Management of thyroid cancer

A comparative analysis of treatment efficacy in intermediate-risk thyroid cancer

PURPOSE

This study aimed to evaluate the efficacy of different treatment combinations on patient survival in intermediate-risk differentiated thyroid cancer (DTC).

METHODS

The 2004-2017 National Cancer Database was queried for intermediate-risk papillary (PTC), follicular (FTC), or Hurthle cell (HTC) thyroid cancer patients. Four treatments were analyzed using Kaplan Meier and multivariable Cox regression: surgery, surgery with adjuvant radioiodine ablation (S + RAI), surgery with adjuvant thyroid-stimulating hormone suppression therapy (S + THST), and S + RAI + THST. Kaplan-Meier and multivariable Cox proportional-hazards analyses evaluated treatment-associated overall survival (OS).

RESULTS

Of 65,736 patients, 72.2% were female and the average age was 45.4 ± 15.4 years. The 10-year OS rates for PTC, FTC, and HTC were 93.2%, 85.2%, and 78.5%, respectively. S + RAI + THST exhibited higher OS than surgery alone and S + RAI (all p < 0.05). Compared to surgery alone, S + RAI + THST demonstrated reduced mortality in PTC (Hazard Ratio [HR]: 0.628, p < 0.001), FTC (HR: 0.490, p < 0.001), and HTC (HR: 0.520, p = 0.006). Similarly, adjuvant RAI + THST reduced mortality regardless of lymphovascular invasion (HR: 0.490, p < 0.001), N1a (HR: 0.570, p < 0.001) or N1b metastasis (HR: 0.621, p < 0.001), or positive margin status (HR: 0.572, p < 0.001).

CONCLUSIONS

Treatment combinations demonstrated varying efficacies in intermediate-risk DTC depending on histology and tumor characteristics, with S + RAI + THST exhibiting the greatest treatment response.

Zoledronic acid inhibits thyroid cancer stemness and metastasis by repressing M2-like tumor-associated macrophages induced Wnt/β-catenin pathway

AIMS

This study aims to explore the effect and underlying mechanism of zoledronic acid (ZA) on the incidence of thyroid cancer (TC) tumorigenesis.

MATERIALS AND METHODS

Human mononuclear cells THP-1 were differentiated into M2-like tumor associated macrophages (TAMs) by incubation with PMA followed by additional incubation of IL-4 and IL-13. TC cells TPC-1 and IHH4 were co-cultured with M2-like TAMs. Identification of M2-like TAMs markers were determined by immunohistochemistry or flow cytometry. Cell proliferation, stemness and migration/invasion ability were measured by colony, sphere formation assay and transwell assay, respectively. The expression levels of cell stemness, EMT and Wnt/β-catenin pathway-related factors were verified by qRT-PCR, Western blotting, and immunofluorescence. A subcutaneous tumor model was established in nude mice to examine the in vivo effects of ZA.

KEY FINDINGS

M2-like TAMs were enriched in TC tissues, and they promoted the colony/sphere formation, accompanied with a down-regulated expression in E-cadherin and an up-regulated expression in N-cadherin, Vimentin and other stemness-associated markers (CD133, Oct4, c-Myc) in TC cells. The effects were suppressed when ZA co-treatment was given, because ZA inhibited the polarization of M2-like TAMs and β-catenin entry into the nucleus. Moreover, in agreement with in vitro data, ZA also limited subcutaneous tumor formation and macrophage enrichment in nude mice.

SIGNIFICANCE

ZA suppressed M2-like TAMs induced TC cell proliferation, stemness and metastasis through inhibiting M2-like TAMs polarization and Wnt/β-catenin pathway, which sheds light on the mechanisms of TC and provides avenues for the development of clinical therapy to TC.

Novel therapeutic clues in thyroid carcinomas: The role of targeting cancer stem cells

Thyroid carcinomas (TCs), the most common endocrine tumors, represent the eighth most common cancer diagnosed worldwide in both women and men. To treat these malignancies, several drugs are now available and a number of novel ones have been enrolling in clinical trials, addressing both oncogenic pathways in cancer cells and angiogenic pathways in tumor endothelial cells. However, their use is not devoid of serious toxicities and their efficacy is limited, being dependent on carcinoma typology and the occurrence of acquired resistance. Accordingly, it is time to recast therapeutic strategies against these types of tumors to get to newer and fully effective drugs. In this perspective, latest findings demonstrate that cancer stem cells (CSCs) represent a challenging target to strike. They possess core traits of self-renewal and differentiation, being resistant to the effects of chemotherapy and radiation and playing a key role in mediating metastasis. Therefore, basic molecular elements sustaining both development of thyroid cancer stem cells and their residence in the stemness condition represent a set of innovative and still unexplored targets to address. In this review, a thorough literature survey has been accomplished, to take stock of mechanisms governing thyroid carcinomas and to point out both their currently available treatments and the novel forthcoming ones. Pubmed, Scifinder and ClinicalTrials.gov were exploited as research applications and registry database, respectively. Original articles, reviews, and editorials published within the last ten years, as well as open clinical investigations in the field, were analyzed to suggest new exciting therapeutic opportunities for people affected by TCs.

Usefulness of Stereotactic Radiotherapy Using CyberKnife for Recurrent Lymph Node Metastasis of Differentiated Thyroid Cancer

A woman in her 60s presented with a recurrent lymph node metastasis from a papillary thyroid carcinoma in the right parapharyngeal space. She had already undergone total thyroidectomy, five resections for cervical lymph node metastases, and right carotid rebuilding. Surgical resection of the current metastasis was impossible. ¹³¹I-radioiodine therapy (RIT) with 3.7 GBq ¹³¹I was not effective; therefore, stereotactic radiation therapy (SRT) using a CyberKnife radiotherapy system was scheduled. The prescription dose was 21 Gy, and a dose covering 95% of the planning target volume (PTV) in three fractions was administered. The PTV was 4,790 mm³. Follow-up magnetic resonance imaging conducted 3 and 12 months after the SRT demonstrated a remarkable and gradual reduction of the recurrent lymph node metastasis in the right parapharyngeal space and no evidence of recurrence. For multidisciplinary therapy of unresectable and/or RIT unresponsive locoregional lymph node metastases and recurrences of DTC, SRT using the CyberKnife system should be considered.

