Importance of tumour size in papillary and follicular thyroid cancer

Papillary thyroid cancer: the value of bilateral diagnostic lymphadenectomy

Purpose

Papillary thyroid carcinoma (PTC) spreads early to lymph nodes (LN). However, prophylactic central (CND) and lateral neck dissection (LND) is controversially discussed in patients with clinically negative nodes (cN0). The preoperative prediction of LN metastasis is desirable as re-operation is associated with higher morbidity and poor prognosis. The study aims to analyse possible benefits of a systemic bilateral diagnostic lateral lymphadenectomy (DLL) for intraoperative LN staging.

Methods

Preoperative prediction of LN metastasis by conventional ultrasound (US) was correlated with the results of DLL and intra-/postoperative complications in 118 consecutive patients with PTC (cN0) undergoing initial thyroidectomy and bilateral CND and DLL.

Results

Lateral LNs (pN1b) were positive in 43/118 (36.4%) patients, including skip lesions (n = 6; 14.0%). Preoperative US and intraoperative DLL suspected lateral LN metastasis in 19/236 (TP: 8.1%) and 54/236 (TP: 22.9%) sides at risk, which were confirmed by histology. Sixty-seven out of 236 (FN: 28.4%) and 32/236 (FN: 13.6%) sides at risk with negative preoperative US and intraoperative DLL lateral LN metastasis were documented. DLL was significantly superior compared to US regarding sensitivity (62.8% vs 22.1%; p < 0.002), positive predictive value (100% vs 76.0%), negative predictive value (82.4% vs 68.2%), and accuracy (86.4% vs 69.1%), but not specificity (100% vs 96.0%; p = 0.039). DLL-related complications (haematoma) occurred in 6/236 [2.5%] sides at risk, including chylous fistula in 2/118 [1.7%] patients.

Conclusion

DLL can be recommended for LN staging during initial surgery in patients with PTC to detect occult lateral LN metastasis not suspected by US in order to plan lateral LN dissection.

Thyroid follicular microcarcinoma

Differentiated thyroid cancers are the most common malignancies arising in thyroid gland. Papillary thyroid cancer presents a very favorable prognosis, while follicular type is slightly more aggressive, mainly for its attitude to hematogenous spreading with distant metastases. Papillary microcarcinoma (10 mm or less) has an excellent prognosis, largely demonstrated, and its management is changed in the last few years, reducing surgical procedure, role of radio iodine ablation (RAI) and TSH suppression. But no effective data are available for follicular thyroid microcarcinoma (mFTC); very few reports and studies are present in literature about mFTC, mainly for its low incidence. Aim of this paper is to review current literature to reach, in absence of evidence, some suggestion in managing mFTC.

The surgical dilemma of primary surgery for follicular thyroid neoplasms

Follicular thyroid carcinoma is the second most prevalent form of differentiated thyroid carcinoma, following papillary thyroid carcinoma. Preoperative diagnosis is hampered by the fact that fine-needle aspiration cytology as well as supplemental molecular analysis cannot unambiguously distinguish between follicular thyroid carcinoma and benign follicular thyroid adenoma. The 2017 WHO classification defines three histological subtypes of follicular thyroid carcinoma: minimally invasive (excellent prognosis), encapsulated angioinvasive, and widely invasive type (higher risk of recurrence and metastatic spread). The fact that definite characterization of follicular neoplasms is predominantly a postoperative histological diagnosis (core criteria: capsular, vascular and adjacent tissue invasion) translates into the challenge for the thyroid surgeon to plan preoperatively for presence of malignancy and, if required, to adapt the surgical strategy according to intraoperative (frozen section) or postoperative histological findings. Until improved tools for pre-/intraoperative diagnosis are available, the malignant potential of a follicular thyroid lesion can be assessed by stratifying the patient according to clinical risk factors (presence of metastases, advanced patient age, tumor size). A stepwise, escalating surgical approach with restricted primary resection (hemithyroidectomy) and completion surgery based on the definite histopathology is another option to solve this dilemma. The currently recommended surgical treatment strategies for FTCs as published by ATA, BTA, CAEK and ESES are discussed. There is consensus that prophylactic lymphadenectomy is not required for FTCs and that hemithyroidectomy is sufficient in low-risk FTCs (capsular invasion only) whereas thyroidectomy with postoperative radioiodine therapy is indicated in high-risk FTCs (angioinvasion; widely invasive FTC).

Larger tumor size predicts nodal involvement in patients with follicular thyroid carcinoma

Aims and background

Lymph node metastases are rare in patients with follicular thyroid carcinoma, with an average incidence of 5.5% of all cases reported in the literature. In the present study we focused on the search for risk factors predictive of lymph node involvement in patients with follicular thyroid carcinoma to plan the most appropriate management and follow-up.

Methods and study design

We carried out a cross-sectional study among patients with follicular thyroid carcinoma and lymph node metastasis at diagnosis and patients without lymph node involvement. From January 1998 to April 2008, 930 patients underwent thyroidectomy in our surgical department for a variety of thyroid disorders, 420 (45.2%) of them for a differentiated thyroid carcinoma. The medical records of 55 patients with histological diagnosis of follicular thyroid carcinoma were analyzed.

