Prognostic importance of histologic grading in papillary thyroid carcinoma

Incidence and Clinicopathological Features of Differentiated High-Grade Thyroid Carcinomas: An Institutional Experience

Differentiated high-grade thyroid carcinoma (DHGTC) is a new entity in the 2022 WHO classification. We aimed to investigate the incidence and clinicopathological features of differentiated HG thyroid carcinoma (DHGTC) and compare the clinicopathological parameters of DHGTC, DTC without HG features, and poorly differentiated thyroid carcinoma (PDTC). A total of 1069 DTCs including papillary thyroid carcinomas (PTCs) and follicular thyroid carcinomas (FTCs) were included in this study. Consecutive 22 PDTCs were also included for comparative purposes. There were a total of 14 (1.3%) cases of DHGTCs, with 13 HGPTCs (1.2% of PTCs) and one HGFTC (6.7% of FTCs). Compared to DTCs without HG features, DHGTCs were associated with larger tumor size, presence of blood vessel invasion, gross extrathyroidal extension, distant metastasis at the time of diagnosis, higher American Joint Committee on Cancer stage, high American Thyroid Association risk, and TERT promoter mutations. DHGTC and PDTC showed a significantly shorter recurrence-free survival (RFS) than DTC without HG features. Multivariate Cox regression analysis revealed that blood vessel invasion, lateral node metastasis, TERT promoter mutations, and HG features were independent prognostic factors (all p < 0.05). When tumor necrosis and increased mitotic count were evaluated separately, tumor necrosis, but not increased mitotic counts, was found to be an independent prognostic factor (p = 0.006). This study confirmed that DHGTC is significantly associated with aggressive clinicopathological features and poor clinical outcomes, similar to PDTC. Although the incidence is low, careful microscopic examination of HG features in DTC is required.

Investigation of genetic sex-specific molecular profile in well-differentiated thyroid cancer: Is there a difference between females and males?

BACKGROUND

Although more common in females, thyroid cancer is deemed to be more aggressive in males. The reasons for sex disparities in thyroid cancer are not well understood. We hypothesised that differences in molecular mutations between females and males contribute to this phenomenon.

METHODS

Retrospective multicentre multinational study of thyroid nodules that underwent preoperative molecular profiling between 2015 and 2022. The clinical characteristics and mutational profiles of tumours in female and male patients were compared. Collected data included demographics, cytology results, surgical pathology, and molecular alterations.

RESULTS

A total of 738 patients were included of which 571 (77.4%) were females. The extrathyroidal extension was more common in malignancies in males (chi-squared, p = 0.028). The rate of point mutations and gene fusions were similar in both sex groups (p > 0.05 for all mutations). Patients with nodules with BRAFV600E mutations were significantly younger than BRAF wild-type nodule patients (t-test, p = 0.0001). Conversely, patients with TERT promoter mutations were significantly older than patients with wild-type TERT (t-test, p < 0.0001). For patients harbouring both BRAFV600E and TERT mutations, the difference in age at presentation was significantly different in females (t-test, p = 0.009) but not in males (t-test, p = 0.433). Among females, patients with BRAFV600E and TERT mutations were significantly older than their wild-type or single-mutation counterpart (t-test, p = 0.003).

CONCLUSION

The absolute rate of molecular mutations was similar in females and males. We found that extrathyroidal extension was more common in males. Moreover, BRAFV600E and TERT mutations occur at a younger age in males than in females. These two findings are factors that may explain the tendency of more aggressive disease in males.

Vascular Endothelial Growth Factor Receptor Inhibitors in Chinese Patients With Advanced Radioactive Iodine-Refractory Differentiated Thyroid Cancer: A Network Meta-Analysis and Cost-Effectiveness Analysis

INTRODUCTION

Two targeted drugs (apatinib and lenvatinib) show clinical efficacy in first-line treatment of Chinese patients with radioactive advanced iodine-refractory differentiated thyroid cancer (RAIR-DTC) and are recommended by the Chinese Society of Clinical Oncology guidelines. Considering the high clinical cost of long-term vascular endothelial growth factor receptor inhibitor administration and to determine which of the two targeted drugs is preferable, we opted to conduct a cost-effectiveness analysis (CEA) and network meta-analysis (NMA).

MATERIAL AND METHODS

The results of NMA and CEA included in the two phase III randomized clinical trials REALITY (NCT03048877) and Study-308 (NCT02966093), in which Bayesian NMA and CEA were performed on 243 and 149 Chinese patients, respectively, were retrieved. Overall survival and progression-free survival (PFS) for apatinib versus lenvatinib were determined by NMA. CEA involved the development of a 20-year Markov model to obtain the total cost and quality-adjusted life-years (QALYs), and this was followed by sensitivity and subgroup analyses.

RESULTS

Compared with lenvatinib, apatinib therapy provided a 0.837 improvement in QALY and $6,975 reduction in costs. The hazard ratio of apatinib versus lenvatinib and the cost of the targeted drugs had a significant impact on the model. According to the sensitivity analysis, apatinib was more cost-effective and had no correlation with willingness-to-pay in China. Subgroup analysis showed that apatinib maintained PFS more economically.

CONCLUSION

NMA and CEA demonstrated that apatinib was more cost-effective compared to lenvatinib in the first-line treatment of Chinese RAIR-DTC patients.

Tall Cell Variant versus Conventional Papillary Thyroid Carcinoma: A Retrospective Analysis in 351 Consecutive Patients

Background: The aim of this retrospective study was to investigate clinical and pathological characteristics of the tall cell variant of papillary thyroid carcinoma compared to conventional variants. Methods: The clinical records of patients who underwent surgical treatment between 2009 and 2015 were analyzed. The patients were divided into two groups: those with a histopathological diagnosis of tall cell papillary carcinoma were included in Group A, and those with a diagnosis of conventional variants in Group B. Results: A total of 35 patients were included in Group A and 316 in Group B. All patients underwent total thyroidectomy. Central compartment and lateral cervical lymph node dissection were performed more frequently in Group A (42.8% vs. 18%, p = 0.001, and 17.1% vs. 6.9%, p = 0.04). Angiolymphatic invasion, parenchymal invasion, extrathyroidal extension, and lymph node metastases were more frequent in Group A, and the data reached statistical significance. Local recurrence was more frequent in Group A (17.1% vs. 6.3%, p = 0.02), with two patients (5.7%) in Group A showing visceral metastases, whereas no patient in Group B developed metastatic cancer (p = 0.009). Conclusions: Tall cell papillary carcinoma is the most frequent aggressive variant of papillary thyroid cancer. Tall cell histology represents an independent poor prognostic factor compared to conventional variants.

Prognostic Impact of Histologic Grade for Papillary Thyroid Carcinoma

BACKGROUND

While numerous factors affect prognosis in papillary thyroid carcinoma (PTC), the comparative impact of histologic grade has not been well described. Moreover, indications for external beam radiation therapy (EBRT) remain imprecise. We evaluate clinicopathologic characteristics and outcomes for PTC stratified by grade.

METHODS

We profiled histologic grade for PTC (well differentiated, moderately differentiated, poorly differentiated) via hospital (National Cancer Database) and population-based (Surveillance, Epidemiology, and End Results) registries. Cox regression was used to adjust for clinicopathologic covariates. Statistical interactions between subtypes and the effect of EBRT on survival were assessed.

RESULTS

Collectively, worsening clinicopathologic factors (age, tumor size, extrathyroidal extension, nodal spread, M1 disease) and outcomes (disease-free survival, overall survival) correlated with less differentiated state, across all histologic grades (p < 0.001). Multivariable analysis showed escalating hazard with loss of differentiation relative to well-differentiated PTC (moderately differentiated hazard ratio [HR] 1.21, 95% confidence interval [CI] 1.04-1.41, p = 0.02; poorly differentiated HR 2.62, 95% CI 2.23-3.08, p < 0.001). Correspondingly, greater survival benefit was associated with EBRT for poorly differentiated cases (HR 0.36, 95% CI 0.18-0.72, p = 0.004). This finding was upheld after landmark analysis to address potential immortal time bias (HR 0.37, 95% CI 0.17-0.80, p = 0.01).

CONCLUSIONS

Worsening histologic grade in PTC is independently associated with parallel escalation in mortality risk, on a scale approximating or surpassing established thyroid cancer risk factors. On preliminary analysis, EBRT was associated with improved survival in the most aggressive or least differentiated subvariants. Further investigation is warranted to examine the efficacy of EBRT for select poorly differentiated thyroid carcinomas.

