External radiation and thyroid neoplasia

Investigating thyroid nodules

Thyroid nodules are common clinically and even more common as an incidental finding during ultrasonography. Routine screening of thyroid nodules in patients with hyperthyroidism or hypothyroidism without risk factors for thyroid cancer is not recommended.

Most thyroid nodules are benign. Sonographic risk-stratification systems should be used to estimate the risk of malignancy and the need for fine-needle aspiration biopsy.

Malignant thyroid nodules require surgical management. Most thyroid cancers are well-differentiated papillary or follicular thyroid neoplasms, which have an excellent prognosis with a low mortality rate.

A glance at the actual role of glutamine metabolism in thyroid tumorigenesis

Thyroid cancers (TCs) are the most prevalent malignancy of the endocrine system and the seventh most common cancer in women. According to estimates from the Global Cancer Observatory (GCO) in 2020, the incidence of thyroid cancer globally was 586,000 cases. As thyroid cancer incidences have dramatically increased, identifying the most important metabolic pathways and biochemical markers involved in thyroid tumorigenesis can be critical strategies for controlling the prevalence and ultimately treatment of this disease. Cancer cells undergo cellular metabolism and energy alteration in order to promote cell proliferation and invasion. Glutamine is one of the most abundant free amino acids in the human body that contributes to cancer metabolic remodeling as a carbon and nitrogen source to sustain cell growth and proliferation. In the present review, glutamine metabolism and its regulation in cancer cells are highlighted. Thereafter, emphasis is given to the perturbation of glutamine metabolism in thyroid cancer, focusing on metabolomics studies.

Prophylactic lymph node dissection in clinically N0 differentiated thyroid carcinoma: example of personalized treatment

Considering the 'differentiated thyroid carcinoma (DTC) epidemic', the indolent nature of DTC imposes a treatment paradigm shift toward elimination of recurrence. Lymph node metastases in cervical compartments, encountered in 20-90% of DTC, are the main culprit of recurrent disease, affecting 5-30% of patients. Personalized risk-stratified cervical prophylactic lymph node dissection (PLND) at initial thyroidectomy in DTC with no clinical, sonographic or intraoperative evidence of lymph node metastases (clinically N0) has been advocated, though not unanimously. The present review dissects the controversy over PLND. Weighing the benefit yielded from PLND up against the PLND-related morbidity is so far hampered by the inconsistent profit yielded by PLND and the challenging patient selection. Advances in tailoring PLND are anticipated to empower optimal patient care.

Advances in metabolomics of thyroid cancer diagnosis and metabolic regulation

Thyroid cancers (TCs) are the most frequent endocrine malignancy with an unpredictable fast-growing incidence, especially in females all over the world. Fine-needle aspiration biopsy (FNAB) analysis is an accurate diagnostic method for detecting thyroid nodules and classification of TC. Though simplicity, safety, and accuracy of FNAB, 15-30% of cases are indeterminate, and it is not possible to determine the exact cytology of the specimen. This demands the need for innovative methods capable to find crucial biomarkers with adequate sensitivity for diagnosis and prediction in TC researches. Cancer-based metabolomics is a vast emerging field focused on the detection of a large set of metabolites extracted from biofluids or tissues. Using analytical chemistry procedures allows for the potential recognition of cancer-based metabolites for the purposes of advancing the era of personalized medicine. Nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS) coupled with separation techniques e.g., gas chromatography (GC) and liquid chromatography (LC) are the main approaches for metabolic studies in cancers. The immense metabolite profiling has provided a chance to discover novel biomarkers for early detection of thyroid cancer and reduce unnecessary aggressive surgery. In this review, we recapitulate the recent advances and developed methods of diverse metabolomics tools and metabolic phenotypes of thyroid cancer, following a brief discussion of recent challenges in the thyroid cancer diagnosis.

Pathologic diagnosis of papillary thyroid carcinoma: today and tomorrow

Papillary thyroid carcinoma is the most common malignancy of the thyroid. It is a well-differentiated tumor and the majority behaves in an indolent fashion. The pathologic diagnosis of papillary carcinoma in both cytology and histologic specimens is based upon demonstration of typical nuclear morphology. Using these morphologic criteria, most papillary cancers can be diagnosed with ease, except cases in which there is a paucity of diagnostic nuclear features. Despite advances in the treatment of thyroid cancer, disease recurrences and metastasis can be observed in 20% of cases. Recently, many advances have been made in the pathogenesis of papillary thyroid carcinoma. The notable genetic events include Ret/PTC rearrangements, Ras and BRAF gene mutations. The identification of these has also led to their use in diagnosis and predicting prognosis of papillary thyroid carcinoma. In addition, these involved genes may also serve as targets for cancer chemotherapy in patients where standard thyroid cancer treatment is not effective.