A phase 2 trial of lenvatinib (E7080) in advanced, progressive, radioiodine-refractory, differentiated thyroid cancer: A clinical outcomes and biomarker assessment

BACKGROUND

Lenvatinib is an oral, multitargeted tyrosine kinase inhibitor of the vascular endothelial growth factor receptors 1 through 3 (VEGFR1-VEGFR3), fibroblast growth factor receptors 1 through 4 (FGFR1-FGFR4), platelet-derived growth factor receptor α (PDGFRα), ret proto-oncogene (RET), and v-kit Hardy-Zuckerman 4 feline sarcoma viral oncogene homolog (KIT) signaling networks implicated in tumor angiogenesis. Positive phase 1 results in solid tumors prompted a phase 2 trial in patients with advanced, radioiodine-refractory, differentiated thyroid cancer (RR-DTC).

METHODS

Fifty-eight patients with RR-DTC who had disease progression during the previous 12 months received lenvatinib 24 mg once daily in 28-day cycles until disease progression, unmanageable toxicity, withdrawal, or death. Previous VEGFR-targeted therapy was permitted. The primary endpoint was the objective response rate (ORR) based on independent imaging review. Secondary endpoints included progression-free survival (PFS) and safety. Serum levels of 51 circulating cytokines and angiogenic factors also were assessed.

RESULTS

After ≥14 months of follow-up, patients had an ORR of 50% (95% confidence interval [CI], 37%-63%) with only partial responses reported. The median time to response was 3.6 months, the median response duration was 12.7 months, and the median PFS was 12.6 months (95% CI, 9.9-16.1 months). The ORR for patients who had received previous VEGF therapy (n = 17) was 59% (95% CI, 33%-82%). Lower baseline levels of angiopoietin-2 were suggestive of tumor response and longer PFS. Grade 3 and 4 treatment-emergent adverse events, regardless of their relation to treatment, occurred in 72% of patients and most frequently included weight loss (12%), hypertension (10%), proteinuria (10%), and diarrhea (10%).

CONCLUSIONS

In patients with and without prior exposure to VEGF therapy, the encouraging response rates, median time to response, and PFS for lenvatinib have prompted further investigation in a phase 3 trial. Cancer 2015;121:2749-2756. © 2015 American Cancer Society.

Prognostic value of positron emission tomography-assessed tumor heterogeneity in patients with thyroid cancer undergoing treatment with radiopeptide therapy

INTRODUCTION

Peptide receptor radionuclide therapy (PRRT) is a treatment option for both iodine-refractory differentiated and advanced medullary thyroid cancer (TC). It requires over-expression of somatostatin receptor subtype II (SSTR) that can be non-invasively assessed by positron emission tomography (PET). Assessment of tumor heterogeneity is increasingly used as a tool for prognostication prediction. We investigated the potential of SSTR-PET to assess intraindividual tumor heterogeneity and thereby treatment response prior to PRRT.

METHODS

12 patients with progressive radioiodine-refractory differentiated (1 papillary, 1 oxyphilic, 2 oncocytic, 4 follicular) or medullary (n=4) TC were enrolled. SSTR-PET was performed at baseline. Conventional PET parameters and heterogeneity parameters were analyzed regarding their potential to predict progression-free (PFS, mean, 221 days) and overall survival (OS, mean, 450 days). Parameters of a subgroup of lesions (n=23) were also correlated with morphological response according to modified RECIST criteria.

RESULTS

In patient-based analysis, all conventional parameters failed to predict PFS. Several textural parameters showed a significant capability to assess PFS. Thereby, "Grey level non uniformity" had the highest area under the curve (AUC, 0.93) in Receiver operating characteristics analysis followed by "Contrast" (AUC, 0.89). In lesion-based analysis, only "Entropy" revealed potential to evaluate disease progression. OS could not be assessed by any parameter investigated.

CONCLUSIONS

Tumor heterogeneity seems to be a predictor of response to PRRT in patients with iodine-refractory differentiated/advanced medullary thyroid cancer and outperforms conventional PET parameters like standardized uptake value. In a "theranostic" approach, assessment of textural parameters may help in selecting patients who might benefit from PRRT.

microRNAs and thyroid cancer: biological and clinical significance (Review)

Despite recent advances in the management of thyroid cancer, the survival rate of this tumor may still be improved. Therefore, the identification of biological and molecular features of indolent and aggressive disease would be critical to define clinically useful predictors of high-risk lesions. microRNAs (miRNAs) are small RNA molecules with regulatory function and marked tissue specificity that modulate multiple targets belonging to several pathways. They are frequently deregulated in cancer and constitute a new class of blood-based biomarkers useful for cancer detection and prognosis definition, including thyroid cancer. In this review, the role of miRNAs in thyroid cancer development is described. The most common miRNAs detected in thyroid cancer along with their clinical significance are also discussed. Further studies aimed to detect plasma-based miRNA biomarkers in thyroid cancer patients may provide further insight into the management of thyroid cancer.

Anti-proliferative effects of evodiamine on human thyroid cancer cell line ARO

The incidence of thyroid cancer increases with age, and it is twice in women as common as in men. The undifferentiated thyroid cancer (UTC) is the most aggressive of all thyroid cancers. Unfortunately, there are almost no efficacious therapeutic modalities. It is important to develop some new effective therapies. Evodiamine is a chemical extracted from a kind of Chinese herb named Wu-Chu-Yu and has been demonstrated to be effective in preventing the growth of a variety of cancer cells. In the present study, the mechanism by which evodiamine inhibited the undifferentiated thyroid cancer cell line ARO was examined. Based on 3-(4,5-dimethylthiazol -2-yle)2,5-diphenyltetrazolium bromide (MTT) assay, cell proliferation rate was reduced dose-dependently by evodiamine, but not by rutaecarpine. According to the flow cytometric analysis, evodiamine treatment resulted in G2/M arrest and DNA fragmentation in ARO cells. The G2/M arrest was accompanied with an increase of the expression of cdc25C, cyclin B1, and cdc2-p161 protein, and it was also with a decrease of the expression of cdc2-p15. Furthermore, by using the TUNEL assay, evodiamine-induced apoptosis was observed at 48 h and extended to 72 h. Western blotting demonstrated that evodiamine treatment induced the activation of caspase-8, caspase-9, caspase-3, and the cleavage of poly ADP-ribose polymerase (PARP). These results suggested that evodiamine inhibited the growth of the ARO cells, arrested them at M phase, and induced apoptosis through caspases signaling.