Divergent Metastatic Patterns Between Subtypes of Thyroid Carcinoma Results From the Nationwide Dutch Pathology Registry

BACKGROUND

Metastatic disease is the main cause of cancer-related mortality in thyroid carcinoma (TC) patients. Clinical studies have suggested differences in metastatic patterns between the different subtypes of TC. This study systematically evaluates the metastatic patterns of different subtypes in TC patients.

METHODS

A nationwide review of pathological records of all 650 patients diagnosed with a primary malignancy in the thyroid who underwent an autopsy between 1991 and 2010 was performed. Patients were selected from the Dutch pathology registry (PALGA).

RESULTS

Metastatic disease was present in 228 (35.1%) patients and was found in 38.7%, 17.3%, 75.4%, and 47.8% of patients with follicular, papillary, anaplastic, and medullary types of TC, respectively (P < .0001). The majority of patients had more than 1 metastasis. The most common site of metastatic disease was the lung for papillary (79.7%), follicular (72.9%), and anaplastic (92.1%) carcinoma but not for medullary carcinoma (56.3%), P < .0001. Medullary carcinoma patients most frequently had metastases to the liver (81.3%). The combination of metastases also differed between subtypes.

CONCLUSION

There are major differences in metastatic patterns between different subtypes of TC. The patterns and frequencies identified in this autopsy study may reflect the underlying biology of metastatic thyroid cancer and have potential to influence future monitoring and treatment strategies depending on clinical correlations.

MALAT1 rs619586 polymorphism functions as a prognostic biomarker in the management of differentiated thyroid carcinoma

This study aimed to explore the roles of miR-214 and MALAT1 rs619586 polymorphism in the control and survival of differentiated thyroid carcinoma (DTC) via Cox regression analyses. The levels of MALAT1, miR-214, and CTNNB1 in different experimental groups were compared to study the interaction among MALAT1, miR-214, and CTNNB1. MTT and colony assays were used to investigate the role of rs619586 polymorphism in cell growth. The G allele of rs619586 polymorphism obviously decreased the 5-year survival of patients with DTC. Additionally, compared with AA-genotyped patients, patients carrying the AG/GG genotypes of MALAT1 rs619586 polymorphism showed much higher levels of DTC grade and CTNNB1 expression, along with lower levels of MALAT1 and miR-214 expression. Furthermore, the transcription activity of MALAT1 was significantly lowered by the rs619586G allele or miR-214 mimic, while the miR-214 inhibitor upregulated the luciferase activity of MALAT1. Additionally, miR-214 inhibited CTNNB1 expression by targeting CTNNB1 3'-untranslated region. Finally, the G allele of MALAT1 rs619586 polymorphism apparently promoted cell proliferation. Our study indicated that miR-214 inhibited MALAT1 expression by directly binding to the G allele of MALAT1 rs619586 polymorphism, thus inhibiting CTNNB1 expression and promoting cell proliferation in the pathogenesis of DTC. Therefore, MALAT1 rs619586 polymorphism could be used to predict the prognosis of DTC.

Impact of the change from the seventh to eighth edition of the AJCC TNM classification of malignant tumours and comparison with the MACIS prognostic scoring system in non-medullary thyroid cancer

Background

In 2018, AJCC TNM staging changed for differentiated (DTC) and anaplastic (ATC) thyroid carcinoma. The impact of this change on mortality rates was investigated and compared with the MACIS prognostic score.

Methods

Analysis of a prospective database of DTC/ATC was undertaken. Patients were staged according to TNM7 and TNM8 criteria, and MACIS scores calculated. Five‐year disease‐specific mortality rates were determined. Proportions were compared with Fisher's exact and χ² goodness‐of‐fit tests.

Results

Between August 2002 and December 2016, 310 patients had primary surgery for thyroid cancer. After exclusions, 159 patients (154 DTC, 5 ATC) remained to be studied. The MACIS score was less than 6 in 105 patients (66·0 per cent), 6–6·99 in 19 (11·9 per cent), 7–7·99 in 14 (8·8 per cent) and 8 or more in 21 (13·2 per cent), with corresponding disease‐specific 5‐year mortality rates of 0, 5, 14 and 86 per cent. For TNM7 the distribution was stage I in 53·5 per cent (85 patients), stage II in 10·1 per cent (16), stage III in 14·5 per cent (23) and stage IV in 22·0 per cent (35), and differed from that for TNM8: 76·7 per cent (122), 10·7 per cent (17), 4·4 per cent (7) and 8·2 per cent (13) respectively (P < 0·001). Overall disease‐specific 5‐year mortality rates by stage for TNM7 versus TNM8 were: stage I, 0 of 85 versus 3 of 100 (P = 0·251); stage II, 0 of 16 versus 6 of 16 (P = 0·018); stage III, 3 of 23 versus 2 of 7 (P = 0·565); stage IV, 20 of 32 versus 11 of 11 (P = 0·020).

Conclusion

Compared with TNM7, TNM8 downstaged more patients to stage I and accurately reflected worse prognosis for stage IV disease. TNM8 is an inferior predictor of mortality compared with MACIS.

The effects of the Union for International Cancer Control/American Joint Committee on Cancer Tumour, Node, Metastasis system version 8 on staging of differentiated thyroid cancer: a comparison to version 7

OBJECTIVE

To assess the changes resulting from the changes from UICC/AJCC TNM version 7 to version 8 and to subsequently determine whether TNM version 8 is an improvement compared to previous iterations of the TNM system and other staging systems for differentiated thyroid cancer (DTC) with regard to prognostic power.

DESIGN

Database study of DTC patients treated in our centre between 1978 up to and including 1 July 2014. Results were compared to our previous comparison of prognostic systems using the same data set.

PATIENTS

2257 DTC patients.

MEASUREMENTS

Staging in accordance with TNM 7 and TNM 8. Thyroid cancer-specific mortality; comparison was based on p-values of univariate Cox regression analyses as well as analysis of the proportion of variance explained (PVE).

RESULTS

There is a redistribution from stage 3 to lower stages affecting 206 (9.1%) patients. DTC-related mortality according to Kaplan-Meier for younger and older patients in TNM 7 had a slightly lower prognostic power than that in accordance with TNM 8 (P = 8.0 10^-16 and P = 1.5 10^-21 , respectively). Overall staging is lower in 627/2257 (27.8%) patients. PVE (TNM 7: 0.29; TNM 8: 0.28) and the P-value of Cox regressions (TNM 7: P = 7.1*10^-52 ; TNM 8: P = 3.9*10^-49 ) for TNM version 8 are marginally lower than that for TNM version 7, but still better than for any other DTC staging system.

CONCLUSION

TNM 8 results in a marked downstaging of patients compared to TNM 7. Although some changes, like the change in age boundary, appear to be associated with an improvement in prognostic power, the overall effect of the changes does not improve the predictive power compared to TNM 7.

Prognostic markers in well differentiated papillary and follicular thyroid cancer (WDTC)

OBJECTIVES

WDTC (papillary and follicular thyroid cancer) make up around 90% of all thyroid tumours. Overall, the prognosis in patients with WDTC is excellent. However, there are small cohorts of patients who experience a more aggressive form of disease which is often associated with certain poor prognostic factors. Identifying these patients at an early stage is imperative for guiding treatment decisions. With recent developments in this area we plan to discuss the current evidence surrounding prognostic markers.

METHODS

The literature regarding prognostic factors in WDTC was reviewed using an electronic database Medline - Pubmed. Using the MeSH search engine specific prognostic factors including age, size, grade, lymph node involvement, distant metastasis, extension/invasion, ethnic background, radioactive iodine avidity, and thyroglobulin level and their association with WDTC were evaluated. A broader search of prognostic markers in thyroid cancer was also carried out to avoid missing other pertinent markers.

RESULTS

Multiple clinical and pathologic variables have been shown to be poor prognostic factors in WDTC with statistical significance. Extensive extrathyroidal extension and age may be the most important factors when predicting clinical outcomes in WDTC, although the age threshold may be increased from 45 to 55 years in due course.

CONCLUSIONS

Management of WDTC has changed considerably over the last two years as reflected in evolving British and American Thyroid Guidelines. In all cases a combined multi-disciplinary approach, with consideration of the available guidelines and stratification systems should be utilised when planning an individualised treatment program to offer the best contemporary care to WDTC patients.

