Radioiodine treatment for differentiated thyroid cancer

I-131 false-positive uptake in a thymic cyst with expression of the sodium-iodide symporter: A case report

RATIONALE

I-131 radioiodine false-positive findings in postoperative patients with differentiated thyroid cancer (DTC) should be recognized to avoid unnecessary therapies.

PATIENT CONCERNS AND DIAGNOSES

A 50-year-old man underwent I-131 therapy 3 times, including the initial ablative therapy after total thyroidectomy for papillary thyroid cancer. The initial I-131 posttherapeutic whole-body scintigraphy showed 2 cervical and one superior mediastinal focal I-131 positive uptake lesions. The serum thyroglobulin level was negative every time when the radioiodine therapy was performed. Although the 2 cervical positive uptake lesions disappeared after the second therapy, the superior mediastinal I-131 positive uptake persisted even after the third therapy, and this lesion was suspicion of I-131 therapy-resistant node metastasis.

INTERVENTIONS AND OUTCOMES

The lesion was resected, and the pathological diagnosis with immune-histochemical analysis was a thymic cyst with thymic epithelial cells having a weak expression of the sodium-iodide symporter (NIS).

LESSONS

The false-positive result may be attributed to the NIS expression in the thymic cyst epithelial cells. It is necessary to include a thymic cyst in the differential diagnosis, when I-131 uptake is noted in the superior mediastinal region on I-131 posttherapeutic scans of patients with postoperative DTC. Although the I-131 positive uptake in a thymic cyst may be influenced by the I-131 administered dose and scan timing after I-131 administration, the NIS expression may be essential to the false-positive uptake in a thymic cyst.

Adrenocortical adenoma manifesting as false-positive iodine accumulation in a patient with history of thyroid carcinoma

A 47-year-old female diagnosed with well-differentiated papillary thyroid carcinoma was referred to our center for a ¹³¹Iodine whole body scintigraphy as follow-up. The patient had been previously treated with total thyroidectomy and ablative dose of 175mCi ¹³¹I three years ago. Diagnostic ¹³¹I scan showed a zone of radioiodine uptake in posterior aspect of the left upper quadrant of the abdomen. Spiral abdominal and pelvic CT scan showed an enhancing solid mass in superior aspect of the left adrenal gland, which was in favor of metastasis to the lymph node or an adrenal tumor. A biopsy was performed from the lesion. Histological examination of the surgical specimen was consistent with adrenocortical adenoma. Even though rare, adrenocortical adenoma should be included in the potential causes of false-positive results of radioiodine scans.

Autosomal dominant polycystic kidney disease: a potential mistake in the interpretation of radioiodine whole-body scintigraphy

There are a few case reports of renal cysts demonstrating radioiodine uptake on scintigraphy. In this case, we report a 49-year-old man who had undergone total thyroidectomy and had been treated with radioiodine. After conventional levothyroxine withdrawal, the patient underwent thyroid remnant ablation by oral administration of 125 mci ¹³¹I. Seven days later, post-therapy whole-body scan demonstrated thyroid remnant tissue and bilaterally multifocal radioiodine uptake in the upper abdomen. By ultrasonography and abdominal computed tomography scan, the iodine uptake was proven to be due to the accumulation of ¹³¹I in bilateral polycystic kidney disease.

It is no longer the time to disregard thyroid metastases from breast cancer: a case report and review of the literature

BACKGROUND

Metastases to the thyroid gland are more frequent than previously thought, although most of them are occult or not clinically relevant. Overall, only 42 cases of metastases to thyroid from breast cancer have been reported thus far. Here we report the case of a patient with breast cancer metastatic to the thyroid. We also review the 42 previously reported cases (published between 1962 and 2012). This is the first review about metastases to thyroid gland from breast cancer.

CASE PRESENTATION

A 64-year-old woman of Caucasian origin was diagnosed with a lobular invasive carcinoma of the breast (luminal A, stage II). She received adjuvant chemotherapy, followed by endocrine therapy. During follow-up, fine-needle cytology of a thyroid nodule revealed malignant cells that were estrogen-positive, which suggested a diagnosis of metastases to the thyroid. Imaging did not reveal any other metastatic site and showed only enlargement of the left thyroid lobe and an inhomogeneous pattern of colloid and cystic degeneration and calcifications. The patient underwent left hemithyroidectomy. Histology of thyroid tissue showed a colloid goitre containing dispersed small atypical neoplastic cells with eccentric nuclei. Immunohistochemistry showed cytokeratin-19 and oestrogen receptor, but not tireoglobulin, e-cadherin or cytokeratin-7, thereby confirming metastases from a lobular breast carcinoma. Hormonal treatment is ongoing.