Results

Four patients (7.3%) had lymph node metastasis from follicular thyroid carcinoma at presentation in both the lateral and central neck compartments. Mean tumor size was significantly greater for follicular thyroid carcinomas with nodal metastasis (5.1 ± 1.4 cm) than for those without nodal involvement (3.0 ± 1.2 cm, P <0.010). Among factors supposed to influence the presence of nodal metastasis at diagnosis (age, gender, tumor size, multifocality, tumor poorly differentiated, tumor widely invasive, vascular invasion, thyroid capsular invasion, and extra thyroid invasion), tumor size larger than 4.0 cm was the only factor retained in the multivariate statistical model.

Conclusions

Lymph node dissection must be planned only in the case of large follicular thyroid carcinomas. Since follicular carcinoma is usually diagnosed postoperatively, more attention should be paid to nodal involvement in the tumor re-staging during follow-up of those patients with tumors larger than 4.0 cm in diameter.

Disease-free survival in papillary and follicular thyroid carcinoma

T stage was redefined for patients with differentiated thyroid carcinoma (DTC) between the 5th and 7th versions of the UICC tumour classification system. Patients, methods: 636 patients (486 women, 150 men; mean age 49.1 ± 15.6 years, mean follow-up 4.6 years) who had been treated with ablative radioiodine therapy after thyroidectomy for papillary (PTC) or follicular thyroid carcinomas (FTC) were retrospectively assessed on occurrence of locoregional recurrent disease, or cervical lymph node or distant metastases. Disease-free survival was calculated from initial T stage, classified according to both versions of the UICC staging system and compared with the prognostic value of primary tumour size. Kaplan-Meier method and two measures of explained variation, (1) R2 based on the (partial) likelihood ratio statistic of the Cox proportional hazards model and (2) a model-free variant of a distance measure proposed by Schemper had the aim to detect the most advantageous classification. Results: Of the 508 patients with PTC, 11 (2.2%) developed a local recurrence, 37 (7.3%) cervical lymph node and 23 (4.5%) distant metastases, 3 (2.3%), 8 (6.3%), and 18 (14.1%) were the numbers for the 128 FTC patients respectively. The two classification systems yielded an equal count of statistically significant differences regarding disease-free survival in patients with PTC while UICC 7th classification appeared slightly advantageous in patients with FTC. Regarding explained variation the UICC 7th classification tended to be superior to the UICC 5th classification, both in PTC and FTC, however statistical significance was not reached. Conclusion: The primary tumour size significantly added to the prognosis regarding local cervical and distant metastases.

Pathologic significance of a novel oncoprotein in thyroid cancer progression

BACKGROUND

The incidence of thyroid cancer is increasing worldwide, and there is an emerging need to develop accurate tools for diagnosis. Fine needle aspiration biopsy has greatly improved evaluation of thyroid nodules, but challenges with indeterminate lesions remain in up to 25% of biopsies. Novel tissue biomarkers may assist in improved nodule characterization. Microcalcifications occurring in thyroid cancers suggest proteins involved in bone formation may play a role in thyroid carcinogenesis. We evaluated the expression of the known osteogenic protein, Enigma, in thyroid cancer as a candidate oncoprotein and role in carcinogenesis based on association with other known oncoproteins such as bone morphogenetic protein-1 (BMP-1).

METHODS

The expression of both Enigma and BMP-1 were evaluated by immunohistochemistry (IHC) in an equal number of benign (n = 120) and different histological subtypes of malignant (n = 120) human archival thyroid nodules with and without calcification. The colocalization of Enigma with BMP-1 was evaluated by confocal microscopy using the BZ analyzer.

RESULTS

Enigma was strongly expressed in thyroid cancer tissue with a higher immunoreactive score in advanced thyroid cancer compared to less advanced and benign nodules. Enigma was localized either in cytoplasm or nucleus depending on the histological subtypes. Higher expression of Enigma was associated with the tumor size and lymph node involvement. There was clear and strong colocalization signal of Enigma and that of BMP-1. Expression of Enigma occurred without regard to calcification in cancer tissue.

CONCLUSION

Enigma may serve as an oncoprotein marker, identifying benign from malignant thyroid tissue on FNA. Enigma may have a role in carcinogenesis of thyroid cancer independent of tissue calcification, possibly in relation to interaction with BMP-1.

SHOULD MULTIFOCAL PAPILLARY THYROID CARCINOMAS CLASSIFIED AS T1A WITH A TUMOR DIAMETER SUM OF 1 TO 2 CENTIMETERS BE RECLASSIFIED AS T1B?

OBJECTIVE

Considering the diameter of the largest tumor while determining T stage in multifocal papillary thyroid microcarcinomas (PTMCs) might cause underestimation of tumoral stage. We aimed to investigate the effect of total tumor diameter (TTD) on tumor node metastasis (TNM) classification in multifocal T1a PTMCs.

METHODS

T1 tumors were grouped as T1a or T1b according to 7th TNM edition. For patients with multifocal T1a, TTD (the sum of the maximal diameter of each focus) was calculated, and these patients were further subgrouped as TTD ≤1 cm or TTD 1 to 2 cm.