Relationship between lymphovascular invasion and clinicopathological features of papillary thyroid carcinoma

Lymphovascular invasion (LVI) is an important prognostic factor in various solid tumors, however, data on the association between LVI and thyroid carcinomas are limited. In this study, we evaluated the relationship between LVI and clinicopathological features of papillary thyroid carcinoma (PTC). Six hundred seventy-eight patients diagnosed with PTC between 2012 and 2015 were included into the study. Patients were classified based on the presence or absence of LVI. Gender, age, ultrasonography (US), tumor size and multifocality, BRAFV600E mutation, perineural and capsular invasion, extrathyroid extension (ETE), nodal metastasis, and recurrences were evaluated, and risk analysis was performed for each parameter. The number of patients with LVI [LVI (+)] was 63, while the number of patients without LVI [LVI (-)] was 615. The female/male ratio was 564/114. LVI was present in 18.4% of male patients and in 7.4 % of female patients. In the age group between 17-25 years LVI was detected in 6/13 patients, and this result was statistically significant compared to other age groups (p = 0.004). Suspicious lymph nodes upon US, perineural or capsular invasion, ETE, tumor size, and nodal metastasis were significantly more frequent in LVI (+) group (p < 0.001). The frequency of BRAFV600E mutation was also significantly higher in LVI (+) group (p < 0.001). Overall, the presence of LVI was associated with gender, tumor size, age, lymph node metastasis, pathological lymph nodes, perineural and capsular invasion, ETE, and BRAFV600E mutation. These results suggest that in PTC patients undergoing thyroidectomy, the presence of LVI should be considered as an indicator of aggressive clinicopathological features and those patients should be followed up carefully for recurrences and metastasis.

Study of Immunohistochemical Markers (CK-19, CD-56, Ki-67, p53) in Differentiating Benign and Malignant Solitary Thyroid Nodules with special Reference to Papillary Thyroid Carcinomas

INTRODUCTION

Solitary Thyroid Nodule (STN) has provoked increased concern owing to higher incidence of malignancy. The inter and intra observer variation in the histomorphological diagnosis of Papillary Thyroid Carcinomas (PTC) may sometimes pose a diagnostic difficulty.

AIM

This study was undertaken to analyse immunohistochemical (IHC) markers (CK-19, CD-56, p53, Ki-67) to differentiate between benign and malignant surgically resected STN along with their utility in the identification of PTC.

MATERIALS AND METHODS

The present cross sectional study was conducted over a period of 4 years. A technique of manual tissue array was employed for cases subjected to IHC. The primary antibodies used were CK-19, CD-56, p53 and Ki-67. Analysis of the expression of IHC markers (p53, Ki-67) to distinguish between benign and malignant STN was done. Evaluation and correlation of expression of IHC markers (CK-19, CD-56) to determine its utility in reaching definitive diagnosis and assessing prognosis of PTC was tried. Results were subjected to statistical analysis. The results were considered to be significant when the p-value <0.05.

RESULTS

Out of the 160 cases of surgically resected STN specimens, 68 cases were non-neoplastic, 24 cases were benign and 68 cases were of malignant tumours (7 cases of follicular carcinoma (FCa), 61 cases of PTC). CK-19 was found to be a sensitive (83.61%) and a highly specific positive marker (100%) for the diagnosis of PTC. The difference in CD-56 expression between PTC and non-PTC group was found to be highly statistically significant. CD-56 was found to be a sensitive (85.86%) and specific (82.25%) negative marker in differentiating PTC from follicular lesions/neoplasms. The difference in p53 expression between the malignant and non-malignant STN cases was found to be highly statistically significant with a sensitivity and specificity 85.29% and 70.65% respectively. The statistical difference in mean Ki-67 Labeling Index (LI) was found to be significant between PTC versus FA, PTC versus non-neoplastic lesions, FA versus FCa and FVPTC versus FA.

CONCLUSION

The panel of four IHC markers (CK-19, CD-56, p53, Ki-67) may be used for differentiating doubtful benign STN cases from malignant ones and also for definitive diagnosis of PTC along with histopathological examination.

Comparing a thyroid prognostic nomogram to the existing staging systems for prediction risk of death from thyroid cancers

OBJECTIVE

Thyroid prognostic nomogram can be applied across different histological types for predicting the individualized risk of death from thyroid cancer. The objective of this study was to compare the strength of our recently published thyroid prognostic nomogram with 12 existing staging systems to predict the risk of death from thyroid cancer.

METHOD

This study included 1900 thyroid cancer patients, from a population based cohort of 2296 patients, on whom adequate staging information was available. Competing risk sub-hazard models were used to compare 12 pre-existing prognostic models with the nomogram model. Their relative strengths for prediction of patients' individualized risks of death from thyroid cancer were compared using Akaike information criterion (AIC), delta AIC, and concordance index. R version 3.2.2 was used to analyze the data.

RESULTS

Our cohort of 450 males and 1450 females included 1796 (93.4%) differentiated thyroid cancers. Amongst the compared models, thyroid prognostic nomogram model appeared to be better than other models for predicting the risk of death from all non-anaplastic thyroid cancer (concordance index = 94.4), differentiated thyroid cancer (concordance index = 94.1) and papillary thyroid cancer (concordance index = 94.7). The difference from next best staging systems was most pronounced in non-anaplastic thyroid cancer (delta AIC = 114.8), followed by differentiated thyroid cancer (delta AIC = 35.6) and papillary thyroid cancer (delta AIC = 8.4).

CONCLUSIONS

Thyroid prognostic nomogram model was found to be better than the other models compared for predicting risk of death from thyroid cancer.

The TNM system (version 7) is the most accurate staging system for the prediction of loss of life expectancy in differentiated thyroid cancer

OBJECTIVE

Many prognostic systems have been developed for differentiated thyroid cancer. It is unclear which one of these performs 'best'. Our aim was to compare staging systems applicable to our patient database to identify which best predicts DTC-related loss of life expectancy and DTC-specific mortality.

DESIGN

Database study of patients with DTC treated in our centre between 1978 (earliest available data) up to and including 1 July 2014. All were staged in accordance with the AMES, Clinical Class, Memorial Sloan Kettering, Ohio State University, TNM versions 5 and 6/7, University of Alabama, University of Münster and qTNM systems.

PATIENTS

A total of 2257 patients with differentiated thyroid cancer.

MEASUREMENTS

Loss of life expectancy expressed as relative survival and thyroid cancer-specific mortality. Comparison was based on P values of univariate Cox regression analyses as well as analysis of the proportion of variance explained (PVE).

RESULTS

Median available follow-up time was 7·2 years (range: 0-35·1 years). Three hundred and twenty-seven patients died, 149 of whom died of DTC. Version 7 of the TNM system was best for predicting DTC-related mortality (P = 7·1 × 10^-52 ; PVE = 0·296), followed by TNM version 5 (P = 6·7 × 10^-44 ; PVE = 0·255). For prediction of loss of life expectancy, version 7 of the TNM system was also best, closely followed by the Clinical Class system (P both < 2 × 10^-16 ).

CONCLUSIONS

The UICC/AJCC TNM system version 7 outperforms other prognostic classification systems based on extent of disease at the start of treatment both for prediction of differentiated thyroid cancer-related death and for prediction of loss life expectancy.

Identifying the most appropriate age threshold for TNM stage grouping of well-differentiated thyroid cancer

OBJECTIVE

Age is integrated in most risk stratification systems for well-differentiated thyroid cancer (WDTC). The most appropriate age threshold for stage grouping of WDTC is debatable. The objective of this study was to evaluate the best age threshold for stage grouping by comparing multivariable models designed to evaluate the independent impact of various prognostic factors, including age based stage grouping, on the disease specific survival (DSS) of our population-based cohort.

METHODS

Data from population-based thyroid cancer cohort of 2125 consecutive WDTC, diagnosed during 1970-2010, with a median follow-up of 11.5 years, was used to calculate DSS using the Kaplan Meier method. Multivariable analysis with Cox proportional hazard model was used to assess independent impact of different prognostic factors on DSS. The Akaike information criterion (AIC), a measure of statistical model fit, was used to identify the most appropriate age threshold model. Delta AIC, Akaike weight, and evidence ratios were calculated to compare the relative strength of different models.

RESULTS

The mean age of the patients was 47.3 years. DSS of the cohort was 95.6% and 92.8% at 10 and 20 years respectively. A threshold of 55 years, with the lowest AIC, was identified as the best model. Akaike weight indicated an 85% chance that this age threshold is the best among the compared models, and is 16.8 times more likely to be the best model as compared to a threshold of 45 years.

CONCLUSION

The age threshold of 55 years was found to be the best for TNM stage grouping.

Is age associated with risk of malignancy in thyroid cancer?

OBJECTIVES

Many predictive models for risk of malignancy in well-differentiated thyroid cancer (WDTC) have been proposed, and many scoring systems for thyroid cancer prognosis have been established. Age is taken in consideration in all. Our main goal is to establish whether patients' age has a correlation with the rate of malignancy, size, and aggressiveness of the tumor.

STUDY DESIGN

Case series with chart review.

SETTING

McGill University Thyroid Teaching Hospitals.

