Pathogenese, Klassifikation und Histologie von Schilddrüsenkarzinomen

New insights into intranuclear inclusions in thyroid carcinoma: Association with autophagy and with BRAFV600E mutation

Background

Intranuclear inclusions (NI) in normal and neoplastic tissues have been known for years, representing one of the diagnostic criteria for papillary thyroid carcinoma (PTC). BRAF activation is involved among others in autophagy. NI in hepatocellular carcinoma contain autophagy-associated proteins. Our aim was to clarify if NI in thyroid carcinoma (TC) have a biological function.

Methods

NI in 107 paraffin-embedded specimens of TC including all major subtypes were analyzed. We considered an inclusion as positive if it was delimited by a lamin AC (nuclear membrane marker) stained intact membrane and completely closed. Transmission electron microscopy (TEM), immunohistochemistry (IHC), immunofluorescence (IF) and 3D reconstruction were performed to investigate content and shape of NI; BRAF^V600E mutation was analyzed by next generation sequencing.

Results

In 29% of the TCs at least one lamin AC positive intranuclear inclusion was detected; most frequently (76%) in PTCs. TEM analyses revealed degenerated organelles and heterolysosomes within such NI; 3D reconstruction of IF stained nuclei confirmed complete closure by the nuclear membrane without any contact to the cytoplasm. NI were positively stained for the autophagy-associated proteins LC3B, ubiquitin, cathepsin D, p62/sequestosome1 and cathepsin B in 14–29% of the cases. Double-IF revealed co-localization of LC3B & ubiquitin, p62 & ubiquitin and LC3B & p62 in the same NI. BRAF^V600E mutation, exclusively detected in PTCs, was significantly associated with the number of NI/PTC (p = 0.042) and with immunoreactivity for autophagy-associated proteins in the NI (p≤0.035). BRAF-IHC revealed that some of these BRAF-positive thyrocytes contained mutant BRAF in their NI co-localized with autophagy-associated proteins.

Conclusions

NI are completely delimited by nuclear membrane in TC. The presence of autophagy-associated proteins within the NI together with degenerated organelles and lysosomal proteases suggests their involvement in autophagy and proteolysis. Whether and how BRAF^V600E protein is degraded in NI needs further investigation.

Buhr H, Lorenz D, Germer CT, E. Goretzki P. Indications for the Surgical Management of Benign Goiter in Adults

BACKGROUND

Thyroidectomy is still three to six times more common in Germany than in the USA, Great Britain, and the Scandinavian countries. Thus, the question is often asked whether thyroidectomy in Germany is being performed for the correct indications.

METHODS

This review is based on studies and guidelines containing information on the indications for surgery in benign goiter and Graves' disease; these publications were retrieved by a systematic literature search in the Medline and Cochrane Library databases (1990-2016). The indications recommended here were determined by vote by the German Society for General and Visceral Surgery (Deutsche Gesellschaft für Allgemein- und Viszeralchirurgie, DGAV).

RESULTS

On the basis of the available evidence (levels 2-4), and in the absence of prospective studies, the indications for surgery in goiter include a well-founded suspicion of malignancy, local compressive symptoms, and, rarely, cosmesis. In hyperthyroid goiter and Graves' disease, surgery is a potential alternative to radio - iodine therapy, particularly if the volume of the thyroid gland exceeds 80 mL, in patients with advanced or active orbitopathy, and in female patients who are, or plan to be, pregnant. Large, asymptomatic, euthyroid nodular goiter without any suspicion of malignancy and scintigraphically "cold" nodules without any other evidence of malignancy are not indications for surgery. Thyroid operations of higher levels of difficulty (e.g., recurrent goiter, retrosternal extension, Graves' disease) should be carried out in institutions with special expertise in thyroid surgery.

CONCLUSION

The decision to operate should be made on an interdisciplinary basis and in conformity with the relevant guidelines after all of the appropriate diagnostic studies have been performed. The radicality of any proposed surgical procedure should be weighed against its potential complications.

