate the offending nodule.

Solitary thyroid nodule. 2. Selective approach to management

Ordinarily, the history and physical examination and routine tests, including thyroid function tests, iodine 123 or technetium Tc 99m scans, and echography, will determine the best therapeutic approach to a solitary thyroid nodule. In the case of an asymptomatic, hypofunctional solid nodule, thyroid hormone suppression and fine-needle aspiration biopsy may be necessary to further delineate the best therapy.