SUBJECTS AND METHODS

A retrospective analysis of 1022 patients undergoing consecutive thyroidectomy was performed. The patients were divided based on age (<45 and ≥ 45 years). Data were gathered for the size of thyroid nodules, the presence of lymph node (LN) metastasis, and the final thyroid pathology, including the presence of extrathyroidal extension.

RESULTS

There were 396 patients younger than 45 years and 626 patients 45 years or older. The rates of malignancy were 67.2% in the first group and 68.7% in the second group (P = .111). When patients were stratified according to different age cutoffs, WDTC and LN metastasis occurred more often in patients younger than 50 years (50.2% vs 43.2%, P = .031 and 18.9% vs 14.1%, P = .0496, respectively). Micropapillary carcinoma occurred more often in patients 50 years or older (23.6% vs 16.1%, P = .0035).

CONCLUSIONS

Tumor behavior and rates of WDTC were similar in patients aged <45 and ≥ 45 years. Well-differentiated thyroid cancer occurred more often in patients younger than 50 years, whereas the rate of micropapillary carcinoma occurred more often in patients 50 years or older.

Radio-guided selective compartment neck dissection improves staging in papillary thyroid carcinoma: a prospective study on 345 patients with a 3-year follow-up

BACKGROUND

Prospective uncontrolled study to investigate in papillary thyroid carcinoma (PTC) patients: (1) Distribution of lymph node metastases within the neck compartments, (2) factors predicting lymph nodes metastases, and (3) disease recurrence after thyroidectomy associated with radio-guided selective compartment neck dissection (RSCND).

METHODS

We studied 345 consecutive PTC patients operated on between February 2004 and October 2011 at the S. Anna University Hospital, Ferrara (Italy). Patients with cervical lymph node metastases on preoperative ultrasonography and fine needle aspiration cytology were excluded. All patients underwent total thyroidectomy associated with SLN identification followed by RSCND in the SLN compartment, without SLN frozen section.

RESULTS

In patients with lymph node metastases, metastatic nodes were not in the central neck compartment in 22.6% of the cases. The presence of infiltrating or multifocal PTC was a predicting factor for lymph nodes metastases. The median follow-up was 35.5 months. RSCND was associated with a false-negative rate of 1.1%, a persistent disease rate of 0.6%, and a recurrent disease rate of 0.9%. The permanent dysphonia rate was 1.3%.

CONCLUSION

RSCND associated with total thyroidectomy may improve: (1) the locoregional lymph node staging, and (2) the identification of the site of lymphatic drainage within the neck compartments. Thus, considering the high false-negative rate of sentinel lymph node biopsy (SLNB), a radio-guided technique in PTC patients may guide the lymphadenectomy (ie, RSCND) to increase the metastatic yield and improve staging of the disease rather than avoid prophylactic lymphadenectomy (ie, SLNB).

Validation of the QTNM staging system for cancer-specific survival in patients with differentiated thyroid cancer

An Australian state database was used to test the validity of the Quantitative tumor/node/metastasis (QTNM) staging system for assessing prognosis of differentiated thyroid cancer (DTC) on the basis of four variables quantified at diagnosis (histopathology, age, node involvement, and tumor size). Using the Queensland Cancer Registry (QCR), we identified 788 cases of DTC diagnosed from 1982 to 2006 with complete staging information. Causes of death were ascertained by linking the QCR database with the Australian National Death Index. Subjects were staged according to AJCC TNM 7th edition and QTNM, and cancer-specific survival (CSS) was calculated by the Kaplan-Meier method. Cancer-specific mortality was observed in 22 (2.8 %) patients, with 10-year CSS for the cohort of 97.0 % at a median follow-up of 262.8 months. QTNM stage specific cancer survival at 10 years was 99.6, 97.0, and 78.6 % for low-, intermediate-, and high-risk groups, respectively. This was comparable to the original US dataset in which the QTNM was initially studied, and it fared better at discriminating survival than the standard TNM system, where there was overlap in survival between stages. The current study validates the QTNM system in an Australian cohort and shows at least equivalent discriminatory capacity to the current TNM staging system. The QTNM utilized prognostic variables of significance to produce an optimal three-stage stratification scheme. Given, its advantage in clearly discriminating between prognostic groups, clinical relevance and simplicity of use, we recommend that TNM be replaced with QTNM for risk stratification for both recurrence and CSS.

The assessment of prognostic histopatholgical parameters depending on histological patterns of papillary thyroid carcinoma

Papillary thyroid carcinoma represents common injuries that can have different histological variants that may influence the patient’s prognostic. The study included a total of 44 papillary thyroid carcinomas, for which were followed a series of histological factors of aggressiveness for grading tumors. Most studied papillary carcinomas corresponded to the conventional type, followed by the follicular, micropapillary and tall cell variants. Depending on the presence of nuclear atypia, tumor necrosis, the frequency of mitosis, also the vascular invasion and the extrathyroidian extension there were distributions differences of the cases according to the tumor type, most of the cases belonged to the conventional and tall cell types. The assessment of histopathological parameters of aggressiveness with certain types known to have an unfavorable behavior, justify the use of the histological grading of papillary thyroid carcinomas.

Surgery of lymph nodes in papillary thyroid cancer

Optimal treatment for differentiated thyroid carcinoma is controversial with respect to the extent of thyroid resection, the extent and technique of nodal dissection and use of prophylactic radioiodine treatment. Postoperative complications, such as recurrent laryngeal nerve injury and definitive hypoparathyroidism, have carried great weight in the discussion regarding how radical the surgical treatment should be. The discussion of whether total thyroidectomy or lesser procedures should be the treatment for thyroid carcinomas has been protracted. Now, reasonable agreement exists that total thyroidectomy is the best treatment and the focus of the discussion has moved to the treatment of lymph nodes. At the time of diagnosis, node metastases are a common finding in patients with differentiated thyroid cancer, in particular papillary carcinoma. The argument supporting a radical approach to lymph node excision is that the presence of node metastases increases the recurrence rate. Advocates for the conservative approach believe that little association exists between node metastases and death from thyroid carcinoma. This paper reviews relevant medical literature published in the English language on surgery of lymph nodes in differentiated thyroid cancer with well-controlled trials. Searches were last updated in June 2006.

The age factor in survival of a population cohort of well-differentiated thyroid cancer

Well-differentiated thyroid carcinoma (WDTC) represents a group of thyroid cancers with excellent prognosis. Age, a well-recognized risk factor for WDTC, has been consistently included in various prognostic scoring systems. An age threshold of 45 years is currently used by the American Joint Cancer Committee-TNM staging system for the risk stratification of patients. This study analyzes the relationship between the patients' age at diagnosis and thyroid cancer-specific survival in a population-based thyroid cancer cohort of 2115 consecutive patients with WDTC, diagnosed during 1970-2010, and evaluates the appropriateness of the currently used age threshold. Oncological outcomes of patients in terms of disease-specific survival (DSS) and disease-free survival (DFS) were calculated by the Kaplan-Meier method, while multivariable analysis was done by the Cox proportional hazard model and proportional hazards regression for sub-distribution of competing risks to assess the independent influence of various prognostic factors. The mean age of the patients was 47.3 years, 76.6% were female and 83.3% had papillary carcinoma. The median follow-up of the cohort was 122.4 months. The DSS and DFS were 95.4 and 92.8% at 10 years and 90.1 and 87.6% at 20 years, respectively. Multivariable analyses confirmed patient's age to be an independent risk factor adversely affecting the DSS but not the DFS. Distant metastasis, incomplete surgical resection, T3/T4 stages, Hürthle cell histology, and male gender were other independent prognostic determinants. The DSS was not independently influenced by age until the age of 55 years. An age threshold of 55 years is better than that of 45 years for risk stratification.

Neoadjuvant chemotherapy in 16 patients with locally advanced papillary thyroid carcinoma

BACKGROUND

It is believed that chemotherapy (ChT) is ineffective in papillary thyroid carcinoma (PTC). The aim of our retrospective chart review was to find out if neoadjuvant ChT before thyroid surgery had any effect on the size of primary tumors in patients with PTC.

METHODS

The study included 16 patients (13 women, 3 men; median age 63.5 years) with PTC, who were treated with neoadjuvant ChT from 1988 to 2005. Poorly differentiated PTC, classical PTC, a follicular variant of PTC, and a Hürthle cell variant of PTC were diagnosed in 5, 5, 3, and 3 cases, respectively. The mean tumor diameter was 9.67 cm. Seven patients had a pT4 tumor. Regional and distant metastases were detected in 10 and 7 patients, respectively. ChT consisted of vinblastine in 11 cases, vinblastine with adriamycin in 2 cases, and other schedules in 3 cases. Four patients were also treated with preoperative external irradiation.