Molecular pathogenesis of follicular cell derived thyroid cancers

Thyroid cancers are the most common endocrine malignancy. Radiation exposure, family history of thyroid cancer and some inherited conditions are the most important predisposing factors for the development of thyroid cancer. Three mitogenic signalling pathways have been described in the thyroid cell, which are influenced by various stimulatory and inhibitory hormones, growth factors and neurotransmitters. Various proto-oncogenes and oncogenes like ras, braf, trk, met and RET also play a role in the signal transduction systems. Two theories have been described in thyroid cancer pathogenesis, the foetal cell carcinogenesis theory and the more common, multistep carcinogenesis theory. The multistep carcinogenesis theory is now the accepted model in many human cancers, including thyroid cancer. The early events of tumour formation are the consequence of activation of either various growth factors or the proto-oncogenes like ras, met or ret. This results in the formation of differentiated thyroid cancers like the papillary, follicular or Hurthle cell cancers. The later stages of tumour formation involve further activation of proto-oncogenes and loss or inactivation of tumour suppressor genes like p53. Based on this theory, follicular carcinomas are generated from follicular adenomas and papillary carcinomas from precursor cells generated from thyrocytes. Anaplastic carcinoma may develop from papillary or follicular carcinoma by dedifferentiation. In this review article, we highlight the molecular pathogenesis of thyroid tumours.

Cl-IB-MECA enhances TRAIL-induced apoptosis via the modulation of NF-kappaB signalling pathway in thyroid cancer cells

Apoptosis is an endogenous process that can be a useful anti-cancer tool. This study aimed to investigate the effect of Cl-IB-MECA, adenosine receptor A3 agonist, on TRAIL-induced apoptosis of thyroid carcinoma cells. Cl-IB-MECA enhanced TRAIL-mediated apoptosis in FRO but not in ARO cells. This effect was correlated to higher expression levels of DR5 on FRO than ARO cells, that instead presented higher levels of decoy receptors, DcR1 and DcR2. To understand the cross-talk between the effect of Cl-IB-MECA and TRAIL, we evaluated the nuclear translocation of p65 and c-Rel. Since the dependency by NF-kappaB, TRAIL promoted the nuclear translocation of both p65 and c-Rel subunits. However, the addition of Cl-IB-MECA led to the predominant translocation of c-Rel after TRAIL addition. Furthermore, Bcl-2, cFLIP and pAkt were lower induced than caspase-3 and -9 in FRO cells. To discriminate a specific effect of TRAIL, we used tumour necrosis factor-alpha (TNF-alpha) with Cl-IB-MECA. In this case, no synergism was observed. In addition, the effect of Cl-IB-MECA was not A3 receptor-dependent since its antagonists, MRS1191 and FA385, failed to block Cl-IB-MECA activity on TRAIL-treated FRO cells. In conclusion, Cl-IB-MECA enhanced TRAIL-mediated apoptosis via NF-kappaB/c-Rel activation and DR5-dependent manner. This study may shed light on a potential drug cocktail that may prove useful as anti-cancer in an in vivo animal model.

[(90)Yttrium-DOTA]-TOC response is associated with survival benefit in iodine-refractory thyroid cancer: long-term results of a phase 2 clinical trial

BACKGROUND

The authors aimed to explore the efficacy of (90)Yttrium-1,4,7,10-tetra-azacyclododecane N,N',N'',N'''-tetraacetic acid [(90)Y-DOTA]-Tyr(3)-octreotide (TOC) in advanced iodine-refractory thyroid cancer.

METHODS

In a phase 2 trial, the authors investigated biochemical response (assessed by serum thyroglobulin levels), survival, and the long-term safety profile of systemic [(90)Y-DOTA]-TOC treatment in metastasized iodine-refractory thyroid cancer. Adverse events were assessed according to the National Cancer Institute criteria. Survival analyses were performed by using multiple regression models.

RESULTS

A total of 24 patients were enrolled. A median cumulative activity of 13.0 GBq (range, 1.7-30.3 GBq) was administered. Response was found in 7 (29.2%) patients. Eight (33.3%) patients developed hematologic toxicity grade 1-3, and 4 (16.7%) patients developed renal toxicity grade 1-4. The median survival was 33.4 months (range, 3.6-126.8 months) from time of diagnosis and 16.8 months (range, 1.8-99.1 months) from time of first [(90)Y-DOTA]-TOC treatment. Response to treatment was associated with longer survival from time of diagnosis (hazard ratio [HR], 0.17; 95% confidence interval [CI], 0.03-0.92; P = .04) and from time of first [(90)Y-DOTA]-TOC therapy (HR, 0.20; 95% CI, 0.04-0.94; P = .04). The visual grade of scintigraphic tumor uptake was not associated with treatment response (odds ratio [OR], 0.98; 95% CI, 0.26-3.14; P = 1.00).

CONCLUSIONS

Response to [(90)Y-DOTA]-TOC in metastasized iodine-refractory thyroid cancer was associated with longer survival. Upcoming trials should aim to increase the number of treatment cycles.

Effectiveness of retinoic acid treatment for redifferentiation of thyroid cancer in relation to recovery of radioiodine uptake

BACKGROUND

Retinoic acid (RA) treatment has been used for redifferentiation of metastatic thyroid neoplasia that have lost radioiodine (131I) uptake with heterogeneous results.

AIM

Retrospective analysis of the recovery rate of 131I uptake after RA treatment in patients from 11 Spanish hospitals.

METHODS

Twenty-seven patients (14 men, 13 women) with papillary [21], follicular [4], and oncocytic [2] thyroid cancer initially treated with total thyroidectomy plus 131I, and with 131I negative metastatic disease, were given 13-cis RA (0.66-1.5 mg/kg for 5-12 weeks) followed by a therapeutic 131I dose (3700-7400 MBq); 3 months later thyroglobulin levels and computed tomography imaging were performed.

RESULTS

In 9 out 27 cases (33%) (8 papillary, 1 follicular) optimal positive 131I scan was observed after RA treatment; in the remaining 18, 10 had a suboptimal uptake (7 papillary, 2 follicular, 1 oncocytic) and in the rest there was no 131I uptake recovery (6 papillary, 1 follicular, 1 oncocytic). In 17 positive responses to RA (either optimal or suboptimal) in which image follow-up was available, decrease or stabilization of metastatic growth was observed in 7, while tumor mass increased at short term in the remaining 10. No major side effects were detected.

CONCLUSION

Quite a high rate of 131I uptake recovery after RA treatment may be obtained in advanced differentiated thyroid cancer, but the potential modification of the natural course of the disease is uncertain. A better biological characterization of these tumors allowing the identification of potential responders to RA may improve the outcome of RA coadjuvant therapy.

Anti-apoptotic effects of protein kinase C-delta and c-fos in cisplatin-treated thyroid cells

BACKGROUND AND PURPOSE

We showed previously that cisplatin inititates a signalling pathway mediated by PKC-delta/extracellular signal-regulated kinase (ERK), important for maintaining viability in PC Cl3 thyroid cells. The studies described herein examined whether c-fos was associated with cisplatin resistance and the signalling link between c-fos and PKC-delta/ERK.

