Fifteen Years of Iodine Prophylaxis in Italy: Results of a Nationwide Surveillance (Period 2015-2019)

CONTEXT

In 2005, a nationwide program of iodine prophylaxis on a voluntary basis was implemented in Italy by law. However, recent data on iodine status are lacking.

OBJECTIVE

The aim of this study was to evaluate efficiency, effectiveness, and possible adverse effects (increased occurrence of thyroid autoimmunity and hyperthyroidism) of the Italian iodine prophylaxis program.

METHODS

From 2015 to 2019, a nationwide survey was performed. The use of iodized salt was evaluated in a sample of 164 593 adults and in 998 school canteens. A sample of 4233 schoolchildren (aged 11-13 years) was recruited to assess urinary iodine concentration, prevalence of goiter, and thyroid hypoechogenicity on ultrasound, with the latter being an indirect indicator of thyroid autoimmunity. Neonatal TSH values of 197 677 infants screened in regions representative of Northern, Central, and Southern Italy were analyzed to investigate the percentage of TSH values >5.0 mIU/L. Data on methimazole prescriptions were analyzed as indirect indicators of new cases of hyperthyroidism.

RESULTS

The prevalence of the use of iodized salt was 71.5% in adult population and 78% in school canteens. A median urinary iodine concentration of 124 μg/L, a prevalence of goiter of 2.2%, and a prevalence of thyroid hypoechogenicity of 5.7% were observed in schoolchildren. The percentage of neonatal TSH values >5.0 mIU/L resulted still higher (5.1%) than the World Health Organization threshold of 3.0%, whereas the prescriptions of methimazole showed a reduction of 13.5%.

CONCLUSION

Fifteen years of iodine prophylaxis have led to iodine sufficiency in Italy, although there still is concern about iodine nutritional status during pregnancy.

A Data-Driven Approach to Refine Predictions of Differentiated Thyroid Cancer Outcomes: A Prospective Multicenter Study

CONTEXT

The risk stratification of patients with differentiated thyroid cancer (DTC) is crucial in clinical decision making. The most widely accepted method to assess risk of recurrent/persistent disease is described in the 2015 American Thyroid Association (ATA) guidelines. However, recent research has focused on the inclusion of novel features or questioned the relevance of currently included features.

OBJECTIVE

To develop a comprehensive data-driven model to predict persistent/recurrent disease that can capture all available features and determine the weight of predictors.

METHODS

In a prospective cohort study, using the Italian Thyroid Cancer Observatory (ITCO) database (NCT04031339), we selected consecutive cases with DTC and at least early follow-up data (n = 4773; median follow-up 26 months; interquartile range, 12-46 months) at 40 Italian clinical centers. A decision tree was built to assign a risk index to each patient. The model allowed us to investigate the impact of different variables in risk prediction.

RESULTS

By ATA risk estimation, 2492 patients (52.2%) were classified as low, 1873 (39.2%) as intermediate, and 408 as high risk. The decision tree model outperformed the ATA risk stratification system: the sensitivity of high-risk classification for structural disease increased from 37% to 49%, and the negative predictive value for low-risk patients increased by 3%. Feature importance was estimated. Several variables not included in the ATA system significantly impacted the prediction of disease persistence/recurrence: age, body mass index, tumor size, sex, family history of thyroid cancer, surgical approach, presurgical cytology, and circumstances of the diagnosis.

CONCLUSION

Current risk stratification systems may be complemented by the inclusion of other variables in order to improve the prediction of treatment response. A complete dataset allows for more precise patient clustering.

Real-World Performance of the American Thyroid Association Risk Estimates in Predicting 1-Year Differentiated Thyroid Cancer Outcomes: A Prospective Multicenter Study of 2000 Patients

Background: One of the most widely used risk stratification systems for estimating individual patients' risk of persistent or recurrent differentiated thyroid cancer (DTC) is the American Thyroid Association (ATA) guidelines. The 2015 ATA version, which has increased the number of patients considered at low or intermediate risk, has been validated in several retrospective, single-center studies. The aims of this study were to evaluate the real-world performance of the 2015 ATA risk stratification system in predicting the response to treatment 12 months after the initial treatment and to determine the extent to which this performance is affected by the treatment center in which it is used. Methods: A prospective cohort of DTC patients collected by the Italian Thyroid Cancer Observatory web-based database was analyzed. We reviewed all records present in the database and selected consecutive cases that satisfied inclusion criteria: (i) histological diagnosis of DTC, with the exclusion of noninvasive follicular thyroid neoplasm with papillary-like nuclear features; (ii) complete data of the initial treatment and pathological features; and (iii) results of 1-year follow-up visit (6-18 months after the initial treatment), including all data needed to classify the estimated response to treatment. Results: The final cohort was composed of 2071 patients from 40 centers. The ATA risk of persistent/recurrent disease was classified as low in 1109 patients (53.6%), intermediate in 796 (38.4%), and high in 166 (8.0%). Structural incomplete responses were documented in only 86 (4.2%) patients: 1.5% in the low-risk, 5.7% in the intermediate-risk, and 14.5% in the high-risk group. The baseline ATA risk class proved to be a significant predictor of structural persistent disease, both for intermediate-risk (odds ratio [OR] 4.67; 95% confidence interval [CI] 2.59-8.43) and high-risk groups (OR 16.48; CI 7.87-34.5). Individual center did not significantly influence the prediction of the 1-year disease status. Conclusions: The ATA risk stratification system is a reliable predictor of short-term outcomes in patients with DTC in real-world clinical settings characterized by center heterogeneity in terms of size, location, level of care, local management strategies, and resource availability.