RESULTS

Altogether, 40 cycles of ChT were given. After ChT, the tumor size decreased in all 16 patients: by >50% in 7 (44%) patients and by <50% in 9 patients. R0, R1, and R2 resection was performed in 2, 10, and 4 cases, respectively. The median survival time of our patients was 88 months. Six patients are still alive; two died of causes not related to carcinoma, while eight patients died of PTC.

CONCLUSIONS

Neoadjuvant ChT before thyroid surgery may be effective in patients with locally advanced PTC. After neoadjuvant ChT, in 44% of patients, the tumor size decreased by >50%.

Chromatin changes in papillary thyroid carcinomas may predict patient outcome

PURPOSE

New insights in prognostic predictions are urgently needed for papillary thyroid carcinoma (PTC). The present study aimed to investigate whether computerized analysis of chromatin texture allows the identification of PTC patients with a poor prognosis.

METHODS

We randomnly selected paraffin-embedded blocks from surgical specimens of 103 classic cases of PTC. During follow-up, 68 of the patients were classified as free of disease, whereas 35 presented with recurrences. Characteristics of chromatin were obtained from digitized images of at least 100 randomly selected tumor nuclei per patient. An independent series of 30 goiters was used to validate our observations.

RESULTS

Stage, age and distant metastases were found to serve as independent prognostic factors for survival. In addition, multivariate Cox regression confirmed variable cluster prominence as an independent prognostic factor. By comparing malignant and benign nodules, we found that the PTC lesions presented with higher nuclear perimeters, nuclear areas, Minkowski fractal dimensions, optical densities and nuclear longest chords.

CONCLUSION

From our results we conclude that, in conjunction with clinical and histopathological data, morphometric data may provide relevant prognostic information in PTC patients.

Age and prognosis of papillary thyroid carcinoma: retrospective stratification into three groups

Purpose

We investigated the prognosis according to age in papillary thyroid carcinoma (PTC) patients.

Methods

We retrospectively evaluated 2,890 patients who underwent thyroidectomy due to PTC between May 2004 and Aug 2008. We divided patients into 3 groups: young (≤35 years old), middle (between 35 and 54 years old), and old (≥55 years old).

Results

Median age was 47.0 years old (range, 15 to 82 years). Within a follow-up period median of 50 months, there were 148 (5.1%) locoregional recurrences, 6 (0.2%) PTC-related deaths, and 18 (0.6%) PTC-unrelated deaths. Outcomes were more favorable in the young group, with no PTC-related death despite the frequent locoregional recurrence. In the old group compared to the middle, there was a higher proportion of male, and more aggressive types as T3 or N1b, higher mean tumor number, more multiplicity, and bilaterality. The old group of ≥55 years did not show a significant difference in PTC-related deaths than other age groups in Cox analysis (OR, 0.9; P = 0.677), but a significant cutoff age in PTC-related deaths at 62.5 years was determined in ROC analysis (area under curve = 0.912).

Conclusion

We showed that the ≤35 years group shows favorable prognosis despite the frequent locoregional recurrence and ≥62.5 years group shows a poor prognosis regardless of other factors such as male sex or tumor aggressiveness. Further multiinstitutional studies are needed to elucidate the prognosis according to patient's age.

Spontaneous remission in thyroid cancer patients after biochemical incomplete response to initial therapy

OBJECTIVE

To validate the American Thyroid Association (ATA) initial risk of recurrence scheme and the Memorial Sloan Kettering Cancer Center (MSKCC) response to therapy re-stratification approach in a large cohort of patients with differentiated thyroid cancer (DTC) treated outside of the United States.

DESIGN

Retrospective chart review.

PATIENTS

Five hundred and six patients with DTC followed for a median of 10 years after total thyroidectomy and RAI remnant ablation at a major cancer centre in Brazil.

MEASUREMENTS

Final clinical outcomes were assessed based on American Joint Cancer Committee (AJCC)/Union Internationale Contre le Cancer (UICC) staging, ATA risk stratification and response to therapy assessment (excellent, acceptable, biochemical incomplete and structural incomplete).

RESULTS

The AJCC/UICC staging system did not adequately stratify patients with regard to the risk of recurrence/persistent disease. However, the ATA system demonstrated a 13% risk of recurrent/persistent disease in low-risk patients, 36% in intermediate risk patients, and 68% in high-risk patients. Furthermore, an excellent response to therapy decreased the risk of recurrent/persistent disease to 1·4%. At the time of final follow-up, 34% of the biochemical incomplete response patients had been re-classified as having no evidence of disease (NED) without having received any additional therapy beyond continue levothyroxine suppression. Conversely, even after additional therapies, only 9% of the patients with an incomplete structural response were eventually re-classified as NED.

CONCLUSIONS

These data validate the ATA risk classification as an excellent initial predictor of recurrent/persistent disease and confirm the clinical utility of the MSKCC dynamic risk assessment system in a cohort of patients evaluated and treated outside the United States.

Classification of parathyroid cancer

PURPOSE

Parathyroid cancer is rare and often has a poor outcome. There is no classification system that permits prediction of outcome in patients with parathyroid cancer. This study was designed to validate two prognostic classification systems developed by Talat and Schulte in 2010 ("Clinical Presentation, Staging and Long-term Evolution of Parathyroid Cancer," Ann Surg Oncol 2010;17:2156-74) derived from a retrospective literature review of 330 patients.

METHODS

This study contains 82 formerly unreported patients with parathyroid cancer. Death due to disease was the primary end point, and recurrence and disease-free survival were the secondary end points. Data acquisition used a questionnaire of predefined criteria. Low risk was defined by capsular and soft tissue invasion alone; high risk was defined by vascular or organ invasion, and/or lymph node or distant metastasis. A differentiated classification system further classified high-risk cancer into vascular invasion alone (class II), lymph node metastasis or organ invasion (class III), and distant metastasis (class IV). Statistical analyses included risk analysis, Kaplan-Meier analysis, and receiver-operating characteristic (ROC) analysis.

RESULTS

Follow-up ranged 2-347 months (mean 76 months). Mortality was exclusive to the high- risk group, which also predicted a significant risk of recurrence (risk ratio 9.6; 95% confidence interval 2.4-38.4; P < 0.0001), with significantly lower 5-year disease-free survival (χ(2) = 8.7; P < 0.005 for n = 45). The differentiated classification also provided a good prognostic model with an area under the ROC curve of 0.83 in ROC analysis, with significant impairment of survival between classes (98.6%, 79.2%, 71.4%, 40.0%, P < 0.05 between each class).

CONCLUSIONS

This study confirms the validity of both classification systems for disease outcome in patients with parathyroid cancer.

Neoadjuvant chemotherapy in 29 patients with locally advanced follicular or Hürthle cell thyroid carcinoma: a phase 2 study

BACKGROUND

It is believed that chemotherapy (ChT) is ineffective in follicular thyroid carcinoma (FTC) and Hürthle cell thyroid carcinoma (HCTC). The aim of our retrospective study was to find out whether neodjuvant ChT before thyroid surgery had any effect on the size of primary tumor in patients with FTC or HCTC.

METHODS

The study included 29 patients (20 women, 9 men; mean age: 60.8 years) with FTC or HCTC who had T3 or T4 tumor and were treated with neoadjuvant ChT from 1979 to 2004. A mean tumor diameter was 9.3 cm. Extrathyroid growth of tumor was present in 15 patients. Regional and distant metastases were detected in 6 and 12 patients, respectively. With respect to the site of metastatic spread, the lung was involved in eight patients and the skeleton in five. ChT consisted of vinblastine in 19 cases, vinblastine with adriamycin in 5 cases, or other ChT regimens in 5 cases.

RESULTS

Altogether, 67 cycles of ChT were given and tumor size decreased by >50% in 13 patients (=45%). ChT was effective in patients with FTC and HCTC in 47% and 43%, respectively. In the patients with and without distant metastases, the primary tumor size decreased by >50% in 17% and 65% (p=0.02), respectively. R0, R1, and R2 resection was performed in 15, 10, and 4 cases, respectively. Histopathology revealed that ChT (i.e., wide areas of tumor necrosis) was effective in seven patients (24%). The 5- and 10-year cause-specific survivals of the patients were 77% and 47%, while the 5- and 10-year disease-free intervals were 57% and 46%, respectively. Six patients are alive (median survival: 162 months), four of them have no evidence of disease, six patients died of other causes (median survival: 101 months), while 17 patients died of FTC or HCTC (median survival: 72 months). Among them, 16 died of distant metastases, while only one succumbed to locoregional recurrence and distant metastases.

