Medullary carcinoma of the thyroid gland

Personalized Medicine in Medullary Thyroid Carcinoma: A Broad Review of Emerging Treatments

Medullary thyroid carcinoma (MTC) arises from parafollicular cells in the thyroid gland, and although rare, it represents an aggressive type of thyroid cancer. MTC is recognized for its low mutational burden, with point mutations in RET or RAS genes being the most common oncogenic events. MTC can be resistant to cytotoxic chemotherapy, and multitarget kinase inhibitors (MKIs) have been considered a treatment option. They act by inhibiting the activities of specific tyrosine kinase receptors involved in tumor growth and angiogenesis. Several tyrosine kinase inhibitors are approved in the treatment of advanced MTC, including vandetanib and cabozantinib. However, due to the significant number of adverse events, debatable efficiency and resistance, there is a need for novel RET-specific TKIs. Newer RET-specific TKIs are expected to overcome previous limitations and improve patient outcomes. Herein, we aim to review MTC signaling pathways, the most recent options for treatment and the applications for personalized medicine.

[Intestinal ganglioneuromatosis as an early extra-endocrine manifestation of type 2B multiple endocrine neoplasia]

Multiple endocrine neoplasia type 2B (MEN 2B) is a rare variant of hereditary tumor syndromes caused by germinal mutations in the proto-oncogene RET. One of the components of the syndrome is multiple neurinomas, the early detection of  which is not always given due attention. We present a description of the case of MEN 2B, manifested in the first months of life by intestinal ganglioneuromatosis. The disease presented with chronic constipation, including episodes of intestinal obstruction that required repeated surgical interventions. MEN 2B was suspected at the age of 15. At the time of diagnosis, an increase in serum calcitonin levels was noted (1041 pg/ml, norm <9.5 pg/ml), and a node in the thyroid gland was also determined (1,3*1,0*1,2 see, TIRADS 5), subsequently verified as a neoplasm of C-cells. By DNA analysis, a pathogenic variant p.Met918Thr, typical for MEN2 B, was detected in the RET gene. No signs of pheochromocytoma were found at the time of investigation. The patient underwent a thyroidectomy with lymphadenectomy. The difficulties of early diagnosis of sporadic cases of MEN 2B due to the nonspecificity of gastrointestinal manifestations of the disease are discussed.

Small Cell Variant of Medullary Thyroid Carcinoma: A Possible Treatment

Small cell variant of medullary thyroid carcinoma is an extremely rare histologic entity with a paucity of data. As such, there is a lack of literature and clinical experience regarding this disease. In this report, we examine a case of small cell variant of medullary thyroid carcinoma that presented with intractable nausea, vomiting and diarrhea. While these symptoms were essentially refractory to the standard symptomatic treatment, further laboratory analysis revealed dramatically elevated calcitonin levels and mildly raised thyroid-stimulating hormone levels. Interestingly, repletion of thyroid hormone and treatment with lanreotide resulted in an abatement of our patient’s symptoms. This temporal clinical improvement highly suggests a potential role involving thyroid-stimulating hormone and calcitonin levels in the pathogenesis of this disease, and consequently suggests a role for thyroxine in treating the associated gastrointestinal symptoms. 

Severe constipation as the first clinical manifestation in multiple endocrine neoplasia type 2B: a case report and literature review

BACKGROUND

The occurrence of multiple endocrine neoplasia type 2B (MEN2B) in Asians is very rare. In particular, patients with intractable constipation as the main clinical manifestation are even rarer. Atypical clinical manifestations are likely to lead to a diagnostic delay. In this report, we described a case of a delayed diagnosis of MEN2B, and the first clinical manifestation was intractable constipation.

CASE PRESENTATION

A female teenager had suffered from intractable constipation since infancy. Because the colonoscopy and biopsy results from local hospitals did not confirm the presence of congenital megacolon, the girl had been followed up at a local clinic for a long time. The diagnosis was not confirmed until thyroid masses were found in the Pediatric Department of Shanghai Ruijin Hospital when she was 12 years old. According to our detailed evaluation, she suffered from Hirschsprung disease (HD), growth retardation, medullary thyroid carcinoma (MTC) and mucosal neuroma due to a mutation in the RET gene. Thus, the diagnosis of MEN2B was confirmed. Afterward, the girl underwent several surgeries and was still being followed up before the article was published.

CONCLUSION

MEN2B has atypical clinical symptoms in the early stage. Refractory constipation may be the only clinical manifestation that lasts for several years. Therefore, we recommend that early screening and gene sequencing should be performed for patients with severe constipation due to HD to determine the cause of the disease and to improve the survival outcome.

Fifty Years After the First Description, MEN 2B Syndrome Diagnosis Is Still Late: Descriptions of Two Recent Cases

BACKGROUND

Multiple endocrine neoplasia type 2B (MEN 2B) is a very rare syndrome characterized by a very peculiar phenotype with mucosal neuromas, marfanoid habitus, and bumpy lips associated with medullary thyroid cancer (MTC) and pheochromocytoma (PHEO). Although the syndrome was first described 50 years ago, it is still diagnosed too late, when the MTC is metastatic and frequently when the PHEO has already developed.

CASE PRESENTATIONS

We report on two cases of MEN 2B that were diagnosed too late, preventing a cure. The cases involve two females who were 25 and 12 years old. Both were previously treated for congenital skeletal abnormalities; however, despite their bumpy lips and mucosal neuromas, MEN 2B syndrome was not recognized. When they arrived at our center for both the presence of thyroid nodules and elevated serum calcitonin values, the MTC was already metastatic, and the older patient had already developed a bilateral PHEO. After 3 years and 1 year of follow-up, the two patients are still alive but with persistent structural and biochemical disease.

DISCUSSION

These two cases show that knowledge of this syndrome is still insufficient and that the lack of knowledge impairs the ability to obtain an early diagnosis and cure. Because most patients with MEN 2B have no familial history, the only way to ensure a timely diagnosis is to recognize the MEN 2B phenotype on a clinical basis.

