Prognostic Factors in Thyroid Carcinoma

Radiomics Analysis of Computed Tomography for Prediction of Thyroid Capsule Invasion in Papillary Thyroid Carcinoma: A Multi-Classifier and Two-Center Study

OBJECTIVE

To investigate the application of computed tomography (CT)-based radiomics model for prediction of thyroid capsule invasion (TCI) in papillary thyroid carcinoma (PTC).

METHODS

This retrospective study recruited 412 consecutive PTC patients from two independent institutions and randomly assigned to training (n=265), internal test (n=114) and external test (n=33) cohorts. Radiomics features were extracted from non-contrast (NC) and artery phase (AP) CT scans. We also calculated delta radiomics features, which are defined as the absolute differences between the extracted radiomics features. One-way analysis of variance and least absolute shrinkage and selection operator were used to select optimal radiomics features. Then, six supervised machine learning radiomics models (k-nearest neighbor, logistic regression, decision tree, linear support vector machine [L-SVM], Gaussian-SVM, and polynomial-SVM) were constructed. Univariate was used to select clinicoradiological risk factors. Combined models including optimal radiomics features and clinicoradiological risk factors were constructed by these six classifiers. The prediction performance was evaluated using the receiver operating characteristic (ROC) curve, calibration curve, and decision curve analysis (DCA).

RESULTS

In the internal test cohort, the best combined model (L-SVM, AUC=0.820 [95% CI 0.758-0.888]) performed better than the best radiomics model (L-SVM, AUC = 0.733 [95% CI 0.654-0.812]) and the clinical model (AUC = 0.709 [95% CI 0.649-0.783]). Combined-L-SVM model combines 23 radiomics features and 1 clinicoradiological risk factor (CT-reported TCI). In the external test cohort, the AUC was 0.776 (0.625-0.904) in the combined-L-SVM model, showing that the model is stable. DCA demonstrated that the combined model was clinically useful.

CONCLUSIONS

Our combined model based on machine learning incorporated with CT radiomics features and the clinicoradiological risk factor shows good predictive ability for TCI in PTC.

Long noncoding RNA cancer susceptibility candidate 2 suppresses papillary thyroid carcinoma growth by inactivating the AKT/ERK1/2 signaling pathway

OBJECTIVES

Cancer susceptibility candidate 2 (CASC2) and long noncoding RNA (lncRNA) have been identified as a tumor suppressor in colorectal, lung, renal, and stomach cancer as well as in patient gliomas, but the function of CASC2 in papillary thyroid carcinoma (PTC) is not yet clear. The present study aimed to explore the effects of CASC2 in PTC.

METHODS

The CASC2 expression was measured in PTC samples and normal tissues by using quantitative real-time polymerase chain reaction. The lentiviral vectors were used to establish CASC2 overexpression models in PTC cell lines to determine the effects of CASC2 on cell proliferation, apoptosis, migration, and invasion. A tumor xenograft animal model was used to examine the functions of overexpression CASC2.

RESULTS

CASC2 expression was significantly decreased in PTC tumor tissues than adjacent normal tissues. CASC2 downregulation in PTC tissues significantly correlated with the tumor size, the presence of multifocal lesions, and the advanced pathological stage. CASC2 overexpression suppressed the cell proliferation and promoted apoptosis in PTC cell lines and CASC2 overexpression resulted in the inactivation of protein kinase B (PKB/AKT) and extracellular signal-regulated kinases (ERK1/2). The regulatory effects of CASC2 on PTC cell biological behavior were further enhanced by mitogen-activated protein kinase kinase (MEK) inhibitor U0126 or AKT1/2/3 inhibitor MK-2206 2HCl. CASC2 overexpression suppressed tumor growth in PTC cells in xenograft mouse models.

CONCLUSION

Our results indicated that CASC2 significantly suppressed tumorigenesis in PTC and CASC2 may serve as a novel prognostic marker or therapeutic target.

Radioactive iodine treatment for node negative papillary thyroid cancer with capsular invasion only: Results of a large retrospective study

AIM

With thyroid carcinoma the decision to use radioactive iodine (RAI) ablation depends on the risk of poor outcomes. Although extrathyroid extension (ETE) is well known as a risk of poor outcomes for papillary thyroid carcinoma (PTC), the definition of minimal ETE is too broad, as it encompasses both microscopic invasion of the thyroid capsule (capsular invasion [CI]) and macroscopic invasion of the sternothyroid muscle.

METHODS

We conducted a retrospective study to analyze the prognostic benefit of RAI ablation according to the presence of CI in a consecutive series of patients with PTC between October 1997 and December 2008. We studied two groups of patients, including those who received RAI (group I, n = 121) and those who did not (group II, n = 108). During follow-up, we assessed the locoregional recurrence of all patients.