Approach to and treatment of differentiated thyroid carcinoma

Thyroid cancer is the most common endocrine malignancy, although representing fewer than 1% of all human tumors. Differentiated thyroid carcinoma (DTC) includes the papillary and follicular histotypes and their variants, accounting for more than 90% of all thyroid cancers. Given the changing presentation of DTC in the last years, the aim of DTC management is to ensure the most effective but least invasive treatment, and adequate follow-up for a disease that nowadays is mostly cured just with surgery and is rarely fatal. This review addresses the multiple steps of current management, based on previous assumptions.

Exposing the thyroid to radiation: a review of its current extent, risks, and implications

Radiation exposure of the thyroid at a young age is a recognized risk factor for the development of differentiated thyroid cancer lasting for four decades and probably for a lifetime after exposure. Medical radiation exposure, however, occurs frequently, including among the pediatric population, which is especially sensitive to the effects of radiation. In the past, the treatment of benign medical conditions with external radiation represented the most significant thyroid radiation exposures. Today, diagnostic medical radiation represents the largest source of man-made radiation exposure. Radiation exposure related to the use of computerized tomography is rising exponentially, particularly in the pediatric population. There is direct epidemiological evidence of a small but significant increased risk of cancer at radiation doses equivalent to computerized tomography doses used today. Paralleling the increasing use of medical radiation is an increase in the incidence of papillary thyroid cancer. At present, it is unclear how much of this increase is related to increased detection of subclinical disease from the increased utilization of ultrasonography and fine-needle aspiration, how much is due to a true increase in thyroid cancer, and how much, if any, can be ascribed to medical radiation exposure. Fortunately, the amount of radiation exposure from medical sources can be reduced. In this article we review the sources of thyroid radiation exposure, radiation risks to the thyroid gland, strategies for reducing radiation exposure to the thyroid, and ways that endocrinologists can participate in this effort. Finally, we provide some suggestions for future research directions.

Thyroid neoplasm after central nervous system irradiation for medulloblastoma in childhood: report of two cases

OBJECTIVE

Surgical excision combined with radio-chemotherapy represents the gold standard of therapy of medulloblastoma. The effectiveness of such a combined treatment has encouraged the use of radiotherapy even in young paediatric patients, in spite of the many adverse effects reported in literature, and, in particular, the increased risk of a second radioinduced malignancy. Irradiation is the well-known risk factor for development of benign and malignant thyroid tumours. Children are more exposed to this risk because of their thyroid gland is more sensitive to carcinogenic effect of ionising radiation.

CASE REPORT

Two children underwent radiotherapy for the treatment of a medulloblastoma when they were 3 and 4 years old, respectively. At the age of 20 and 23, both of them underwent the surgical excision of a papillary thyroid carcinoma, 20 and 17 years after the radiotherapeutic treatment, respectively.

CONCLUSIONS

Radioinduced thyroid tumours are a well-recognised nosographic entities due to the particular sensitivity of this gland to ionising radiations. However, only a few papers on radioinduced thyroid neoplasms after CNS irradiation have been published in the literature. We report on two additional cases of thyroid neoplasms following childhood CNS irradiation for the treatment of a posterior fossa medulloblastoma.

Risk of thyroid cancer after childhood exposure to ionizing radiation for tinea capitis

BACKGROUND

The thyroid gland is known to be sensitive to the carcinogenic effect of ionizing radiation, especially in children. The role of potential modifiers of the risk and latency period effects needs further investigation. We examined the effect of low doses of ionizing radiation (4.5-49.5 cGy) on the risk of developing thyroid cancer after long latent periods of up to 54 yr after childhood exposure.

METHODS

The study population included 10,834 individuals irradiated against tinea capitis in the 1950s and two matched nonirradiated groups (general population and siblings) for comparison. Cancer statistics and vital status data were obtained from national registries, updated to December 2002. Excess relative and absolute risks [excess relative risk per gray (ERR/Gy), excess absolute risk (EAR)] were estimated using Poisson regression for survival analysis.