CONCLUSIONS

ChT before surgical procedure may be effective in order to decrease the tumor size in FTC or HCTC in 45% of patients.

In differentiated thyroid cancer, an incomplete structural response to therapy is associated with significantly worse clinical outcomes than only an incomplete thyroglobulin response

BACKGROUND

We previously demonstrated the clinical utility of using response to therapy variables obtained during the first 2 years of follow-up to actively modify initial risk estimates which were obtained using standard clinic-pathologic staging systems. While our proposed dynamic risk stratification system accurately reclassified patients who demonstrated an excellent response to therapy as low-risk patients, it grouped patients with either biochemical or structural evidence of disease into a single incomplete response to therapy cohort. This cohort included a wide variety of patients ranging from very minor thyroglobulin (Tg) elevations in the absence of structurally identifiable disease to widespread, progressive structural disease. Here we determined whether subdivision of the incomplete response to therapy category more precisely predicted clinical outcomes. We hypothesized that patients with an incomplete response to therapy based on persistently abnormal Tg values alone would have better clinical outcomes than patients having structurally identifiable disease.

METHODS

Following total thyroidectomy and radioactive iodine (RAI) ablation, 192 adult thyroid cancer patients were retrospectively identified as having either a biochemical incomplete response (abnormal Tg without structural evidence of disease) or structural incomplete response (structurally identifiable disease with or without abnormal Tg) as the best response to initial therapy within the first 24 months after RAI ablation. Clinical outcomes evaluated included structural disease progression, biochemical disease progression, and overall survival.

RESULTS

Sixty-three patients (33%) had a biochemical incomplete response while 129 (67%) had a structural incomplete response. Eleven to 156 months after evaluation of their responses (mean=70 months), patients with structural incomplete response were significantly more likely to have structural evidence of disease at final follow-up (37% vs. 17%, p=0.0004), structural progression (52% vs. 5%, p<0.001), biochemical progression (45% vs. 11%, p<0.001), and death from disease (38% vs. 0%, p<0.0001) than patients demonstrating a biochemical incomplete response. Overall survival was significantly better in patients with either a biochemical incomplete response or a loco-regional structural incomplete response than patients demonstrating a structural incomplete response with distant metastasis (Kaplan-Meier analysis, p<0.0001).

CONCLUSIONS

A structural incomplete response to initial therapy is associated with significantly worse clinical outcome than a biochemical incomplete response to therapy.

A comparison of prognostic classification systems for differentiated thyroid carcinoma

OBJECTIVE

To identify and compare prognostic classification systems based on basic tumour characteristics that were developed and/or validated for differentiated thyroid carcinoma (DTC).

DESIGN

Retrospective chart study.

METHODS

Literature was studied using PubMed. Fifteen different prognostic classification systems were identified, of which seven were developed or validated for DTC patients and were based on basic tumour characteristics. These systems were applied to 1225 DTC patients who were treated in our hospital between 1978 and 2002.

RESULTS

Log-rank analysis of Kaplan-Meier cancer-specific survival curves showed that the curve of the Tumor, Lymph-Node, Metastasis (TNM) system had the greatest discriminatory power (log-rank test, log P = -84.9). Cox-regression analysis showed that the TNM system was the most powerful determinant of cancer-specific survival curves. Proportion of variance explained (PVE) analysis showed that the TNM system had the highest PVE.

CONCLUSION

Of the prognostic classification systems analysed in this study, the TNM system performs best in all the three analyses, and is therefore the most suitable for predicting outcome in DTC-patients.

Classification of follicular cell tumors of the thyroid gland: analysis involving Japanese patients from one institute

Prognostic analyses of thyroid carcinomas of follicular cell origin were carried out on patients treated at Kuma Hospital, Kobe, Japan. A new histopathological classification based on the prognostic evidence is proposed in this study, and it is applicable to the patients treated curatively. Major histological types of papillary carcinoma, follicular carcinoma and poorly differentiated carcinoma were combined into one single entity of follicular cell adenocarcinoma because (i) they have the same cell origin (follicular cell); (ii) clear-cut separation of papillary and follicular carcinoma is not always possible, and 10 year cause-specific survival was essentially similar when the patients were treated curatively; and (iii) poorly differentiated carcinoma usually has a background of either papillary or follicular carcinoma. This adenocarcinoma together with undifferentiated carcinoma was stratified into four prognostic groups using pure morphological criteria of the degree of cellular differentiation and histological grade. They are termed well-differentiated adenocarcinoma, moderately differentiated adenocarcinoma, poorly differentiated carcinoma and undifferentiated carcinoma of the thyroid. The 10 year disease-free survival rates were 86.3-93.1%, 65.4-78.7%, and 43.0-53.8%, and 0%, respectively. The 10 year cause-specific survival rates were 97.2-100%, 91.5-97.4%, and 71.2-80.0%, and 0%, respectively.

Accuracy of fine-needle aspiration biopsy for predicting neoplasm or carcinoma in thyroid nodules 4 cm or larger

HYPOTHESIS

All thyroid nodules 4 cm or larger should be surgically removed regardless of fine-needle aspiration biopsy (FNAB) results because of an unacceptably high rate of false-negative preoperative biopsy results in these large nodules.

DESIGN

Retrospective cohort study.

SETTING

Single-institution, tertiary academic referral center.

PATIENTS

A retrospective analysis was performed on all patients who underwent surgery for a thyroid nodule 4 cm or larger from May 1, 1994, through January 31, 2007.

MAIN OUTCOME MEASURES

Preoperative FNAB results were correlated with final surgical pathologic results. The FNAB results were reported as nondiagnostic, benign, inconclusive (follicular neoplasm), or malignant, whereas the final surgical pathologic data were reported as benign or malignant.

RESULTS

Of 155 patients who underwent a thyroidectomy for a nodule 4 cm or larger, 21 patients (13.5%) had a clinically significant thyroid carcinoma within the nodule on final pathologic analysis. Preoperative cytologic testing of the mass was performed on 97 patients, and the results read as benign for 52, inconclusive for 23, nondiagnostic for 11, and malignant for 11. In lesions 4 cm or larger, 26 of 52 FNAB results reported as benign (50.0%) turned out to be either neoplastic (22) or malignant (4) on final pathologic analysis. Among patients with nondiagnostic FNAB results, the risk of malignant neoplasms was 27.3%.

CONCLUSIONS

In patients with thyroid nodules 4 cm or larger, the FNAB results are highly inaccurate, misclassifying half of all patients with reportedly benign lesions. Furthermore, those patients with a nondiagnostic FNAB result display a high risk of differentiated thyroid carcinoma. Therefore, we recommend that diagnostic lobectomy be strongly considered in patients with thyroid nodules 4 cm or larger regardless of FNAB cytologic test results.

Simplifying the TNM System for Clinical Use in Differentiated Thyroid Cancer

Purpose

The TNM stratification has been found useful at stratifying patients with differentiated thyroid carcinoma (DTC) into prognostic risk groups. However, it is cumbersome to implement clinically given the large number of bins within this system and the complicated system of arriving at stage information.

Patients and Methods

We decided to quantify each variable in this system to arrive at a simplified quantitative alternative to the TNM system (QTNM) and compare this with the conventional system. We used our electronic record system to identify 614 cases of DTC managed at our institution from 1987 to 2006. Cancer-specific survival (CSS) and disease-free survival (DFS) were calculated by the Kaplan-Meier method, and a simplified QTNM score was devised using a Cox proportional hazards model.

Results

We were able to quantify the TNM system as follows: 4 points each for age older than 45 years and presence of neck nodal metastases while 6 points for tumor size larger than 4 cm or extrathyroidal extension and 1 point for nonpapillary DTC. A sum of 0 to 5 points was low risk, 6 to 10 points intermediate, and 11 to 15 points high risk. Comparison with the conventional TNM system and two other systems revealed similar or better discrimination with the QTNM and this discrimination was maintained when this risk stratification was applied to a unique validation set.

Conclusion

The QTNM system as opposed to the conventional TNM system seems to be a simple and effective method for risk stratification for both recurrence and cancer-specific mortality.

Is level IIb lymph node dissection always necessary in N1b papillary thyroid carcinoma patients?

INTRODUCTION

Papillary thyroid carcinoma (PTC) patients show a high rate of cervical lymphatic metastasis. However, there are no universal binding guidelines for the extent of lateral cervical lymph node dissection (LND) in such cases. In particular, the need for LND above the spinal accessory nerve (SAN) remains controversial. The present study examined whether level IIb lymph node (LN) dissection is always necessary in PTC patients with lateral cervical LN metastasis.