Calcitonin as a biomarker of C cell disease: recent achievements and current challenges

The neoplastic proliferation of parafollicular thyroid cells (C cells) may occur as either medullary thyroid carcinoma (MTC) or C cell hyperplasia (CCH) and is generically defined C cell disease. Since Calcitonin (CT) expression is fully maintained in neoplastic C cells, this hormone represents a sensitive marker for neoplasia of C cell derivation such as CCH and MTC. Serum CT levels display a high prognostic value and accurate estimation of tumor burden, allowing early detection of persistence/relapse and representing a reliable marker of response to treatment. Indeed, elevated CT levels can occur in other non-C cell-related conditions (i.e., other malignancies, systemic diseases, and pharmacological treatments). Moreover, some de-differentiated, more aggressive MTCs may present disproportionately low-circulating CT levels, as compared with tumor burden. During the postsurgical follow-up of MTC patients, CT levels usually parallel tumor progression and their increase unambiguously announces persistence/relapse. In this respect, CT Doubling Time (DT) has been proposed as prognostic factor of potential use for the identification of more aggressive MTCs. The present review will summarize the novel achievements on the clinical suitability of CT as a biomarker in clinical oncology and will point the attention to the most recent results concerning the usefulness and the possible drawbacks of circulating CT as a surrogate marker for the identification of rapidly progressing MTC patients, such as those candidate to targeted therapies. The emerging role of circulating CT as a parameter of response to local and systemic therapies will also be illustrated.

Thyroid nodule recurrence following lobo-isthmectomy: incidence, patient's characteristics, and risk factors

PURPOSE

This study was aimed at assessing the incidence and timing of thyroid nodules recurrence, defined as appearance of new benign or malignant nodules in contralateral lobe in patients with benign thyroid nodules or thyroid microcarcinoma treated with lobo-isthmectomy. Patient's characteristics and risk factors associated with this phenomenon were also investigated.

METHODS

A retrospective study was performed by evaluating 413 patients undergoing lobo-isthmectomy with a minimum follow-up of 1 year. Clinical characteristics, surgical interventions and complications, histological diagnosis, and thyroid function at last follow-up were collected.

RESULTS

Single or multiple thyroid nodule recurrence equally occurred in 80 patients (23%) with a median time to relapse of ~ 5 years (range 0.3-34.5 years) after lobo-isthmectomy. Recurrence was significantly associated with younger age (< 46 years) and number of pregnancies in women. Development of hypothyroidism was not rare either (~ 10%) and appeared in 3-19 months; a preoperative TSH level > 2.43 mIU/L was associated with the need of l-thyroxin replacement therapy after surgery. The most frequent surgical complication was transient hypoparathyroidism (4.6%), while the rate of permanent hypoparathyroidism significantly increased in patients submitted to completion thyroidectomy (5.3%).

CONCLUSIONS

Thyroid nodules recurrence following lobo-isthmectomy is not a rare event and occurs within 5 years after surgery, more frequently in younger patients with family history of nodular goiter and in women with multiple pregnancies. Pre-surgical TSH levels may predict the development of post-surgical hypothyroidism, possibly improving the management of patients addressed to surgery.

Are Evidence-Based Guidelines Reflected in Clinical Practice? An Analysis of Prospectively Collected Data of the Italian Thyroid Cancer Observatory

OBJECTIVES

The goal of evidence-based practice guidelines is to optimize the management of emerging diseases, such as differentiated thyroid cancer (DTC). The aim of this study was to assess therapeutic approaches for DTC in Italy and to see how closely these practices conformed to those recommended in the 2009 American Thyroid Association (ATA) guidelines.

METHODS

The Italian Thyroid Cancer Observatory was established to collect data prospectively on thyroid cancers consecutively diagnosed in participating centers (uniformly distributed across the nation). Data on the initial treatment of all pathologically confirmed DTC cases present in the database from January 1, 2013 (database creation) to January 31, 2016, were analyzed.

RESULTS

A total of 1748 patients (77.2% females; median age 48.1 years [range 10-85 years]) were enrolled in the study. Most (n = 1640; 93.8%) were papillary carcinomas (including 84 poorly differentiated/aggressive variants); 6.2% (n = 108) were follicular and Hürthle cell carcinomas. The median tumor diameter was 11 mm (range 1-93 mm). Tumors were multifocal in 613 (35%) and presented extrathyroidal extension in 492 (28%) cases. Initial treatments included total thyroidectomy (involving one or two procedures; n = 726; 98.8%) and lobectomy (n = 22; 1.2%). A quarter of the patients who underwent total thyroidectomy had unifocal, intrathyroidal tumors ≤1 cm (n = 408; 23.6%). Neck dissection was performed in 40.4% of the patients (29.5% had central compartment dissection). Radioiodine remnant ablation (RRA) was performed in 1057 (61.2%) of the 1726 patients who underwent total thyroidectomy: 460 (41.2%) of the 983 classified by 2009 ATA guideline criteria as low-risk, 570 (87.1%) of the 655 as intermediate-risk, and 82 (93.1%) of the 88 as high-risk patients (p < 0.001). RRA was performed in 44% of the cases involving multifocal DTCs measuring ≤1 cm.

