Octreotide therapy in advanced thyroid cancer

Refractory thyroid carcinoma: which systemic treatment to use?

The incidence of thyroid cancer has increased markedly in recent decades, but has been stable in terms of mortality rates. For the most part, these cancers are treated with surgery, which may or may not be followed by radioactive iodine depending on the tumor subtype. Still, many of these cancers will recur and may be treated with radioactive iodine or another surgery. It is unclear what treatment is best for cases of locally advanced or metastatic thyroid cancer that are refractory to radioactive iodine. Chemotherapy has a very low response rate. However, in the past few years, several systemic therapies, primarily targeted, have emerged to improve the overall survival of these patients. Alternative treatments are also of interest, namely peptide receptor radionuclide therapy or immunotherapy.

Thyroid cancer: pathogenesis and targeted therapy

Therapeutic options for advanced, unresectable radioiodine-resistant thyroid cancers have historically been limited. Recent progress in understanding the pathogenesis of the various subtypes of thyroid cancer has led to increased interest in the development of targeted therapies, with potential strategies including angiogenesis inhibition, inhibition of aberrant intracellular signaling in the MAPK and PI3K/AKT/mTOR pathways, radioimmunotherapy, and redifferentiation agents. On the basis of a recent positive phase III clinical trial, the RET, vascular endothelial growth factor receptor (VEGFR), and epidermal growth factor receptor (EGFR) inhibitor vandetanib has received FDA approval as of April 2011 for use in the treatment of advanced medullary thyroid cancer. Several other recent phase II clinical trials in advanced thyroid cancer have demonstrated significant activity, and multiple other promising therapeutic strategies are in earlier phases of clinical development. The recent progress in targeted therapy is already revolutionizing management paradigms for advanced thyroid cancer, and will likely continue to dramatically expand treatment options in the coming years.

Somatostatin receptor 2 expression determined by immunohistochemistry in cold thyroid nodules exceeds that of hot thyroid nodules, papillary thyroid carcinoma, and Graves' disease

BACKGROUND

There is a plethora of partly contradictory reports on somatostatin receptor (SSTR) expression in thyroid tumors. Therefore, our goal was to systematically determine SSTR2 expression in benign cold thyroid nodules (CNs), hot thyroid nodules (HNs), papillary carcinomas (PCs), and Graves' disease (GD) in comparison with intraindividual control tissues by means of immunohistochemistry.

METHODS

Tissue sections from 19 HNs, 10 CNs, 17 PCs and their surrounding tissues, and 8 GD thyroids were immunostained for SSTR2. Membranous SSTR2 staining was quantitated by evaluating 10 high-power fields (HPFs) systematically distributed along the largest diameter of the tissue section.

RESULTS

The area covered by thyroid epithelial cells in 10 HPFs expressed as median (in mm(2)) was 0.53 for CNs, 0.44 for HNs, 1.5 for PCs, 1.3 for GD, and 0.3 for the surrounding tissues. The SSTR2 staining density determined by dividing the area of SSTR2 positively stained thyroid epithelial cells (in mm(2)) by the area of all thyroid epithelial cells (in mm(2)) in 10 HPFs was 0.1662 for CNs, 0.0204 for HNs, 0.0369 for PCs, and 0.0386 for GD.

CONCLUSIONS

SSTR2 expression is inhomogeneous in thyroid disease, with the highest density detected in CNs. It remains to be determined whether this finding could be of pathophysiologic or therapeutic relevance. The high SSTR2 density in CNs should be considered in the interpretation of SSTR scintigraphy-positive findings.

Relative quantification of indium-111 pentetreotide and gallium-68 DOTATOC uptake in the thyroid gland and association with thyroid pathologies

BACKGROUND

Recent data suggest that increased somatostatin receptor (SSTR) expression is detectable in several thyroid diseases. This raises the question as to the specificity and pathophysiologic relevance of these findings. Therefore, we systematically evaluated Indium-111 (In-111) pentetreotide scintigraphies and Gallium-68 (Ga-68) DOTA-Phe(1)-Tyr(3)-Octreotide (DOTATOC) positron emission tomography (PET) scans for thyroid radiotracer uptake.