CONCLUSION

This case report and first review of the literature on metastases to thyroid from breast cancer highlight the importance of a correct early diagnostic work-up in such cases. Indeed, a primary lesion should be distinguished from metastases given the different treatment protocol related to primary cancer and the clinical impact on prognosis.

Hiatal hernia uptake of iodine-131 mimicking mediastinal metastasis of papillary thyroid carcinoma

There are a few case reports of hiatal hernia demonstrating thoracic uptake on I-131 scintigraphy. In this case, high thyroglobulin levels in combination with misinterpretation of I-131 uptake in the mediastinum, leaded to mismanagement of the patient. Here we present a case of focal I-131 uptake within a hiatal hernia initially mimicking an isolated mediastinal metastasis. There are many potential causes of false-positive I-131 scan result. In this case, adjunctive chest computed tomography and gastroesophageal barium study helped to elucidate the true nature of this I-131 uptake. False-positive findings may be caused by a wide variety of nonthyroidal carcinomas, which can concentrate radioiodine or from skin contamination. Several organs, such as the gastric, salivary glands, renal cyst, pericardial effusion, and ovarian can accumulate I-131. It should be borne in mind as a potential source of false-positive whole-body I-131 imaging.

Analytical functions for beta and gamma absorbed fractions of iodine-131 in spherical and ellipsoidal volumes

BACKGROUND

The beta and gamma absorbed fractions in organs and tissues are the important key factors of radionuclide internal dosimetry based on Medical Internal Radiation Dose (MIRD) approach.

OBJECTIVES

The aim of this study is to find suitable analytical functions for beta and gamma absorbed fractions in spherical and ellipsoidal volumes with a uniform distribution of iodine-131 radionuclide.

METHODS

MCNPX code has been used to calculate the energy absorption from beta and gamma rays of iodine-131 uniformly distributed inside different ellipsoids and spheres, and then the absorbed fractions have been evaluated.

RESULTS

We have found the fit parameters of a suitable analytical function for the beta absorbed fraction, depending on a generalized radius for ellipsoid based on the radius of sphere, and a linear fit function for the gamma absorbed fraction.

CONCLUSION

The analytical functions that we obtained from fitting process in Monte Carlo data can be used for obtaining the absorbed fractions of iodine-131 beta and gamma rays for any volume of the thyroid lobe. Moreover, our results for the spheres are in good agreement with the results of MIRD and other scientific literatures.

Diagnostic Whole-Body Scan May Not Be Necessary for Intermediate-Risk Patients with Differentiated Thyroid Cancer after Low-Dose (30 mCi) Radioactive Iodide Ablation

BACKGROUND

A diagnostic whole-body scan (WBS) is recommended 6 to 12 months after total thyroidectomy and radioactive iodide ablation in intermediate- or high-risk patients with differentiated thyroid cancer (DTC). The aim of this study was to evaluate the necessity of a diagnostic WBS after radioactive iodide ablation in intermediate-risk patients with DTC.

METHODS

A total of 438 subjects were included in the study: 183 low-risk subjects and 255 intermediate-risk subjects according to the American Thyroid Association guideline. All subjects diagnosed with DTC received 1,100 MBq (30 mCi) activity of radioiodine (I-131) following total thyroidectomy. On follow-up, all subjects underwent a diagnostic I-131 WBS after thyroid hormone withdrawal.

RESULTS

After initial radioactive iodide ablation, 95.1% of low-risk patients and 91.4% of intermediate-risk patients showed no uptake on diagnostic WBS (P=0.135). Intermediate-risk patients with stimulated thyroglobulin (Tg) levels higher than 2.0 ng/mL showed a greater rate of radioactive iodine uptake on diagnostic WBS. Four intermediate-risk patients showed recurrence during the 16 to 80 months follow-up period. Three of the four patients with recurrence showed no uptake on diagnostic WBS and had a stimulated Tg level less than 2.0 ng/mL.

CONCLUSION

A diagnostic I-131 WBS after radioactive iodide ablation in intermediate-risk patients with DTC may not be necessary. A large prospective study is necessary to determine the necessity of diagnostic WBS in intermediate-risk patients with DTC.