RESULTS

There were no statistically significant difference between the groups regarding locoregional recurrence at follow-up (13.2% for group I vs 9.3% for group II, P = 0.441). The association between RAI and locoregional recurrence in PTC patients with CI remained insignificant after adjusting for potential confounders, such as age, tumor size, sex, lymphatic invasion, vascular invasion and tumor multiplicity (P = 0.409, hazard ratio = 0.698, 95% confidence interval, 0.298-1.639).

CONCLUSIONS

This retrospective study suggests that RAI treatment is not associated with less locoregional recurrence in PTC patients who only demonstrate CI, although further prospective studies are required to confirm these findings.

Coexistence of chronic lymphocytic thyroiditis with papillary thyroid carcinoma: clinical manifestation and prognostic outcome

The study aimed to identify the clinical characteristics of coexisting chronic lymphocytic thyroiditis (CLT) in papillary thyroid carcinoma (PTC) and to evaluate the influence on prognosis. A total of 1,357 patients who underwent thyroid surgery for PTC were included. The clinicopathological characteristics were identified. Patients who underwent total thyroidectomy (n = 597) were studied to evaluate the influence of coexistent CLT on prognosis. Among the total 1,357 patients, 359 (26.5%) had coexistent CLT. In the CLT group, the prevalence of females was higher than in the control group without CLT (P < 0.001). Mean tumor size and mean age in the patients with CLT were smaller than without CLT (P = 0.040, P = 0.047, respectively). Extrathyroidal extension in the patients with CLT was significantly lower than without CLT (P = 0.016). Among the subset of 597 patients, disease-free survival rate in the patients with CLT was significantly higher than without CLT (P = 0.042). However, the multivariate analysis did not reveal a negative association between CLT coexistence and recurrence. Patients with CLT display a greater female preponderance, smaller size, younger and lower extrathyroidal extension. CLT is not a significant independent negative predictive factor for recurrence, although presence of CLT indicates a reduced risk of recurrence.

Quantitative high-throughput drug screening identifies novel classes of drugs with anticancer activity in thyroid cancer cells: opportunities for repurposing

CONTEXT

Despite increased understanding of the pathogenesis and targets for thyroid cancer and other cancers, developing a new anticancer chemical agent remains an expensive and long process. An alternative approach is the exploitation of clinically used and/or bioactive compounds.

OBJECTIVE

Our objective was to identify agents with an anticancer effect in thyroid cancer cell lines using quantitative high-throughput screening (qHTS).

DESIGN

We used the newly assembled National Institutes of Health Chemical Genomic Center's pharmaceutical collection, which contains 2816 clinically approved drugs and bioactive compounds to perform qHTS.

RESULTS

Multiple agents, across a variety of therapeutic categories and with different modes of action, were found to have an antiproliferative effect. We found the following therapeutic categories were the most enriched categories with antiproliferative activity: cardiotonic and antiobesity agents. Sixteen agents had an efficacy of greater than 60% and a 50% inhibitory concentration (IC50) in the nanomolar range. We validated the results of the qHTS using two agents (bortezomib and ouabain) in additional cell lines representing different histological subtypes of thyroid cancer and with different mutations (BRAF V600E, RET/PTC1, p53, PTEN). Both agents induced apoptosis, and ouabain also caused cell cycle arrest.

CONCLUSIONS

To our knowledge, this is the first study to use qHTS of a large drug library to identify candidate drugs for anticancer therapy. Our results indicate such a screening approach can lead to the discovery of novel agents in different therapeutic categories and drugs with nonclassic chemotherapy mode of action. Our approach could lead to drug repurposing and accelerate clinical trials of compounds with well-established pharmacokinetics and toxicity profiles.

Medullary thyroid carcinoma with micronodular lung metastases: a case report with an emphasis on the imaging findings

Medullary thyroid carcinoma is a rare malignancy that arises from calcitonin-producing C-cells and frequently metastasizes to lymph nodes in the neck. Distant metastases may involve bone, lung, and liver. The infrequent number of cases limits the clinical nature and ability to optimize diagnostic tools. Here, we present a case of a micronodular radiographic pattern in metastatic medullary thyroid cancer in order to enhance awareness of the disease process. A case discussion and relevant review of the literature are provided.

Multiple genetic alterations in papillary thyroid cancer are associated with younger age at presentation

BACKGROUND

There is a significant gender and age disparity in thyroid cancer incidence and outcome. The molecular basis for these divergent clinical presentations and outcome are essentially unknown.

METHODS

The primary tumor genotype in 217 patients with papillary thyroid cancer was determined for six common somatic genetic alterations (RET/PTC1, RET/PTC3, and NTRK1 rearrangements, and BRAF V600E, KRAS, and NRAS hotspot mutations) by PCR and direct sequencing, and nested PCR. Univariate and multivariate analyses were performed to determine the association of genetic changes and age, gender, and other clinicopathologic factors.