EXPERIMENTAL APPROACH

Cells were treated with various pharmacological inhibitors of PKCs and ERK, or were depleted of c-fos, PKC-delta, PKC-epsilon and caspase-3 by small interfering RNA (siRNA), then incubated with cisplatin and cytotoxicity assessed.

KEY RESULTS

Cisplatin provokes the induction of c-fos and the activation of conventional PKC-beta, and novel PKC-delta and -epsilon. The cisplatin-provoked c-fos induction was decreased by Gö6976, a PKC-beta inhibitor; by siRNA for PKC-delta- but not that for PKC-epsilon or by PD98059, a mitogen-activated protein kinase/ERK kinase inhibitor. Expression of c-fos was abolished by GF109203X, an inhibitor of all PKC isoforms, or by PD98059 plus Gö6976 or by PKC-delta-siRNA plus Gö6976. When c-fos expression was blocked by siRNA, cisplatin cytotoxicity was strongly enhanced with increased caspase-3 activation. In PKC-delta-depleted cells treated with cisplatin, caspase-3 activation was increased and cell viability decreased. In these PKC-delta-depleted cells, PD98059 did not affect caspase-3 activation.

CONCLUSIONS AND IMPLICATIONS

In PC Cl3 cells, in the cell signalling pathways that lead to cisplatin resistance, PKC-delta controls ERK activity and, together with PKC-beta, also the induction of c-fos. Hence, the protective role of c-fos in thyroid cells has the potential to provide new opportunities for therapeutic intervention.

Oncogenic role of miR-17-92 cluster in anaplastic thyroid cancer cells

Micro RNAs (miRNAs) are non-coding small RNAs and constitute a novel class of negative gene regulators that are found in both plants and animals. Several miRNAs play crucial roles in cancer cell growth. To identify miRNAs specifically deregulated in anaplastic thyroid cancer (ATC) cells, we performed a comprehensive analysis of miRNA expressions in ARO cells and primary thyrocytes using miRNA microarrays. MiRNAs in a miR-17-92 cluster were overexpressed in ARO cells. We confirmed the overexpression of those miRNAs by Northern blot analysis in ARO and FRO cells. In 3 of 6 clinical ATC samples, miR-17-3p and miR-17-5p were robustly overexpressed in cancer lesions compared to adjacent normal tissue. To investigate the functional role of these miRNAs in ATC cells, ARO and FRO cells were transfected with miRNA inhibitors, antisense oligonucleotides containing locked nucleic acids. Suppression of miR-17-3p caused complete growth arrest, presumably due to caspase activation resulting in apoptosis. MiR-17-5p or miR-19a inhibitor also induced strong growth reduction, but only miR-17-5p inhibitor led to cellular senescence. On the other hand, miR-18a inhibitor only moderately attenuated the cell growth. Thus, we have clarified functional differences among the members of the cluster in ATC cells. In conclusion, these findings suggest that the miR-17-92 cluster plays an important role in certain types of ATCs and could be a novel target for ATC treatment.

BRAF mutation associated with other genetic events identifies a subset of aggressive papillary thyroid carcinoma

PURPOSE

BRAF(V600E) mutation represents the most common oncogenic event in sporadic papillary thyroid cancer (PTC). There are, however, significant discrepancies regarding the overall frequency, its prevalence in PTC-variants, and its relationship with clinico-pathological parameters of poor outcome. Moreover, the impact of BRAF(V600E) mutants on tumour-related patient's death has not been evaluated.

DESIGN

We analysed, by PCR-SSCP and/or PCR-direct sequencing, exons 8, 10, 11 and 15 of BRAF in 113 tumour samples from 49 PTC-patients. Matched lymph node metastases and/or distant metastases (DMs) were screened in 35 patients. Focal changes in the growth pattern or microscopic grade within the primary tumour (Pt) or the metastases were separately genotyped. Mutations at H-, K-, N-ras and PIK3CA exons 9 and 20 were also investigated. For comparison with PTC cases, the BRAF and Ras mutational status was evaluated in 89 specimens obtained from 24 poorly differentiated thyroid carcinomas (PDCs) and 36 anaplastic thyroid carcinomas (ATCs).

RESULTS

BRAF(V600E) was found in 13/16 classical PTCs (CL-PTCs), 6/17 follicular variant PTCs (FV-PTCs) and 8/16 mixed (papillary/follicular) PTCs (Mx-PTCs), being significantly associated with CL-PTCs (P = 0.015). BRAF(V600E) segregated with metastatic PTC-cells in 43% of the patients, but only one DM disclosed the mutation. PTC-tumours featuring concurrent less-differentiated foci were BRAF wild-type in both components. Noteworthy, the frequency of BRAF mutations among PDCs and ATCs resulted considerably lower (16.6% and 25%, respectively) than in PTCs (55%). The prevalence of Ras mutations among PDCs and ATCs (46% and 36%, respectively) was, however, much higher than in PTCs (14%). Five (71%) of the patients who died of PTC displayed somatic mutations. Four of them had other gene alteration associated with BRAF(V600E) and the only one that did not, BRAF(V600E) was restricted to the Pt. The occurrence of BRAF(V600E) associated with other genetic events was an independent predictor of DMs during follow-up, recurrence and tumour-related death. Remarkably, two PDCs (8.3%) and five ATCs (14%) revealed concurrent BRAF and Ras mutations.

CONCLUSION

BRAF(V600E)'alone' does not represent a marker for poor outcome, however, when associated with alterations in other genes identifies a subset of PTCs with increased risk of recurrence and decreased survival.

Thyroid carcinoma with bone metastases: a prognostic factor study

Objective

Occult clinical presentations usually hinder the early detection and management of patients with bone metastases from thyroid carcinoma. We retrospectively investigated the clinical outcomes of such patients from 1993 to 2004 and analyzed the prognostic parameters.

Design

The basic demographic data and manifestations of 44 patients who had thyroid carcinoma with bone metastases were reviewed. We studied the gender, age, locations of metastases, histological types, treatment methods, hypercalcemic episodes and results of treatments. We used Kaplan-Meier survival analysis and log-rank tests to access the statistical significance.

Main outcome

The incidence of bone metastasis from thyroid carcinomas in this series was 5.0%. Twenty patients (45.4%) had follicular, 16 (36.3%) had papillary, 3 (6.8%) had anaplastic, 3 (6.8%) had medullary, and 2 (4.5%) had Hurthel cell carcinomas. Twelve patients had hypercalcemic episodes, ranging from 2.6 to 2.9 mmolL⁻¹ (mean ± SD: 2.68 ± 0.15 mmolL⁻¹). Survival time after bone metastases ranged from 2 months to 8 years (mean ± SD: 5.3 ± 1.3 years). The 5-year survival rate was 79.4% and the 10-year survival rate was 52.9%. Regarding the histological cancer type, patients with papillary and follicular cancers survived significantly longer than those with anaplastic and medullary cancers (p < 0.05). In addition, the patients presenting with hypercalcemia had the worst survival (p < 0.05).