The biology of the sodium iodide symporter and its potential for targeted gene delivery

The sodium iodide symporter (NIS) is responsible for thyroidal, salivary, gastric, intestinal and mammary iodide uptake. It was first cloned from the rat in 1996 and shortly thereafter from human and mouse tissue. In the intervening years, we have learned a great deal about the biology of NIS. Detailed knowledge of its genomic structure, transcriptional and post-transcriptional regulation and pharmacological modulation has underpinned the selection of NIS as an exciting approach for targeted gene delivery. A number of in vitro and in vivo studies have demonstrated the potential of using NIS gene therapy as a means of delivering highly conformal radiation doses selectively to tumours. This strategy is particularly attractive because it can be used with both diagnostic (99mTc, 125I, 124I)) and therapeutic (131I, 186Re, 188Re, 211At) radioisotopes and it lends itself to incorporation with standard treatment modalities, such as radiotherapy or chemoradiotherapy. In this article, we review the biology of NIS and discuss its development for gene therapy.

The management of advanced thyroid cancer

Although the prognosis of the majority of patients with thyroid cancer is excellent there are some patients with advanced thyroid cancer in whom the prognosis is poor. Such patients include: patients with locally invasive or recurrent differentiated thyroid cancer and medullary thyroid cancer, and all patients with anaplastic cancer. The management of patients with advanced thyroid cancer is reviewed with emphasis on the role of external beam radiotherapy.

Metastases to the thyroid gland: the Royal Marsden experience

AIM

A review of patients seen at the Royal Marsden Hospital with metastases to the thyroid gland.

METHOD

Experience reported on 15 patients that were seen at our institution between 1985 and 2002.

RESULTS

The most common site of origin was the kidney (4/15). Ages ranged between 26 and 76 years. Twelve presented with a neck mass. Most had metastatic disease elsewhere at the time of presentation (9/15). Diagnosis was made by fine needle aspiration cytology (5), tru-cut biopsy (1), or surgery (9); surgery comprised total thyroidectomy (3), subtotal thyroidectomy (3) or lobectomy (3). Radiotherapy resulted in disease stabilisation in three patients. Chemotherapy was used to treat local recurrence in two patients post-operatively. The interval from diagnosis of the primary tumour to thyroid metastasis varied from 0 months to 15 years. Thyroid gland metastasis was the initial manifestation of metastatic disease in five patients. Five patients are alive, with one disease free 7 years following resection of the thyroid metastasis.

CONCLUSIONS

Thyroid metastases are clinically rare, with the kidney the most common primary site of origin. They usually occur when there are metastases elsewhere, sometimes many years after diagnosis of the original primary tumour. Surgical resection of an isolated metastasis may result in prolonged disease-free survival. Radiotherapy and chemotherapy may be of value in specific situations.

Treatment of advanced differentiated thyroid carcinoma with high activity radioiodine therapy

OBJECTIVES

This was a retrospective study to assess the efficacy and morbidity of high activity I therapy in patients with advanced differentiated thyroid carcinoma.

METHODS

From 1975 to 2003, 38 patients with locally advanced or metastatic differentiated thyroid cancer (16 follicular, 20 papillary, one Hurthle cell, one insular) were treated with high activity radioiodine therapy (9 GBq) as the cancers had previously not responded to standard activities (5.5 GBq).

RESULTS

Cumulative total activities received ranged from 11.8 to 84.5 GBq (mean 29.4 GBq per patient). Staging at presentation showed pT4 and/or M1 disease in 27/38 of patients (71.1%). Moderate (grade 2) and poorly differentiated (grade 3) tumours were present in a total of 9/38 patients (23.7%). Outcomes were evaluated according to the results of I whole-body scans, serum thyroglobulin, radiological assessments and physical examination. Neither [18F]flurodeoxyglucose positron emission tomography (F-FDG PET) nor 99mTc sestamibi were available during this study. The mean duration of follow-up was 83 months. A complete response was observed in 7/38 patients (18.4%), progressive disease in 27/38 (71.1%) and stable disease in 4/38 (10.5%). The mean survival from initiation of high activity treatment was 36.6 months. For patients with lung disease the mean survival was 45 months, neck disease 38.9 months, bone disease 35 months and multiple sites was 30.9 months. Twelve patients died during follow-up (10 due to thyroid carcinoma). After high activity treatment, 9.7% of patients suffered grade 3 and 3.2% suffered grade 4 WHO haematological toxicity. Significant salivary gland morbidity was observed (30% dry mouth, 27% salivary swelling).

