An evaluation of thallium imaging for detection of carcinoma in clinically palpable solitary, nonfunctioning thyroid nodules

Evaluation and imaging of a thyroid nodule

The approach to the thyroid nodule has been incrementally modified over the past decade. The widespread adoption of fine needle aspiration in the 1980s, coupled with increased use of serial ultrasound monitoring, arguably led to the biggest changes in recommendations for surgical intervention during the past 50 years. For the office-based practitioner, thyroid nodule presentation patterns are changing with discoveries of more thyroid "incidentalomas" and with new risk assessment challenges associated with small (<1 cm) nodules. At the same time, improved primary evaluation techniques, most notably the increasing use of small, portable ultrasound imaging units, are making many clinicians more comfortable in recommending less invasive follow-up.

Medullary thyroid cancer: medical management and follow-up

Medullary thyroid carcinoma (MTC) is a neuroendocrine malignancy that occurs in hereditary (25%) and sporadic (75%) clinical settings. MTC is present in all patients with the multiple endocrine neoplasia type 2 (MEN 2) syndromes. MTCs produce calcitonin, measurement of which indicates the presence of tumor in at-risk individuals and the effectiveness of therapy in treated patients. Surgery is the mainstay of therapy for primary and recurrent disease. Routine serial postoperative measurement of calcitonin levels should be done. Patients with elevated calcitonin levels should have imaging by computed tomography scan, magnetic resonance imaging, and/or fluorodeoxyglucose positron emission tomography to identify sites of recurrence and metastasis. The role of radiation therapy is not well defined. There is no effective systemic therapy for MTC at present. Activating mutations in a tyrosine kinase receptor gene are present in the majority of MTCs, and experience with tyrosine kinase inhibitors and other agents in the setting of clinical trials is critical for the identification of effective systemic treatment.

[Diagnosis of thyroid nodule. Application of evidence-based medicine]

OBJECTIVE

The frequency of thyroid nodules requires an appropriate and consistent undertaking of such pathology by the entire medical profession. Over the past few years, the ANAES (National Agency of Health Accreditation and Evaluation - 1995 - 1997) had formulated medical recommendations. Our work aimed at updating such recommendations considering recent literature developments and their level of evidence.

MATERIAL AND METHODS

We have selected high-level of evidence's articles published since 1997 dealing with the diagnostic undertaking of thyroid nodule. Such analysis was conducted using the search engine "Medline" and the level of evidence of the selected articles was evaluated by taking into account the professional recommendations of the "literature analysis and gradation of recommendations' guide" of ANAES.

RESULT

At present, two diagnostic tests are necessary in the diagnostic evaluation of a thyroid nodule (ultrasonography and fine-needle aspiration).

CONCLUSION

The medical recommendation will hence result in the synthesis of these two different diagnostic tests, nevertheless fine-needle aspiration being essential and having priority in evaluating the risk of cancer.

Comparison of thallium-201 SPET and CT/MRI in the detection of residual/recurrent squamous cell carcinoma of the oral cavity

This study was designed to compare the effectiveness of thallium-201 single-photon emission tomography (SPET) and conventional imaging, comprising computed tomography (CT) and magnetic resonance imaging (MRI), in the detection of residual/recurrent squamous cell carcinoma (SCC) of the oral cavity. Thirty-two patients with clinically suspected recurrent SCC of the oral cavity were recruited. All patients underwent (201)Tl SPET and CT or MRI within 2 weeks. The final diagnoses were based on the histology of the biopsy specimen. (201)Tl SPET and CT/MRI both accurately detected 17 of 18 residual/recurrent tumours. CT/MRI yielded eight false-positive studies, whereas (201)Tl SPET successfully excluded all tumours. The sensitivity, specificity, positive and negative predictive values and accuracy of (201)Tl SPET for the detection of recurrent oral SCC were 94%, 100%, 100%, 93% and 97%, respectively. The sensitivity, specificity, positive and negative predictive values and accuracy of CT/MRI for the detection of recurrent oral SCC were 94%, 43%, 68%, 86% and 72%, respectively. Thallium-201 SPET is more accurate than conventional imaging (CT or MRI) in differentiating residual/recurrent oral SCC from post-therapy changes.

Evaluation of a thyroid nodule

Solitary thyroid nodules are common entities and the majority of these are benign. The main goal in evaluating these nodules is to identify the [figure: see text] nodules with malignant potentials. A multitude of diagnostic tests is available to the clinician. FNA biopsy is now considered the gold standard diagnostic test in the evaluation of a thyroid nodule. Ultrasound and nuclear scans are also useful tests, but are best used in conjunction with FNA. Clinical decisions are often based on the results of the FNA. A diagram of the clinical decision process based on FNA findings is presented in Fig. 1. Despite the clinical advantages that are provided by the FNA results, the clinician should not dismiss the importance of other clinical prognostic indicators to optimize timely treatment.

Management of simple nodular goiter: current status and future perspectives

The simple nodular goiter, the etiology of which is multifactorial, encompasses the spectrum from the incidental asymptomatic small solitary nodule to the large intrathoracic goiter, causing pressure symptoms as well as cosmetic complaints. Its management is still the cause of considerable controversy. The mainstay in the diagnostic evaluation is related to functional and morphological characterization with serum TSH and (some kind of) imaging. Because malignancy is just as common in patients with a multinodular goiter as patients with a solitary nodule, we support the increasing use of fine-needle aspiration biopsy (cytology). Most patients need no treatment after malignancy is ruled out. In case of cosmetic or pressure symptoms, the choice in multinodular goiter stands between surgery, which is still the first choice, and radioiodine if uptake is adequate. In addition to surgery, the solitary nodule, whether hot or cold, can be treated with percutaneous ethanol injection therapy. If hot, radioiodine is the therapy of choice. Randomized studies are scarce, and the side effects of nonsurgical therapy are coming into focus. Therefore, the use of the optimum option in the individual patient cannot at present be based on evidence. However, we are of the view that levothyroxine, although widely used, should no longer be recommended routinely for this condition. Within a few years, the introduction of recombinant human TSH and laser therapy may profoundly alter the nonsurgical treatment of simple nodular goiter.

Endocrine tumors: evaluation of the thyroid nodule

Thyroid nodules are found in 4 to 7% of the population, and with the increased use of radiographic methods, incidental nodules are becoming more prevalent. Only 5% of all nodules will be malignant, and thyroid cancer accounts for only 0.4% of all cancer deaths. The preferred diagnostic approach is early referral, avoidance of numerous radiologic evaluations, and early performance fine-needle aspiration. This article reviews the literature of the last 12 months and discusses some of the new molecular, genetic, and immunostaining techniques in the evaluation of thyroid nodules.

Thyroid nodules: diagnosis and therapy

Less than 1% of all cancers are present in the thyroid, yet thyroid nodules are found in 4 to 10% of the adult population. Because thyroid nodules are relatively common, the diagnostic dilemma is to distinguish between a more common benign nodule, which usually does not require specific treatment, and a malignant nodule, which requires thyroidectomy and further treatment. Thyroid nodules usually are an incidental finding on a routine examination by a primary care physician. When patients seek treatment for symptomatic nodules, a more serious problem may be indicated, and thyroid cancer is suggested. However, additional studies have demonstrated the use of genetic markers and immunohistochemistry in the diagnosis of thyroid nodules, which may lead to a more rational approach to the treatment. This article reviews literature published in the last 12 months pertaining to the pathogenesis, diagnosis, and treatment of thyroid nodules.