RESULTS

One hundred twenty-one of the 190 conventional papillary thyroid carcinoma samples (63.7%) had at least one genetic alteration, and 27 of the samples (14.2%) had more than one alteration. In the follicular variant of papillary thyroid carcinomas, 13 of the 27 samples (48.1%) had at least one genetic alteration and three of the 27 samples (11.1%) had more than one. The presence of multiple genetic alterations was associated with younger age at diagnosis (P=0.034), mean difference of 8 y earlier. We found no significant association with the number or type of genetic alterations present by gender, tumor size, extent of tumor differentiation, multicentricity, lymph node metastasis, distant metastases, TNM stage, and the AMES risk group. The association of multiple genetic alterations and younger age were independent of tumor size, lymph node or distant metastasis, TNM stage, or AMES risk group.

CONCLUSIONS

Multiple genetic alterations are more common in younger patients with papillary thyroid cancer, but there is no difference in the type or number of genetic alterations by gender. Our findings suggest that multiple genetic alterations in thyroid cancer may be associated with earlier disease initiation and or progression.

Total thyroidectomy for the treatment of Hashimoto's thyroiditis coexisting with papillary thyroid carcinoma

The coexistence of Hashimoto's thyroiditis (HT) and papillary thyroid carcinoma (PTC) is controversial. This study was conducted to evaluate the correlation between HT and PTC and to identify predictive factors for the coexistence of PTC and HT. A total of 922 patients underwent surgery for thyroid disorders between January 2001 and August 2005. In all, 199 patients had been diagnosed with PTC, 37 of whom had coexistent HT; in 689 patients, benign thyroid disease had been diagnosed. Patients' age and sex, as well as histopathology, tumor size, nodal involvement status, multicentricity, presence of metastasis, and serum thyroglobulin levels, were retrospectively reviewed. A significant correlation was observed between HT and PTC, although no statistical significance was noted between PTC and HT type (nodular or diffuse). Most patients with PTC+HT were female and younger (<40 y old) than those with PTC only. The rate of occult tumor in patients with PTC+HT was higher than that in patients with PTC alone. Data indicate the coexistence of PTC and HT and suggest that PTC may develop even in cases of diffuse HT. Total thyroidectomy is the surgical procedure of choice, especially in young, female patients with HT.

Lymphovascular Invasion is Associated With Lateral Cervical Lymph Node Metastasis in Papillary Thyroid Carcinoma

OBJECTIVES

The objective of this retrospective study to evaluate whether lymphovascular invasion (LVI) is associated with lateral cervical lymph node metastasis and tumor recurrence in papillary thyroid carcinoma (PTC).

METHODS

We evaluated the medical records of patients with PTC who had undergone total thyroidectomy and subsequent I remnant ablation at Asan Medical Center, Seoul, Korea, from January 1997 thorough December 2000.

RESULTS

A total of 662 patients (585 women and 77 men; mean age, 44.8 years) with PTC were enrolled in the study. Of these patients, 33 were found to have LVI. We found a significant association between LVI and lateral cervical lymph node metastasis at the time of initial surgery (P = .001). Multivariate analyses adjusting for clinicopathologic parameters known to predict recurrence such as age, gender, tumor size, extrathyroid extension, and multifocality also showed a significant association between LVI and lateral cervical lymph node metastasis. For the 633 patients without distant metastasis at the time of initial surgery, LVI was also significantly associated with tumor recurrence during the follow-up period (median, 68 months; range, 3-108 months): 29% versus 13.6% for patients with and without LVI, respectively (P = .048 by log-rank test). However, this association was lost on multivariate analyses adjusting for conventional clinicopathologic predictors of recurrence.

CONCLUSIONS

In patients with PTC, LVI is associated with lateral cervical lymph node metastasis and clinical recurrence.

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.

COMPLETION THYROIDECTOMY FOR MALIGNANCY AFTER INITIAL MINIMAL ACCESS THYROID SURGERY

BACKGROUND

Minimal access thyroid surgery (MATS), carried out through a lateral 2.5-cm incision, provides excellent clinical and cosmetic outcomes when carried out for small (<3 cm), single nodules. However, if the final pathology shows thyroid malignancy and a completion thyroidectomy is required, the small lateral incision requires conversion to a standard collar incision and the second operation must be carried out in the presence of previous lateral dissection. The aim of this study is to determine if there is any demonstrable disadvantage to completion thyroidectomy for malignancy after MATS when compared with the same procedure after conventional hemithyroidectomy.

METHODS

This retrospective cohort study examined all patients undergoing completion thyroidectomy for malignancy in the University of Sydney Endocrine Surgical Unit from January 2002 to January 2005. Outcome measures were complication rates, final scar length and patient's self-assessment of scar appearance.