CONCLUSIONS

Repeated treatment with high activity (9 GBq) I in patients with advanced differentiated thyroid carcinoma appears to be of no apparent benefit and may lead to late morbidity.

Indium-111-labelled octreotide scintigraphy in the diagnosis and management of non-iodine avid metastatic carcinoma of the thyroid

Treatment of differentiated thyroid cancer is a success of modern medicine with the use of radioiodine ((131)I). However, a significant proportion of thyroid cancers may be non-iodine avid. Thyroid tumours are known to express somatostatin receptors. Octreotide, an analogue of somatostatin, can be combined with a radioactive isotope, such as (111)In-DTPA(0) to visualise tumours with high concentrations of somatostatin receptors. We assessed 18 patients with histologically proven metastatic or locally recurrent non-iodine avid thyroid carcinoma to determine the usefulness of (111)In-DTPA(0) octreotide scintigraphy compared to conventional radiology in diagnosing sites of metastasis. The diagnosis of metastatic disease was made using conventional radiology and all had prospective scintigraphy using (111)In-DTPA(0)octreotide. Of the 18 patients, 14 had octreotide-positive scans. In eight, the octreotide scans identified the same sites of metastases as conventional radiology, that is, were concordant. In nine patients, conventional radiology showed more extensive disease than revealed on the octreotide scans. In one patient with widespread bone metastases, octreotide gave a more detailed assessment of metastatic disease than conventional radiology. These data indicate that (111)In-DTPA(0)octreotide imaging for patients with non-iodine avid carcinoma of the thyroid may be a useful diagnostic and staging tool. One patient with Hurthle cell carcinoma metastatic to bone and a positive octreotide scan has been treated with (90)yttrium-labelled octreotide.

Long-term results in elderly patients with differentiated thyroid carcinoma

BACKGROUND

The authors assessed the biologic behavior of differentiated thyroid carcinoma in patients age 70 years or older and evaluated factors that influenced long-term survival.

METHODS

Among 1448 patients with differentiated thyroid carcinoma who were treated at the authors' institution over the past 60 years, 111 patients were identified who were age 70 years or older at the time of their initial diagnosis (range, 70-93 years). The authors conducted a retrospective analysis of the outcome of these 111 patients, who had a median follow-up of 9 years (range, 2-9 years).

RESULTS

There were 83 female patients and 28 male patients (female to male ratio, 3:1). Fifty-eight tumors were papillary, 46 tumors were follicular, and 7 tumors were Hürthle cell carcinoma. Eighty percent of patients presented with a thyroid mass, and 70% of tumors were pathologic stage T3 (pT3) or pT4. Lymph node disease was evident at presentation in 44% of patients, and distant metastases were documented at diagnosis in 23% of patients. Forty-six patients underwent total thyroidectomy, and the remaining patients underwent subtotal thyroidectomy or biopsy only. Radioiodine was administered to 80 patients, and external beam radiotherapy was administered to 19 patients. The cause specific survival rates were 75%, 50%, and 50% at 5 years, 10 years, and 15 years, respectively. Multivariate analysis showed that the presence of metastases was the most important independent prognostic factor for survival. External beam radiotherapy was associated with a poorer prognosis, in that it was reserved for patients with either inoperable disease or residual disease after surgery and patients with no uptake of radioiodine.

CONCLUSIONS

A large proportion of thyroid tumors showed extrathyroid spread and distant metastases, which frequently were not iodine-avid. The prevalent histologic type was papillary, often with features of poor differentiation. Thyroid carcinoma in the elderly appears to behave more aggressively, and they have a less favorable prognosis compared with younger adults.