RESULTS

There were 724 patients with T1 tumors. Multifocality was observed in 150 (28.5%) of 527 patients with T1a and 84 (42.6%) of 197 patients with T1b tumors (P<.001). Lymph node metastasis (LNM), thyroid capsule invasion, and lymphovascular invasion were significantly higher in T1b compared to T1a (P<.001, P<.001, and P = .015, respectively). There were 8 (1.5%) patients with persistence but not any with recurrence in the T1a group. Persistence and recurrence were observed in 3 (1.5%) and 5 (2.5%) patients in the T1b group, respectively. Among 150 T1a patients with multifocal tumors, TTD was ≤1 cm in 89 (59.3%) and 1 to 2 cm in 61 (40.7%) patients. Number of tumor foci, LNM, and thyroid capsule invasion were significantly higher in multifocal T1a patients with TTD 1 to 2 cm compared to with TTD ≤1 cm (P<.001, P = .032, P = .014, respectively).

CONCLUSION

TTD might be used as a parameter to determine patients at higher risk for persistence, and T1a multifocal PTMCs with TTD 1 to 2 cm can be reclassified as T1b.

ABBREVIATIONS

ETE = extrathyroidal extension LNM = lymph node metastasis PTC = papillary thyroid carcinoma PTMC = papillary thyroid microcarcinoma RAI = radioactive iodine TNM = tumor, node, metastasis TTD = total tumor diameter.

Downregulation of Nrf2 by the combination of TRAIL and Valproic acid induces apoptotic cell death of TRAIL-resistant papillary thyroid cancer cells via suppression of Bcl-xL

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) represents an effective agent for the treatment of many cancers, though the majority of thyroid cancers are found to be resistant. Therefore it would be necessary to identify agents capable of increasing the sensitivity of these cancers to TRAIL-mediated cell death. Here, we examined the therapeutic effect and its underlying mechanism of combination treatment of TRAIL and histone deacetylase inhibitor, Valproic acid (VPA) in vitro using human papillary thyroid cancer (PTC) cells and in vivo using an orthotopic mouse model of PTC. TRAIL-VPA combination therapy synergistically induced apoptotic cell death in TRAIL-resistant PTC through caspase activation. In addition, downregulation of antioxidant transcription factor, Nrf2 by co-treatment of TRAIL-VPA induces cell death via suppression of Bcl-xL in vitro and in vivo; these effects were further enhanced following siRNA inhibition of these proteins in combination with TRAIL or TRAIL-VPA. Taken together, VPA sensitized TRAIL-resistant PTC cells to apoptotic cell death through involvement of Nrf2 and Bcl-xL. Thus, the combination of VPA and TRAIL may be a promising therapy for TRAIL-resistant PTC.

Conventional papillary thyroid carcinoma: effects of cystic changes visible on ultrasonography on disease prognosis

Purpose

To investigate the characteristics of papillary thyroid carcinoma (PTC) with cystic changes visible on ultrasonography (US).

Methods

This study included 553 PTCs in 553 patients between January 2003 and August 2004. One radiologist with 10 years of experience in thyroid imaging retrospectively reviewed the preoperative US images. Two different groups were formed according to two different reference points (group 1, 25%; group 2, 50%) of the cystic component. Patients between the groups were compared according to their clinicopathologic characteristics. Disease-free survival (DFS) was estimated. Cox’s multivariate proportional hazards regression model was used to identify the effect of variable factors on the recurrence risk.

Results

Fifty-six patients (10.1%) were confirmed to have tumor recurrence within the follow-up period. Thirty-five patients had regional metastasis, one had distant metastasis, eight had multiple site metastases, and 12 had biochemical recurrence. PTC patients with a ≤ 50% or PTC patients with a ≤ 25% cystic component did not have a statistically significant longer DFS than those with a >50% (hazard ratio [HR], 1.118; 95% confidence interval [CI], 0.255 to 4.910; P=0.883) or those with a >25% cystic component (HR, 0.569; 95% CI, 0.164 to 1.976; P=0.375), respectively. Moreover, independent predictors of recurrence were pathologic size, male gender, and lymph node metastasis, not a >50% or >25% cystic component.

Conclusion

The proportion of the cystic component in PTCs did not affect DFS.

[Current TNM system of the UICC/AJCC : the prognostic significance for differentiated thyroid carcinoma]

BACKGROUND

The aim of study was an evaluation of prognostic factors of the current TNM version (UICC/AJCC 2009, 7th revision) for differentiated thyroid carcinoma (DTC).

PATIENTS AND METHODS

A total of 368 patients with DTC (papillary thyroid carcinoma [PTC] n = 269, follicular thyroid carcinoma [FTC] n = 99) were included. Disease-specific survival (DSS) was calculated based on the different TNM stages (mean follow-up 60 ± 37.5 months).

RESULTS

When compared to patients with FTC, PTC patients had smaller tumors (diameter 19 mm versus 33 mm), more often lymph node metastases (40.9% versus 9.1%) but less frequent distant metastases (2.6 versus 13.1%) and poorly differentiated variants (PDTC 3.0% versus 8.1%). The 5-year and 10-year DSS for PTC versus FTC were 97.3% versus 91.5% and 96.2% versus 91.5% (p = 0.086), respectively. When comparing different TNM categories between well-differentiated PTC and FTC, no statistically significant differences were found but PDTCs, had a significantly worse DSS.