METHODS

Relative binding of In-111 pentetreotide in the thyroid was measured by region of interest (ROI) technique in 4-hour and 24-hour post-injection (p.i.) planar images of 73 patients undergoing In-111 pentetreotide scintigraphy. Ga-68 DOTATOC PET scans of 77 patients were analyzed by ROI technique applied to coronal slices of 1 cm (0.39 inch) thickness with highest uptake in the thyroid region.

RESULTS

A basal indium In-111 and Ga-68 DOTATOC uptake was found in normal thyroid glands. Hot nodules, disseminated thyroid autonomy, and most cases of active Hashimoto's disease as well as goiters and nodular thyroids showed increased In-111 pentetreotide and/or Ga-68 DOTATOC uptake. Higher relative In-111 pentetreotide uptake in the 24-hour p.i. images as compared to the 4-hour p.i. images except for patients after thyroidectomy indicates specific receptor binding in the thyroid.

CONCLUSIONS

The increased In-111 pentetreotide and Ga-68 DOTATOC uptake in active Hashimoto's disease is most likely related to the lymphocytic infiltration of the thyroid. However, the physiologic or pathophysiologic relevance of the increased In-111 pentetreotide and Ga-68 DOTATOC uptake in normal thyroid glands, hot and cold nodules, and goiters and nodular thyroids remain to be determined.

Is there a role for sandostatin treatment in patients with progressive thyroid cancer and iodine-negative but somatostatin-receptor-positive metastases?

INTRODUCTION

The aim of our study was to determine whether treatment with a long-acting somatostatin-receptor analogue is effective in patients with (131)I-negative but somatostatin-receptor-positive metastases from dedifferentiated and anaplastic thyroid cancer.

MATERIALS AND METHODS

Twelve patients were screened for the study. All of them showed progressive disease confirmed by radiologic evaluation, increasing serum thyroglobulin (Tg), and negative diagnostic or posttherapeutic (131)I whole-body scans (WBS). Eight of 12 patients (4 males and 4 females; age range, 57-89 years; 1 papillary thyroid cancer; 4 poorly differentiated follicular thyroid cancer; 1 follicular and anaplastic thyroid cancer; 2 anaplastic thyroid cancer) showed positive somatosatin-receptor expression in Tc-99m depreotide WBS/SPECT (Tc-99m Dep.WBS). Initially, in all patients fluorine-18 2-fluoro-2- D-glucose-positron emission tomography-computed tomography ((18)F-FDG-PET-CT), Tc-99m Dep.WBS, and Tg measurements were performed. In the case of positive receptor scintigraphy, patients were treated with 20mg Sandostatin LAR (Novartis Pharmaceuticals, Basel, Switzerland) once per month intramuscularly over a period of 6 months followed by repeated (18)F-FDG-PET-CT, Tc-99m Dep.WBS, and Tg measurement to determine metabolic activity and tumor size. In case of tumor progression, the dose was increased to 30mg of Sandostatin LAR once per month.

RESULTS

Only 3 patients were able to undergo long-term treatment. Two patients were treated with octreotide long-acting release (LAR) for 1 year and 1 patient for 1(1/2) years. All patients showed progressive disease during the treatment: an increase of serum Tg on one hand and an increase in the number of lesions and extent in tumor size visible on FDG-PET-CT and Tc-99m Dep.WBS on the other. During the treatment there was no change in receptor expression, nevertheless, clear tumor progression under therapy with a somatostatin analogue was visible in FDG-PET-CT and in Tc-99m Dep.WBS.

CONCLUSION

Our data demonstrate that all of our patients treated with a somatostatin analogue showed clinical progression and that our attempt to achieve a stabilization of the disease failed.