Evolution of Our Understanding of the Hyperparathyroid Syndromes: A Historical Perspective

We review advancing and overlapping stages for our understanding of the expressions of six hyperparathyroid (HPT) syndromes: multiple endocrine neoplasia type 1 (MEN1) or type 4, multiple endocrine neoplasia type 2A (MEN2A), hyperparathyroidism-jaw tumor syndrome, familial hypocalciuric hypercalcemia, neonatal severe primary hyperparathyroidism, and familial isolated hyperparathyroidism. During stage 1 (1903 to 1967), the introduction of robust measurement of serum calcium was a milestone that uncovered hypercalcemia as the first sign of dysfunction in many HPT subjects, and inheritability was reported in each syndrome. The earliest reports of HPT syndromes were biased toward severe or striking manifestations. During stage 2 (1959 to 1985), the early formulations of a syndrome were improved. Radioimmunoassays (parathyroid hormone [PTH], gastrin, insulin, prolactin, calcitonin) were breakthroughs. They could identify a syndrome carrier, indicate an emerging tumor, characterize a tumor, or monitor a tumor. During stage 3 (1981 to 2006), the assembly of many cases enabled recognition of further details. For example, hormone non-secreting skin lesions were discovered in MEN1 and MEN2A. During stage 4 (1985 to the present), new genomic tools were a revolution for gene identification. Four principal genes ("principal" implies mutated or deleted in 50% or more probands for its syndrome) (MEN1, RET, CASR, CDC73) were identified for five syndromes. During stage 5 (1993 to the present), seven syndromal genes other than a principal gene were identified (CDKN1B, CDKN2B, CDKN2C, CDKN1A, GNA11, AP2S1, GCM2). Identification of AP2S1 and GCM2 became possible because of whole-exome sequencing. During stages 4 and 5, the newly identified genes enabled many studies, including robust assignment of the carriers and non-carriers of a mutation. Furthermore, molecular pathways of RET and the calcium-sensing receptor were elaborated, thereby facilitating developments in pharmacotherapy. Current findings hold the promise that more genes for HPT syndromes will be identified and studied in the near future. © 2018 American Society for Bone and Mineral Research.

Histology-proven recurrence in the lateral or central neck after systematic neck dissection for medullary thyroid cancer

PURPOSE

To delineate risk factors for, and examine temporal patterns of, histology-proven recurrent medullary thyroid cancer (MTC) after compartment-oriented surgery.

METHODS

Multivariate Cox regression on overall, node, and soft tissue infiltrate recurrence per previously dissected neck compartment.

RESULTS

Mean follow-up for the 203 (and 158) patients with central (and ipsilateral lateral) neck dissection was 56.1 months. On multivariate Cox regression, tumor size > 20 mm predicted overall and node recurrence in the central neck, whereas extranodal growth predicted overall and node recurrence in the ipsilateral lateral neck. Extrathyroidal extension alone predicted soft tissue infiltrate recurrence in the central neck, and extranodal growth alone soft tissue infiltrate recurrence in the ipsilateral lateral neck. When analyses were restricted to patients not biochemically cured after initial surgery, only extranodal growth predicted overall and node recurrence in the dissected neck compartments.

CONCLUSIONS

Patients not biochemically cured, specifically those with extranodal growth at the initial operation, carry greater risks of node recurrence.

Prognostic Value of Early Postoperative Calcitonin Level in Medullary Thyroid Carcinoma

Aims

Serum calcitonin (CT) assay is commonly used in the diagnosis and follow-up of medullary thyroid carcinoma (MTC). The aim of this study was to ascertain whether serum CT levels, measured in the first few days after surgery, could be used to evaluate the efficacy of treatment.

Methods

A group of 33 patients was studied. In all patients the follow-up was more than 20 months.

Results

Preoperatively basal CT serum levels were high in all patients. Twenty-four hours after surgery CT serum levels dropped to within the normal range in 8 patients and 72 hours after operation in 7 others. In this group 1 patient was at stage I, 11 at stage II and 3 at stage III. Basal and pentagastrin stimulated CT levels continued to be in the normal range in these 15 patients 6 and 12 months after surgery and at the subsequent year by follow-up visits. No clinical or radiological evidence of disease was found during the follow-up in this group. In the other 18 patients CT was reduced but still high 72 hours after surgery; 6 months later basal serum CT levels continued to be elevated or responsive to pentagastrin stimulation. In this group restaging showed tumor relapse in the thyroid bed in 2 patients, cervical lymphadenopathy in 11, and distant metastases (bone, liver) in 3.

Conclusions

Immediate postoperative CT serum levels seem to be the most useful index to evaluate the efficacy of surgical treatment and the presence of residual neoplastic tissue.

A comprehensive review on MEN2B

MEN2B is a very rare autosomal dominant hereditary tumor syndrome associated with medullary thyroid carcinoma (MTC) in 100% cases, pheochromocytoma in 50% cases and multiple extra-endocrine features, many of which can be quite disabling. Only few data are available in the literature. The aim of this review is to try to give further insights into the natural history of the disease and to point out the missing evidence that would help clinicians optimize the management of such patients. MEN2B is mainly characterized by the early occurrence of MTC, which led the American Thyroid Association to recommend preventive thyroidectomy before the age of 1 year. However, as the majority of mutations are de novo, improved knowledge of the nonendocrine signs would help to lower the age of diagnosis and improve long-term outcomes. Future large-scale studies will be aimed at characterizing more in detail the main characteristics and outcomes of MEN2B.

MicroRNA-21 and long non-coding RNA MALAT1 are overexpressed markers in medullary thyroid carcinoma

BACKGROUND

Non-coding RNAs, including microRNAs (miRNAs) and long non-coding RNAs (lncRNAs), are well-recognized post-transcriptional regulators of gene expression. This study examines the expression of microRNA-21 (miR-21) and lncRNA MALAT1 in medullary thyroid carcinomas (MTCs) and their effects on tumor behavior.

METHODS

Tissue microarrays (TMAs) were constructed using normal thyroid (n=39), primary tumors (N=39) and metastatic MTCs (N=18) from a total of 42 MTC cases diagnosed between 1987 and 2016. In situ hybridization with probes for miR-21 and MALAT1 was performed. PCR quantification of expression was performed in a subset of normal thyroid (N=10) and primary MTCs (N=32). An MTC-derived cell line (MZ-CRC-1) was transfected with small interfering RNAs (siRNAs) targeting miR-21 and MALAT1 to determine the effects on cell proliferation and invasion.

RESULTS

In situ hybridization (ISH) showed strong (2+ to 3+) expression of miR-21 in 17 (44%) primary MTCs and strong MALAT1 expression in 37 (95%) primary MTCs. Real-time PCR expression of miR-21 (P<0.001) and MALAT1 (P=0.038) in primary MTCs were significantly higher than in normal thyroid, supporting the ISH findings. Experiments with siRNAs showed inhibition of miR-21 and MALAT1 expression in the MTC-derived cell line, leading to significant decreases in cell proliferation (P<0.05) and invasion (P<0.05).