CONCLUSIONS

The current TNM system is a sufficient tool for predicting DSS in well-differentiated PTC. In FTC, the extent of capsular and vascular invasion should also be considered. The implementation of a specific TNM system for PDTC needs to be confirmed in further studies.

German Association of Endocrine Surgeons practice guideline for the surgical management of malignant thyroid tumors

INTRODUCTION

Over the past years, the incidence of thyroid cancer has surged not only in Germany but also in other countries of the Western hemisphere. This surge was first and foremost due to an increase of prognostically favorable ("low risk") papillary thyroid microcarcinomas, for which limited surgical procedures are often sufficient without loss of oncological benefit. These developments called for an update of the previous practice guideline to detail the surgical treatment options that are available for the various disease entities and tumor stages.

METHODS

The present German Association of Endocrine Surgeons practice guideline was developed on the basis of clinical evidence considering current national and international treatment recommendations through a formal expert consensus process in collaboration with the German Societies of General and Visceral Surgery, Endocrinology, Nuclear Medicine, Pathology, Radiooncology, Oncological Hematology, and a German thyroid cancer patient support organization.

RESULTS

The practice guideline for the surgical management of malignant thyroid tumors includes recommendations regarding preoperative workup; classification of locoregional nodes and terminology of surgical procedures; frequency, clinical, and histopathological features of occult and clinically apparent papillary, follicular, poorly differentiated, undifferentiated, and sporadic and hereditary medullary thyroid cancers, thyroid lymphoma and thyroid metastases from primaries outside the thyroid gland; extent of thyroidectomy; extent of lymph node dissection; aerodigestive tract resection; postoperative follow-up and surgery for recurrence and distant metastases.

CONCLUSION

These evidence-based recommendations for surgical therapy reflect various "treatment corridors" that are best discussed within multidisciplinary teams and the patient considering tumor type, stage, progression, and inherent surgical risk.

Poorer prognosis and higher prevalence of BRAF (V600E) mutation in synchronous bilateral papillary thyroid carcinoma

BACKGROUND

The clinical significance of synchronous bilateral papillary thyroid carcinoma (SBiPTC) has not been fully defined, and the prevalence of BRAF (V600E) mutation in SBiPTC remains unknown. The purpose of this study is to compare the clinical outcomes and BRAF (V600E) mutation incidence of SBiPTC patients with those of unilateral papillary thyroid carcinoma (UiPTC) patients.

METHODS

From 1997 to 2008, a total of 903 patients with papillary thyroid cancer were treated at a single institution. Of 891 studied patients, 177 (19.9%) had SBiPTC and 714 had UiPTC. SBiPTC was defined as cancer diagnosed in both thyroid lobes at the same time or within a period of 3 months. The mean follow-up time was 6 years, ranging from 2.5 to 13.5 years. Rates of disease-free survival (DFS) and overall survival (OS) were calculated and compared. BRAF (V600E) mutation was determined by polymerase chain reaction (PCR) amplification and DNA sequencing.

RESULTS

Compared with UiPTC patients, patients with SBiPTC were more likely to have larger tumor size, extrathyroidal invasion, lymph node metastasis, and more advanced stage. The 5-year DFS rate was 86.0% for SBiPTC patients and 94.0% for UiPTC patients (p = 0.013). The prevalence of BRAF (V600E) mutation in the SBiPTC group was significantly higher than that in the UiPTC group (65.7% vs. 50.4%; p = 0.038).

CONCLUSIONS

Patients with SBiPTC present with more advanced tumor stage and have shorter disease-free survival than UiPTC patients. Poorer outcomes of these patients may be at least partially explained by the high incidence of BRAF (V600E) mutation.

Predictive value of the Delphian and level VI nodes in papillary thyroid cancer

BACKGROUND

Recent published data has shown that metastatic involvement of the prelaryngeal or Delphian lymph node (DLN), the highest of the central (level VI) cervical lymph nodes, is highly predictive of advanced nodal disease in papillary thyroid cancer (PTC). The aims of this study were to determine the diagnostic accuracy of all the level VI cervical nodes in PTC and to determine which node group, if any, is the most accurate in predicting lateral node (N1b) disease.

METHODS

This was a retrospective cohort study. Data were obtained from the University of Sydney Endocrine Surgical Unit Database and through a review of the histopathology records. The study cohort was composed of 177 consecutive patients with a final diagnosis of PTC who underwent total thyroidectomy and lymph node dissection, spanning the period from May 2001 to December 2006.

RESULTS

Of the 177 patients with PTC, 86 had the DLN removed, 51 had a pretracheal node removed and 76 had the paratracheal group removed. DLN, paratracheal and pretracheal node disease was present in 21%, 39% and 46%, respectively. Lateral node (N1b) disease was present in 35%. Paratracheal node involvement was mildly predictive of further disease with patients 1.7 times more likely to have lateral node involvement (sensitivity=55%, specificity=68%). Pretracheal node involvement was moderately predictive of further disease with patients three times more likely to have lateral node involvement (sensitivity=72%, specificity=74%). DLN involvement was highly predictive of further node involvement with patients nine times more likely to have lateral node disease (sensitivity=53%, specificity=94%) and 40 times more likely to have any nodal disease (sensitivity=41%, specificity=100%).