Conclusions

Thyroid carcinoma can present with bone metastases in its early stage. We found that both tumor type and hypercalcemia were significant prognostic factors for survival time.

Clinicopathological correlations of Bcl-xL and Bax expression in differentiated thyroid carcinoma

OBJECTIVE

The Bcl-2 family proteins are essential mediators in the apoptotic process. Our aim was to investigate whether anti-apoptotic Bcl-xL and pro-apoptotic Bax were over-expressed in a large series of differentiated thyroid carcinomas (DTC) and to study their association with tumour presentation at diagnosis and prognosis.

DESIGN AND PATIENTS

We examined the immunohistochemical expression of Bcl-xL and Bax in benign nodular thyroid disease (BNTD) and DTC and their association with clinicopathological parameters. Thyroid tissue samples were collected from an unselected series of patients undergoing surgical resection for DTC (n = 74) or BNTD (n = 15).

RESULTS

Among DTC cases, expression of Bcl-xL was found to be high in 43.2% and low or absent in 56.8%. Expression of Bax was high in 75.7% and low or absent in 24.3%. Non-neoplastic thyroid tissue was largely unstained for both proteins. Among BNTD cases, expression of Bcl-xL was high in 13.3% and low or absent in 86.6%. Expression of Bax was high in 14.3% and low or absent in 86.6%. A significant association was found between Bcl-xL expression and the presence of high-risk histological subtype (P < 0.05), and regional lymph node (P < 0.01) and distant metastases (P < 0.01). The association between high Bcl-xL expression levels and a longer time of persistent disease after radioiodine ablation was also significant (P < 0.01). Bcl-xL expression was confirmed as an independent prognostic factor for persistent disease in DTC (relative risk, 2.5; 95% confidence interval, 1.1-5.9; P < 0.05).

CONCLUSIONS

Immunohistochemical expression of Bcl-xL might be a valuable tool in the prediction of tumour aggressiveness in DTC.

Response to [90Yttrium-DOTA]-TOC treatment is associated with long-term survival benefit in metastasized medullary thyroid cancer: a phase II clinical trial

PURPOSE

We aimed to explore the efficacy of (90)Yttrium-1,4,7,10-tetra-azacyclododecane N,N',N'',N-'''-tetraacetic acid ((90)Y-DOTA)-Tyr(3)-octreotide (TOC) therapy in advanced medullary thyroid cancer.

EXPERIMENTAL DESIGN

In a phase II trial, we investigated the response, survival, and long-term safety profile of systemic [(90)Y-DOTA]-TOC treatment in metastasized medullary thyroid cancer. Adverse events were assessed according to the criteria of the National Cancer Institute. Survival analyses were done using multiple regression models.

RESULTS

Thirty-one patients were enrolled. A median cumulative activity of 12.6 GBq (range, 1.7-29.6 GBq) of [(90)Y-DOTA]-TOC was administered. Response was found in nine patients (29.0%). Four patients (12.9%) developed hematologic toxicities and seven patients (22.6%) developed renal toxicities. Response to treatment was associated with longer survival from time of diagnosis (hazard ratio, 0.20; 95% confidence interval, 0.05-0.81; P = 0.02) and from time of first [(90)Y-DOTA]-TOC therapy (hazard ratio, 0.16; 95% confidence interval, 0.04-0.63; P = 0.009). The visual grade of scintigraphic tumor uptake was not associated with treatment response or survival.

CONCLUSIONS

Response to [(90)Y-DOTA]-TOC therapy in metastasized medullary thyroid cancer is associated with a long-term survival benefit. Treatment should be considered independently from the result of the pretherapeutic scintigraphy.

Biological role and potential therapeutic targeting of the chemokine receptor CXCR4 in undifferentiated thyroid cancer

Anaplastic thyroid carcinoma (ATC) is a rare thyroid cancer type with an extremely poor prognosis. Despite appropriate treatment, which includes surgery, radiotherapy, and chemotherapy, this cancer is invariably fatal. CXCR4 is the receptor for the stromal cell-derived factor-1 (SDF-1)/CXCL12 chemokine and it is expressed in a variety of solid tumors, including papillary thyroid carcinoma. Here, we show that ATC cell lines overexpress CXCR4, both at the level of mRNA and protein. Furthermore, we found that CXCR4 was overexpressed in ATC clinical samples, with respect to normal thyroid tissues by real-time PCR and immunohistochemistry. Treatment of ATC cells with SDF-1 induced proliferation and increase in phosphorylation of extracellular signal-regulated kinases and protein kinase B/AKT. These effects were blocked by the specific CXCR4 antagonist AMD3100 and by CXCR4 RNA interference. Moreover, AMD3100 effectively reduced tumor growth in nude mice inoculated with different ATC cells. Thus, we suggest that CXCR4 targeting is a novel potential strategy in the treatment of human ATC.

Molecular profiling related to poor prognosis in thyroid carcinoma. Combining gene expression data and biological information

Undifferentiated and poorly differentiated thyroid tumors are responsible for more than half of thyroid cancer patient deaths in spite of their low incidence. Conventional treatments do not obtain substantial benefits, and the lack of alternative approaches limits patient survival. Additionally, the absence of prognostic markers for well-differentiated tumors complicates patient-specific treatments and favors the progression of recurrent forms. In order to recognize the molecular basis involved in tumor dedifferentiation and identify potential markers for thyroid cancer prognosis prediction, we analysed the expression profile of 44 thyroid primary tumors with different degrees of dedifferentiation and aggressiveness using cDNA microarrays. Transcriptome comparison of dedifferentiated and well-differentiated thyroid tumors identified 1031 genes with >2-fold difference in absolute values and false discovery rate of <0.15. According to known molecular interaction and reaction networks, the products of these genes were mainly clustered in the MAPkinase signaling pathway, the TGF-beta signaling pathway, focal adhesion and cell motility, activation of actin polymerization and cell cycle. An exhaustive search in several databases allowed us to identify various members of the matrix metalloproteinase, melanoma antigen A and collagen gene families within the upregulated gene set. We also identified a prognosis classifier comprising just 30 transcripts with an overall accuracy of 95%. These findings may clarify the molecular mechanisms involved in thyroid tumor dedifferentiation and provide a potential prognosis predictor as well as targets for new therapies.