Evidence for Somatostatin receptor 2 in thyroid tissue

Somatostatin receptor scintigraphy has found considerable interest for imaging thyroid tumours. Recently, also therapeutic application of Somatostatin analogues labelled with beta-emitting radionuclides has been suggested as treatment option for thyroid tumours with absent radioiodine uptake. Most of the radiolabelled analogues available show a predominant affinity for Somatostatin receptor subtype 2. This study reports on the in vitro characterisation of Somatostatin receptor subtype mRNAs in thyroid tumours and normal thyroid tissue by means of RT-PCR. Surgical samples of 21 patients were collected, and mRNA of 16 tumour and 17 control specimen was isolated. mRNA expression for Somatostatin, SSTR subtype 1-5, thyroid markers (NIS, TSH, Tg, TPO) and control markers (GAPDH, beta-actin) was determined. PCR results were correlated with immunohistochemistry staining using SSTR2 receptor specific antibodies. 94% of all samples expressed Somatostatin receptor mRNA with predominant expression of subtype 2, less predominant of subtype 5 and subtype 3. Somatostatin receptor subtype 2 mRNA expression correlated well with immunohistochemical staining pattern in 13/16 samples, SSTR2 immunohistochemistry was positive in 87% of the samples. Our results show that Somatostatin receptor 2 is predominantly expressed on thyroid tissue and is a valid target for treatment of thyroid tumours. Octreotide derivatives currently used in Nuclear medicine seem to be well suited to target receptors expressed in thyroid tumours.

Capecitabine therapy for refractory metastatic thyroid carcinoma: a case series

OBJECTIVE

There are few effective therapies for metastatic medullary (MTC) or radioiodine-resistant follicular thyroid carcinomas (FTC). We report a single institution's experience with capecitabine, a thymidylate synthase (TS) inhibitor, in the treatment of MTC and FTC.

DESIGN

We retrospectively analyzed five cases of metastatic thyroid carcinoma, three MTCs and two radioiodine-resistant FTCs, treated with capecitabine alone or in combination with other chemotherapeutics. Patients were selected for treatment based on low tumor TS immunohistochemical staining (< or =5%). Staining for thymidylate phosphorylase (TP) and dihydropyrimidine dehydrogenase (DPD) was also performed. Therapeutic response was assessed by imaging studies and serum tumor markers: calcitonin and carcinoembryonic antigen (MTC), and thyroglobulin (FTC).

MAIN OUTCOME

Two of three patients with MTC had stable disease or disease regression on capecitabine. One of these patients had a 90% reduction in calcitonin and stabilization by imaging that lasted 4 years. Both patients with FTC initially had stable disease on capecitabine. One patient, who was treated with capecitabine in combination first with doxorubicin and then etoposide, had an initial decrease in tumor burden, followed by stable disease for 2.8 years. The second patient had stable disease, but capecitabine was discontinued after 11 months because of hand/foot syndrome.

CONCLUSIONS

This series demonstrates promising results for the use of capecitabine in treatment of MTC and radioiodine-resistant FTC, for which there is a limited repertoire of therapeutic agents. Larger studies are needed to confirm these findings and to establish the role of fluoropyramidine metabolism markers in predicting response.

Staging and treatment of differentiated thyroid carcinoma with radiolabeled somatostatin analogs

In patients with progressive metastatic (or recurrent) differentiated thyroid carcinoma that either do not take up radioiodine or are unresponsive to continued radioiodine therapy, staging is difficult and treatment options are few. However, in most of these patients uptake of radiolabeled somatostatin analogs is evident on somatostatin-receptor scintigraphy (SRS). Using SRS, patients with sufficient uptake of radiolabeled somatostatin analogs can be selected for high-dose peptide receptor radionuclide therapy (PRRT) as an alternative targeted-treatment option. PRRT with the beta-particle-emitting radionuclides (90)yttrium ((90)Y) and (177)lutetium ((177)Lu) gives the best results in terms of objective tumor response. Promising, novel, radiolabeled somatostatin analogs that have a broader receptor affinity profile and, thus, a potentially wider therapeutic range are being tested clinically.

Six month follow-up after 111In-DTPA-octreotide therapy in patients with progressive radioiodine non-responsive thyroid cancer: a pilot study

BACKGROUND AND AIM

111In-DTPA-octreotide is internalized by thyroid and neuroendocrine cancer cells via somatostatin receptor subtypes and can cause DNA damage by the emission of conversion and Auger electrons. The aim of the study was to determine the effect of 111In-DTPA-octreotide therapy in patients with progressive radioiodine non-responsive thyroid cancer in relation to 111In-DTPA-octreotide uptake by tumour localizations assessed on pre-treatment diagnostic octreotide scans.