CONCLUSION

This is the first study to examine the diagnostic accuracy of all level VI lymph nodes in PTC. While, metastatic involvement of all central nodal groups is indicative of further disease, the DLN is the most accurate predictor.

Update on recent developments in the therapy of differentiated thyroid cancer

In the past decade, the management of differentiated thyroid carcinoma changed significantly and thus contributed to the improvement of the already favorable prognosis of this malignant disease. Surgical treatment techniques improved and the extent of initial surgery is more individualized. Radioiodine therapy is an essential part of therapeutic regimens in almost all cases, and the use of recombinant human thyroid-stimulating hormone has established for ablation of remnant tissue, treatment of iodine-positive cancer, and sensitive thyroglobulin measurement during follow-up. Risk stratification has become more important to plan treatment and follow-up individually, particularly to evaluate the need for thyroid-stimulating hormone suppression therapy. Especially for inoperable and radioiodine-negative thyroid carcinomas, novel treatment options such as tyrosine kinase inhibitor therapy have emerged. This article deals with the current options of optimal therapy regimens in differentiated thyroid carcinoma.

Diagnosis and treatment of small follicular thyroid carcinomas

BACKGROUND

Follicular thyroid microcarcinomas (mFTCs) of 10 mm or less in size rarely manifest clinically and their clinical significance is controversial. This study assessed their characteristics and incidence, and analysed treatment modalities used for mFTC.

METHODS

Members of the German Association of Endocrine Surgeons were asked to review patients with mFTC operated on between 1990 and 2005.

RESULTS

Data for 90 patients from 26 institutions were reported. Histopathological slides were available for re-evaluation in 35 patients. Most initial diagnoses had to be revised because of incorrect size assessment or incorrect diagnosis (benign adenoma, papillary thyroid carcinoma (PTC), follicular variant of PTC). The diagnosis of mFTC was confirmed in only four patients. As a result of the incorrect histopathological diagnosis, unnecessary completion thyroidectomy and radioiodine ablation were performed in 17 and 20 patients respectively. The incidence of mFTC was calculated to be 0.12 per million population per year.

CONCLUSION

mFTC is exceptionally rare. Such tumours are overdiagnosed, resulting in unnecessary treatment associated with avoidable morbidity. Histopathological re-evaluation by an experienced pathologist is recommended before embarking on further treatments when a diagnosis of mFTC is made.

[Surgery of thyroid carcinoma]

The 5 main types of thyroid cancer (papillary, PTC, follicular, FTC, poorly differentiated, PDTC undifferentiated, UTC, medullary, MTC) not only differ regarding morphology, pathogenesis, genetics,and pathophysiology (iodine metabolism, thyroglobulin and calcitonin production), but also concerning tumor biology, metastatic behavior (lymphogenous, locally invasive and hematogenous routes) and prognosis. Knowledge of these features is the basis of the surgical concept of one or two-stage thyroidectomy, the exceptions and the concept of locoregional lymph node dissection. Lymph node surgery plays an important role in those cancers exhibiting mainly lymph node metastases (PTC, MTC) not only due to frequent recurrences but also due to its potential curative intent. Differentiated carcinomas may have an acceptable prognosis despite local invasion of the cervical aerodigestive system, thus resections are justified when technical prerequisites are given.

Indeterminate thyroid nodules: a challenge for the surgical strategy

BACKGROUND

Because no clinical parameter can establish the final status of a cytologically indeterminate thyroid nodule (ITN) or nodal-metastases in case of malignancy, the initial surgical strategy should define an oncologically adequate procedure with low morbidity.

METHODS

The prognostic relevance of sex, age, tumor sizes, multifocality, thyroid function, and recurrence was analyzed in 156 consecutive patients according to the presence of malignancy and nodal metastases. The accuracy of frozen sections to reveal malignancy was determined. Clinical parameters were compared with regard to their ability to identify malignancy and nodal metastases in an ITN to determine an appropriate initial operative strategy.

RESULTS

One hundred and eighteen (75.6%) patients underwent (total) thyroidectomy, 37 (23.7%) patients underwent hemithyroidectomy, and 1 patient underwent isthmus resection. Fifty-five (35.3%) patients showed malignancy. First step lymphadenectomy (lymph node dissection along the recurrent laryngeal nerve before removing the thyroid lobe) was performed in 142 patients documenting 10 nodal metastases. Comparing benign and malignant ITN, no association was found for sex (P = .17), age (P = 1.0), tumor sizes (P = .33, P = .12, P = .19 for < or =30 mm, < or =40 mm, and < or =50 mm, respectively), or thyroid function (P = .26). The determination of malignancy by frozen section showed a sensitivity of 30.9% and a specificity of 100%. No permanent hypoparathyroidism or recurrent laryngeal nerve palsy was observed postoperatively.

CONCLUSION

Because of the failure of available clinical parameters to predict malignancy in cytologically ITN, hemithyroidectomy in unilateral goiter and thyroidectomy in bilateral goiter is recommended. Ipsilateral "first step central neck dissection" on the side of ITN offers the advantages of oncologically adequate resection and staging with a low morbidity, as well as avoids reoperation.