CONCLUSION

There is increased expression of miR-21 and MALAT1 in MTCs. This study also showed an in vitro pro-oncogenic effect of MALAT1 and miR-21 in MTCs. The results suggest that overexpression of miR-21 and MALAT1 may regulate MTC progression.

Medullary Thyroid Carcinoma: Recent Advances Including MicroRNA Expression

Medullary thyroid carcinoma (MTC) is an uncommon neuroendocrine tumor arising from the C cells in the thyroid and accounts for about 5 % of all thyroid cancers. MTC exhibits more aggressive behavior than follicular tumors, with the majority of cases presenting with lymph node metastasis. It is particularly common among patients carrying germline RET mutations with almost 100 % penetrance. Because activating RET mutations occur in over 90 % of hereditary and 40 % of sporadic MTC, clinical trials of several RET-targeting multikinase inhibitors (MKIs) have resulted in FDA approval of vandetanib and cabozantinib for the treatment of MTC. Nevertheless, in light of significant individual differences in tumor behavior and treatment responses, there has been a persistent need for research efforts to decipher the molecular events within RET-driven or non-RET-driven tumors. Recently, the gene regulatory roles of microRNAs (miRNAs) in MTC have been studied extensively. Multiple miRNA deregulations have been discovered in MTC with potential prognostic and therapeutic implications. This review provides an overview of the basic pathology of MTC and an update on recent investigational progress.

Recurrent spinal metastasis of a sporadic medullary carcinoma of the thyroid after radiation therapy: a case report and review of the literature

Sporadic Medullary Carcinoma of the Thyroid is a relatively uncommon entity and at the time of diagnosis, most already present loco-regional metastasis. Therapy should be aggressive to reduce recurrence and mortality. Follow-up period should continue lifelong and should also include calcium/pentagastrin infusion test, as well as 6-month interval diagnostic imaging.

Surgical curability of medullary thyroid cancer in multiple endocrine neoplasia 2B: a changing perspective

OBJECTIVE

This investigation aimed at exploring the suitability of nonendocrine manifestations preceding medullary thyroid cancer (MTC) for early diagnosis of multiple endocrine neoplasia type 2B (MEN 2B).

BACKGROUND

MEN 2B patients, running a high risk of metastatic MTC, must be diagnosed early for biochemical cure.

METHODS

Forty-four MEN 2B patients carrying inherited (3 patients) and de novo (41 patients) M918T RET mutations were examined for signs and symptoms prompting MEN 2B.

RESULTS

All 3 patients with inherited mutations were diagnosed before the age of 1 year and cured of their C-cell disease. Among 41 patients with de novo mutations, MEN 2B was diagnosed in 12 patients after recognition of nonendocrine manifestations [intestinal ganglioneuromatosis (6 patients), oral symptoms (5 patients), ocular ("tearless crying") (4 patients), and skeletal stigmata (1 patient) alone or concomitantly]. In the remaining 29 patients with de novo mutations, the diagnosis of MEN 2B was triggered by symptomatic MTC (28 patients) or pheochromocytoma (1 patient). The former patients, being significantly (P < 0.001) younger (means of 5.3 vs 17.6 years) and having lower calcitonin levels (means of 115 vs 25,519 pg/mL), smaller tumors (67% vs 0% were ≤10 mm) and less often extrathyroidal extension (0% vs 81%), lymph node (42% vs 100%), and distant metastases (8% vs 79%), were biochemically cured more often (58% vs 0%).

CONCLUSIONS

MTC is curable in patients with de novo mutations when nonendocrine MEN 2B components are quickly appreciated and surgical intervention is performed before patients turn 4 years old.

Hereditary paraganglioma-pheochromocytoma syndromes associated with SDHD and RET mutations

BACKGROUND

Hereditary paraganglioma-pheochromocytoma syndromes (PGL/PCC) are rare tumors arising from neuroendocrine cells.

METHODS AND RESULTS

The proband, a 59-year-old white man and his 42-year-old elder son had a medical history of bilateral carotid body PGL and both presented for treatment of abdominal PGLs. His 36-year-old daughter had excision of recurrent malignant carotid body PGL and vertebral metastasis. His 33-year-old youngest son presented for excision of a unilateral carotid body PGL. All 4 members had succinate dehydrogenase subunit D (SDHD) mutations, whereas the proband and youngest son also had concurrent rearranged during transfection (RET) mutation.

CONCLUSION

This is the first report of PGL/PCC with SDHD and RET mutations. The role of the RET gene as a modifier remains speculative. Additionally, the family pedigree suggests maternal inheritance of disease from the probands' paternal grandmother. Clinicians should refer PGL/PCC families for mutation analysis as well as being alert to changes in the classification of mutations.

Surgical management of thyroid cancer

Thyroid cancer is the most common endocrine neoplasm; however, it only accounts for less than 1% of all human malignances. Thyroid cancers are divided into well differentiated and non-well differentiated cancers, according to their histology and behavior. The surgical management options of well-differentiated thyroid cancer include total or near-total thyroidectomy, subtotal thyroidectomy and lobectomy plus isthmusectomy. The extent of surgery for thyroid cancer continues to be an area of controversy. Complications associated with thyroid surgery are directly proportional to the extent of thyroidectomy and inversely proportional to the experience of the operating surgeon. They occur less frequently with good surgical technique and better understanding of surgical anatomy, and include wound healing and infections (seroma, hematoma and wound infection), nerve injury, hypoparathyroidism, hypothyroidism, postoperative hemorrhage and respiratory obstruction.

Novel withanolides target medullary thyroid cancer through inhibition of both RET phosphorylation and the mammalian target of rapamycin pathway

BACKGROUND

Despite development of current targeted therapies for medullary thyroid cancer (MTC), long-term survival remains unchanged. Recently isolated novel withanolide compounds from Solanaceae physalis are highly potent against MTCs. We hypothesize that these withanolides uniquely inhibit RET phosphorylation and the mammalian target of rapamycin (mTOR) pathway in MTC cells as a mechanism of antiproliferation and apoptosis.