CONCLUSIONS

The treatment approaches for DTCs used in Italy display areas of inconsistency with those recommended by the 2009 ATA guidelines. Italian practices were characterized by underuse of thyroid lobectomy in intrathyroidal, unifocal DTCs ≤1 cm. The use of RRA was generally consistent with risk-stratified recommendations. However, its frequent use in small DTCs (≤1 cm) that are multifocal persists, despite the lack of evidence of benefit. These data provide a baseline for future assessments of the impact of international guidelines on DTC management in Italy. These findings also illustrate that the dissemination and implementation of guideline recommendations, and the change in practice patterns, require ongoing education and time.

Temporal Changes in Thyroid Nodule Volume: Lack of Effect on Paranodular Thyroid Tissue Volume

BACKGROUND

The term "nodular goiter" has long been used to refer to a nodular thyroid gland, based on the assumption that nodule growth may be associated with hyperplasia of the surrounding non-nodular tissue. The aim of this prospective, multicenter, observational study was to determine whether nodule growth is accompanied by growth in the non-nodular tissue.

METHODS

Eight Italian thyroid-disease referral centers enrolled 992 consecutive patients with one to four benign nodules. Nodular and non-nodular thyroid tissue volumes were assessed for five years with annual ultrasound examinations.

RESULTS

In participants whose nodules remained stable (n = 839), thyroid volumes did not change (baseline 15.0 mL [confidence interval (CI) 14.5-15.6]; five-year evaluation 15.1 mL [CI 14.5-15.7]). In participants with significant growth of one or more nodule (n = 153), thyroid volumes increased and by year 5 were significantly greater than those of the former group (17.4 mL [CI 16-18.7]). In 76 individuals with unilateral nodules that grew, the mean nodular lobe volume significantly exceeded that of the contralateral lobe (8.6 mL [CI 7.4-9.8] vs. 6.7 mL [CI 6-7.4]). The unaffected lobe volumes remained stable over time, while nodular lobes grew steadily and were significantly greater at the end of follow-up (10.1 mL [CI 8.9-11.3]). Excluding the volume of the largest growing nodule in these cases, the remaining volume of the affected lobe remained virtually unchanged with respect to its baseline value. Furthermore, there was no significant difference in the non-nodular tissue volume between the unaffected lobe and the affected lobe (with the largest growing nodule volume subtracted), both at baseline and at the end of follow-up.

CONCLUSIONS

The growth of thyroid nodules is a local process, not associated with growth of the surrounding non-nodular tissue. Therefore, a normal-sized thyroid containing nodules should be referred to as a "uni- or multinodular thyroid gland" and considered a distinct entity from "uni- or multinodular goiter."

Papillary thyroid carcinomas with biochemical incomplete or indeterminate responses to initial treatment: repeat stimulated thyroglobulin assay to identify disease-free patients

Papillary thyroid cancer (PTC) patients treated with thyroidectomy and radioiodine remnant ablation (RRA) often have detectable TSH-stimulated thyroglobulin (Tg) levels without localizable disease after primary treatment. To assess the value of repeat stimulated Tg assays in these patients' follow-up, we retrospectively analyzed 86 cases followed in 5 Italian thyroid-cancer referral centers. We enrolled 86 patients with PTCs treated with total/near-total thyroidectomy plus RRA between January 1,1990 and January 31, 2006. In all cases, the initial postoperative visit revealed stimulated serum Tg ≥1 ng/mL, negative Tg antibodies, and no structural evidence of disease. None received empiric radioiodine therapy. Follow-up (median: 9.6 years) included neck ultrasound and basal Tg assays (yearly) and at least 1 repeat stimulated Tg assay. Of the 86 patients analyzed (initial risk: low 63 %, intermediate 35 %, high 2 %), one (1 %) had ultrasound-detected lymph node disease and persistently elevated stimulated Tg levels at 3 years. In 17 (20 %), imaging findings were consistently negative, but the final stimulated Tg levels was still >1 ng/mL (median 2.07 ng/mL, range 1.02-4.7). The other 68 (80 %) appeared disease-free (persistently negative imaging findings with stimulated Tg levels ≤1 ng/mL). Mean intervals between first and final stimulated Tg assays were similar (5.2 and 4.8 years) in subgroups with versus without Tg normalization. Reclassification as disease-free was significantly more common when initial stimulated Tg levels were indeterminate (<10 ng/mL). In unselected PTC cohorts with incomplete/indeterminate biochemical responses to thyroidectomy and RRA, periodic remeasurement of stimulated Tg allows most patients to be classified as disease-free.

Comparison Between Echo-Color Doppler Sonography Features and Angioarchitecture of Thyroid Nodules

This study compared echo-color Doppler sonography features of thyroid nodules with the 3-dimensional reconstruction to find parameters useful for the preoperative diagnosis. Forty nodules relative to 29 patients were examined with echo-color Doppler before surgery. After histologic diagnosis, blocks were deparaffinized and prepared for 3-dimensional examination using a stereomicroscope. Echo-color Doppler type I nodules (8 nodules) always corresponded to colloid goiter. Type II and III nodules corresponded to colloid goiter with intralesional hemorrhage or were associated with hyperplastic nodules, follicular adenoma, follicular carcinoma minimally invasive, papillary carcinoma, and medullary carcinoma. Of interest was that 9 of 11 follicular lesions were characterized by a large central vessel, which was also evident in echo-color Doppler images. This architectural pattern is not seen in benign nodules or in papillary carcinomas. Comparison with histology suggests that echo-color Doppler images can visualize vessels showing a muscular wall.