MUC1 oncoprotein promotes refractoriness to chemotherapy in thyroid cancer cells

Overexpression of MUC1 oncoprotein is frequently observed in cancer and contributes to confer resistance to genotoxic agents. Papillary, follicular, and anaplastic thyroid carcinomas are the three forms of thyroid epithelial cancer. Anaplastic tumors are less differentiated and extremely aggressive, characterized by a poor prognosis. Little is known about the role of MUC1 in thyroid cancer. We recently showed that autocrine production of interleukin (IL)-4 and IL-10 controls thyroid cancer cell survival, growth, and resistance to chemotherapy through activation of Janus-activated kinase/signal transducers and activators of transcription (JAK/STAT) and phosphatidylinositide 3'-OH kinase (PI3K)/Akt pathways. In the present study, we showed that MUC1 COOH-terminal subunit (MUC1-C) is overexpressed in all the histologic variants of thyroid cancer cells and localizes to mitochondria where it interferes with the release of mitochondrial proapoptotic proteins. Moreover, IL-4 and IL-10 promote the increase of MUC1-C expression levels in normal thyroid cells, whereas blockage of both cytokines or neutralization of JAK/STAT and PI3K/Akt pathways through the exogenous expression of SOCS-1 and Akt(K179M) leads to a significant decrease of MUC1-C in primary thyroid cancer cells. Interestingly, down-regulation of MUC1 expression by direct targeting with RNA interference sensitizes anaplastic thyroid cancer cells to chemotherapy-induced apoptosis in vitro. Thus, MUC1 is a main component of the survival network acting in thyroid cancer and could be considered a key molecular target for sensitizing cancer cells to conventional or novel treatments.

Sonographic detection of thyroid cancer in breast cancer patients

The purpose of our study was to analyze the incidence of incidental thyroid cancers which were detected by simultaneous sonographic examination of breast and thyroid glands. Between January 2001 and March 2004, 518 patients were diagnosed with breast cancer after modified radical mastectomy (n=369) or breast conserving surgery (n=149). We screened thyroid glands when we examined breast for diagnosis and follow-up after surgery. If we found the sonographic finding of suspicious for malignancy in thyroid, we immediately performed ultrasound-guided fine needle aspiration biopsy (FNAB). Forty-two cases showed suspicious sonographic findings and of those, 18 cases (42.9%) were determined to have suspicious malignant cytology by ultrasound guided FNAB. Among 518 breast cancers, total 13 cases (2.5%) were diagnosed with papillary carcinoma after thyroidectomy. The mean longest diameter of the thyroid masses was 9.9 mm (range 1-30 mm). Six cases (6/13, 46.2%) were diagnosed as simultaneous breast and thyroid cancers, and the rest of the thyroid cancers were detected after 6 to 33 months (mean 16.5 months) after surgery. In conclusion, the patients with breast cancer had a high incidence (2.5%) of thyroid cancer. Sonographic screening is useful for the early detection of thyroid cancer.

The status of CDKN2A alpha (p16INK4A) and beta (p14ARF) transcripts in thyroid tumour progression

CDKN2A locus on chromosome 9p21 encodes two tumour suppressor proteins pl6^INK4A, which is a regulator of the retinoblastoma (RB) protein, and p14^ARF, which is involved in the ARF–Mdm2–p53 pathway. The aim of this study was to determine if CDKN2A gene products are implicated in differentiated thyroid carcinogenesis and progression. We used real-time quantitative RT–PCR and immunohistochemistry to assess both transcripts and proteins levels in 60 tumours specimens. Overexpression of p14^ARF and pl6^INK4A was observed in follicular adenomas, follicular carcinomas and papillary carcinomas, while downregulation was found in oncocytic adenomas compared to nontumoral paired thyroid tissues. These deregulations were statistically significant for pl6^INK4a (P=0.006) in follicular adenomas and close to statistical significance for p14^ARF in follicular adenomas (P=0.06) and in papillary carcinomas (P=0.05). In all histological types, except papillary carcinomas, we observed a statistically significant relationship between p14^ARF and E2F1 (r=0.64 to 1, P<0.05). Our data are consistent with involvement of CDKN2A transcript upregulation in thyroid follicular tumorigenesis as an early event. However, these deregulations do not appear to be correlated to the clinical outcome and they could not be used as potential prognostic markers.

Novel molecular markers in well-differentiated thyroid cancers

Conventional cytopathology is an excellent tool for distinguishing benign from malignant thyroid nodules with high sensitivity and specificity. However, significant numbers of cases are indeterminate, resulting in many ultimately unnecessary diagnostic thyroidectomies. Numerous molecular markers have been studied in an attempt to improve the diagnostic accuracy of thyroid fine-needle aspiration cytology. Several markers, such as galectin-3 and thyroid peroxidase, have been extensively assessed and shown not only to differentiate malignant tumors from benign thyroid lesions with high sensitivity and specificity, but also to identify tumors associated with poor outcome. More recently, four other genes (PTTG, PBF, BRAF and MUC1) have been identified that show real promise as potential molecular markers in thyroid cancer, offering discrimination between tumor subtypes and providing valuable prognostic information. However, larger, well-controlled studies are needed before their introduction into routine clinical practice. The search for molecular markers represents one of the most exciting areas in translational thyroid cancer research. We are optimistic that molecular markers will be used in the near future as adjuncts to conventional histological techniques to improve diagnostic accuracy of fine-needle aspiration cytology for thyroid lesions, particularly those that are cytologically indeterminate.

Sonographic Screening for Thyroid Cancer in Females Undergoing Breast Sonography

OBJECTIVE

The purpose of our prospective study was to evaluate incidental thyroid cancer diagnosed by screening sonography in a population who underwent breast sonography and the differences in the incidences of thyroid cancer between those with and those without breast cancer.

SUBJECTS AND METHODS

Between January 2003 and March 2004, we examined thyroid glands during routine diagnostic or follow-up breast sonography. A total of 5,549 females underwent breast and thyroid screening sonography (n = 4,864) or sonography for diagnosis or follow-up of breast cancer (n = 685). When a thyroid lesion was suspicious for malignancy, sonographically guided fine-needle aspiration was performed. We compared the cases of pathologically proven thyroid cancer in two groups: a cancer group, including patients with breast cancer, and a noncancer group, including patients with negative or benign breast disease.

RESULTS

Among the 5,549 cases, 42 (0.76%) were diagnosed as thyroid cancer; all were papillary carcinomas. Pathologically proven thyroid cancers were identified in 13 (1.9%) of the 685 breast cancer patients and in 29 (0.6%) of the 4,864 non-breast-cancer patients. The diameters of the 13 thyroid masses were 0.1-3.0 cm; the mean diameters in the cancer and noncancer groups were 9.9 and 8.6 mm, respectively.