Primary tumour diameter as a risk factor for advanced disease features of differentiated thyroid carcinoma

OBJECTIVE

To study the relationship between primary tumour size and the risk of advanced disease features (multifocal or locally invasive disease, lymph-node or distant metastases) in differentiated thyroid carcinoma (DTC).

DESIGN

A retrospective chart review study.

PATIENTS

The study sample comprised 935 papillary (PTC) and 291 follicular thyroid carcinoma (FTC) patients treated in our hospital from 1978 to 2007.

MEASUREMENTS

Kaplan-Meier analyses and log-rank tests were performed to calculate tumour size-adjusted cumulative risk of advanced disease features.

RESULTS

Accounting for primary tumour diameter, there were no significant differences in cumulative risks of multifocal carcinoma (P = 0.12) or distant metastases (P = 0.49) between PTC and FTC. PTC showed higher cumulative risks of local invasion (P < 0.0001) or lymph-node metastases (P < 0.0001). The cumulative risk of tumour multifocality increased 5%/cm of primary tumour diameter. The cumulative risk of local invasion or lymph-node metastases in PTC and of distant metastases in DTC increased exponentially at a threshold tumour diameter of 10 mm. In FTC, lymph-node metastases are associated almost exclusively with primary tumours showing extrathyroidal growth.

CONCLUSIONS

Starting with a 1 cm primary tumour diameter, increasing tumour size is associated with an exponentially increasing risk of local invasion or lymph-node or distant metastases of DTC. The current classification of carcinomas < 2 cm as T1 is therefore questionable.

Surgical approaches in thyroid cancer and lymph-node metastases

Thyroid cancer collectively encompasses a variety of tumors of disparate morphology and biology. With the exception of radio-iodine therapy for iodine-concentrating well-differentiated thyroid cancers, surgery is the foremost and generally sole effective treatment. Because the growth patterns of these tumors vary tremendously, there is a need to tailor the extent of dissection to the respective tumor entity, especially for less aggressive tumors. No international consensus exists about what precisely constitutes a 'low-risk' or 'high-risk' tumor. Established indications for less-than-total thyroidectomy include small (<or=1 cm), unifocal, and non-metastatic papillary thyroid carcinomas (PTC), and minimally invasive follicular thyroid carcinomas (FTC; invasion of the tumor capsule only). Whether occult multifocal PTC and minimally invasive FTC with histopathological evidence of vascular invasion also fall into the 'low-risk' category remains unclear. For node-positive thyroid cancers, compartment-oriented microdissection is the gold standard of care, whereas the concept of prophylactic lymph-node dissection continues to arouse controversy. Most experts agree that routine lymph-node dissection is unnecessary for low-risk well-differentiated thyroid cancer (DTC). Because occult lymph-node metastases are frequent in high-risk PTC and medullary thyroid carcinoma, compartment-oriented microdissection helps prevent reoperations for 'recurrences' arising from residual nodes, sparing patients the excess morbidity from reoperations in the neck. Because of the looming epidemic of early forms of thyroid cancer, an international consensus is needed regarding (1) the definition of low- versus high-risk tumors; (2) classification of neck nodes; and (3) lymph-node dissection terminology.

Prognosis and risk stratification in young papillary thyroid carcinoma patients

Controversies remain regarding to the therapeutic methods of papillary thyroid cancer (PTC) in young patients. TNM staging and other risk evaluation system are not perfectly applicable for all young PTC patients in view of disease outcome. The aims of this study are to identify the clinical presentations, prognostic factors and risk analysis methods. From January, 1977, to June, 2006, seventy-seven patients with primary PTC younger than 20 years old at Chang Gung Medical Center in Taiwan were enrolled in this retrospective study. The patients were classified as disease-free or non-disease-free according to presence or absence of distant metastases or local recurrence at the end of follow-up. Clinical data of these patients were analyzed and compared. The average follow-up period was 10.3 years. Two patients died of PTC during the follow-up period; one died of brain metastasis, and one died of airway obstruction. Patients undergoing total thyroidectomy, especially those with disease beyond the thyroid, had better outcomes than patients not undergoing total thyroidectomy (p = 0.003). Moreover, the DeGroot clinical classification system was a better predictor of prognosis than TNM (p<0.001 vs p = 0.007). Our results suggest that prognosis for PTC is not worse in younger patients. However, patients who had undergone total thyroidectomy might have a better prognosis. Clinical classification is a good alternative classification system for predicting disease outcome in young PTC patients. Patients with confined intrathyroid lesion (<or=T2, N0, M0) may be regarded "low risk" PTC patients.

The Delphian lymph node in thyroid cancer

OBJECTIVE

To determine the significance of Delphian lymph node (DLN) involvement in thyroid cancer.

SUMMARY BACKGROUND DATA

The DLN has long been regarded as a predictor of thyroid malignancy and indicator of advanced disease; however, there are no published data in relation to the thyroid.

METHODS

A retrospective cohort study with data obtained from the University of Sydney Endocrine Surgery database and histopathology records. The study cohort comprised 1000 consecutive patients undergoing total thyroidectomy.