BRAF V600E and risk stratification of thyroid microcarcinoma: a multicenter pathological and clinical study

Studies from single institutions have analyzed BRAF in papillary microcarcinomas, sometimes with contradictory results. Most of them have provided limited integration of histological and clinical data. To obtain a comprehensive picture of BRAF V600E-mutated microcarcinomas and to evaluate the role of BRAF testing in risk stratification we performed a retrospective multicenter analysis integrating microscopical, pathological, and clinical information. Three hundred and sixty-five samples from 300 patients treated at six medical institutions covering different geographical regions of Italy were analyzed with central review of all cases. BRAF V600E statistical analysis was conducted on 298 microcarcinomas from 264 patients after exclusion of those that did not meet the required criteria. BRAF V600E was identified in 145/298 tumors (49%) including the following subtypes: 35/37 (95%, P<0.0001) tall cell and 72/114 (64%, P<0.0001) classic; conversely 94/129 follicular variant papillary microcarcinomas (73%, P<0.0001) were BRAF wild type. BRAF V600E-mutated microcarcinomas were characterized by markedly infiltrative contours (P<0.0001) with elongated strings of neoplastic cells departing from the tumor, and by intraglandular tumor spread (P<0.0001), typically within 5 mm of the tumor border. Multivariate analysis correlated BRAF V600E with specific microscopic features (nuclear grooves, optically clear nuclei, tall cells within the tumor, and tumor fibrosis), aggressive growth pattern (infiltrative tumor border, extension into extrathyroidal tissues, and intraglandular tumor spread), higher American Thyroid Association recurrence risk group, and non-incidental tumor discovery. The following showed the strongest link to BRAF V600E: tall cell subtype, many neoplastic cells with nuclear grooves or with optically clear nuclei, infiltrative growth, intraglandular tumor spread, and a tumor discovery that was non-incidental. BRAF V600E-mutated microcarcinomas represent a distinct biological subtype. The mutation is associated with conventional clinico-pathological features considered to be adverse prognostic factors for papillary microcarcinoma, for which it could be regarded as a surrogate marker. BRAF analysis may be useful to identify tumors (BRAF wild type) that have negligible clinical risk.

The natural history of benign thyroid nodules

IMPORTANCE

Detection of asymptomatic thyroid nodules has increased. Consensus is lacking regarding the optimal follow-up of cytologically proven benign lesions and sonographically nonsuspicious nodules. Current guidelines recommend serial ultrasound examinations and reassessment of cytology if significant growth is observed.

OBJECTIVE

To determine the frequency, magnitude, and factors associated with changes in thyroid nodule size.

DESIGN, SETTING, AND PARTICIPANTS

Prospective, multicenter, observational study involving 992 consecutive patients with 1 to 4 asymptomatic, sonographically or cytologically benign thyroid nodules. Patients were recruited from 8 hospital-based thyroid-disease referral centers in Italy between 2006 and 2008. Data collected during the first 5 years of follow-up, through January 2013, were analyzed.

MAIN OUTCOMES AND MEASURES

Baseline nodule growth (primary end point) was assessed with yearly thyroid ultrasound examinations. Size changes were considered significant for growth if an increase of 20% or more was recorded in at least 2 nodule diameters, with a minimum increase of 2 mm. Baseline factors associated with growth were identified. Secondary end points were the sonographic detection of new nodules and the diagnosis of thyroid cancer during follow-up.

RESULTS

Nodule growth occurred in 153 patients (15.4% [95% CI, 14.3%-16.5%]). One hundred seventy-four of the 1567 original nodules (11.1% [95% CI, 10.3%-11.9%]) increased in size, with a mean 5-year largest diameter increase of 4.9 mm (95% CI, 4.2-5.5 mm), from 13.2 mm (95% CI, 12.1-14.2 mm) to 18.1 mm (95% CI, 16.7-19.4 mm). Nodule growth was associated with presence of multiple nodules (OR, 2.2 [95% CI 1.4-3.4] for 2 nodules; OR, 3.2 [95% CI, 1.8-5.6 for 3 nodules; and OR, 8.9 [95% CI, 4.4-18.0] for 4 nodules), main nodule volumes larger than 0.2 mL (OR, 2.9 [95% CI, 1.7-4.9] for volumes >0.2 to <1 mL and OR, 3.0 [95% CI, 1.8-5.1] for volumes ≥1 mL), and male sex (OR, 1.7 [95% CI, 1.1-2.6]), whereas an age of 60 years or older was associated with a lower risk of growth than age younger than 45 years (OR, 0.5 [95% CI 0.3-0.9]). In 184 individuals (18.5% [95% CI, 16.4%-20.9%]), nodules shrank spontaneously. Thyroid cancer was diagnosed in 5 original nodules (0.3% [95% CI, 0.0%-0.6%]). Only 2 had grown. An incidental cancer was found at thyroidectomy in a nonvisualized nodule. New nodules developed in 93 patients (9.3% [95% CI, 7.5%-11.1%]), with detection of one cancer.

CONCLUSIONS AND RELEVANCE

Among patients with asymptomatic, sonographically or cytologically benign thyroid nodules, the majority of nodules exhibited no significant size increase during 5 years of follow-up and thyroid cancer was rare. These findings support consideration of revision of current guideline recommendations for follow-up of asymptomatic thyroid nodules.

Clinical aggressiveness and long-term outcome in patients with papillary thyroid cancer and circulating anti-thyroglobulin autoantibodies

OBJECTIVE

The association between papillary thyroid cancer (PTC) and Hashimoto's thyroiditis is widely recognized, but less is known about the possible link between circulating anti-thyroglobulin antibody (TgAb) titers and PTC aggressiveness. To shed light on this issue, we retrospectively examined a large series of PTC patients with and without positive TgAb.