RESULTS

A total of 106 patients underwent MATS during the study period, 11 of whom required completion thyroidectomy for malignancy. During the same period, 42 patients required completion thyroidectomy for malignancy after previous conventional hemithyroidectomy. There was no difference in complication rates between the two groups. The two complications in the study consisted of one case of flap oedema (control) and one case of keloid scar (MATS). Mean final incision length, scar appearance and patient's satisfaction with scar did not differ between the two groups.

CONCLUSION

There is no demonstrable disadvantage when completion thyroidectomy for malignancy is required after MATS.

Prognostic factors for sporadic medullary thyroid carcinoma

INTRODUCTION

Medullary thyroid carcinoma (MTC) originates from the thyroid parafollicular cells and accounts for 3% to 10% of all thyroid malignancies. Approximately 84% of cases are sporadic. The aim of this study was to evaluate the outcomes of treatment for sporadic medullary thyroid carcinoma (SMTC) and define the prognostic factors for overall survival.

METHODS

The records of 32 SMTC patients treated at Ankara Oncology Education and Research Hospital between September 1993 and April 2003 were retrospectively evaluated. The effects of age, gender, tumor localization, extent of the primary surgical resection, tumor size, capsule invasion, lymph node metastasis, extranodal extension, tumor stage, local recurrence, and distant metastasis on the overall survival rate were evaluated by univariate and multivariate analyses.

RESULTS

There were 32 patients (19 females, 13 males) with a median age of 45 years (21-76 years). Altogether, 22 patients had undergone complete resection and 10 patients incomplete resection. The median follow-up was 48 months (9-111 months), and the overall 5-year survival rate was 51%. Based on the univariate analysis, the extent of primary surgical resection, pathologic tumor size, capsule invasion, lymph node invasion, extranodal extension, tumor stage, local recurrence, and distant metastasis were factors that significantly affected survival. In the multivariate analysis, however, only the extent of the primary surgical resection, capsule invasion, and distant metastasis were found to be statistically significant factors.

CONCLUSIONS

The extent of the primary surgical resection significantly influences the survival of patients with SMTC. Capsule invasion and distant metastasis were additional factors affecting the prognosis.

Diagnostic and prognostic value of angiogenesis-modulating genes in malignant thyroid neoplasms

BACKGROUND

Angiogenesis is an essential biologic event in the pathogenesis of human malignancies. We postulated that expression analysis of genes that modulate angiogenesis would identify differentially expressed genes that would help to distinguish benign from malignant thyroid neoplasms and serve as markers of aggressive differentiated thyroid cancer.

METHODS

A complementary DNA (cDNA) array with 96 genes that modulate angiogenesis was used to identify differentially expressed genes (2-fold higher or lower) in malignant versus benign thyroid neoplasms. Real-time quantitative polymerase chain reaction was used to confirm cDNA array expression data in 123 patients (4 normal thyroid, 26 hyperplastic nodules, 27 follicular adenomas, 23 follicular cancers, 18 follicular variant of papillary cancers, 25 papillary cancers).

RESULTS

Twenty-two genes were upregulated in malignant thyroid neoplasms by cDNA array analysis, but only 13 genes had higher messenger RNA (mRNA) expression levels in malignant than in benign thyroid neoplasms by real-time quantitative polymerase chain reaction (P < or = .04). Of the 13 differentially expressed genes, the combined use of angiopoietin 2 (ANGPT2) and tissue inhibitor of metalloproteinase 1 (TIMP1) mRNA expression levels was best for distinguishing malignant from benign thyroid neoplasms, with a sensitivity of 90%, specificity of 85%, positive predictive value of 75%, and negative predictive value of 94%. Epidermal growth factor receptor and ephrin B2 mRNA expression was elevated in higher TNM stage neoplasms and in patients with high-risk AMES (Age, distant Metastasis, Extrathyroidal invasion, and tumor Size) differentiated thyroid cancers (P < or = .005).

CONCLUSIONS

Angiopoietin 2 and tissue inhibitor of metalloproteinase 1 are diagnostic markers of malignant thyroid nodules and could improve the diagnostic accuracy of FNA biopsy. Epidermal growth factor receptor and ephrin B2 are markers of aggressive differentiated thyroid cancer.

Prognostic importance of histologic vascular invasion in papillary thyroid carcinoma

OBJECTIVE

To conduct a retrospective study of 39 patients with papillary carcinoma of the thyroid with histologic vascular invasion (VI+) and 361 patients without any sign of vascular invasion (VI-).

SUMMARY BACKGROUND DATA

In the present study, we undertook a retrospective analysis of papillary carcinoma of the thyroid to assess whether histologically determined vascular invasion can be considered a predictive factor for prognosis.

METHODS

By means of a retrospective study, we evaluated the department's database of patients with papillary thyroid carcinoma who had undergone total thyroidectomy from January 1993 to December 1999.