METHODS

MTC cells were treated with novel withanolides and MTC-targeted drugs. In vitro studies assessed cell viability and proliferation (MTS; trypan blue assays), apoptosis (flow cytometry with Annexin V/PI staining; confirmed by Western blot analysis), long-term cytotoxic effects (clonogenic assay), and suppression of key regulatory proteins such as RET, Akt, and mTOR (by Western blot analysis).

RESULTS

The novel withanolides potently reduced MTC cell viability (half maximal inhibitory concentration [IC(50)], 270-2,850 nmol/L; 250-1,380 nmol/L for vandetanib; 360-1,640 nmol/L for cabozantinib) with induction of apoptosis at <1,000 nmol/L of drug. Unique from other targeted therapies, withanolides suppressed RET and Akt phosphorylation and protein expression (in a concentration- and time-dependent manner) as well as mTOR activity and translational activity of 4E-BP1 and protein synthesis mediated by p70S6kinase activation at IC(50) concentrations.

CONCLUSION

Novel withanolides from Physalis selectively and potently inhibit MTC cells in vitro. Unlike other MTC-targeted therapies, these compounds uniquely inhibit both RET kinase activity and the Akt/mTOR prosurvival pathway. Further translational studies are warranted to evaluate their clinical potential.

Management of medullary thyroid carcinoma and MEN2 syndromes in childhood

Medullary thyroid carcinoma (MTC) and the multiple endocrine neoplasia (MEN) type 2 syndromes are rare but important endocrine diseases that are increasingly managed by pediatric providers. MTC is generally associated with a favorable prognosis when diagnosed during childhood, where it frequently occurs secondary to activating mutations in the RET proto-oncogene and arises from pre-existing C-cell hyperplasia. MEN2A accounts for 90-95% of childhood MTC cases and is most commonly due to mutations in codon 634 of RET. MEN2B is associated with the most aggressive clinical presentation of MTC and is almost always due to the Met918Thr mutation of RET. Surgery is the primary treatment and only chance of cure, although the advent of targeted therapies seems to be improving progression-free survival in advanced cases. Since the discovery of the role of RET in MEN2A, considerable advances in the management of this syndrome have occurred, and most of the children with MEN2A who have undergone early thyroidectomy will now lead full, productive lives. Strong genotype-phenotype correlations have facilitated the development of guidelines for interventions. Contemporary approaches for deciding the appropriate age at which surgery should take place incorporate data from ultrasonography and calcitonin measurements in addition to the results of genotyping. To optimize care and to facilitate ongoing research, children with MTC and the MEN2 syndromes are optimally treated at tertiary centers with multidisciplinary expertise.

Multi-targeted approach in the treatment of thyroid cancer

While accounting for only 1% of solid organ malignancies (9% in women), thyroid carcinoma is the most common malignancy of the endocrine system. Although most patients have a favorable prognosis, over 1,500 people will die from thyroid carcinoma each year. The spectrum of disease types range from papillary thyroid cancer, which is a well-differentiated indolent tumor, to anaplastic carcinoma, a poorly differentiated fulminant cancer. With advances in diagnostic methods, surgical techniques, and clinical care of patients with thyroid carcinoma, the current management of thyroid cancer demands a multidisciplinary approach. The majority of patients with well-differentiated thyroid carcinoma of follicular cell origin are cured with adequate surgical management; however, some thyroid malignancies such as medullary thyroid carcinoma (MTC) or poorly differentiated thyroid carcinomas frequently metastasize, precluding patients from a curative resection. As such, novel palliative and therapeutic strategies are needed for this patient population. Here, we explore the current management of thyroid carcinoma, including surgical management of the primary tumor, lymph node disease, and locoregional recurrence. Likewise, we explore the application of current molecular techniques, reviewing nearly two decades of data that have begun to elucidate critical genetic pathways and therapeutic drug targets which may be important in specific thyroid tumor types.

Influence of lymph node metastases on survival in pediatric medullary thyroid cancer

PURPOSE

Lymph node metastases (LNM) from medullary thyroid cancer (MTC) are common in adults and are a poor prognostic factor. Less is known about LNM in children, who often have hereditary forms of MTC. Guidelines recommend prophylactic thyroidectomy in early childhood, but randomized prospective trials are not feasible. We hypothesized that LNM is associated with poor prognosis in children.

METHODS

Patients with MTC 21 years or younger from the National Cancer Data Base from 1985 to 2007 were studied. Multivariable logistic regression was used to identify factors associated with lymph node evaluation. Survival was estimated using the Kaplan-Meier method.

RESULTS

Of 430 patients, 276 (64.2%) had nodal evaluation with LNM present in 121 (28.1%). Older patients, those with tumors larger than 2 cm, and those with involved margins were more likely to have LNM (all P < .05). Patients undergoing total thyroidectomy, those with involved margins, and older patients were more likely to undergo lymph node evaluation after controlling for patient, tumor, and hospital factors (all P < .05). Over time an increasing number of patients with MTC have undergone total thyroidectomy. Patients 16 to 21 years of age had lower 10-year overall survival compared to patients 0 to 15 years old (88.7% vs 98.1%, P = .005). Lymph node metastases were also associated with decreased 10-year overall survival (84.4% vs 100%, P < .001).

CONCLUSIONS

In pediatric MTC, LNM predict poorer overall survival. Adequate lymph node assessment can provide valuable prognostic information for the pediatric MTC patient. Lymph node assessment should be considered for older pediatric patients undergoing surgery for hereditary MTC or biopsy confirmed MTC.

Positive correlation between urinary excretion of catecholamine metabolites and tumour mass in pheochromocytoma. Results in patients with sustained and paroxysmal hypertension and multiple endocrine neoplasia

In a series of 53 pheochromocytoma patients operated on at Sahlgren's Hospital during 1956-82, a positive linear correlation is established between the 24-hour urinary excretion of vanilmandelic acid (mumol/24 h) and tumour mass (g). A similar correlation was found between the excretion of metanephrines and tumour mass in 33 subjects. The patients were subgrouped according to their type of hypertension. A statistically significant correlation between vanilmandelic acid excretion and tumour mass persisted in groups IA (sustained hypertension without attacks), IB (sustained hypertension with attacks), and II (paroxysmal hypertension) but not in group III (miscellaneous patients). There was also a correlation between metanephrine excretion and tumour mass in groups IB (n = 8) and II (n = 12). In 10 patients with the syndrome of multiple endocrine neoplasia, a positive correlation was found between tumour mass and the excretion of vanilmandelic acid, metanephrines and adrenaline.