METHODS

Data on 220 TgAb-positive PTC patients (study cohort) were retrospectively collected in 10 hospital-based referral centers. All the patients had undergone near-total thyroidectomy with or without radioiodine remnant ablation. Tumor characteristics and long-term outcomes (follow-up range: 2.5-24.8 years) were compared with those recently reported in 1020 TgAb-negative PTC patients with similar demographic characteristics. We also assessed the impact on clinical outcome of early titer disappearance in the TgAb-positive group.

RESULTS

At baseline, the study cohort (mean age 45.9 years, range 12.5-84.1 years; 85% female) had a significantly higher prevalence of high-risk patients (6.9% vs. 3.2%, p<0.05) and extrathyroidal tumor extension (28.2% vs. 24%; p<0.0001) than TgAb-negative controls. Study cohort patients were also more likely than controls to have persistent disease at the 1-year visit (13.6% vs. 7.0%, p=0.001) or recurrence during subsequent follow-up (5.8% vs. 1.4%, p=0.0001). At the final follow-up visit, the percentage of patients with either persistent or recurrent disease in the two cohorts was significantly different (6.4% of TgAb-positive patients vs. 1.7% in the TgAb-negative group, p<0.0001). At the 1-year visit, titer normalization was observed in 85 of the 220 TgAb-positive individuals. These patients had a significantly lower rate of persistent disease than those who were still TgAb positive (8.2% vs. 17.3%. p=0.05), and no relapses were observed among patients with no evidence of disease during subsequent follow-up.

CONCLUSIONS

PTC patients with positive serum TgAb titer during the first year after primary treatment were more likely to have persistent/recurrent disease than those who were consistently TgAb-negative. Negative titers at 1 year may be associated with more favorable outcomes.

Papillary thyroid cancer: time course of recurrences during postsurgery surveillance

CONTEXT

The current use of life-long follow-up in patients with papillary thyroid cancer (PTC) is based largely on the study of individuals diagnosed and treated in the latter half of the 20th century when recurrence rates were approximately 20% and relapses detected up to 20-30 years after surgery. Since then, however, diagnosis, treatment, and postoperative monitoring of PTC patients have evolved significantly.

OBJECTIVES

The objective of the study was to identify times to PTC recurrence and rates by which these relapses occurred in a more recent patient cohort.

PATIENTS AND DESIGN

We retrospectively analyzed follow-up data for 1020 PTC patients consecutively diagnosed in 1990-2008 in 8 Italian hospital centers for thyroid disease. Patients underwent thyroidectomy, with or without radioiodine ablation of residual thyroid tissue and were followed up with periodic serum thyroglobulin assays and neck sonography.

RESULTS

At the initial posttreatment (≤ 12 months) examination, 948 patients had no structural/functional evidence of disease. During follow-up (5.1-20.4 years; median 10.4 years), recurrence (cervical lymph nodes, thyroid bed) was diagnosed in 13 (1.4%) of these patients. All relapses occurred 8 or fewer years after treatment (10 within the first 5 years, 6 within the first 3 years). Recurrence was unrelated to the use/omission of postoperative radioiodine ablation.

CONCLUSION

In PTC patients whose initial treatment produces disease remission (no structural evidence of disease), recurrent disease is rare, and it usually occurs during the early postoperative period. The picture of recurrence timing during the follow-up provides a foundation for the design of more cost-effective surveillance protocols for PTC patients.

Long-term surveillance of papillary thyroid cancer patients who do not undergo postoperative radioiodine remnant ablation: is there a role for serum thyroglobulin measurement?

CONTEXT

Serum thyroglobulin (Tg) assays are considered fundamental in postoperative surveillance of differentiated thyroid cancer (DTC) patients. However, the postsurgical profile of Tg levels has never been specifically investigated in patients who do not undergo radioiodine remnant ablation (RRA).

OBJECTIVES

Our objective was to explore the evolution of Tg levels over time in DTC patients treated with total or near-total thyroidectomy without RRA.

DESIGN

We retrospectively analyzed 290 consecutively diagnosed cases of low-risk (American Thyroid Association criteria) DTC treated with thyroidectomy alone and followed yearly with neck ultrasonography and serum Tg assays. We compared final Tg values in this group and a matched group of 495 RRA-positive patients. Temporal trends of serial Tg levels were also analyzed in 78 of the RRA-negative patients monitored with a high-sensitivity immunoradiometric assay.

RESULTS

After follow-up of 2.5-22 yr (median 5 yr), final Tg levels were undetectable (<1 ng/ml) in 274 of 290 RRA-negative patients (95%) and 492 of 495 RRA-positive controls (99%). In the subset of 78 RRA-negative patients, undetectable Tg levels (<0.2 ng/ml) were recorded in 60% at the first postoperative evaluation (3-12 months) and in 79% after 5 yr. Tg levels increased in the single patient who experienced disease recurrence during the observation period.

CONCLUSION

In most RRA-negative patients, postoperative serum Tg values spontaneously drop to undetectable levels within 5-7 yr after thyroidectomy. Thus, in later phases, Tg assays may be a valuable tool for follow-up even in patients who do not undergo RRA.

Identification and optimal postsurgical follow-up of patients with very low-risk papillary thyroid microcarcinomas

CONTEXT

Most papillary thyroid microcarcinomas (PTMCs; ≤ 1 cm diameter) are indolent low-risk tumors, but some cases behave more aggressively. Controversies have thus arisen over the optimum postoperative surveillance of PTMC patients.