RESULTS

Group I consisted of papillary carcinoma without any sign of vascular invasion (VI-) comprising 361 patients. Group II consisted of papillary carcinoma with vascular invasion (VI+) comprising 39 patients. At the time of diagnosis, we observed no metastases in patients with VI-, whereas a pulmonary metastasis was observed in 1 patient with VI+ (P = 0.0023). In 3.6% patients with VI- and in 20.5% patients with VI+, we observed recurrences in the regional lymph nodes (P < 0.001); we observed 6 (1.66%) distant metastases in patients with VI- and in the 12.8% patients with VI+ (P < 0.001). Three patients with VI+ (7.7%) and 2 patients with VI- (0.6%) died of tumor-related causes; these figures were found to be statistically significant (P < 0.001).

CONCLUSIONS

In papillary carcinoma, it should be noted that histologic vascular invasion may be considered as a sign of an increased tendency toward hematogenic invasion and consequent increase in the relative percentage of metastases; ultimately, this means a poorer prognosis. In the presence of risk factors indicating a possible increase in biologic aggressiveness, adequate postoperative treatment and close follow up become essential.

Prognostic scoring systems in patients with follicular thyroid cancer: a comparison of different staging systems in predicting the patient outcome

BACKGROUND

The use of prognostic scoring systems is important for predicting the survival of individuals with thyroid carcinoma. Relatively few studies have addressed this issue for patients with follicular thyroid cancer. The goal of this retrospective study was to establish the best and most pertinent prognostic scoring system to predict survival in patients with follicular thyroid cancer.

METHODS

We selected 86 patients with follicular thyroid cancer treated at University of California, San Francisco (UCSF) hospitals from January 1954 to April 1998. The mean follow-up time was 11.5 years. There were 60 women (70%) and 26 men (30%), with a mean age if 48.6 years. Prognostic scoring systems included tumor, node, metastases (TNM), European Organization for Research and Treatment of Cancer (EORTC), Age, Grade, Extent, Size (AGES), Age, Metastases, Extent, Size (AMES), and the Metastases, Age, Completeness of resection, Invasion, Size (MACIS). Survival time was calculated using the Kaplan-Meier method. Using Cox proportional hazards analysis, the relative importance of each scoring method was determined by calculating the proportion of variation in survival time explained (PVE).

RESULTS

Kaplan-Meier analysis indicated that all scoring systems were significant predictors of survival time (p < 0.0001). The PVE associated with each system was (from highest to lowest) 0.48 for MACIS, 0.46 for AGES, 0.44 for EORTC, 0.40 for AMES, and 0.33 for TNM. These results indicate that the MACIS scoring system accounted for a great proportion of explained variance in survival and is a more precise predictor of survival compared to the other scoring systems.

CONCLUSIONS

TNM, EORTC, AGES, AMES, and MACIS, all provided useful prognostic information about the survival in our 86 patients with follicular thyroid cancers. The MACIS classification, however, was the most accurate predictor using PVE as a method of evaluation. Future scoring systems considering additional prognostic factors, may obtain a higher PVE.

False-negative fine-needle aspiration cytology results delay treatment and adversely affect outcome in patients with thyroid carcinoma

Clinicians have become reliant on fine-needle aspiration (FNA) cytology in the diagnosis of thyroid nodules. We encountered several patients who had thyroid cancer at operation despite having had FNAs that never showed malignant or suspicious cells. Hence, we retrospectively studied 100 consecutive patients with histologically proven thyroid cancer who had undergone preoperative FNA. Fourteen of these patients had cancers that were not detected by FNA, three of whom developed widespread disease. The sensitivity of FNA was 79%, the false-negative rate 21%, and the inadequate rate 12%. FNA was less sensitive in detecting follicular and Hürthle cell carcinomas compared to papillary carcinomas. FNAs interpreted by cytopathologists at a major university center were more sensitive than those performed elsewhere. A single false-negative FNA delayed surgical treatment by 28 months, sometimes despite clinical evidence suggesting malignancy. Subjects whose tumors were not detected by FNA experienced delayed treatment, had higher rates of vascular and capsular invasion, and were more likely to have persistent disease at follow up (hazard ratio 2.28). False-negative results remain a concern in the cytologic diagnosis of thyroid cancer. Although FNA is a useful test, clinical findings should overrule cytologic data in order for timely treatment to occur.

Death from differentiated thyroid carcinoma: retrospective study of a 40-year investigation

Differentiated thyroid carcinoma (DTC) usually has a good prognosis, but sometimes the course of the disease results in death. The aim of the present study was to assess the effect of some variables in time to death on fatal cases in our series. A total of 83 patients with DTC who died between 1958 and 1998 from differentiated thyroid cancer were retrospectively analyzed with respect to gender, age at diagnosis, histology, percentage of (131)I uptake by postoperative thyroid remnant, site of tumor growth, and its (131)I uptake, metastases and time to death. Univariate analysis revealed a significantly shorter time to death in local recurrence when comparing local lymph node metastases and distant metastases even if neither show (131)I uptake. Multivariate analysis revealed that age at diagnosis was the most important factor in conditioning the time to death. In conclusion, in those patients who died from DTC an older age at diagnosis and presence of local recurrence influenced the time to death independently of (131)I uptake.