METHODS

Eleven consecutive patients, selected on positive pretreatment diagnostic scans, were treated with fixed doses of approx. 7400 MBq of 111In-DTPA-octreotide with an interval of 2-3 weeks between the doses. In one patient, the dose was adjusted because of sickle-cell disease. To assess the effects during treatment with 111In-DTPA-octreotide thyroglobulin levels were gathered from 2 years before treatment, during treatment and up to 1 year after treatment. A computed tomography scan was performed 3 months after the last treatment.

RESULTS

Two patients died during and shortly after the treatment course. Death was due to a sepsis and an insulin overdose, respectively. In 44% of the patients, stable disease was achieved up to 6 months after the first treatment according to both criteria. All four had relative low pretreatment thyroglobulin values (mean value 275 microg.l), representing limited metastasized disease. In two patients biochemical stable disease was observed, whereas computed tomography showed tumour progression.

CONCLUSION

Treatment with high doses of 111In-DTPA-octreotide in differentiated thyroid cancer results in a stable disease in a subgroup of patients. Our results suggest that a low pre-treatment thyroglobulin value, representing a small tumour load, may be a selection criterion for treatment.

Somatostatin receptors: from basic science to clinical approach--thyroid

Somatostatin and its receptors are expressed in the thyroid gland, but somatostatin analogs which are currently available have provided contradictory results in the diagnosis and treatment of thyroid neoplasia. Somatostatin and its analogs fail to influence follicular thyroid function, whereas their administration in patients with medullary thyroid carcinoma induces a reduction of serum calcitonin concentrations and clinical symptoms, but fails to influence tumour size and patient survival rate. Radiolabelled somatostatin analogs can localise tumours expressing somatostatin receptors, but somatostatin receptor-targeted radiotherapy of thyroid malignancies has provided conflicting and inconclusive results. Our recent results indicate that somatostatin receptor 2 activation by somatostatin receptor 2 agonists inhibits cell proliferation in the human medullary thyroid carcinoma cell line, TT. This effect can be hampered by concurrent somatostatin receptor 5 selective agonist treatment, which fails to influence TT cell proliferation, suggesting an antagonism between somatostatin receptors 5 and 2 agonists in medullary thyroid carcinoma cells. Moreover, somatostatin receptors 2 or 5 agonists fail to inhibit calcitonin secretion and calcitonin gene expression. On the other hand, somatostatin receptor 1 agonists inhibit proliferation, calcitonin secretion and calcitonin gene expression in parafollicular C cells, suggesting that analogs with enhanced somatostatin receptor 1 affinity and selectivity besides having great potentiality as pharmacological tools to control neoplastic growth, may also be used to reduce symptoms in patients with medullary thyroid carcinoma.

Recurrent and/or metastatic thyroid cancer: therapeutic options

Thyroid cancer is relatively rare, accounting for 0.5 - 10 cases per 100,000 individuals per year. Despite their generally favourable prognosis, patients with differentiated thyroid cancer are at risk of tumour recurrence for decades after diagnosis. The optimal management remains controversial even in the low-risk patients because of the high cure rates, long natural history and rarity of these tumours. Therapeutic interventions in recurrent and metastatic differentiated thyroid cancer depend on the type of initial treatment, the site and the extent of disease. Surgical excision of the amenable-to-surgery lesions and radioiodine administration remain the first approach. External radiotherapy may be given to patients with inoperable lesions or those not concentrating radioiodine. Chemotherapy has not provided consistently successful results. Various therapeutic approaches for anaplastic carcinoma give poor results, making the development of novel treatments necessary. Innovative strategies, including recombinant human thyroid stimulating hormone, retinoic acid redifferentiation therapy and gene therapy, may lead to further improvement in the management of thyroid cancer arising from follicular cells.

The clinical role of somatostatin analogues as antineoplastic agents: much ado about nothing?

BACKGROUND

Somatostatin (SST) analogues represent a novel approach for the treatment of certain cancers. The objective of this article is to summarise the current knowledge on SST analogues in the treatment of cancer patients.

METHODS

Computerised (Medline) and manual searches were performed to identify publications on clinical trials published in the English-speaking literature between 1966 and 2000. Information abstracted included patients' pre-treatment status, histology, SST receptor (SSTR) evaluation, type of SST analogue, application schedule and dose, duration of treatment, side-effects, response criteria applied (i.e. WHO response criteria, biochemical criteria or symptomatic investigations) and survival.