OBJECTIVES

We tested the hypothesis that clinical criteria could be used to identify PTMC patients with very low mortality/recurrence risks and attempted to define the best strategy for their management and long-term surveillance.

DESIGN

We retrospectively analyzed data from 312 consecutively diagnosed PTMC patients with T1N0M0 stage disease, no family history of thyroid cancer, no history of head-neck irradiation, unifocal PTMC, no extracapsular involvement, and classic papillary histotypes. Additional inclusion criteria were complete follow-up data from surgery to at least 5 yr after diagnosis. All 312 had undergone (near) total thyroidectomy [with radioactive iodine (RAI) remnant ablation in 137 (44%) - RAI group] and were followed up yearly with cervical ultrasonography and serum thyroglobulin, TSH, and thyroglobulin antibody assays.

RESULTS

During follow-up (5-23 yr, median 6.7 yr), there were no deaths due to thyroid cancer or reoperations. The first (6-12 months after surgery) and last postoperative cervical sonograms were negative in all cases. Final serum thyroglobulin levels were undetectable (<1 ng/ml) in all RAI patients and almost all (93%) of non-RAI patients.

CONCLUSION

Accurate risk stratification can allow safe follow-up of most PTMC patients with a less intensive, more cost-effective protocol. Cervical ultrasonography is the mainstay of this protocol, and negative findings at the first postoperative examination are highly predictive of positive outcomes.

Predictive value of recombinant human TSH stimulation and neck ultrasonography in differentiated thyroid cancer patients

BACKGROUND

Serum thyroglobulin (Tg) stimulation by recombinant human TSH (rhTSH), in combination with neck ultrasonography (US), is an important tool in the first follow-up of differentiated epithelial cell thyroid carcinoma (DTC) patients. The objective of this study was to investigate if a second rhTSH stimulation, performed 2-3 years later, is of clinical utility in the follow-up of these patients.

METHODS

One hundred and one consecutive ambulatory DTC patients were studied. The great majority of them (89/101) were low-risk patients, being stage I or II at tumor node metastasis (TNM) staging classification. All study patients had been treated by surgery and radioiodine ablation, and exhibited, at first rhTSH follow-up, either undetectable Tg (<or=1 ng/mL) (rhTSH1-Tg-, n = 89 patients considered as free of disease) or low Tg (>1-5 ng/mL) (rhTSH1-Tg+, n = 12 patients considered with uncertain prognosis), with no US evidence of residual disease. In all patients, serum Tg measurement after a second rhTSH stimulation and neck US were performed.

RESULTS

At the second follow-up, all 89 rhTSH1-Tg-patients showed a negative US, and Tg became low positive only in one case, whereas it remained undetectable in the other patients. The overall negative predictive value of rhTSH1-Tg- was, then, 98.9%. Out of the remaining 12 patients (i.e., rhTSH1-Tg+ patients), 2 showed disease persistence/recurrence (with a positive predictive value of rhTSH1-Tg+ of 16.7%) and 6 became Tg-.

CONCLUSIONS

A second rhTSH stimulation is useless in DTC patients who were rhTSH-Tg and imaging negative at first follow-up, while it is suggested in patients with detectable, although low, rhTSH-Tg levels at first follow-up: in the absence of clinical or US evidence of disease persistence, these patients should not be retreated by radioiodine, but simply scheduled for a later rhTSH stimulation.

Age influences TSH serum levels after withdrawal of l-thyroxine or rhTSH stimulation in patients affected by differentiated thyroid cancer

Recombinant human TSH (rhTSH) has been recently suggested for radioiodine ablation in patients with differentiated thyroid cancer (DTC). To date, studies are still not available about the effectiveness of rhTSH stimulation depending on the age, since serum TSH clearance may be different in younger and in older patients. The aim of this study was to investigate the influence of age to serum TSH levels after rhTSH stimulation and thyroid hormone withdrawal (THW). We retrospectively evaluated two groups of consecutive DTC patients: group 1 (311 patients, age 49.0+/-13.6 years, ranging 15-86) underwent rhTSH stimulation 6-12 months after thyroid ablation (rhTSH-group); group 2 (84 patients, age 46.9+/-13.5 years, ranging 20-77) was followed by THW (THW-group). The influence of age, gender, body mass index and body surface area to serum TSH levels were evaluated in both groups. RhTSH-group: on day 5 (d5), TSH levels were 32.7+/-21.4 microU/ml (range 0.8-136.6). By univariate analysis, d5-TSH was positively related to age (r=0.27, p=0.0001) and no correlations were found with the other parameters. At multivariate analysis, both age and gender (female) were independently associated with d5-TSH levels. THW-group: after thyroid hormone withdrawal, TSH levels were 71.1+/-36.4 microU/ml (range 8.5-200). At univariate analysis, only age was significantly and negatively related to serum TSH levels (r=-0.31, p=0.004). Our data indicate that age and gender seem to positively influence serum TSH levels after rhTSH stimulation. An opposite effect of age on serum TSH levels has been observed after THW. Therapeutic implications ((131)I-treatment) of these findings have to be better investigated in prospective studies.

hNIS protein in thyroid: the iodine supply influences its expression and localization

OBJECTIVE

Nonfunctioning thyroid nodules (NFTNs) display a diminished iodide-concentrating ability, owing to defective expression and cell membrane targeting of the sodium-iodide symporter (NIS). Since NIS expression is primarily modulated by thyroid iodine content in vitro and in animal models, we attempted to determine whether iodine supply influences the expression and localization of human NIS (hNIS) in NFTNs.