MATERIALS AND METHODS

The study prospectively examined 167 PTC patients with lateral cervical LN metastasis who underwent modified radical neck dissection (MRND) in our institution from November 2005 to March 2007. The MRND was bilateral in 24 cases. All patients underwent level II, III, IV, and V LND. Levels IIa and IIb LNs were individually dissected in all cases. All LND was performed using strict leveling criteria by a single operating team. The patterns of lymphatic metastasis and potential risk factors for level IIb LN involvement were evaluated.

RESULTS

The most common site of metastasis was level III (80.6% of cases), followed by level IV (74.9%) and II (55.5%). The metastasis rates in level IIa and IIb were 55.5% and 6.8%, respectively; all level IIb LN metastasis was accompanied by level IIa metastasis (p=0.001). In addition, level IIb LN metastasis was found to be associated with the aggressiveness of lymphatic metastasis (i.e., the total number of metastatic LNs) (p<0.0001).

CONCLUSIONS

A level IIb LND should be performed when there is clinical or radiological evidence of lymphatic metastasis. In the absence of such evidence, the findings suggest that level IIb LND is not necessary in N1b PTC patients when there is no level IIa LN metastasis, or when the metastasis is not aggressive.

Subclassification of non-solid-type papillary thyroid carcinoma identification of high-risk group in common type

Two hundred and sixty-three cases of primary human papillary thyroid carcinoma (PTC) were analyzed. All cases met the following parameters: tumor size > or = 10 mm, no distant metastasis at presentation, and no coexistence of other histological type. The histological features of the solid/trabecular component, encapsulation, tall/columnar cell component and loss of polarity/cohesiveness were utilized to subclassify the 263 cases of PTC into five groups: solid type (15.6%), encapsulated group (9.5%), tall/columnar cell group (7.2%), micropapillary/discohesive group (19.8%) and not-otherwise-specified group (47.9%). We focused on the latter four non-solid groups and compared their prognosis with the solid type. The tall/columnar cell group showed the worst disease-free survival rate (DFS) analyzed by the Kaplan-Meier method, followed by the micropapillary/discohesive group. The not-otherwise-specified group and encapsulated group showed a better DFS rate than the solid type. Cancer-related death was noted in the tall/columnar cell group (21.1%) and micropapillary/discohesive group (3.8%), but not in the other groups. The four non-solid histological groups were further categorized into two prognostic groups: high-risk group (including tall/columnar cell group and micropapillary/discohesive group); and low-risk group (including encapsulated group and not-otherwise-specified group). Their 10-year disease-free survival rates were 78.7% and 93.1%, respectively. In the present study, histological grouping was significantly correlated with prognosis in the multivariate analysis according to the Cox proportional hazards regression model in addition to clinical parameters of extrathyroid invasion and gross lymph node metastasis, which predicts the patient outcome in terms of tumor recurrence and cancer-related death more precisely.

Staging systems for papillary thyroid carcinoma: a study of 2 tertiary referral centers

OBJECTIVE

To find out the most applicable and consistent staging system for papillary thyroid carcinoma (PTC) available in the literature.

BACKGROUND

The commonly used staging systems for PTC have predicted cancer-specific survival (CSS) well. However, their applicability and generalizability have not yet been evaluated in different clinical settings.

METHODS

A MEDLINE search from 1965 to 2005 was carried out to identify different staging systems available in the literature and 9 systems were applicable to 1634 PTC patients within 2 tertiary-referral centers. The CSS of each staging system within individual centers were calculated using Kaplan-Meier method and the CSS of each tumor stage in one individual center was compared with that of the other by log-rank test. In addition, within each center, the predictability of each staging system relative to the others was ranked based on the proportion of variation explained (PVE) value.

RESULTS

Clinicopathologic features, treatment received, and tumor stages were significantly different between the 2 centers. There were also significant differences in CSS within at least one tumor stage between the 2 centers in 8 of the 9 staging systems. The TNM was a highly predictive and consistent staging system within the 2 centers. Although the absolute PVE values differed between the 2 centers, the relative ranking of the 9 staging systems within each center correlated significantly to each other (P < 0.05).

CONCLUSIONS

Despite referral, treatment, and data collection biases inherent within each center, the TNM system remained to be the most applicable and consistent staging system for PTC in 2 centers managing the same population group.

Staging systems for papillary thyroid carcinoma: a review and comparison

OBJECTIVE

To find out the most predictive staging system for papillary thyroid carcinoma (PTC) currently available in the literature.

BACKGROUND

Various staging systems or risk group stratifications have been used extensively in the clinical management of patients with PTC, but the most predictive system for cancer-specific survival (CSS) based on distinct histologic types remains unclear.

METHODS

Through a comprehensive MEDLINE search from 1965 to 2005, a total of 17 staging systems were found in the literature and 14 systems were applied to the 589 PTC patients managed at our institution from 1961 to 2001. CSS were calculated by Kaplan-Meier method and were compared by log-rank test. Using Cox proportional hazards analysis, the relative importance of each staging system in determining CSS was calculated by the proportion of variation (PVE).

RESULTS

All 14 staging systems significantly predicted CSS (P < 0.001). The 3 highest ranked staging systems by PVE were the Metastases, Age, Completeness of Resection, Invasion, Size (MACIS) (18.7) followed by the new AJCC/UICC 6th edition tumor, node, metastases (TNM) (17.9), and the European Organization for Research and Treatment of Cancer (EORTC) (16.6).

CONCLUSIONS

All of the currently available staging systems predicted CSS well in patients with PTC regardless of which histologic type from which they were derived. When predictability was measured by PVE, the MACIS system was the most predictive staging system and so should be the staging system of choice for PTC in the future.

Prognostic Factors in Papillary and Follicular Thyroid Carcinoma: Their Implications for Cancer Staging

BACKGROUND

Papillary thyroid carcinoma (PTC) and follicular thyroid carcinoma (FTC) are two distinct histological types of thyroid carcinoma but have often been studied and staged as a collective group, known as differentiated thyroid carcinoma (DTC). However, this may not be an optimal approach to cancer staging.

METHODS

A total of 760 patients with DTC, comprising 589 (77.5%) with PTC and 171 with (22.5%) FTC, being managed at our institution from 1961 to 2001 were retrospectively reviewed. Their clinicopathological features, treatment modalities received, and postoperative outcome were analyzed. Both univariate and multivariate analyses were performed to identify prognostic factors related to cancer-specific survival (CSS) for PTC and FTC.

RESULTS

There were statistically significant differences between PTC and FTC in terms of age >/=50 years at diagnosis (P = .040), tumor size (P < .001), lymph node metastases (P < .001), distant metastases (P < .001), extrathyroidal extension (P < .001), multifocality (P = .002), capsular invasion (P < .001), extent of thyroid resection (P < .001), radioiodine ablation (P < .001), and external-beam irradiation (P = .003). Although PTC and FTC had similar 10-year and 15-year CSS (P = .846), each possessed its own set of independent prognostic factors for CSS. Age at diagnosis and completeness of resection were independent prognostic factors in both PTC and FTC.

CONCLUSIONS

There were marked differences in clinicopathologic features, treatment, and prognostic factors between the two histologic types of DTC. Different staging systems should be evaluated and validated for PTC and FTC individually in the future.

Prognostic significance of cytologic features in fine-needle aspiration cytology samples of papillary thyroid carcinoma: preliminary report

BACKGROUND

The influence of clinicopathologic features on prognosis of papillary thyroid cancer has been examined. However, the relationship between cytologic features obtained by fine-needle aspiration (FNA) and prognosis has been minimally studied.

METHODS

We retrospectively studied 85 patients with usual-type papillary thyroid cancer diagnosed by FNA who underwent total or near-total thyroidectomy, had disease confirmed by pathological study, and were followed for more than 10 years except for one patient with metastasis at diagnosis. Cytologic features of FNA and recurrence of cancer were examined statistically.

RESULTS

Four cytologic features were significantly related to recurrence: bigger nuclei, more irregularly shaped nuclei, nuclear atypia, and simultaneous presence of lighter staining nuclei and apparent nucleoli. A prognostic score of 1 (light nuclei and apparent nucleoli) plus 1.5 (irregularly shaped nuclei away from fibrous cord) plus 1 (high nucleus-to-cytoplasm ratio) plus 1 (nuclear atypia) was generated statistically. Sensitivity and specificity using a cut point of 2.5 in predicting outcome were 83.33% and 77.55%, respectively.

CONCLUSIONS

Cytologic features of FNA samples have prognostic significance. If the prognostic score of cytologic features is high, a more radical surgical procedure and aggressive treatment plan should be considered.