Can we rely on pathologic parameters to define conservative treatment of papillary thyroid carcinoma?

Papillary thyroid carcinoma is the most common malignant tumor of the thyroid and usually behaves in an indolent fashion. At most institutions these tumors are treated by near-total or total thyroidectomy followed by radioactive iodine ablation. The 2 main reasons for this extensive treatment include high rate of multicentricity in papillary carcinoma and difficulty in ablating large thyroid remnants with radioactive iodine after partial thyroidectomy. Some authors believe, however, that this treatment protocol may not be justified in all cases of papillary carcinoma. We analyzed 253 total thyroidectomies performed for papillary thyroid carcinoma for the following pathologic variables: tumor size, presence of tumor capsular and/or vascular invasion, intrathyroidal spread, tumor in the contralateral lobe, and lymph node metastases. Tumors measuring less than 1 cm and those with extrathyroidal soft tissue extension were excluded from this study. Among 253 cases (197 females, 56 males, age range 14-88 years), the primary tumor size ranged from 1-9.5 cm; 162 cases were completely encapsulated. Tumor capsule invasion was seen in 139 (86%) and vascular invasion was present in 32 (13%) cases; of these 27 (11% of the total) patients showed both tumor capsule and vascular invasion. Seventy-four (29%) patients showed tumor in the contralateral lobe; in 35 (47%) of these cases the contralateral tumor measured less than 1.0 cm. Lymph nodes were sampled in 106 cases, metastases were present in 67 (67/106 = 63%) and only 16 cases with lymph node metastases showed contralateral tumors. No significant correlation was noted between tumor size, occurrence of contralateral tumors, and lymph node metastases. Seventy-one percent of cases included in this study failed to show contralateral tumors. Hence, pathologic parameters such as lack of vascular invasion and lack of multifocality may be used to identify patients who can benefit from conservative therapy alone.

Does radioiodine therapy have disadvantageous effects in non-iodine accumulating differentiated thyroid carcinoma?

BACKGROUND

Although radioiodine therapy in differentiated thyroid carcinoma without radioiodine accumulation has not been considered harmful, increased thyrotrophin levels during thyroxine withdrawal without the benefit of radiotoxicity as well as the selection of de-differentiated cells may have disadvantageous effects on tumour course.

OBJECTIVE

We therefore analysed retrospectively the effects of radioiodine therapy on the course of serum thyroglobulin levels as a tumour marker in patients with progressive residual or metastatic differentiated thyroid carcinoma, with or without radioiodine accumulation on post-therapeutic whole body scintigraphy.

PATIENTS AND METHODS

Patients who had undergone radioiodine therapies with sufficient pre- and post-therapy thyroglobulin measurements to allow for regression analysis and not preceded or followed by other treatment modalities within a 1-year interval were selected. All patients had undergone total thyroidectomy and ablative therapy. Thirty-nine patients and radioiodine therapies were included (10 males, 29 females, mean age 57 years), and divided into a negative- (n = 17) and a positive post-therapeutic whole body scintigraphy group (n = 22). Pre- and post-therapeutic thyroglobulin course were analysed using non-linear regression, comparing the difference in the thyroglobulin growth coefficient b1 post- and pre-therapy (delta b1: b1(post-therapy)-b1(pre-therapy)). In addition, absolute post- and pre-therapeutic thyroglobulin levels, radiological follow-up and clinical outcome were also analysed.

RESULTS

The two groups were comparable with respect to age, sex, tumour stage, histology and prior therapies. Differences between post- and pre-therapeutic b1 values differed significantly in the positive post-therapeutic whole body scintigraphy group (delta b1: -0.65 microg/l-1 years-1, P < 0.001) but not in the negative post-therapeutic whole body scintigraphy group (delta b1: -0.14). Absolute serum thyroglobulin levels and radiological follow-up revealed a favourable response of radioiodine therapy in the positive whole body scintigraphy group but not in the negative group. Delta b1 was related significantly with clinical outcome as revealed by receiver operator curves (ROC): all patients with a positive delta b1 (n = 8) had an unfavourable outcome (progression or death), whereas from the 31 patients with negative delta b1, 61% had an unfavourable outcome.

CONCLUSION

We did not find disadvantageous effects of a single radioiodine therapy on serum thyroglobulin increments in patients with negative post-therapeutic whole body scintigraphy. However, as we did not observe a beneficial effect either, we would not advise the continuation of radioiodine therapy in patients with negative post-therapeutic whole-body scintigraphy, unless a positive response is observed in individual cases.