RESULTS

The DLN was separately removed and identified as such in 263 of 1000 (26.3%) patients. Of 1000 patients 203 (20.3%) had a diagnosis of papillary/medullary cancer. Of this group 150 patients had surgery performed for suspected cancer, and in 53 the diagnosis of cancer was unsuspected. In only 1 case did the DLN operative appearance alert the surgeon to an otherwise unsuspected thyroid cancer. The DLN was separately identified in 103 patients with cancer and, in this group, 22 of 103 (21.4%) had DLN metastases. DLN involvement was associated with greater nodal disease (9.8 vs. 1.6 nodes; P < 0.001), larger tumor size (19.4 vs. 11.1 mm; P < 0.003) and younger age (41 vs. 47 years; P = 0.058). DLN involvement was highly predictive of further disease in the central compartment (sensitivity = 41%, specificity = 95%), moderately predictive of further disease in the lateral compartment (sensitivity = 50%, specificity = 88%), and strongly suggestive of further nodal disease in the neck (sensitivity = 64%, specificity = 100%).

CONCLUSIONS

Although the clinical appearance of the DLN is not an accurate indicator of the presence of unsuspected thyroid cancer, metastatic involvement of the DLN is an adverse prognostic marker in papillary/medullary thyroid cancer. The presence of DLN metastasis in patients with thyroid cancer should alert the surgeon to the high probability of advanced disease and need for greater attention to the central and lateral lymph node compartments.

Imaging for staging and management of thyroid cancer

The management of thyroid cancer has been controversial and, as a result, the routine use of imaging in this disease, especially for pre-operative staging, has lagged behind other head and neck cancers. However, as more is known about the natural history of thyroid cancer, the role of imaging is becoming more established. This review focuses on how imaging now influences the staging and management of the primary cancer, nodal metastases and distant metastases. This is followed by a brief review of the role of imaging in planning post-operative radiotherapy and post-treatment surveillance.

Intrathyroidal Differentiated Thyroid Carcinoma: Tumor Size-Based Surgical Concepts

INTRODUCTION

Total thyroidectomy (TT) remains the treatment of choice for differentiated thyroid carcinomas (DTCs), but a limited approach can be proposed when tumors are at an early stage and limited to a single lobe. The aim of this study was to analyze the pathologic and clinical aspects of a retrospective series of DTCs in an attempt to determine whether these features might prove useful for limiting the surgical strategy in selected cases.

METHODS

From 2000 to 2005, a total of 2798 patients (637 males, 2161 females; mean age 44.6 years) underwent TT for papillary thyroid carcinoma in our department. The histologic features considered were size, histologic subtype and capsule of the tumor, its multifocality/bilaterality, infiltration of the thyroid capsule, and the presence of nodal metastases.

RESULTS

Statistical analysis revealed that among tumors < or = 1 cm the presence of the tumor capsule, infiltration of the thyroid capsule, bilaterality, and the presence of node metastases were all significantly lower when the tumor size was < or = 0.5 cm (p < 0.0001). Furthermore, patients with bilateral carcinomas demonstrated a significantly higher presence of a tumor capsule (p = 0.012), infiltration of the thyroid capsule (p < 0.0001), and node metastases (p < 0.0001) and a higher incidence of the "tall-cells" variant (p < 0.0001) when compared to the unilateral population.

CONCLUSIONS

Based on these data it is suggested that tumors < or = 1 cm cannot be considered a homogeneous class of DTCs. Nevertheless, in tumors < or = 0.5 cm the absence of a "tall-cells" variant and the absence of infiltration of the thyroid capsule might be useful for avoiding an unnecessary completion thyroidectomy after lobectomy.

TNM Classification of Thyroid Carcinoma

BACKGROUND

The understanding of biology of well-differentiated thyroid cancer has improved in the last two decades with the detailed understanding of prognostic factors and risk group stratification. The risk groups are crucial in the management of thyroid cancer and overall prognosis.

TNM STAGING SYSTEM

The TNM staging system has been used in all human cancers, and it adheres to the biology of tumors. The data in thyroid cancer comes from retrospective studies, as there are no prospective randomized trials. The most recent TNM staging system was revised and published (6th edition) in 2002. The major attributes of the staging system include: age as the most important prognostic factor, and age is included in the staging system, below and above the age of 45; T1 tumors are considered to be those below 2 cm; T3 tumors include minor extrathyroidal extension invading the strap muscles; T4 tumors includes T4a and T4b, T4a being operable tumors; all anaplastic cancers are T4, although operable anaplastic thyroid cancers are considered to be T4a.

CONCLUSION

These changes in the TNM system are consistent with our current philosophy in the overall management of thyroid cancer and adjuvant therapy. The N staging system includes N1a and N1b-N1a being level VI lymph nodes, while N1b includes level IV and superior mediastinal and contralateral neck nodes. The TNM staging system helps reporting our data and comparing results in different parts of the world. However, there is no level I evidence in thyroid cancer.