RESULTS

Within the study period, 159 cases of thyroid cancer were diagnosed. Total ERR/Gy and excess absolute risk per gray per 10(4) person-years for developing thyroid cancer reached 20.2 (95% confidence interval 11.8-32.3) and 9.9 (95% confidence interval 5.7-14.7), respectively. The risk was positively associated with dose and negatively associated with age at exposure. ERR/Gy was significantly elevated 10-19 yr after exposure, peaking at 20-30 yr, and decreasing dramatically (although still significantly elevated) 40 yr after exposure.

CONCLUSIONS

Our findings agree with patterns of risk modification seen in most studies of radiation-induced thyroid cancer, although risk per unit dose seems higher. Our data show that 40 yr after irradiation, ERR decreases dramatically, although remaining significantly elevated. The hypothesis of different genetic susceptibility of the Jewish population deserves further exploration.

Long-term risks for thyroid cancer and other neoplasms after exposure to radiation

Radiation-related thyroid cancer continues to be a clinical concern for two reasons: the risks associated with the widespread use of radiation treatments for benign conditions in the middle of the last century persist for decades after exposure; and radiation continues to be an effective component of the treatment of several childhood malignancies. Patients who were irradiated in the head and neck area need to be evaluated for thyroid cancer, benign thyroid nodules, hyperparathyroidism, salivary-gland neoplasms and neural tumors, including acoustic neuromas. Radiation-related thyroid cancers appear to have the same clinical behavior as other thyroid cancers, but many irradiated patients are entering the age range when more aggressive neoplasms occur. In this paper, we review how to approach the clinical management of a patient with a history of radiation exposure in the thyroid area, and how to treat radiation-exposed patients who develop related neoplasms, especially thyroid cancer.

Thyroid cancer review 1: presentation and investigation of thyroid cancer

Thyroid cancer is uncommon with an estimated lifetime risk of 0.8% for women and 0.3% for men. The incidence appears to be increasing by 4% per year and is currently the eighth commonest cancer in women. Managing thyroid cancer is challenging, as no prospective randomised trials exist. Most of the information is derived from large patient cohorts in which therapy has not been randomly assigned. This is the first of the three review papers we have written on the management of thyroid cancer.

A pilot case-control study of gamma-radiation sensitivity and risk of papillary thyroid cancer

In vitro gamma-radiation-induced chromatid breaks per cell (b/c) in lymphocytes may be associated with risk of papillary thyroid cancer (PTC). This pilot case-control study involved 106 patients with thyroid disease (57 with PTC and 49 with benign thyroid disease) and 105 cancer-free matched controls. Multivariate logistic regression analyses identified that an elevated gamma-radiation-induced b/c value was a risk factor for PTC (adjusted odds ratio = 4.54; 95% CI, 2.07-9.95), and a dose-response relationship was evident when the b/c values were categorized into tertiles. High levels of chromatid breaks induced by gamma-radiation may constitute an independent risk factor for PTC, but further study is needed.

6: Thyroid nodules and thyroid cancer

Thyroid nodules are common clinically (prevalence, about 5%) and even more common on ultrasound examination (about 25%). About 5% of thyroid nodules are malignant. Most thyroid cancers are well-differentiated papillary or follicular tumours with an excellent prognosis (10-year survival, 80%-95%). The incidence of papillary thyroid cancer appears to be increasing on the east coast of Australia. Fine-needle aspiration biopsy of the thyroid is the most cost-effective diagnostic tool. Recommended initial management of all follicular carcinomas and of papillary carcinomas > 1.0 cm is total thyroidectomy followed by radioiodine ablation. Most patients should be managed postoperatively with doses of thyroid hormone sufficient to suppress plasma levels of thyroid-stimulating hormone. Recurrences can occur many years after initial therapy, and follow-up should be lifelong. Thyroid nodules are very common, but have a relatively low risk of malignancy

Gamma radiation-induced apoptosis, G2 delay, and the risk of salivary and thyroid carcinomas?a preliminary report

BACKGROUND

While radiation has been the only well-established risk factor for salivary and thyroid cancers, the exact mechanisms remain unknown. We hypothesized that individuals with altered apoptotic response to gamma irradiation may be susceptible to salivary and thyroid cancers.