[Lymph node and distant metastases of thyroid gland cancer. Metastases in the thyroid glands]

The different biological features of the various major entities of thyroid cancer, e.g. papillary, follicular, poorly differentiated, anaplastic and medullary, depend to a large extent on their different metastatic spread. Papillary thyroid cancer (PTC) has a propensity for cervical lymphatic spread that occurs in 20-50 % of patients whereas distant metastasis occurs in < 5 % of cases. Cervical lymphadenopathy may be the first symptom particularly of (micro) PTC. In contrast follicular thyroid cancer (FTC) has a marked propensity for vascular but not lymphatic invasion and 10-20 % of FTC develop distant metastases. At the time of diagnosis approximately one third of medullary thyroid cancer (MTC) cases show lymph node metastases, in 10-15 % distant metastases and 25 % develop metastases during the course of the disease. Poorly differentiated (PDTC) and anaplastic thyroid cancer (ATC) spread via both lymphatic and vascular invasion. Thus distant metastases are relatively uncommon in DTC and when they occur, long-term stable disease is the typical clinical course. The major sites of distant metastases are the lungs and bone. Metastases to the brain, breasts, liver, kidneys, muscle and skin are relatively rare or even rare. The thyroid gland itself can be a site of metastases from a variety of other tumors. In autopsy series of patients with disseminated cancer disease, metastases to the thyroid gland were found in up to 10 % of cases. Metastases from other primary tumors to the thyroid gland have been reported in 1.4-3 % of patients who have surgery for suspected cancer of the thyroid gland. The most common primary cancers that metastasize to the thyroid gland are renal cell (48.1 %), colorectal (10.4 %), lung (8.3 %) and breast cancer (7.8 %) and surprisingly often sarcomas (4.0 %).

[Differentiated thyroid cancer]

Thyroid carcinoma is a rare and heterogeneous disease. Initial therapy and follow-up has to be adjusted to the individual risk for an excellent vs. poor prognosis. Differentiated thyroid cancer has a very high cure rate and is treated by surgery, usually followed by radioiodine ablation. Depending on the response to initial therapy the risk for persisting or recurrent disease should be re-evaluated. Continued TSH suppressive levothyroxine therapy is only recommended in high-risk patients. In contrast, metastatic radioiodine-refractory thyroid cancers have a poor prognosis and may benefit from multidisciplinary treatment concepts including tyrosine kinase inhibitors. Due to its complexity, management of thyroid cancer patients should be performed in close collaboration with a specialized thyroid cancer team.

Best supportive care from the conservative/non-surgical perspective and its costs in the treatment of patients with advanced medullary thyroid cancer: results of a Delphi panel

BACKGROUND

Medullary thyroid cancer (MTC) is a rare tumor entity. The contents of best supportive care (BSC) have not been defined in advanced MTC. The objective of this work is to describe the epidemiology, the treatment patterns with respect to symptom management, as well as palliative treatment and associated costs.

METHOD

A Delphi panel with 9 clinical experts experienced in treating MTC was conducted to obtain details on the epidemiology of MTC and to gain insights into the therapeutic options considered for BSC in advanced MTC in Germany. Unit costs were applied to the described resources from the perspective of the German National Healthcare System in 2011.

RESULTS

The annual incidence of MTC in Germany was estimated at about 220. 32% of all patients were estimated to have aggressive/symptomatic MTC, with an estimated mean survival of 36.7 months (median: 36 months). The core element of BSC is relief of symptoms to maintain quality of life. The total mean cost of BSC per patient/year was estimated at € 9,248, lifetime cost at € 28,283.

CONCLUSION

There was consistent agreement within the panel on the epidemiology of MTC and on the structure of the provided therapeutic measures for BSC in advanced MTC, also defining the management of symptoms as a crucial goal of treatment.

Long-term results of radiotherapy in anaplastic thyroid cancer

Background

Anaplastic thyroid cancer (ATC) is an aggressive malignant tumour with a poor prognosis. The median overall survival is described in the literature to be just 6 months, however, in series of selected patients treated by multimodal therapy cases of long-time-survival have been reported. We analyzed the role of radiotherapy and the impact of other therapies and clinical features on survival in patients with ATC.

Methods

In a retrospective analysis of all patients (n = 40), who presented with histologically proven ATC at a single centre between 1989 and 2008, patient and treatment characteristics with a focus on details of radiotherapy were registered and the survival status determined.