Trend in thyroid carcinoma size, age at diagnosis, and histology in a retrospective study of 500 cases diagnosed over 20 years

Recently, the Italian Network of Cancer Registries analyzed 5101 cases of thyroid carcinoma showing a reduction of mortality rate of 4%/year. This prompts us to evaluate the temporal trend in tumor size, age at diagnosis, and histology in a retrospective analysis of 500 thyroid cancers diagnosed over 20 years. Thyroid cancers were divided in two groups. The first included 193 cases diagnosed from 1985 to 1994, and the second 307 from 1995 to 2004. The size of all tumors was significantly reduced from 30 +/- 1.4mm in the first group to 15 +/- 0.8mm in the second group. In particular, papillary thyroid carcinoma (PTC) size decreased from 28 +/- 1.2mm to 14 +/- 0.8mm and follicular carcinoma from 40 +/- 6.3mm to 17 +/- 4.5 mm. Age at diagnosis of all carcinomas increased significantly from 40 +/- 1.3 years in the first group to 48 +/- 0.9 years in the second group. Analysis of the histological types revealed a significant increase of PTC rate in the second decade from 82% to 92% and a concomitant reduction of anaplastic thyroid carcinoma (ATC) from 3.7% to 1.0%. Moreover, a significant increase of micro-PTC rate, from 7.3% to 36.4%, was observed. In conclusion, it may be speculated that the above mentioned decreased mortality rate for thyroid carcinoma could be related to the significant reduction with time of cancer size, to the progressive increase of PTC rate and to the reduction of ATC rate. These data, if confirmed in other series, underscore the importance of evaluating thyroid nodules smaller than 10mm and corroborate recent findings suggesting that age be reconsidered as an independent prognostic factor for differentiated thyroid cancers.

The readability of original articles in surgical journals

BACKGROUND

Readability indices have been developed based on sentence length and the use of long words. One such measure is the Reading Ease Scale developed by Rudolf Flesch. Texts that are easy to read have high scores: texts with scores below 30 are similar to legal contracts. This study uses Flesch scores to evaluate the readability of surgical journals.

METHODS

Flesch scores were calculated for articles published in the Archives of Surgery, the British Journal of Surgery, and the ANZ Journal of Surgery. The first 30 original articles published in each journal in 2005 were selected for study. Excluded from study were editorials, reviews and case reports.

RESULTS

The overall median score was 15.1 (0.0-29.1). The median scores for each of the journals were 12.4 (Archives of Surgery), 14.4 (British Journal of Surgery), and 18.6 (ANZ Journal of Surgery). There was only a minor link between Flesch scores and the use of surgical terms.

CONCLUSION

Original articles published in surgical journals contain too many long sentences and complex words. Readability indices are useful tools because they promote the use of simple English. It is realistic for authors to aim for Flesch scores above 30 when creating manuscripts.

Thyroid carcinoma

PURPOSE OF REVIEW

Diagnostic methods and treatment options for differentiated and medullary thyroid carcinoma are continuously influenced by new trends and techniques. Our review therefore displays the most recent clinical practices for diagnosis and operative treatment of differentiated and medullary thyroid carcinoma.

RECENT FINDINGS

Among the new diagnostic methods, high-resolution ultrasonography plays an important role for both the evaluation of thyroid nodules and the detection of enlarged suspicious cervical lymph nodes. The results of ultrasound will definitely influence operative decisions. A second step to diagnose medullary thyroid carcinoma is calcitonin measurement before surgery, which is sensitive and specific enough to detect medullary thyroid carcinoma in patients with thyroid nodules. Surgical treatment for differentiated or medullary thyroid carcinoma mostly consists of total or near-total thyroidectomy. An additional central or lateral modified-radical neck dissection might help to reduce local recurrence, especially in medullary carcinoma, but still does not influence significantly the survival rates. Monitoring of the recurrent laryngeal nerve during surgery is used increasingly. According to the newest literature, however, compared with visual identification of the laryngeal nerve, it cannot be considered as superior.

SUMMARY

Diagnosis and treatment of thyroid carcinoma are still subjected to changes and the different options of surgical treatment in particular will be continuously discussed in the future.

Real-time prognosis for metastatic thyroid carcinoma based on 2-[18F]fluoro-2-deoxy-D-glucose-positron emission tomography scanning

CONTEXT/OBJECTIVE

Approximately 15% of thyroid cancer patients develop subsequent metastases. The clinical course of patients with metastatic thyroid carcinoma is highly variable. We hypothesized that the metabolic activity of metastatic lesions, as defined by retention of 2-[(18)F]fluoro-2-deoxyglucose (FDG), would correlate with prognosis.

DESIGN/PATIENTS

The initial FDG-positron emission tomography (PET) scans from 400 thyroid cancer patients were retrospectively reviewed and compared with overall survival (median follow-up, 7.9 yr). We examined the prognostic value of clinical information such as gender, age, serum thyroglobulin, American Joint Committee on Cancer (AJCC) stage, histology, radioiodine avidity, FDG-PET positivity, number of FDG-avid lesions, and the glycolytic rate of the most active lesion.

RESULTS

Age, initial stage, histology, thyroglobulin, radioiodine uptake, and PET outcomes all correlated with survival by univariate analysis. However, only age and PET results continued to be strong predictors of survival under multivariate analysis. The initial American Joint Committee on Cancer stage was not a significant predictor of survival by multivariate analysis. There were significant inverse relationships between survival and both the glycolytic rate of the most active lesion and the number of FDG-avid lesions.

CONCLUSIONS

FDG-PET scanning is a simple, expensive, but powerful means to restage thyroid cancer patients who develop subsequent metastases, assigning them to groups that are either at low (FDG negative) or high (FDG positive) risk of cancer-associated mortality. We propose that the aggressiveness of therapy for metastases should match the FDG-PET status.