DESIGN

Using immunohistochemistry, we analyzed cold hyperplastic nodules and nonnodular thyroid samples (controls) from patients living in iodine-sufficient (n = 19) or severely iodine-deficient (n = 15) areas.

MAIN OUTCOME

Nodules from the iodine-sufficient area exhibited weak or absent hNIS immunostaining whereas almost all nodules from the iodine-deficient area were hNIS positive. Heterogeneous hNIS staining was common among the iodine-deficient samples (p = 0.028). hNIS was localized on membrane in all nodular samples from the iodine-deficient area and in less than 40% in the iodine-sufficient area.

CONCLUSIONS

hNIS is adequately expressed and appropriately localized in NFTNs cell membrane from iodine-deficient areas and its expression in vivo is modulated by iodine supply.

Predictive value of serum calcitonin levels for preoperative diagnosis of medullary thyroid carcinoma in a cohort of 5817 consecutive patients with thyroid nodules

CONTEXT

Routine serum calcitonin (CT) measurement in patients with thyroid nodules for diagnosis of medullary thyroid carcinoma (MTC) is controversial.

OBJECTIVE

The objective of this study was to evaluate the diagnostic accuracy of systematic CT measurement in non-multiple endocrine neoplasia type 2 patients with nodular thyroid disease.

SETTINGS

This study was conducted at a national healthcare system hospital (outpatient and inpatient sectors).

SUBJECTS

Consecutive patients with nodular thyroid disease (n = 5817) were studied.

MAIN OUTCOME MEASURES

Serum CT levels were measured under basal conditions, and when basal values were more than or equal to 20 and less than 100 pg/ml, testing was repeated after pentagastrin stimulation. Basal or stimulated levels more than 100 pg/ml were indication for surgery.

RESULTS

Fifteen cases of MTC and seven of C cell hyperplasia (CCH) were identified. MTCs were diagnosed in all patients with basal CT more than 100 pg/ml. The four patients with basal CT more than or equal to 50 and less than 100 pg/ml included two diagnosed with MTC and two with CCH. In 10 patients with basal levels more than or equal to 20 and less than 50 pg/ml, histology confirmed the presence of MTC in four, four others had CCH, and the remaining two were negative for thyroid malignancy. Positive predictive values for basal CT levels in the preoperative diagnosis of MTC were: 23.1% for values more than or equal to 20 pg/ml, 100% for values more than 100 pg/ml, 25% for levels more than or equal to 50 and less than 100 pg/ml, and 8.3% for values more than or equal to 20 and less than 50 pg/ml. Positive predictive values for the pentagastrin test (>100 pg/ml) were 40% in the entire series.

CONCLUSIONS

CT screening of thyroid nodules is a highly sensitive test for early diagnosis of MTC, but confirmatory stimulation testing is necessary in most cases to identify true positive increases.

Follow-up of low risk patients with papillary thyroid cancer: role of neck ultrasonography in detecting lymph node metastases

Persistent or recurrent disease is rare in low risk patients with papillary thyroid cancer, and follow-up of these patients is a matter of debate. Neck ultrasonography (US), serum thyroglobulin (Tg), and whole body scan (WBS) after T(4) withdrawal were performed in 456 patients, followed up to 5 yr. At the end of the first year, 335 patients were Tg negative, and 121 were Tg positive; 65 of 96 patients with Tg levels between 1 and 10 ng/ml became spontaneously Tg negative after 2 yr. During follow-up, WBS discovered node metastases in 13 subjects, and US discovered node metastases in 38 subjects (31 Tg positive and 7 Tg negative). WBS did not add any information, because all WBS-positive patients were also US and Tg positive. Fifty percent of metastases were less than 1 cm and not palpable. Finally, the negative predictive value of both negative Tg and US at first follow-up was 98.8%. We suggest a first follow-up based upon US assessment and stimulated (after T(4) withdrawal or recombinant human TSH) serum Tg determination; subsequently, 1) US should not be mandatory at each examination in initially Tg- and US-negative subjects, but is strongly suggested in all other cases; 2) Tg determination should be repeated 1 yr later, after exogenous or endogenous TSH stimulation only in initially Tg-positive patients without any other evidence of residual disease; and 3) Tg measurement during therapy should be sufficient in all other cases.

Three-dimensional reconstruction of vessel distribution in benign and malignant lesions of thyroid

In order to better understand the spatial distribution of thyroid vessels, a series of benign and malignant thyroid lesions were studied with three-dimensional (3D) histological stereomicroscopic reconstruction. Cases consisted of normal autoptic thyroids (n=6), colloid goitres (n=6), Basedow's disease (n=2), follicular adenoma (FA) (n=4) one of which with Hurthle cells (HC), minimally invasive, well-differentiated follicular carcinoma (FTC) (n=1), well-differentiated FTC with HC (n=1), poorly differentiated FTC (n=13) with extensive angioinvasion, papillary carcinoma (PTC) (n=8) and medullary carcinoma (MTC) (n=1). From each selected nodule, parallel sections were obtained for 3D reconstruction and for histological and immunohistochemical studies. In normal thyroid, large vessels were located at the periphery of the gland with smaller branches present within the thyroid parenchyma that encircled follicles. The same pattern of vascularisation is maintained in lesions showing a follicular architecture as colloid goitre, Basedow's disease, FA, well-differentiated FTC and the follicular variant of PTC. Neoplastic lesions, at variance with non-neoplastic lesions, contained rare anastomoses. Poorly differentiated FTC and MTC contained large intratumoural vessels surrounding avascular areas corresponding to solid neoplastic cellular sheets with necrosis. PTC were more vascularised and contained numerous vascular anastomoses. In conclusion, the present data indicate that the vascular distribution is related to the follicular, papillary or solid type of growth. Vascular anastomoses and intratumoural vessels surrounding solid avascular areas are signs of malignancy.