Results

39 of 40 patients received radiotherapy, 80% underwent surgery and 15% had chemotherapy. The median dosis of radiation was 50 Gy (6–60.4 Gy), in 87.5% fractionation was once daily. In 49.4% opposing-field techniques were applied, in 14% 3D-conformal-techniques and 32.5% combinations of both.

The median overall survival (OS) was 5 months, 1-year survival 35.2% and 5-year-survival 21.6%. Interestingly, 24.3% survived 2 years or longer. Three factors could be identified as predictors of improved overall survival: absence of lymph node metastasis (N0) (median OS 18.3 months), median dose of radiation of 50 Gy or more (median OS 10.5 months) and the use of any surgery (median OS 10.5 months).

Conclusions

Despite the generally poor outcome, the combination of surgery and intensive radiotherapy can result in long-term survival in selected patients with ATC.

[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.

Euthyroid goiter with and without nodules--diagnosis and treatment

BACKGROUND

Thyroid enlargement and thyroid nodules are common in the general population. This review concerns their proper diagnostic assessment and treatment.

METHODS

We selectively reviewed the literature from 1990 to 2012 and evaluated original articles and reviews retrieved from the PubMed database, as well as the recommendations of the following specialty societies: the German Societies of Endocrinology and Nuclear Medicine (Deutsche Gesellschaft für Endokrinologie, Deutsche Gesellschaft für Nuklearmedizin), the German Working Group for Endocrine Surgery (Chirurgische Arbeitsgemeinschaft Endokrinologie, CAEK), the European Thyroid Association, and the American Thyroid Association.

RESULTS

There have been very few randomized trials concerning the diagnosis and treatment of goiter. Nodular goiter can be managed by watchful waiting, drug treatment (initially with levothyroxine and iodide), radioactive iodine therapy, or surgery.

CONCLUSION

Many patients with nodules need no treatment at all. Treatment is indicated, however, if the patient is symptomatic and/or has an autonomously functioning ("hot") nodule, or if cancer is suspected. Potentially cancerous nodules must be operated on. If euthyroid nodular goiter is to be treated with the main goal of size reduction, either surgery or radioactive iodine therapy can be used. Drug treatment is an option for small nodules or goiters, but iatrogenic hyperthyroidism must be avoided at all costs. The type of follow-up that is required depends on the chosen treatment.

Ultrasound-guided fine-needle aspiration biopsy of clinically suspicious thyroid nodules with an automatic aspirator: a novel technique

BACKGROUND

Fine-needle aspiration biopsy (FNAB) is a simple technique for the investigation of suspicious thyroid nodules. However, low success rates are reported in the literature. The aim of this prospective study was to compare the clinical performance and impact of an automatic aspirator, referred to here as Aspirator 3, to those of the manual technique for the FNAB of clinically suspicious thyroid nodules.

METHODS

One hundred nine consecutive patients with 121 clinically suspicious thyroid nodules underwent a biopsy twice of the same site with the clinically approved Aspirator 3 and with the manual technique. The number of follicular cell formations and the total number of follicular cells in the aspirate were counted using the ThinPrep® method.

RESULTS

With the Aspirator 3, the total number and the mean number of extracted cell formations were significantly higher than the values achieved with the manual technique (total: 3222 vs. 1951, p=0.02; mean: 27 vs. 16). The total number of cells that were biopsied was also higher when the Aspirator 3 was utilized (47,480 vs. 23,080, p=0.005). Overall, the Aspirator 3 was superior in 65 biopsies, and the manual technique was superior in 39 biopsies.

CONCLUSIONS

In terms of cell formations and the total number of cells aspirated, the Aspirator 3 was superior to the manual technique. Further, the Aspirator 3 was more convenient to use and had a greater precision in needle guidance.

[When is thyroid fine-needle biopsy most effective?]

The essentially desirable standardisation of various European and American guidelines for the evaluation of thyroid nodules has led to the recommendation to perform fine-needle biopsy (FNB) in all nodules >1 cm in order to detect clinically occult thyroid carcinoma early. However, in iodine-deficient areas such as Germany (where thyroid nodules are found in approximately 25% of the adult population) this recommendation would substantially increase both the number of FNB and thyroid operations without significantly increasing the cancer detection rate. The recommendation for FNB in Germany, therefore, should be restricted to hypofunctioning ("cold") nodules >1 cm.