Long-term outcome of reoperations for medullary thyroid carcinoma

BACKGROUND

Most patients with medullary thyroid carcinoma (MTC) have persistent disease after primary surgery, as evidenced by calcitonin elevation. Previous reports showed that reoperation on selected patients yields immediate calcitonin normalization in one-third of patients. Long-term follow-up data are needed to assess the outcome in such patients. This report aims to provide 8- to 10-year follow-up on reoperations for persistent or recurrent MTC.

METHODS

An Internal Review Board (IRB) approved database on patients treated for MTC has been prospectively maintained. This database was reviewed to report follow-up data on calcitonin levels and survival.

RESULTS

Between 1992 and 2006, 148 patients underwent reoperations for recurrent or persistent MTC (55 patients had 59 reoperations for palliation, and 93 patients had 105 reoperations for cure). Of the 93 patients operated on for cure (44 with hereditary MTC, 49 with the sporadic form), 8-10-year follow-up data were available on 56. Four patients died of disease (4.3% of 93). Two died of unrelated causes, and were excluded from calcitonin outcome analysis. Fourteen patients of 54 (26.0%) have unstimulated calcitonin levels of <10 pg/ml at 8-10 years. Eleven additional patients (20.4%) have levels<100 pg/ml. None of these 25 patients (46.4%) have radiologic recurrence.

CONCLUSIONS

Previous reports demonstrated the low morbidity of reoperation for MTC in experienced hands, and success was determined by lowering of calcitonin levels. Follow-up data demonstrate that at least one third of such patients have long-term eradication of their disease following reoperation, as evidenced by biochemical and imaging studies.

Surgical approaches to thyroid tumors

This article includes discussions of the surgical approach to benign and malignant disease and the role of prophylactic thyroidectomy and nodal dissection for medullary thyroid cancer. The controversy regarding the extent of dissection for differentiated thyroid cancer and the role of lymph node dissection are reviewed also. A description of the authors' surgical technique for thyroidectomy is detailed. Finally, several emerging technologies are introduced.

Chronic diarrhea and facial dysmorphism in children--a clue to men 2B syndrome: a case report

Medullary thyroid cancer (MTC) is a highly malignant tumor of the thyroid gland in children, rarely diagnosed and treated by pediatric oncologists. The authors describe a 9-year-old male who presented with facial dysmorphism and history of chronic diarrhea before being diagnosed with advanced MTC. Familiarity with its clinical variants, associated RET protooncogene mutation and its clinical implication, can lead to early identification of this aggressive tumor. To date, surgery remains the only definitive therapy, with continuing dismal prognosis in metastatic disease. However, evolving newer therapeutic strategies like tyrosine kinase inhibitors and pretargeted radioimmunotherapy (pRAIT) may provide hope to children with this aggressive tumor.

Neck management in medullary thyroid carcinoma

AIMS

The aims of this study were to retrospectively evaluate incidence and patterns of lymph node metastases, surgical treatment and prognostic factors of medullary thyroid carcinoma.

METHODS

Out of a group of 70 MTC patients data of 67 patients were collected. Sixty-two of these patients underwent surgery. Apart from thyroidectomy, 16 patients underwent a bilateral neck dissection, 21 a unilateral neck dissection and 29 a paratracheal dissection or node-picking operation. Thirty-six patients were irradiated, of which 31 postoperatively and five with palliative intent.

RESULTS

Lymph node metastases were found in 91% of the ipsilateral neck dissection specimens, 91% of the paratracheal dissections and 63% of the contralateral dissections. Of the 12 elective neck dissections, 5 were tumor positive. Level VI was positive in 91% of the cases where a dissection was done, whereas preoperatively only 16% were scored tumor positive. During follow-up 22 of the 67 patients developed one or more locoregional recurrences (in total 28 recurrences). The most important factors that were correlated with a worse prognosis of survival were late stage of disease (stage III and IV) (p=0.0014), high number of positive lymph nodes (p=0.0023) and incomplete surgical resection (p=0.0002).

CONCLUSIONS

The high rate of locoregional recurrences in this study are a strong argument for a more aggressive approach to the primary and neck. A routine central and ipsilateral selective neck dissection of levels II-V should be considered in all MTC patients based on the high incidence of metastases and the relative low morbidity of a unilateral neck dissection. Patients referred after thyroidectomy alone with elevated (stimulated) calcitonin levels should be re-operated, performing an elective or therapeutic central and unilateral neck dissection.

Medullary thyroid cancer: a retrospective analysis of a cohort treated at a single tertiary care center between 1970 and 2005

OBJECTIVE

To identify prognostic factors of clinical outcome and long-term survival in medullary thyroid cancer (MTC).

DESIGN

Retrospective case series of 51 consecutive patients (mean age 46.9 years, 57% female) treated at a single tertiary university medical center from 1970 to 2005. Medical records were reviewed for demographic data, laboratory and clinical course, treatment, and long-term outcome.

MAIN OUTCOME

At presentation, 25 patients (49%) had local disease and 26 (51%) had metastatic disease (three with distant metastases). RET mutations were identified in nine of 23 patients tested. The patients with hereditary disease were younger than the patients with sporadic disease (p < 0.001) and had lower calcitonin levels at diagnosis (p = 0.004) and more multicentric tumors (p = 0.02). Initial surgery consisted of total thyroidectomy in 47 patients, with neck dissection in 26; 22 patients achieved long-term remission. The 5-, 10- and 15-year survival rates were 88%, 85%, and 77%, respectively. On univariate analysis, distant metastases during the course of the disease and elevated calcitonin levels postoperatively were significant prognostic factors of reduced survival (p = 0.001 and 0.016, respectively). Lymph node involvement at initial surgery was associated with a lower remission rate (p = 0.016) but had no impact on long-term survival (p = 0.269).

CONCLUSION

Patients with MTC have a generally favorable outcome, perhaps owing to recent advances in diagnosis and treatment. Although postoperative serum calcitonin level and distant metastases are the only determinants of long-term survival, the presence of cervical metastases is predictive of a higher risk of recurrent or persistent disease.