METHODS

We tested our hypothesis in a pilot case-control study of 29 patients with neoplasms of the salivary and thyroid glands and 29 cancer-free control subjects. Patients and control subjects were matched on age, sex, and ethnicity. In vitro gamma radiation-induced apoptosis in lymphocytes was quantified utilizing the TUNEL assay and flow cytometry.

RESULTS

The mean apoptotic capacity was 13.55 +/- 10.54 for control subjects, 5.75 +/- 4.96 for patients with salivary gland carcinomas (p =.003), and 6.87 +/- 4.45 for patients with thyroid carcinomas (p =.006). These differences were associated with a 10-fold increased risk of salivary gland carcinoma (odds ratio [OR] = 10.71; 95% confidence interval [CI], 1.21-94.86) and a four-fold increased risk of thyroid carcinoma (OR = 3.93; 95% CI, 0.90-17.08).

CONCLUSIONS

Our data suggests that gamma radiation-induced apoptosis may serve as a biomarker of genetic susceptibility to salivary and thyroid carcinoma, and further confirmatory studies with larger sample size are warranted.

Thyroid neoplasia following irradiation in adolescent and young adult survivors of childhood cancer

OBJECTIVES

To describe a cohort of survivors of childhood malignancy at risk of developing thyroid abnormality, and propose guidelines for management of such patients.

DESIGN

Retrospective case series.

SETTING

Late-effects oncology clinic at a large children's hospital in Sydney.

SUBJECTS

142 patients who had received irradiation to the thyroid from the 1970s onwards, who attended the late-effects clinic from May 1989 to December 1998.

INTERVENTIONS

Thyroid palpation by an endocrinologist or surgeon, serum thyroid-stimulating hormone assay and thyroid ultrasound examination were performed on all subjects and, depending on findings, some subjects proceeded to fine-needle biopsy or surgery (total thyroidectomy). A few patients required adjuvant (131)I administration.

OUTCOME MEASURES

Radiation dose received; results of thyroid palpation; thyroid function tests; ultrasound findings; diagnosis of the abnormalities; and outcomes of surgical interventions.

RESULTS

49 subjects (24 of 65 patients who received scatter irradiation to the thyroid and 25 of 78 patients who received direct irradiation) had thyroid surgery. Of these, 12 in the scatter and six in the direct irradiation group were found to have thyroid malignancy. Fifty subjects with abnormal ultrasound results remain under surveillance. Having a palpable thyroid was predictive of malignancy, but age at original diagnosis, sex, current age, time since irradiation, radiation dose, nodule type and nodal involvement were not.

CONCLUSION

There is a significant risk of cancer in thyroid glands exposed to radiation as part of therapy for childhood cancer. This risk is greater for patients who received scatter (versus direct) irradiation. Nodular change is usually not apparent for many years, so lifelong surveillance is necessary. Palpation alone is not sufficient to detect thyroid cancer and thyroid ultrasound examination is recommended.

Increasing incidence and characteristics of differentiated thyroid cancer in Huntington, West Virginia

Since 1985, we have observed an increasing number of differentiated thyroid cancer cases in Huntington, West Virginia. We describe tumor incidence, patient and tumor characteristics, treatment modalities, and tumor recurrence and death. One hundred seventeen patients with differentiated thyroid cancer were identified between 1976 and 1999. Data were collected from patient records in our practice and the tumor registries at the three hospitals serving our community. The annual incidence of differentiated thyroid cancer increased significantly from fewer than 3 cases per 100,000 prior to 1996 to 9.4 cases per 100,000 in 1999. The median age at diagnosis was 49 years (range, 16-80). The median tumor size was 2.5 cm (range, 1.2-10). Forty-seven percent of the patients had bilateral disease, 28% had three or more tumors, 44% had thyroid capsular invasion, and 16% had gross extrathyroid invasion at surgery. Twenty-two percent had cervical lymph node involvement and 9% had distant metastases at diagnosis. During 1-month to 23-year follow-up, 11% had recurrence, and 5% died of thyroid cancer. In summary, differentiated thyroid cancer has increased dramatically in our community. The tumors appear to be aggressive at diagnosis as reflected by the high percentage of tumors with bilateral, multicentric, and locally invasive disease.