RESULTS

Our search disclosed 22 case reports, five phase 1 and 47 phase II trials, and eight randomised clinical trials using SST analogues (octreotide, lanreotide and vapreotide) as antineoplastic agents. With regard to the phase II trials, conflicting results have been demonstrated in almost all tumour entities investigated. The few randomised studies published so far have shown an impact on survival in patients with hepatocellular cancer, while the effect attributed to treatment in patients with gastrointestinal adenocarcinomas might well have been due to an exceptionally short survival in the control group. There appears to be evidence that SST analogues are able to enhance the therapeutic effects of hormonal intervention in patients with breast cancer, prostate cancer and probably pancreatic cancer. Interpretation of the findings, however, is complicated by the fact that patients were heavily pre-treated in some studies and response criteria have not been uniformly applied. In addition, most studies have not been designed to distinguish between receptor-mediated (direct) and indirect effects of SST analogues in tumour patients.

CONCLUSIONS

According to the results obtained so far, there can be no doubt about the wide therapeutic index and the high efficacy of SST analogues in the symptomatic management of neuroendocrine tumours. Apart from these indications, the data do not justify recommendation of SST analogues as antineoplastic agents outside of clinical trials, as the optimal dose and schedule of application for antineoplastic activity has not been defined for currently used agents. Carefully designed clinical trials including investigation of SSTR status before treatment, evaluation of an indirect mechanism of SST analogues, and assessment of optimal combination of hormone therapy and chemotherapy with SST analogues are clearly needed in the near future.

Hürthle cell carcinoma: a 60-year experience

BACKGROUND

The aim of this study was to define the clinical behavior and prognostic indicators of outcome in Hürthle cell cancer (HCC).

METHODS

Diagnosis was confirmed for 56 patients with HCC treated between 1940 and 2000, who form the basis of this study. Primary end points were relapse-free survival (RFS) and disease-specific survival (DSS). Data were analyzed with the Kaplan-Meier method and by log-rank test.

RESULTS

The extent of thyroid resection did not predict outcome. Recurrence was a significant predictor of tumor-related mortality. Significant adverse predictors of RFS and DSS were degree of invasion, size >4 cm, extrathyroidal extension, and initial nodal or distant metastases. The most significant predictor of outcome was extent of invasion. Eight-year RFS values for low- and high-risk groups were 100% and 24%. Corresponding rates of 8-year DSS were 100% and 58%.

CONCLUSIONS

Widely invasive HCC is an aggressive malignancy that identifies patients who are at high risk for recurrence and tumor-related death. Patients with HCC have a prognosis that is reliably predicted by degree of invasion, tumor size, extrathyroidal disease extension, and initial nodal or distant metastasis. Recurrence portends a poor outcome. High-risk patients and those with recurrence should be considered for adjuvant therapy.

Differentiated thyroid carcinoma in the elderly

The overall prognosis of patients with differentiated thyroid cancer is excellent, but the prognosis is rapidly worsening, when the disease is diagnosed in elderly patients. Old patients more often present with poor prognostic features, such as large tumors, follicular or Hürthle cell subtypes, extrathyroidal growth and distant metastases. Therefore, an optimal therapeutic approach is recommended. Current therapy includes a total thyroidectomy, if necessary combined with a lymph node dissection and followed by high dose radioiodine ablation. Radioiodine therapy in elderly patients meets specific problems, concerning thyroid hormone withdrawal, side effects of 131I and nursing problems. Additional treatment of residual, recurrent or metastatic disease must be tailored, according to the stage of the disease, and should not be denied on the basis of chronological age. Lifelong treatment with suppressive thyroid hormone therapy does not lead to important long-term side effects at old age.