Multiple cutaneous neuromas and macular amyloidosis associated with medullary thyroid carcinoma

Multiple cutaneous neuromas are rarely seen in dermatology practice. We report a case of multiple cutaneous neuromas, macular amyloidosis (MA), and medullary thyroid carcinoma (MTC) and discuss the interrelationship of the associated conditions. Multiple endocrine neoplasia 2 (MEN 2) is a hereditary syndrome that comprises MEN 2A, MEN 2B, and familial MTC. Germline mutations in the RET proto-oncogene is the underlying cause of the syndrome. MEN 2A and MEN 2B show some common endocrine manifestations including MTC and pheochromocytoma. There are reports of families with MA and MEN 2A. Multiple mucosal neuromas occur in 100% of patients with MEN 2B syndrome. Cutaneous neuromas are infrequently reported in MEN 2B syndrome. Our patient was a heterozygote carrier of GAG-->GAC mutation (Glu 768 Asp) in exon 13, codon 768 of the RET proto-oncogene. We speculate that our patient may represent an unusual presentation of MEN 2B or an overlap of MEN 2A and MEN 2B syndromes or a sporadic MTC case with unusual associations.

Hamartomatous polyps of the colon: ganglioneuromatous, stromal, and lipomatous

Intestinal ganglioneuromas comprise benign, hamartomatous polyps characterized by an overgrowth of nerve ganglion cells, nerve fibers, and supporting cells in the gastrointestinal tract. This polyposis has been divided into 3 subgroups, each with a different degree of ganglioneuroma formation: polypoid ganglioneuroma, ganglioneuromatous polyposis, and diffuse ganglioneuromatosis. The ganglioneuromatous polyposis subgroup is not known to coexist with systemic disorders that often have an associated intestinal polyposis, such as multiple endocrine neoplasia type IIb, neurofibromatosis type I, and Cowden syndrome. We report a case of ganglioneuromatous polyposis plus cutaneous lipomatosis in a 41-year-old man with no established systemic disease. However, he possessed unique anatomic findings in addition to his ganglioneuromatosis, suggesting that the ganglioneuromatosis-lipomatosis in our patient may represent an unrecognized syndrome. This case report and brief review of the literature provide an overview of intestinal ganglioneuromatosis in relation to the hereditary polyposis syndromes and describe the individual ganglioneuromatosis subgroups.

Medullary thyroid carcinoma: multivariate analysis of prognostic factors influencing survival

BACKGROUND

Medullary thyroid carcinoma (MTC) is a rare development of thyroid cancer with a no negligible mortality rate. Our aim was to determine factors that predict outcome in patients with MTC.

METHODS

We reviewed the records of all patients with MTC (n=56) who underwent treatment at our institution between January 1990 and December 2000. Univariate and multivariate analysis of clinicopathologic predictors of MTC outcome were performed to identify subsets of patients with different probabilities in terms of overall survival, local recurrence, and distant metastases.

RESULTS

Multivariate analysis demonstrated that a statistically significant decrease in overall survival is associated with T4b tumours (p=0.06), the presence of distant metastases at the time of presentation (p=0.033), lymphatic invasion (p=0.099), and postoperative treatment (p=0.045).

CONCLUSIONS

The analysis of survival curves of patients with MTC shows that the occurrence of locoregional and distant metastases occurs preferentially within the first 5 years, which identifies this as a crucial period for follow-up. In this series of patients with MTC, the tumours classified as T4b, metastases at presentation, the presence of lymphovascular invasion, and postoperative treatment were the most important prognostic features. At present, there is no available beneficial adjuvant therapy. However, as the development of molecular therapy progresses, it should be tested in clinical trials with the purpose of achievement of novel targeted therapies for selected MTC patients with risk factors.

An introduction to managing medullary thyroid cancer

MTC is a rare neuroendocrine thyroid tumour accounting for 3% to 10% of all thyroid malignancies. It can occur in a sporadic and a hereditary clinical setting. Hereditary MTC may either occur alone (familial MTC, FMTC) or as part of multiple endocrine neoplasia (MEN) type 2A, or MEN 2B. These disorders are due to germline mutations in the RET (REarranged during Transfection) gene. In carriers of MEN 2B-associated RET mutations, prophylactic thyroidectomy is indicated before the first year of life. In the case of MEN 2A-associated germline RET mutations with a high-risk profile, total thyroidectomy is warranted before the age of 2 years and certainly before the age of 4 years. At that age the risk of invasive MTC and metastases is acceptably low. Depending on the type of RET mutation, thyroidectomy can take place at an older age in patients with a lower risk profile. In case of elevated basal or stimulated serum calcitonin, preventive surgery including total thyroidectomy and central compartment dissection should be performed regardless of age. When MTC presents as a palpable tumour, total thyroidectomy should be combined with extensive lymph node dissection of levels II-V on both sides and level VI to prevent locoregional recurrences.

Prophylactic thyroidectomy in multiple endocrine neoplasia type 2A

BACKGROUND

Medullary thyroid carcinoma is the most common cause of death in patients with multiple endocrine neoplasia (MEN) type 2A (MEN-2A) or type 2B or familial medullary thyroid carcinoma. We sought to determine whether total thyroidectomy in asymptomatic young members of kindreds with MEN-2A who had a mutated allele of the RET proto-oncogene could prevent or cure medullary thyroid carcinoma.

METHODS

A total of 50 patients 19 years of age or younger who were consecutively identified through a genetic screening program as carriers of a RET mutation characteristic of MEN-2A underwent total thyroidectomy. Five to 10 years after the surgery, each patient was evaluated by physical examination and by determination of plasma calcitonin levels after stimulation with provocative agents.

RESULTS

In 44 of the 50 patients, basal and stimulated plasma calcitonin levels were at or below the limits of detection of the assay (proportion, 0.88; 95 percent confidence interval, 0.76 to 0.95). Two patients had basal and stimulated plasma calcitonin levels above the normal range. Stimulated plasma calcitonin levels had increased but remained within the normal range in four patients. The data suggest that there was a lower incidence of persistent or recurrent disease in children who underwent total thyroidectomy before eight years of age and in children in whom there were no metastases to cervical lymph nodes.

CONCLUSIONS

In this study, young patients identified by direct DNA analysis as carriers of a RET mutation characteristic of MEN-2A had no evidence of persistent or recurrent medullary thyroid carcinoma five or more years after total thyroidectomy. A longer period of evaluation will be necessary to confirm that they are cured.