Postoperative Surveillance of Differentiated Thyroid Carcinoma: A Selective Approach

This review was conducted to evaluate the selective use of 131I whole-body scanning (WBS) and radioablation (RA) after thyroidectomy for patients with differentiated thyroid carcinoma (DTC). A review of patients undergoing thyroidectomy for DTC between July 1, 1980 and December 31, 1999 was performed. Postoperative surveillance involved a selective RA protocol based on a modification of the AMES criteria (age, metastases, extent of cancer, size, and multifocality of tumor). Lower-risk patients were followed by yearly thyroglobulin (Tg) levels and physical examinations (PE) whereas higher-risk patients additionally underwent WBS and RA when appropriate. Three hundred forty-three patients were identified; of these 27 per cent had positive lymph nodes or metastatic disease at their initial operation. Two hundred thirteen (64%) patients underwent postoperative WBS with 174 (82%) requiring RA. One hundred thirty (36%) low-risk patients were followed with yearly Tg and PE that when abnormal led to WBS and RA. No additional patient morbidity or mortality resulted from this protocol. Factors identified during multivariate analyses as being predictive of occult metastasis and recurrence ( P < 0.05) included tumor size and lymph node status. These data support a selective approach to the postoperative surveillance of DTC using Tg and PE to monitor low-risk patients and WBS for those with a higher risk of recurrence.

Management of thyroid cancer

Thyroid cancers are a diverse group of malignant disorders ranging from indolent micropapillary carcinoma, which has no effect on life expectancy, to anaplastic tumours, which are invariably fatal even with aggressive treatment. Although the estimated incidence has increased by 14.6% over the past 40 years, the estimated death rate has fallen by 21%, probably as a result of earlier diagnosis. The natural history of thyroid tumours is no longer a mystery, and the prognostic factors identified can predict outcome fairly accurately. Improvements in management have mostly depended on information from large retrospective series, though there are still many areas open to debate. There has been, however, a general acceptance that thyroid cancer should be managed by multidisciplinary teams in specialised units following evidence-based guidelines.

Papillary thyroid carcinoma: prognostic factors and the role of radioiodine and external radiotherapy

PURPOSE

To evaluate the role of radioiodine and external radiotherapy treatment in papillary thyroid carcinoma (PTC).

METHODS AND MATERIALS

This is a retrospective study of 842 patients with the diagnosis of PTC registered from 1960 to 1997 at the Department of Clinical Oncology, Queen Elizabeth Hospital, Hong Kong. The mean follow-up was 9.2 years. The stage distribution according to UICC/AJCC TNM staging was as follows: 58.6%, Stage I; 9.6%, Stage II; 26.1%, Stage III; 2.3%, Stage IV; and 3.4%, not stated.

RESULTS

The 10-year cause-specific survival (CSS) rates were as follows: Stage I, 99.8%; Stage II, 91.8%; Stage III, 77.4%; and Stage IV, 37.1%. Multivariate analysis showed that the statistically significant poor prognostic factors for CSS were as follows: age older than 45, postoperative gross locoregional (LR) residual disease, distant metastasis (DM) at presentation, and lack of radioactive iodine (RAI) treatment. In patients with no DM and no postoperative LR disease, adjuvant RAI ablation reduced both LR failure (RR [relative risk] = 0.29) and DM (RR = 0.2), although the CSS was not affected. In the subgroup of T1N0 M0 disease, no patient with RAI treatment had a relapse. External radiotherapy reduced the risk of LR failure to 0.35. Subgroup analysis revealed that external radiotherapy was particularly effective in increasing the probability of LR control of disease in patients with gross postoperative LR disease (RR = 0.36).

CONCLUSIONS

Both RAI and external radiotherapy were effective treatment in PTC. Total or near-total thyroidectomy followed by RAI treatment appears to result in the best outcome. External radiotherapy to improve LR control is indicated in patients with gross postoperative residual disease. Treatment should be individualized for patients with T1N0 M0 disease.

Prognosis for fertility and ovarian function after treatment with radioiodine for thyroid cancer

The aim of this study was to review the outcome of ablative radioiodine treatment on ovarian function in young women treated for differentiated thyroid carcinoma. Of 1398 patients with differentiated thyroid cancer, 496 were women under the age of 40 at the time of diagnosis who had received radioiodine therapy. Of these, 322 received a single 3 GBq ablation dose of radioiodine while the remainder received subsequent treatment with (131)I with a cumulative activity of 8.5-59 GBq for residual, recurrent, or metastatic disease. Transient amenorrhoea or menstrual irregularities lasting up to 10 months were experienced in 83 patients (17%). No cases of permanent ovarian failure were recorded. There were 427 children born to 276 women; only one patient wishing to achieve a successful pregnancy outcome has been unsuccessful. Four premature births and 14 miscarriages occurred but no congenital abnormalities were reported. The risk of permanent damage to the ovaries after ablative radioiodine treatment appears to be low and patients can be reassured they can have normal pregnancies after this treatment.