CONCLUSION

The incidence of thyroid cancer was significantly higher in the group with breast cancer than in the group who did not have breast cancer. The results of routine concurrent sonographic breast and thyroid examinations were helpful in detecting small thyroid tumors in both patient groups.

Detection and surgical treatment of cervical lymph nodes in differentiated thyroid cancer

There is considerable controversy regarding the treatment of patients with cervical metastases from differentiated thyroid cancer. Most have papillary carcinoma and the main areas of contention relate to methods of assessment and staging, surgical management and mode of follow up. there is little evidence to support elective anatomical imaging with CT or MRI in those patients with suspected or proven malignancy at the primary site as indicated by fine needle aspiration cytology (FNAC) but who have no clinical evidence of nodal disease. The role of routine ultrasound (US) in the pre-operative assessment of suspected or known malignancy is developing but is largely unproven. When it is performed, high risk areas for metastatic neck disease (levels II-V) should be assessed. Suspicious nodes on US should be further evaluated by FNAC. Suspected or proven neck disease may be further assessed pre-operatively with CT or MRI and then treated surgically. Disease in the central compartment requires a total thyroidectomy and level VI central compartment neck dissection. Suspected or proven lateral compartment cancer should be treated by selective neck dissection (at least levels III, IV, and V) below the accessory nerve. There is no role for 'Berry picking' and clinically node negative high risk patients should have an elective central compartment level VI neck dissection. Sentinel node biopsy lays no role and neither does elective lateral compartment surgery in patients with no clinical or radiological evidence of disease. For follow up, US represents the most sensitive means of detecting neck recurrences and in the presence of an elevated serum thyroglobulin, imaging may also include whole body iodine-131 scanning and anatomical imaging with CT or MRI. The role of PET remains controversial but is likely to develop further as the technique becomes more widely available. In the future, the concentration of patients with this disease in large center can only improve the way we treat differentiated thyroid cancer.

Estimating the optimal radiotherapy utilization for carcinoma of the central nervous system, thyroid carcinoma, and carcinoma of unknown primary origin from evidence-based clinical guidelines

BACKGROUND

In this one in a series of articles, the objective was to estimate the ideal proportion of patients with cancer who should receive radiotherapy at least once during the course of their illness based on the best available evidence. This estimate should be useful in planning for future radiotherapy facilities. Optimal rates of radiotherapy for patients with central nervous system (CNS) carcinoma, thyroid carcinoma, or carcinoma of unknown primary site (CUP) have not been studied previously.

METHODS

A systematic review of evidence-based treatment guidelines for the treatment of CNS carcinoma, CUP, and thyroid carcinoma was undertaken. An optimal radiotherapy utilization tree was constructed for each of these malignancies depicting the indications for radiotherapy at various stages of disease. The proportion of patients who had clinical attributes that indicated a possible benefit from radiotherapy was calculated by adding epidemiological data to the radiotherapy utilization tree. The optimal proportion of patients who should receive radiotherapy was then calculated using specialized decision-analysis software. Sensitivity analyses using univariate analysis and Monte Carlo simulations were performed.

RESULTS

The optimal rates of radiotherapy utilization for carcinoma of the CNS, thyroid carcinoma, and CUP were 92%, 10%, and 61%, respectively. Comparison with actual rates of utilization in South Australia, Sweden, and the U.S. suggested an under-utilization of radiotherapy for CNS carcinoma and CUP. However, the actual rates of radiotherapy for thyroid carcinoma exceeded the optimal rate for some jurisdictions, although some data may have included radioactive iodine, which was not included in the current project.

CONCLUSIONS

It was possible to estimate optimal radiotherapy utilization rates based on evidence. This methodology allowed a comparison of optimal rates with actual rates to identify areas in which improvements in the evidence-based use of radiotherapy can be made, and it may provide valuable data for future radiotherapy service planning.

Differentiated thyroid carcinoma with distant metastases at presentation: prognostic factors and outcome

BACKGROUND

Differentiated thyroid cancer (DTC) presenting with distant metastases is uncommon. Prognostic factors that affect survival remain unclear.

AIM

To evaluate factors influencing the survival of patients with DTC presenting with distant metastases.

METHOD

A retrospective study of 111 patients (62 F, 49 M) with DTC who presented with distant metastases (M1) treated at the Royal Marsden Hospital from 1940 to 2002.

RESULTS

The median follow-up of living patients was 3.9 years (0.3-48) with a 10-year cause-specific survival rate of 31%. Histology identified 46 papillary, 60 follicular and five Hürthle cell cancers. Sites of metastases comprised 54 lung (49%), 27 bone (24%), 21 multiple sites (19%) and nine with other single sites affected (8%). Near-total, total or completion thyroidectomy was performed in 56% of patients, radioiodine ablation in 76% and radioiodine therapy in 67%. External beam radiotherapy was given to 12 patients and the same number received chemotherapy. Univariate analysis was performed with cause-specific survival as the main outcome measure. Age over 70, poorly differentiated tumours and Hürthle cell cancers were associated with worse outcomes (P < 0.01). Patients with multiple organ metastases had a worse survival (P = 0.02). Radical surgery did not significantly improve outcome compared to more conservative forms of surgery (subtotal thyroidectomy, hemi-thyroidectomy or lobectomy) but patients receiving radioiodine ablation and therapy had improved survival (P < 0.01). Multivariate analysis identified age over 70, poorly differentiated tumours and Hürthle cell variant to be the only independent factors associated with worse outcome (P < 0.01). Treatment in the 1991-2002 era was associated with an improved survival compared to all previous decades (P = 0.009).

CONCLUSIONS

Patients with DTC presenting with distant metastases have a worse outcome if aged over 70, have poorly differentiated tumours or have Hürthle cell variant. Despite their unfavourable prognosis, a dramatic improvement in survival was observed in the most recent era (1991-2002).

Wiederholungseingriffe beim Schilddr�senkarzinom

Reoperation for thyroid cancer needs to consider patient-, tumor- and therapy-related aspects as well as present diagnostic results. Reoperation because of thyroid remnants, persistence of the primary tumor and lymph node metastasis (completion surgery) has to be distinguished from reoperation due to locoregional recurrence (primary tumor, lymph nodes). The primary surgical strategy should avoid the need for reoperation. The extent of reoperation is related to the extent of primary surgery, stage, and distant metastasis. The timing and indication of reoperation for differentiated thyroid carcinoma in an interdisciplinary multimodal treatment setting depends on diagnostic radioiodine scans and radioiodine therapy. Long-term, recurrence-free survival is achieved by sufficiently radical surgery with acceptable morbidity, including all additive or adjuvant treatment options.