Cohort study of thyroid cancer in a San Francisco Bay area population

Using data from a large health plan, we performed a cohort study of thyroid cancer among 204,964 persons (aged 10--89 at baseline in 1964--1973, 54% female) followed for a median of 20 years. There were 196 incident thyroid cancers (73 in men, 123 in women). Risk was independently and positively related to female gender [relative risk (RR) = 1.56, 95% confidence interval (CI) = 1.12--2.19], Asian race (RR = 2.86, 95% CI = 1.76--4.65), completed college or post-graduate education (RR = 1.76, 95% CI = 1.20--2.59), history of goiter (RR = 3.36, 95% CI = 1.82--6.20), radiation of the neck region (RR = 2.33, 95% CI = 1.28--4.23) and family history of thyroid disease (RR = 2.18, 95% CI = 1.17--4.05). An inverse association was found for black race (RR = 0.55, 95% CI = 0.33--0.91). Cigarette smoking, alcohol consumption, personal history of hyperthyroidism, hypothyroidism, overweight or obesity, weight gain since age 20, height, occupational exposures, reproductive factors, oral contraceptives and hormone use did not show statistically significant relations to thyroid cancer. These results provide further evidence for a role of female gender, radiation, goiter, Asian race, high educational attainment and family history of thyroid disease in the etiology of thyroid cancer.

Thyroid ultrasound

Evaluation of the thyroid gland can be performed by several imaging techniques. Although ultrasound (US) lacks specificity for tissue diagnosis and can rarely distinguish benign from malignant disease, it can distinguish solid nodules from simple and complex cysts. It allows accurate estimation of thyroid size, gives a rough estimate of tissue density (echogenicity), shows vascular flow and velocity (color-flow Doppler), can identify regional lymphadenopathy, and aids in the accurate placing of needles for diagnostic or therapeutic purposes. In addition, it is widely available, relatively rapid and cheap, visualizes the whole anterior neck, and does not involve ionizing irradiation. This article aims at clarifying the role of US in clinical thyroidology by pointing to areas where the technology can aid in clinical decision making. It is argued that more clinician endocrinologists should master and use this technology for diagnostic and therapeutic purposes.

The epidemiology and etiology of differentiated thyroid carcinoma

Differentiated thyroid carcinoma (DTC) is a rare tumor with a relatively good prognosis, but in about 10% of cases it may be the cause of death. Papillary carcinoma is more frequent (about 70-80% of cases) and less aggressive than follicular cancer: the papillary/follicular ratio is increased in areas of high iodine intake. In recent years many genes have been found to be mutated in DTC, the most important of these being ras, ret, trk, and met. The relationship between radiation exposure and DTC is well recognized, especially in children. Since the Chernobyl nuclear accident, a high incidence of DTC has been found in children exposed to fallout.

Second malignant neoplasms after treatment for Hodgkin's disease in childhood or adolescence

PURPOSE

To determine the frequency of and risk factors for second malignant neoplasms (SMNs) after treatment for Hodgkin's disease diagnosed in children and adolescents.

PATIENTS AND METHODS

One hundred eighty-two consecutive, previously untreated patients with Hodgkin's disease who were younger than 20 years of age at diagnosis and who were referred to Roswell Park Cancer Institute (Buffalo, NY) for treatment between January 1, 1960, and December 31, 1989, were studied. Sex-specific standardized incidence ratios (SIRs) were calculated. Kaplan-Meier survival estimates and Cox regression analyses were performed to determine the relationship of several demographic and treatment variables to SMN incidence.

RESULTS

Twenty-eight patients developed an SMN at a mean of 14.93 +/- 8.09 years (range, 2.65 to 29.88 years) after diagnosis of Hodgkin's disease. The cumulative percentage of patients who developed an SMN was 26.27 +/- 6.75% at 30 years after diagnosis. The SIR was 9.39 (95% confidence interval [CI], 4.05 to 18.49) for male patients and 10.16 (95% CI, 5.56 to 17.05) for female patients. The most frequent SMNs were thyroid cancer, breast cancer, nonmelanoma skin cancer, non-Hodgkin's lymphoma, and acute leukemia. Multivariate analysis of sex, treatment with any alkylating agent, treatment with doxorubicin, splenectomy, and relapse (as a time-dependent covariate) with time to SMN onset gave nonsignificant results.

CONCLUSION

Successfully treated children and adolescents with Hodgkin's disease have a substantial risk for the occurrence of subsequent neoplasms. The most frequent SMNs (skin, thyroid, and breast) are readily detected by physical examination and available screening procedures.