Management of undifferentiated thyroid cancer

Management of thyroid carcinoma relies upon the tumour cells maintaining the differentiated functions that are typical of normal thyroid follicular cells, such as: dependence upon thyrotropin for growth, production of thyroglobulin and effective transport of iodine. Likewise, differentiated thyroid carcinomas often exhibit an auspicious clinical behaviour with a slow rate of growth and low potential for invasion and distant metastasis. These features permit therapy of disseminated tumour, effective follow-up surveillance and the assumption of a good prognosis. As each of these features are lost, the opportunities for both disease status assessment and therapeutic intervention diminish accordingly. A major obstacle is our failure to define effective systemic treatments to replace radioiodine therapy, whose loss is consonant with the loss of iodine transport and retention. The extreme of undifferentiated clinical behaviour is epitomized by anaplastic thyroid carcinoma, a rare, terminally dedifferentiated malignancy that is rapidly and invariably fatal. It is important to be attuned to clinical clues suggesting the presence of dedifferentiated tumour and related prognostic signs. This allows the application of currently limited therapeutic options and defines the need for research to develop new systemic treatments.

Inhibition of metabolic activity in papillary thyroid carcinoma by a somatostatin analogue

Two patients with widely metastatic papillary thyroid cancer demonstrated progressive growth of diffuse pulmonary lesions. One patient had no apparent response to high doses of 131I and the other hand no 131I uptake. 111In-pentetreotide scans revealed that many of the metastatic lesions expressed somatostatin receptors. The baseline metabolic activity and three-dimensional volume of the lesions were determined by 18F-fluoro-de-oxyglucose positron emission tomography (FDG-PET). After 3 or 4 months of octreotide (Sandostatin LAR Depot; Novartis Pharmaceutical, East Hanover, NJ) therapy, repeat FDG-PET scans revealed reductions in tumor volume and decreases in the standard uptake values of FDG. We conclude that octreotide therapy can change the biological activity of metastatic thyroid cancer lesions that exhibit somatostatin receptors.

Somatostatin receptor subtype expression in human thyroid and thyroid carcinoma cell lines

Somatostatin (SRIH) analogs can suppress the proliferation of human differentiated thyroid carcinoma cell lines that express SRIH receptors (SSTRs) demonstrated by radioligand binding analysis. Five distinct human SSTR subtypes (hSSTR1-5) that bind native SRIH exhibit diverse affinities to a wide range of SRIH analogs. Reverse transcriptase-PCR amplification of ribonucleic acids (RNAs) obtained from normal thyroid tissues and nine human thyroid carcinoma cell lines, grown as monolayer cultures and xenograft tumors in nude mice, were used to discriminate expression of SSTR subtype messenger RNAs (mRNAs). The cell lines were derived from a follicular adenoma (KAK-1), two follicular carcinomas (MRO-87 and WRO-82), two papillary carcinomas (NPA87 and KAT-10), and four anaplastic thyroid carcinomas (DRO-90, ARO-81, KAT-4, and KAT-18). Most thyroid cancer cell line monolayers and xenografts expressed SSTR3 and SSTR5 mRNAs. SSTR1 expression was more varied between monolayers and xenografts, whereas SSTR2 mRNA was only faintly detectable at the most extreme resolution. SSTR4 mRNA was faintly positive in only one anaplastic carcinoma xenograft. Normal thyroid also expressed SSTR3 and SSTR5 mRNAs, with only faint expression of SSTR1 and SSTR2 mRNAs (in one of five and three of five samples, respectively). SSTR mRNA expression was dependent upon in vitro culture conditions, as xenograft SSTR mRNA expression tended to decrease compared to that in each respective monolayer culture. Characterization of SSTR subtype expression in human thyroid carcinomas may permit targeting of specific SRIH analogs to inhibit proliferation of differentiated and anaplastic thyroid carcinomas in patients.

Hurthle Cell Carcinoma

BACKGROUND: Hurthle cell carcinoma represents approximately 3% of all differentiated thyroid cancers. The terminology is often confusing, and discrimination between Hurthle cell carcinoma and benign Hurthle cell tumors can be unclear. Thus, optimal treatment of patients with these diseases remains unsettled. METHODS: The authors reviewed published evidence on the presentation, biologic behavior, and treatment outcomes for this disease. In addition, they summarized their experience involving a series of 14 patients with Hurthle cell carcinoma. RESULTS: Hurthle cell carcinoma generally produces thyroglobulin and rarely takes up radioactive iodine. It is frequently bilateral or multifocal within the thyroid gland and often presents with local invasion. Hurthle cell carcinoma is associated with a high rate of locoregional recurrence and significant mortality. CONCLUSIONS: The authors advocate total thyroidectomy with central neck dissection as the therapy of choice for patients with Hurthle cell carcinoma.