Anaplastic thyroid carcinoma: dismal outcome despite current treatment approach

BACKGROUND

Anaplastic thyroid carcinoma (ATC) accounts for <5% of all thyroid malignancies and is one of the most aggressive malignancies known. Survival is limited to months and death is often caused by uncontrolled neck disease. There is evidence that multimodality treatment, incorporating surgery (Sx), external beam radiotherapy (RT) and chemotherapy (CT), might enhance local control and improve survival.

METHODS

Between 1979 and 2002, 18 patients with ATC were referred to the multidisciplinary Head and Neck Cancer Service, Westmead Hospital, Sydney, Australia. The aim of the present study is to report on the treatment and outcome of these patients. Survival was calculated from the time of diagnosis until death using the Kaplan-Meier method.

RESULTS

Median age at diagnosis was 72 years (29-92 years) in 12 women and six men. Five patients had distant metastases at diagnosis. Seven patients were treated with various combinations of Sx, RT and/or CT. Ten patients received a single modality, including three undergoing a total thyroidectomy. Many patients died from local disease progression. Only one patient received triple modality treatment (Sx/RT/CT), surviving 26 months, and maintaining local control until death. Sixteen patients died from disease with a median survival of 6.2 months (0.3-56.8 months).

CONCLUSION

Most patients with ATC are incurable; however, a multimodality approach incorporating Sx and RT +/- CT, in selected individuals, might improve local control and extend survival.

Differentiated thyroid cancer: radioiodine following lobectomy — a clinical feasibility study

The surgical management of differentiated thyroid cancer remains controversial. Total thyroidectomy has been associated with higher rates of post-operative morbidity than more conservative surgery, but radioiodine ablation of residual thyroid tissue is considered to be particularly difficult after lobectomy. The purpose of this retrospective study was to assess the feasibility of 131I ablation after lobectomy, compared with total thyroidectomy, in patients who had undergone surgery for differentiated thyroid carcinoma. A retrospective analysis was performed of 225 post-surgical thyroid cancer patients treated with 3500 MBq 131I for the ablation of thyroid remnants. One hundred and sixty-five patients (73%) had previously undergone total thyroidectomy, whilst 60 patients (27%) had been treated by lobectomy. All patients underwent diagnostic scintigraphy, with 40 MBq 131I, 2 days prior to ablative therapy and at 3 months post-ablation. The median pre-ablative 131I neck uptake values were 3.3% and 20.1% in patients treated by total thyroidectomy and lobectomy, respectively (P < 0.001). Pre-ablation neck uptake correlated strongly with the whole-body 131I burden 2 days after 131I therapy (P < 0.001), and the biological half-life of the radioiodine was markedly longer after lobectomy than after total thyroidectomy. Ninety-eight per cent of patients treated by total thyroidectomy were successfully ablated by one 131I treatment, compared with 90% after lobectomy (P < 0.05). There were no significant differences in 131I neck uptake or serum thyroglobulin levels between the two patient groups at 3 months post-ablation. These data show that high rates of thyroid ablation can be achieved with a single fixed dose of 131I after thyroid lobectomy. The use of this surgical procedure may result in a longer period of patient isolation than that required after total thyroidectomy. However, the clear correlation between pre-ablation neck uptake and 131I burden at 2 days post-therapy enables effective treatment scheduling, so making lobectomy followed by 131I ablation a practical option for the management of differentiated thyroid cancer.

Treatment of aggressive thyroid cancer with an oncolytic herpes virus

Although many thyroid cancers carry a favorable prognosis, there is a subgroup of patients with more aggressive histologies. Current therapies offer no significant survival benefit to patients with anaplastic thyroid carcinomas, which are considered fatal. Oncolytic herpes simplex viruses (HSVs) have potent antitumor effects against a variety of human malignancies. We assessed the activity of a replication-competent, attenuated, oncolytic HSV (NV1023) against 7 different thyroid cancers, including one papillary (NPA-187), one follicular (WRO82-1), one medullary (DRO81-1) and 4 anaplastic (DRO90-1, ARO, KAT-4C and KAT-18) cell lines. Only the follicular WRO82-1 line was resistant to NV1023 infection and cell lysis at a concentration of 5 viral pfu per cell (MOI 5). All other cell lines at MOI 5 demonstrated >95% infection in vitro at day 2 by X-gal staining and >88% cell death at day 4 by cytotoxicity assays. Even at MOI 0.1, 4 of these lines displayed complete cell death by day 7. Viral proliferation assays revealed that all of the nonfollicular cell lines supported logarithmic viral replication. Flank tumors of NPA-187, DRO81-1, DRO90-1 and ARO in athymic nude mice were treated with NV1023 (2 x 10(7) pfu). All NPA-187 tumors completely regressed following a single dose. DRO81-1 tumors demonstrated partial response with a single dose and significant improvement with 3 serial doses. ARO and DRO90-1 tumors showed a significant response following either single injection (54 +/- 22 and 292 +/- 138 mm3, respectively) or 3 serial injections (33 +/- 14 and 241 +/- 68 mm3, respectively) compared to saline injections (472 +/- 193 and 1,257 +/- 204 mm3, respectively) at day 20. These data suggest that herpes oncolytic therapy may be effective for the treatment of aggressive thyroid carcinomas and merits further investigation.

External Beam Radiotherapy in the Management of Differentiated Thyroid Cancer

AIMS

No randomised trials have addressed the use of external beam radiotherapy (EBRT) in the treatment of differentiated thyroid cancer. The indications for EBRT, the technique and recommended dose all remain controversial.

MATERIALS AND METHODS

We included patients treated with EBRT with curative intent from two cancer centres between 1988 and 2001. Data were collected from hospital notes, radiotherapy prescriptions and local cancer registry.

RESULTS

The indications for treatment in the 41 identified patients were macroscopic residual disease 23 (56%), microscopic residual disease 10 (25%), Hurthle cell variants 3 (7%), multiple lymph-node involvement 3 (7%) and other 2 (5%). Delivered doses ranged from 37.5-66 Gy over 3-6.5 weeks. Rate of local recurrence and overall survival at 5 years were as follows: papillary 26% and 67%; follicular 43% and 48%; well differentiated 21% and 67%; focus of poor differentiation/Hurthle cell variants 69% and 32%; complete excision 25% and 61%; residual disease 37% and 59%; EBRT total dose < 50 Gy 63% and 42%; 50-54 Gy 15% and 72%; > 54 Gy 18%, and 68%.

CONCLUSIONS

The results in this study are consistent with previous retrospective studies of EBRT. The wide range of indications and doses used with radical intent highlights the lack of clinical and radiobiological data on the response of differentiated thyroid cancer to EBRT. Despite the small study size, the 5-year local recurrence results indicate a possible dose response within the dose range used.