Fine-needle aspiration of thyroid nodules in radiation-exposed patients

External radiation used to treat benign conditions in the head and neck area results in an increased risk of thyroid cancer in exposed individuals. Fine-needle aspiration (FNA) biopsy is the standard procedure used to evaluate suspicious thyroid nodules. Its accuracy has been extensively studied, but little is known about FNA in irradiated patients. We analyzed the FNA experience of 136 irradiated subjects. Fifty-two had surgery enabling a comparison of the histologic diagnosis with the FNA results. In these 52 patients with a total of 53 FNAs, 20 were reported as benign, 14 as follicular neoplasms, 6 as papillary cancer, and 13 as inadequate samples. Seven malignant nodules were aspirated; 4 were reported as papillary cancer, 1 was reported as benign and 2 had inadequate specimens. An additional 11 patients had thyroid cancer in foci that were not subjected to FNA. For the nodules that were aspirated, and considering an FNA report of follicular neoplasm as a false-positive when a follicular adenoma or a colloid nodule was found at surgery, the calculated sensitivity was 80%, specificity 54%, positive predictive value 20%, and negative predictive value 95%. Of the 14 follicular neoplasm FNA diagnoses, 10 were colloid nodules (71%), and 4 only were follicular adenomas. We conclude that the sensitivity of FNA in irradiated patients is similar to what is reported for the general population. However, smaller malignant nodules are common and are not diagnosed by the FNA. Also, the FNA diagnosis of follicular neoplasm is often inaccurate and inadequate aspirations are frequent in this patient group.

Second thyroid neoplasms after prophylactic cranial irradiation for acute lymphoblastic leukemia

An understanding of the pathogenesis of second cancers may help in their prevention. We report on two children who were treated for acute lymphoblastic leukemia (ALL), with an exclusively cranial prophylactic irradiation (18 Gy) and who presented with a thyroid carcinoma (TC) 12 and 13 years later. From a thorough review of the literature of TC after ALL and of radiation-induced TC, a strong case can be made that these tumors are caused by late effects of scattered radiation. The risk is at its highest in small children. After cranial irradiation, patients require clinical monitoring of the thyroid and cervical area for nodules, continued indefinitely. We suggest that, in most cases, an alternative form of neuromeningeal prophylaxis should be offered in small children with ALL.

Thyroid nodules in the follow-up of irradiated individuals: comparison of thyroid ultrasound with scanning and palpation

In 1974 we began a prospective study of a cohort of 4296 individuals exposed to therapeutic head and neck irradiation during childhood for benign conditions. To define the role of thyroid ultrasonography in following irradiated individuals, we studied a subgroup of 54 individuals. They all had been screened between 1974-1976 and had normal thyroid scans and no palpable nodules at that time. Thyroid ultrasonography, thyroid scanning, physical examination, and serum thyroglobulin measurements were performed. One or more discrete ultrasound-detected nodules were present in 47 of 54 (87%) subjects. There were a total of 157 nodules, 40 of which were 1.0 cm or larger in largest dimension. These 40 nodules occurred in 28 (52%) of the subjects. Thirty (75%) of these 1.0-cm or larger nodules matched discrete areas of diminished uptake on corresponding thyroid scans. The 10 that did not match (false negative scans for > or = 1.0-cm nodules) were the only nodules of this size in 7 subjects. Of 11 nodules 1.5 cm or larger, only 5 were palpable. Serum thyroglobulin correlated to the number (P = 0.04; r2 = 0.10), but not the volume of the thyroid nodules (P = 0.07; r2 = 0.08). We conclude that thyroid nodules are continuing to occur and are exceedingly common in this irradiated cohort of individuals. The results confirm that thyroid ultrasonography is more sensitive than physical examination and scanning. However, thyroid ultrasound is so sensitive and nodules so prevalent that great caution is needed in interpreting the results.

Changing concepts in the diagnosis and management of thyroid nodules

Thyroid nodules are extremely common, affecting from 4% to 7% of the population. Fine-needle aspiration biopsy is the most accurate and cost-effective technique for nodule diagnosis. It is simple, safe, and should be the first test used in patient work-up. Routine thyroxine (T4) suppressive therapy is no longer recommended for cytologically benign nodules. T4 suppression can cause or aggravate osteoporosis, especially in postmenopausal women. New data on T4 suppressive therapy, cost analysis, and nodule guidelines are reviewed.