Contemporary management of thyroid cancer

Thyroid cancer is a relatively common and frequently curable malignant neoplasm, accounting for nearly 2% of all new cancers diagnosed annually in the United States. The diagnostic and management options have evolved considerably in the past decade, and a current understanding of these trends in the standard of care have assumed an important consideration in the practices of head and neck surgeons and endocrinologists alike. We sought to review the epidemiology and pathology of the several types of thyroid cancer and to present our evidence-based management algorithm. Every effort was made to offer alternative treatment strategies and supporting data where available. In addition to reviewing well-established approaches to diagnosis and management, emphasis is placed on newer techniques, including minimally invasive thyroidectomy, molecular detection of disease propensity, and the use of recombinant thyrotropin prior to radioiodine ablation.

Familial Multiple Endocrine Neoplasia

In 1903, Erdheim described the case of an acromegalic patient with a pituitary adenoma and three enlarged parathyroid glands. Fifty years later, Underdahl et al reported 8 patients with a syndrome of pituitary, parathyroid, and pancreatic islet adenomas. In 1954, Wermer found that the syndrome was transmitted as a dominant trait. In 1959, Hazard et al described medullary (solid) thyroid carcinoma (MTC), a tumor that later was found to be a component of two endocrine syndromes. The first of these described by Sipple in 1961 comprised pheochromocytoma, MTC, and parathyroid adenoma. The second, described by Williams et al in 1966, was the combination of mucosal neuromas, pheochromocytoma, and MTC. In 1968, Steiner et al introduced the term "multiple endocrine neoplasia" (MEN) to describe disorders featuring combinations of endocrine tumors; they designated the Wermer syndrome as MEN 1 and the Sipple syndrome as MEN 2. In 1974, Sizemore et al concluded that the MEN 2 category included two groups of patients with MTC and pheochromocytoma: one with parathyroid disease and a normal appearance (MEN 2A) and the other without parathyroid disease but with mucosal neuromas and mesodermal abnormalities (MEN 2B). Later, additional nonendocrine conditions (von Recklinghausen neurofibromatosis and von Hippel-Lindau disease) were found accompanying other more recently described familial MEN syndromes, indicating that these diseases are very complicated disorders.

Multiple endocrine neoplasia 2B syndrome due to codon 918 mutation: clinical manifestation and course in early and late onset disease

More than 50% of patients with typical MEN-2B have a de novo M918T germline mutation of the RET protooncogene. However, even in typical MEN-2B, extrathyroidal manifestations of MEN-2B can be found to be differently expressed. We analyzed the clinical manifestation and course in 21 patients harboring a de novo RET M918T mutation. Mean age at MEN-2B diagnosis was 14.2 years (range: 1-31 years). All patients had medullary thyroid carcinoma (MTC). At the time of syndrome diagnosis, oral manifestations (bumpy lips, ganglioneuroma), ocular manifestations (corneal fibers, conjunctivitis sicca), intestinal dysfunctions, musculoskeletal manifestations, and pheochromocytoma were found in 86%, 90%, 74%, 79%, and 19% of the patients, respectively. At the time of follow-up examination, the symptoms were found at higher frequency. Severe intestinal manifestation was predominantly found in patients with prepubertal onset (< or = 12 years) of MTC (n = 4/10) compared with patients with late onset (> 12 years) of MTC (n = 0/11) (40% versus 0%; p = 0.019). Although biochemical cure was found only in four patients with early onset of MTC, the long-term prognosis for patients with early onset of MTC was poorer than for patients presenting with late onset of MTC (p = 0.005). During mean follow-up of 55.8 months (range: 3-161 months), seven patients (33%) died from MTC. In conclusion, whereas most typical MEN-2B symptoms were found to be age-related, severe intestinal manifestation was found to be predominantly expressed in patients with early onset of MTC. Furthermore, in patients with early onset of MTC who could not be biochemically cured, the long-term prognosis was found to be worse than that of non-cured patients with late onset of MTC, suggesting an additional pathological process in the younger subgroup reinforcing the very high transforming in vitro activity of the M918T RET mutation.

PGP9.5 mRNA could contribute to the molecular-based diagnosis of medullary thyroid carcinoma

The protein gene product 9.5 (PGP9.5) is a ubiquitin hydrolase that is widely expressed in neuronal tissues at all stages of neuronal differentiation and is a known neuroendocrine marker. Medullary thyroid carcinoma (MTC) arises from parafollicular cells and is reported to overexpress several mRNAs such as RET, calcitonin, and CEA. These markers are thought to be useful in determining a molecular-based diagnosis of MTC. We examined the expression levels of PGP9.5 mRNA in 80 thyroid tissues using real-time quantitative reverse transcription (RT-PCR) and found that PGP9.5 mRNA was overexpressed in all 11 MTCs examined, both hereditary and sporadic, but not in other histological tumour types. Furthermore, by RT-PCR, PGP9.5 mRNA was detected only in aspirates from three medullary carcinomas, and not in aspirates from other tumour types. These results demonstrate that, in addition to the expression of RET, calcitonin and CEA, PGP9.5 mRNA expression may contribute to the molecular-based diagnosis of MTCs.

Surgical treatment of medullary thyroid carcinoma

Medullary thyroid carcinoma (MTC) is a malignancy of the parafollicular C cells of the thyroid gland. It occurs sporadically or as part of the multiple endocrine neoplasia type 2 (MEN 2) syndromes. Patients who have inherited a mutation in the RET proto-oncogene should have thyroidectomy early in life to prevent formation and spread of this cancer. Most patients with sporadic disease present with a palpable neck mass. The diagnosis is made by fine needle aspiration biopsy and by measuring calcitonin levels in the blood. Primary treatment consists of surgical resection including a total thyroidectomy, central neck nodal dissection and functional lateral neck nodal dissections. Most patients with a palpable primary tumour have nodal disease present at the time of operation, and nodal involvement is often bilateral. Adequate resection of the primary tumour and cervical lymph nodes is important to optimize outcome and minimize the risk of recurrent disease. Proper handling of the parathyroid glands prevents hypoparathyroidism. Following primary surgical resection, more than half of the patients will have recurrent disease with persistent elevation of calcitonin levels. Currently, there is no adequate systemic therapy for treating recurrent disease. Surgical reoperation or conservative observation are the best available options. Diagnostic laparoscopy for liver evaluation is the most sensitive diagnostic test to detect the presence of distant metastases.