Carcinoma diferenciado de tireóide: avaliação inicial e acompanhamento

O câncer de tireóide é responsável por cerca de 1% dos novos casos de doença maligna diagnosticados. A maioria destes tumores são carcinomas papilares e foliculares, também denominados de carcinomas diferenciados de tireóide (CDT). Estes carcinomas têm uma taxa de cura de aproximadamente 80%, enquanto 20% apresentarão recorrência local e 5 a 10% desenvolverão metástases à distância. Porém, alguns pacientes apresentam uma doença mais agressiva. A identificação de tais pacientes tem grande impacto no manejo clínico do CDT. Várias classificações de estádio clínico e fatores prognósticos são apresentados, bem como os principais exames para seguimento dos pacientes com CDT.

Prognostic factors in papillary thyroid cancer: an evaluation of 601 consecutive patients

BACKGROUND

Although papillary thyroid cancer (PTC) is among the most curable cancer types, it can be a distressing disease for those patients suffering from frequent recurrences or even distant metastases leading to death. Age over 45 years is the most important indicator of poor prognosis. Our aim was to evaluate markers which might predict the outcome of an individual patient better than does TNM classification alone.

MATERIALS AND METHODS

Of 601 consecutive patients who underwent surgery for PTC, retrospectively we selected 36 patient pairs in which one recovered completely after primary surgery, and the other suffered from aggressive disease. Formalin-fixed, paraffin-embedded tumor samples from these 72 patients were analyzed by immunohistochemistry for COX-2, MMP-2, VEGF-C, Bcl-2, Ki-67, and p21 expression.

RESULTS AND CONCLUSIONS

None of the markers we studied showed a superiority over TNM classification in selecting patients likely to progress to aggressive disease. However, the expression of COX-2 and VEGF-C seemed to be increased in patients over 45, which could explain the more aggressive behavior of these tumors. Moreover, we found that age over 45, tumor size over 4 cm, extrathyroidal extension of tumor, nodal metastases, distant metastases, and stage IV had an unfavorable effect on survival.

Is patient's age a prognostic factor for follicular thyroid carcinoma in the TNM classification system?

The knowledge of prognostic factors is essential for an optimal treatment of patients. The aim of our study was to find out if age is an independent prognostic factor for patients with follicular or Hürthle cell carcinoma. This retrospective study was carried out in 261 patients (median age, 62 years) with follicular or Hürthle cell thyroid carcinoma treated at our institute from 1972-2002. For all patients the follow-up was performed at our institute at least once per year. The data on gender and age of the patients, disease history, extent of disease, morphologic characteristics, mode of therapy, outcome, and survival were collected. Statistical correlation between possible prognostic factors and cause-specific survival was analyzed by univariate and Cox's multivariate survival analysis. The 10-year and 20-year survival of all 261 patients were 70% and 42%, respectively. Even 10 of 49 (20%) of our patients who were under 45 years of age (i.e., in stage II of the tumor, node, metastases [TNM] classification system) died of disease. Multivariate analysis showed that primary tumor size and distant metastases were independent prognostic factors for survival. Lymph node metastases as well as the age of patients were not found to be independent prognostic factors. Therefore, the patients with distant metastases or tumor stage T4 who are under 45 years of age cannot be considered to have favorable prognosis.

Importance of tumour size in papillary and follicular thyroid cancer

BACKGROUND

The most controversial change in the new pathological tumour node metastasis (pTNM) classification of thyroid tumours is the extension of the pT1 classification to include tumours up to 20 mm.

METHODS

Four hundred and three patients with pT1 or pT2 differentiated thyroid carcinomas were divided into three groups according to tumour diameter (group 1, 10 mm or less; group 2, 11-20 mm; group 3, 21-40 mm). They were analysed retrospectively with respect to carcinoma-specific and disease-free survival.

RESULTS

No patient in group 1 died from papillary thyroid carcinoma, compared with three patients in group 2 and six in group 3. There was a statistically significant difference in carcinoma-specific survival between groups 1 and 2 (P = 0.033). Two patients in group 1, six in group 2 and eight in group 3 developed recurrence. The difference in disease-free survival between groups 1 and 2 was significant (P = 0.025). One patient in group 1, three in group 2 and four in group 3 died from follicular thyroid carcinoma, but there were no significant differences in survival between the three groups.

CONCLUSION

Extension of the pT1 classification to cover all tumours up to 20 mm does not appear to be justified for papillary thyroid carcinoma.

A model for predicting outcomes in patients with differentiated thyroid cancer and model performance in comparison with other classification systems

BACKGROUND

This study was performed to determine the prognostic factors for differentiated thyroid cancer, and to establish a mathematical prognostic model.

STUDY DESIGN

A retrospective study was conducted in 347 differentiated thyroid cancer patients. Univariate and multivariate prognostic factor analyses were carried out using the Kaplan-Meier and Cox regression methods.

RESULTS

Without adjustment for treatment in the multivariate analysis, age, tumor size, angioinvasion, and distant metastasis were significant predictors of outcomes. The very low-risk, low-risk, high-risk, and very high-risk groups were identified from the logistic regression equation. Overall and event-free survival estimations at 10 years were 100% and 100% for very low-risk patients, 88% and 75% for low-risk patients, 30% and 16% for high-risk patients, and 5% and 0% for very high-risk patients. Inclusion of treatment in the multivariate analysis showed, in addition to other variables, that both total or near total thyroidectomy (versus thyroidectomy less than total and near total thyroidectomy, p = 0.0002; hazard ratio, 0.4; 95% CI, 0.3-0.7) and adjuvant radioactive iodine treatment (versus no treatment with radioactive iodine, p = 0.0001; hazard ratio, 0.5; 95% CI, 0.2-0.8) were associated with a reduced hazard of death in the followup period. By subgroup analysis, total and near total thyroidectomy, along with radioactive iodine, appeared to provide a survival benefit for all patients except those in the very low-risk group.

CONCLUSIONS

The proposed mathematical model is satisfactory for predicting outcomes. Total and near total thyroidectomy along with radioactive iodine treatment might provide a survival advantage for differentiated thyroid cancer, except for those with very low risk.

Expression of COX-2 is increased with age in papillary thyroid cancer

AIMS

To study cyclooxygenase-2 (COX-2) and matrix metalloproteinase-2 (MMP-2) expression in papillary thyroid cancer (PTC). Expression of COX-2 is elevated in various human tumours and it has an important role in carcinogenesis. MMP-2 is also an important component of the metastatic potential of tumours. In PTC the most important factor affecting survival is age, but it is poorly understood why older PTC patients have a worse prognosis.

METHODS AND RESULTS

This retrospective study comprised 108 patients with PTC, and we compared patients who were either younger than 35 (n = 59) or older than 55 (n = 49). Paraffin-embedded tumour samples were analysed for COX-2 and MMP-2 protein expression using immunohistochemistry. High (scores 2-3) COX-2 immunostaining was observed in 38/108 (35%) of the tumours, and COX-2 expression was significantly (P = 0.002) higher in the older age group (25/49; 51%) than in the young one (13/59; 22%).

CONCLUSIONS

Our study shows that COX-2 expression increases with age. It is possible that the age-related increase in COX-2 expression could explain the more aggressive behaviour of PTC in the older age group compared with the young one.

Papillary carcinoma of the thyroid in Japan: subclassification of common type and identification of low risk group

AIMS

Papillary thyroid carcinoma (PTC) is classified into two subgroups-common type and other histological variants. Correlations between further subgrouping of the common type and patient prognosis are not well documented.

AIMS

To introduce two novel histological parameters to characterise PTC-loss of cellular polarity and loss of cellular cohesiveness. To investigate a new subgroup of common type PTC with possible prognostic value.

METHODS

In total, 213 patients with PTCs larger than 1 cm were studied. Histological characteristics of these PTCs, including tumour growth pattern, encapsulation, extrathyroidal invasion, loss of cellular polarity, and loss of cellular cohesiveness were examined and correlated with disease free survival (DFS).

RESULTS

Multivariate analysis revealed that invasive growth of unencapsulated PTC, in addition to sex (male) and tumour size (>4 cm) were significant and independent parameters for poor DFS, whereas loss of cellular polarity and cohesiveness, old age (>60 years), extrathyroid invasion, and completeness of surgery were significant only in univariate analysis. PTCs that showed expansive growth and retained cellular polarity had a favourable course, with no recurrence and no cancer related deaths. In contrast, PTCs exhibiting loss of cellular polarity and/or invasive growth with no tumour capsule had a higher risk of recurrence.

CONCLUSION

Cytological features alone cannot predict patient outcome in PTC. This study indicates for the first time that loss of cellular polarity and the tumour growth pattern are useful parameters for identifying the so called low risk group in common type PTC and in predicting patient outcome in terms of tumour recurrence and cancer related death.