Impaired estrogen-induced negative feedback on gonadotropin secretion in patients with gonadotropin-secreting and nonfunctioning pituitary adenomas

BACKGROUND

Several in vitro studies suggest that gonadotropin-secreting pituitary adenomas (Gn-omas) and non functioning pituitary adenomas (NFPA) originate from gonadotroph cells. Patients with Gn-oma and NFPA frequently show abnormal gonadotropin response to TRH. The aim of the study was to investigate whether the estrogen-induced negative feedback is operating in either patients with Gn-oma or NFPA.

MATERIALS AND METHODS

Serum gonadotropin levels were evaluated at 24 h after ethinylestradiol administration (1 mg per os; EE2 test) in seven patients with a diagnosis of Gn-oma, based on the presence of high follicle-stimulating hormone (FSH) and/or lutenising hormone (LH) levels with normal or high levels of sex steroids, in 22 patients with NFPA with normal or low levels of gonadotropin and sex steroids, and 30 sex- and age-matched healthy subjects. A normal response to EE2 test was arbitrarily defined as a serum LH and FSH decrease of at least 40 and 30% below basal levels.

RESULTS

Among patients with Gn-oma, only one had a normal FSH inhibition and another, a normal LH inhibition. Among the 22 patients with NFPA, the EE2 test caused a normal FSH or LH reduction in 10 and 15, respectively, while a normal reduction of both FSH and LH was observed in nine.

CONCLUSIONS

The study demonstrates that estrogen-induced negative feedback of gonadotropin secretion is disrupted in almost all patients with Gn-oma and in half of those with NFPA. This defective feedback is reminiscent of the resistance to thyroid hormones and glucocorticoids observed in patients with thyroid-stimulating hormone- (TSH-) and adrenocorticotropic hormone- (ACTH-)secreting adenomas, respectively.

Analysis of RET proto-oncogene abnormalities in patients with MEN 2A, MEN 2B, familial or sporadic medullary thyroid carcinoma

Medullary thyroid carcinoma (MTC) may occur either as a sporadic or familial (FMTC) disease. Multiple endocrine neoplasia (MEN) type 2, inherited as an autosomal dominant disease, is characterized by coexistence of MTC with other endocrine neoplasia. Activating mutations of the RET proto-oncogene, involving the somatic or the germinal cell lineage, are found in both inherited and acquired forms. In this study, RET mutations were screened in 47 individuals either affected by MTC or belonging to families with hereditary MTC. Exons 10, 11, 13, 14, 15 and 16 of the RET gene were amplified by polymerase chain reaction and examined by DNA sequence and/or restriction enzyme analysis to detect mutations in purified amplicons. Six MEN 2A families with a germline mutation at codon 634, one FMTC family carrying a mutation at codon 618 and two MEN 2B families with a mutation at codon 918 were identified. In affected members of a MEN 2A family no known RET mutations were observed. Besides, we identified a germline mutation in a patient with apparently sporadic MTC and in two out of three sons, indicating the presence of a sporadic misclassified familial disease. In all of the families examined we were able to distinguish the affected vs unaffected (not at risk) members. A somatic mutation of codon 918 was detected in three out of ten patients with apparently sporadic MTC.

A case of metastatic medullary thyroid carcinoma: early identification before surgery of an RET proto-oncogene somatic mutation in fine-needle aspirate specimens

Medullary thyroid carcinoma (MTC) management requires determination of the sporadic or familial nature of the disease. RET proto-oncogene mutation analysis in the tumor tissue obtained at surgery and in the peripheral blood identifies somatic vs. germinal mutations. We now report a case of MTC in which a RET somatic mutation at codon 918 was detected in fine-needle aspiration specimens obtained from both the thyroid nodule and two enlarged neck lymph nodes but not in peripheral blood. Therefore, a diagnosis of sporadic MTC was made before surgery. Thus, this approach, by excluding preoperatively multiple endocrine neoplasia disease, permitted immediate thyroidectomy without search for pheochromocytoma. PCR-based genetic analysis in fine-needle aspiration biopsy specimens, therefore, preoperatively identifies genetic abnormalities at an early and easily manageable stage and may well contribute to the management strategy of MTC.

Effects of dopaminergic receptor stimulation and opioid receptor blockade on GH incretion: preliminary findings

The Authors describe the effects of CB 154 (2.5 mg, per os) and naloxone (0.4 mg, i.m) on GH levels in normal man serum. Preliminary results point to a clear potentiation of GH release when the opiate receptor blockade is added to a dopamine receptor stimulation.

[Effects of interaction between 2-Br-alpha-ergocriptine (CB 154) and naloxone on the control of insulin secretion in normal men]

The effects of 2-Br-alpha-ergocriptine (CB 154, 2.5 mg per os) and naloxone (0.4 mg i.m.) as well as the interaction between these two drugs on insulin serum levels have been studied in six normal male volunteers. Both CB 154 and naloxone lower insulin serum levels, while a more clear-cut reduction is observed after CB 154 plus naloxone. These results are discussed in view of a possible involvement of dopaminergic and enkephalinergic systems in the control of insulin secretion at hypothalamic or pancreatic level.