Medullary thyroid cancer

Medullary thyroid cancer is a rare neoplasm that arises from the parafollicular C cells. It occurs in a sporadic form, or less commonly as a hereditary form, as part of multiple endocrine neoplasia syndromes types 2A and 2B. The RET proto-oncogene is currently the primary factor that is implicated in the hereditary forms of this neoplasm. The knowledge about the genetic makeup of the neoplasm impacts upon management as it allows for screening, early detection, and prophylactic treatment. Surgery is the main modality that offers a cure. This entails a total thyroidectomy and vigilant management and surveillance of the neck. Prognosis of patients with MTC is variable, but the more constant factors that affect it are the stage of disease and the age of the patient. The emerging molecular genetic understanding of this malignancy will provide the foundation for prognostic and therapeutic decision-making in the future. Interdisciplinary management by surgeons, endocrinologists, pathologists, radiotherapists, radiologists, and medical oncologists should be sought.

The role of radiotherapy in the management of elevated calcitonin after surgery for medullary thyroid cancer

Among 139 patients with medullary thyroid cancer (MTC) treated at the Royal Marsden Hospital between 1957-1998, 51 had persistently elevated calcitonin levels after initial surgery in the absence of clinically or radiologically demonstrable residual disease. Of these, 24 were treated with radiotherapy because of advanced local disease at presentation; this resulted in normalization of calcitonin in only 1 patient, although 10 remained free of clinical recurrence. Surveillance alone was used in the remaining 27 patients, of whom 8 (30%) remained free of overt disease. Local relapse rate was significantly lower after radiotherapy (29% vs. 59%) but there was no significant difference in 10-year survival between the two groups (72% vs. 60%). In view of this favorable long-term survival of patients with elevated calcitonin on observation, we cannot recommend the routine use of radiotherapy. However, it does appear to have a role in those presenting with more advanced disease to reduce the incidence of loco-regional relapse.

Sporadic versus familial medullary thyroid microcarcinoma: a histopathologic study of 50 consecutive patients

By means of calcitonin screening programs, sporadic and hereditary medullary thyroid carcinoma (MTC) can be detected at an early stage. We investigated the histopathologic findings of 16 familial (mean age 32 +/- 21 years, female/male ratio 1.6:1) and 34 sporadic (mean age 58 +/- 15 years; female/male ratio 2.4:1) MTCs with stage T1 comparatively. Patients with hereditary tumors were younger. Hereditary tumors were more often found multifocal (13 of 16 vs 3 of 34; p < 0.001), bilateral (11 of 16 vs 3 of 34; p < 0.001), displaying desmoplastic stroma (14 of 16 vs 19 of 34; p = 0.02), and accompanied by C cell hyperplasia (16 of 16 vs 24 of 34; p = 0.01), but all of these factors were present in some sporadic patients. Only tumors with desmoplastic stroma showed lymph node metastasis, which was observed in eight of the 50 patients. After surgery all patients showed permanent normalization of calcitonin levels. We conclude that 1) morphologic parameters considered to indicate familial MTC risk are of no value in the individual patient, 2) many sporadic MTCs develop on the background of CCH, 3) tumors with desmoplastic stroma are more likely to develop lymph node metastasis, and 4) early detection of MTC permits curative surgery in the majority of patients.

Advances in diagnosis and therapy of neuroendocrine tumors

Neuroendocrine tumors represent a group of neoplasias characterized by significant histopathologic and biological heterogeneity. Diagnosis of neuroendocrine tumors relies upon histological examination augmented by newer techniques such as position emission tomography, meta-iodobenzylguanidine scintigraphy or octreoscan. Surgery represents the definite and curative therapeutic approach in early phase tumors. In metastatic or advanced disease, medical treatment is the best choice. Somatostatin analogs allow adequate control of the carcinoid syndrome, without a significant effect on tumor cell growth. Interferon-alpha may represent an alternative, alone or in association with somatostatin analogs. Chemotherapy is the best choice in the treatment of neuroendocrine tumors characterized by a poor differentiation grade and a high proliferation rate.

Prognostic factors in well-differentiated follicular-derived carcinoma and medullary thyroid carcinoma

This paper reviews both clinicopathologic and biological factors in differentiated thyroid carcinoma of follicular and C-cell derivation. The value of specific histological parameters including tumor subtypes, vascular invasion as predictors of prognosis in these tumors is discussed and the pertinent literature reviewed. The utility of ploidy analysis and immunohistochemical assessment of hormonal and tumor markers are described. Current information on biological and molecular markers that may be helpful in predicting behavior is discussed. The commonly used staging systems for thyroid cancer are briefly described.

Radiopeptide transmitted internal irradiation of non-iodophil thyroid cancer and conventionally untreatable medullary thyroid cancer using

AIM

Differentiated thyroid carcinomas (DTC) and medullary thyroid carcinomas (MTC) overexpress somatostatin receptor subtypes (sstr). The aim of this pilot study was to evaluate the tumour response of thyroid carcinomas to targeted irradiation with the radiolabelled somatostatin analogue [90Y]-1,4,7,10-tetra-azacyclododecan-4,7,10-tricarboxy-methyl-1-yl-acetyl-D-Phe1-Tyr3-octreotide ([90Y]-DOTA-D-Phe1-Tyr3-octreotide, or 90Y-DOTATOC) which has a high affinity to subtype 2 and a low affinity to subtype 5. It shows no affinity to sstr1, sstr3 and sstr4.

PATIENTS AND METHODS

Twenty patients (mean age 58 years; 50% female, 50% male) with thyroid cancer were included (medullary thyroid cancer (MTC), 12 patients; differentiated thyroid cancer (DTC), seven patients; papillar carcinoma (PC), four patients; follicular carcinoma (FC), three patients; anaplastic carcinoma (AC), one patient). All patients had been therapy resistant and had progressive disease before 90Y-DOTATOC therapy. The dose applied was between totals of 1700 MBq x m(-2) to 7400 MBq x m(-2) 90Y-DOTATOC, administered in one to four injections at intervals of 6 weeks. In the case of tumour progression under therapy, treatment was terminated.

RESULTS

The overall antitumour effect (objective response and stable disease) was 35%; in MTC 42%, in DTC 29%, and in AC 0%. The objective overall response rate was 0%. A stable disease was achieved in 35% (7/20), and progressive disease was found in 65% (13/20). The median time to progression was 8 months, with a median follow-up of 15 months. The treatment was very well tolerated. There were no grade III/IV haematological or renal toxicities.

CONCLUSION

Targeted radiotherapy using 90Y-DOTATOC is able to stop tumour progression in a small number of patients and therefore may be an alternative treatment option for resistant disease. More significant tumour responses in thyroid and medullary thyroid cancer may be obtained by using radiopeptides with pan-somatostatin characteristics.