Phenylacetate enhances the antiproliferative effect of retinoic acid in follicular thyroid cancer

BACKGROUND

Retinoic acid (RA) has antiproliferative as well as redifferentiating effects in thyroid cancers. Similar effects have been seen with phenylacetate (PA) therapy. These observations prompted us to evaluate the potential antiproliferative effects of the combination of RA and PA in follicular thyroid cancer.

METHODS

Three follicular cell lines were treated in vitro with varying concentrations of all-trans RA or PA alone or in combination. Growth was measured by dimethyl-thiazol-diphenyltetrazolium bromide assays.

RESULTS

RA (1-2.5 micromol/L) and PA (1-10 mmol/L) alone inhibited cell growth in a time- and dose-dependent manner, with maximum effect at 5 days. The combination of RA and PA had synergistic antiproliferative effects. In the FTC-133 cell line, RA alone (2.5 micromol/L) inhibited growth 16% and PA alone (10 mmol/L) inhibited growth 35% versus controls, whereas the combination of the 2 inhibited growth by 60% at 5 days (P < .005). Similar results were seen with FTC-236 and FTC-238 cell lines.

CONCLUSIONS

Our results support that RA and PA have antiproliferative effects in follicular thyroid cancer and are synergistic. The combination of RA and PA may be beneficial in the treatment of advanced thyroid cancers for which conventional therapy fails or as an adjuvant to radioactive iodine therapy in aggressive tumors.

Medullary thyroid cancer

Patients with clinically evident medullary thyroid cancer should have a total extracapsular thyroidectomy with bilateral central neck dissection and an ipsilateral prophylactic or therapeutic modified (functional) radical neck dissection when the primary tumor is greater than 1 cm and when the central neck nodes are positive. A prophylactic contralateral neck dissection should be done when the primary tumor is bilateral and when there is extensive lymphadenopathy on the side of the primary tumor. Patients who have gross, unresectable residual medullary thyroid cancer should receive postoperative external radiotherapy. Patients who are carriers of germ-line RET proto-oncogene point mutations or have an elevated (basal or stimulated) calcitonin levels on screening should have a prophylactic total thyroidectomy before age 6 years. In patients with an elevated basal or stimulated plasma calcitonin level and an intrathyroidal nodule on ultrasound, a total thyroidectomy and central neck lymph node dissection should be done. Patients with persistent or recurrent medullary thyroid cancer should have a complete thyroidectomy (if not done initially) and bilateral central and modified radical neck dissection, including upper mediastinal lymphadenectomy. Patients who are symptomatic from distant medullary thyroid cancer metastases (diarrhea, flushing, weight loss, or bone pain) should be treated with somatostatin analogs. Bone metastases should be resected if possible, and symptomatic lesions that are unresectable should be treated with external radiotherapy. Cytoreductive procedures such as radiofrequency ablation or cryoablation for liver metastases should be considered in symptomatic patients to reduce tumor burden. Localized pulmonary metastases should be resected. Chemotherapy or radioactive immunotherapy (iodine 131 labeled carcinoembryonic antigen monoclonal antibody) protocols should be considered in patients with nonoperative widely metastatic progressing medullary thyroid cancer.

Medullary thyroid carcinoma: clinical characteristics, treatment, prognostic factors, and a comparison of staging systems

BACKGROUND

The clinical courses of patients with medullary thyroid carcinoma (MTC) vary, and a number of prognostic factors have been studied, but the significance of some of these factors remains controversial.

METHODS

The study group consisted of 104 patients with MTC or C-cell hyperplasia managed at the hospitals of the University of California, San Francisco, between January 1960 and December 1998. Patients were classified as having sporadic MTC, familial non-multiple endocrine neoplasia (MEN) MTC, MEN 2A, or MEN 2B. The TNM, European Organization for Research and Treatment of Cancer (EORTC), National Thyroid Cancer Treatment Cooperative Study (NTCTCS), and Surveillance, Epidemiology, and End Results (SEER) extent-of-disease stages were determined for each patient. The predictive values of these staging or prognostic scoring systems were compared by calculating the proportion of variance explained (PVE) for each system.

RESULTS

Fifty-six percent of the patients had sporadic MTC, 22% had familial MTC, 15% had MEN 2A, and 7% had MEN 2B. The overall average age at diagnosis was 38 years, and patients with sporadic MTC presented at an older age (P < 0.05). Thirty-two percent of the patients with hereditary MTC were diagnosed by screening (genetic and/or biochemical). These patients had a lower incidence of cervical lymph node metastasis (P < 0.05) and 94.7% were cured at last follow-up (P < 0.0001) compared with patients not screened. Patients with sporadic MTC who had systemic symptoms (diarrhea, bone pain, or flushing) had widely metastatic MTC and 33.3% of those patients died within 5 years. Overall, 49.4% of the patients were cured, 12.3% had recurrent MTC, and 38.3% had persistent MTC. The mean follow-up time was 8.6 years (median, 5.0 years) with 10.7% (n=11) and 13.5% (n=14) cause specific mortality at 5 and 10 years, respectively. Patients with persistent or recurrent MTC who died of MTC lived for an average of 3.6 years (ranging from 1 month to 23.7 years). Patients who had total or subtotal thyroidectomy were less likely to have persistent or recurrent MTC (P < 0.05), and patients who had total thyroidectomy with cervical lymph node clearance required fewer reoperations for persistent or recurrent MTC (P < 0.05) than patients who underwent lesser procedures. In univariate analysis, age, gender, clinical presentation, TNM stage, sporadic/hereditary MTC, distant metastasis, and extent of thyroidectomy were significant prognostic factors. Only age and stage, however, remained independent prognostic factors in multivariate analysis. The TNM, EORTC, NTCTCS, and SEER staging systems were all accurate predictors of survival, but the EORTC prognostic scoring system had the highest PVE in this cohort.

CONCLUSIONS

Screening for MTC and early treatment (total thyroidectomy with central neck lymph node clearance) had nearly a 100% cure rate. Patients with postoperative hypercalcitoninemia without clinical or radiologic evidence of residual tumor after apparently curative surgery may enjoy long term survival but have occult MTC. Only patient age at presentation and TNM stage were independent predictors of survival. The EORTC criteria, which included the greatest number of significant prognostic factors in our cohort, had the highest predictive value.

Degradation of extracellular matrix by metastatic follicular thyroid carcinoma cell lines: role of the plasmin activation system

The plasmin activation system plays a key role in extracellular matrix degradation in many malignant tumors. Because no data are available on the involvement of the plasmin activation system in matrix degradation by thyroid carcinoma, the present study was performed using follicular thyroid carcinoma cell lines obtained from a primary tumor (FTC-133) and metastases (FTC-236 and FTC-238) of one patient. Matrix degradation by these cell lines was studied assessing the release of radioactivity from S35-methionine labeled extracellular matrix coated onto plastic. The involvement of constituents of the plasmin activation system as well as matrix metalloproteinases (MMPs), another class of proteolytic enzymes, which can be activated by plasmin, were assessed by semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR) and zymography. In the matrix degradation experiment, S35 release by FTC-133 was significantly higher than FTC-236 and FTC-238. S35 degradation could be inhibited by the plasmin inhibitor aprotinin and by anti-human urokinase-type plasminogen activator (uPA) antibody, indicating the involvement of the plasmin activation system. Matrix degradation could also be inhibited by the MMP inhibitor marimastat, thus demonstrating the involvement of MMPs in matrix degradation by these cell lines. Zymographic assays revealed activity of uPA in all cell lines. However, in contrast with FTC-236 and FTC-238, no plasminogen activator inhibitor (PAI) or PAI1 mRNA were found in FTC-133. Therefore, the differences in PAI activity as observed between the cell lines may originate from differences in PAI1 gene transcription. Differences in PAI1 expression did not affect the attachment of these cell lines to vitronectin. We conclude that the plasmin activation system is involved in extracellular matrix degradation by these metastatic follicular thyroid carcinoma cell lines. Differences in extracellular matrix degradation between the cell lines correspond with differences in PAI1 gene expression, indicating the significance of PAI1 in extracellular matrix degradation by metastatic follicular thyroid carcinoma.

Image analysis of papillary thyroid carcinoma fine-needle aspirates: significant association between aneuploidy and death from disease

BACKGROUND

Papillary thyroid carcinoma is the most common thyroid malignancy in the U.S. As many as half of patients with papillary carcinoma present with cervical lymph node metastases at the time of diagnosis. Metastatic disease involving cervical lymph node tissue has not historically been proven to correlate with a more aggressive course; however, distant metastases worsen prognosis.

METHODS

Diagnostic fine-needle aspiration (FNA) smears from 26 primary and metastatic papillary carcinomas underwent Feulgen reaction and were studied by image analysis to determine DNA pattern, proliferation index, and the percentage of cells with DNA content >5C. The medical records of all the patients were reviewed for metastatic disease pattern and survival data. For metastatic pattern, two groups were defined: 1) confined to thyroid/local lymph node metastases/soft tissues of the neck involved by tumor, and 2) distant metastases.

RESULTS

Among the 26 patients, 16 had "nonaggressive" DNA patterns described as diploid, abnormal diploid, or tetraploid, and 10 had "aggressive" DNA patterns described as aneuploid. Only 2 of the 16 patients in the "nonaggressive" DNA pattern group developed distant metastases, whereas 5 of the 10 patients in the aneuploid group developed distant metastatic disease. In addition, none of the 16 patients with "nonaggressive" DNA patterns died of disease, whereas 3 of the 10 individuals with DNA histograms interpreted as aneuploid did die of metastatic disease complications.

CONCLUSIONS

Aneuploidy identified by image analysis of FNA of papillary thyroid carcinoma is significantly associated with death from papillary carcinoma (log rank test, P=0.027).