Prognostic factors in differentiated thyroid carcinoma: a multivariate analysis of 234 consecutive patients

Causal inference between aggressive extrathyroidal extension and survival in papillary thyroid cancer: a propensity score matching and weighting analysis

Background

Extrathyroidal extension is a major risk factor for poor prognosis in papillary thyroid cancer. However, the effect of different degrees of extrathyroidal extension on prognosis remains controversial. We performed a retrospective study to elucidate how the extent of extrathyroidal extension in papillary thyroid cancer affected the clinical prognosis of patients and its covariates.

Methods

The study included 108,426 patients with papillary thyroid cancer. We categorized the extent of extension into none, capsule, strap muscles, and other organs. Three causal inference methods for retrospective studies, namely, inverse probability of treatment weighting, standardized mortality ratio weighting, and propensity score matching analysis, were used to minimize potential selection bias. Kaplan-Meier analysis and univariate Cox regression analyses were applied to analyze the precise effect of ETE on survival in papillary thyroid cancer patients.

Results

In the Kaplan-Meier survival analysis, only extrathyroidal extension into or beyond the strap muscles was statistically significant for both overall survival (OS) and thyroid cancer-specific survival (TCSS). In univariate Cox regression analyses before and after matching or weighting based on causal inference, extrathyroidal extension into soft tissues or other organs is a high-risk factor for both overall survival and thyroid cancer-specific survival. Sensitivity analysis revealed that lower overall survival was observed in patients with older age (≥55) and larger tumor size (>2 cm) of papillary thyroid cancer with extrathyroidal extension into or beyond the strap muscles.

Conclusions

Our study indicates that extrathyroidal extension into soft tissues or other organs is a high-risk factor in all papillary thyroid cancer. Even though invasion into the strap muscles did not seem to be a marker for poor prognosis, it still impaired the overall survival of patients with older age (≥55 years old) or larger tumor size (>2 cm). Further investigation is needed to confirm our results and to clarify further risk factors independent of extrathyroidal extension.

The role of the size in thyroid cancer risk stratification

Only a minority of cases of differentiated thyroid carcinoma (DTC) have a poor clinical outcome. Clinical outcomes and molecular aspects were assessed in: 144 DTC ≤ 40 mm without distant metastases (group 1); 50 DTC > 40 mm without distant metastases (group 2); and 46 DTC with distant metastases (group 3). Group 3 had a worse outcome than the other two groups: during the follow-up, patients more frequently had persistent disease, died, or underwent further treatment. The outcomes did not differ between groups 1 and 2. Group 3 had a higher prevalence of TERT promoter mutations than group 2 (32.6% vs 14%). Group 1 had a higher frequency of BRAF mutations than groups 2 or 3 (61.1% vs 16.0% and 26.1%, respectively), while RAS mutations were more common in group 2 than in groups 1 and 3 (16.0% vs 2.1% and 6.5%, respectively). Groups 1 and 2 shared the same outcome, but were genetically distinct. Only lymph node involvement, distant metastases, older age and (among the molecular markers) TERT promoter mutations were independent predictors of a worse outcome. Metastatic DTC had the worst outcome, while the outcome was identical for large and small non-metastatic DTC, although they showed different molecular patterns. TERT promoter mutations emerged as an independent factor pointing to a poor prognosis.

Innovative analysis of distant metastasis in differentiated thyroid cancer

Differentiated thyroid cancer (DTC) is the most common thyroid cancer with a relatively high survival rate. The association between certain risk factors of distant metastasis (DM) remains uncertain. In order to assess the prognosis of patients with DTC better, the present study aimed to investigate the synergistic effects between histologic subtype, tumor size, lymph node metastasis (LNM) status and extrathyroidal extension (ETE) on the incidence of DM in DTC. Data of 96,788 patients with DTC were obtained from the Surveillance, Epidemiology and End Results database. The association between clinicopathological factors and DM was evaluated by univariate and multivariate analyses. The synergistic effects of relevant factors were determined by measuring the relative excess risk due to interaction (RERI), attributable proportion due to interaction (AP) and synergy index (SI). The results demonstrated that tumor size, LNM status, histologic subtype and ETE were independent risk factors for DM [odds ratio (OR)=2.433; P<0.001; OR=3.998; P<0.001; OR=6.266; P<0.001; and OR=3.873; P<0.001, respectively]. In addition, a significant additive synergistic effect on DM was identified between ETE and histologic subtype, ETE and LNM status, as well as between ETE and tumor size (RERI=34.097; AP=0.706; SI=3.585; RERI=6.425; AP=0.410; SI=1.781; and RERI=76.973; AP=0.864; SI=7.930, respectively). Therefore, the results of this study revealed that ETE with follicular thyroid histology, N1 stage or large tumor size may have a synergistic effect on the risk of DM in patients with DTC. These results suggested that individualized treatment may benefit patients with DTC, and when ETE coexists with one of the identified risk factors, radical treatments may be required.

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.

A immunosuppressive triterpenoid saponin from the stems of Epigynum griffithianum

Chemical investigation of the stems of Epigunum griffithianum led to the isolation and identification of a new triterpenoid saponin (1) and two known compounds (epigynosides A (2) and B (3)). These structures were elucidated by means of spectroscopic analysis (1D and 2D NMR, MS, UV, IR) as well as comparison with the reported data. Compound 1 was evaluated in vitro for the immunosuppressive activities on proliferation of mice splenocyte and displayed significant immunosuppressive activities compared to the positive control (dexamethasone) with the concentration at 25 μM.[Formula: see text].

Risk Factors for Central Neck Lymph Node Metastases in Micro- Versus Macro- Clinically Node Negative Papillary Thyroid Carcinoma

BACKGROUND

Tumor size has been advocated as possible risk factors for occult central lymph node metastases (CNM) in papillary thyroid carcinoma (PTC) patients. This prospective study evaluated factors that could identify patients at higher risk of occult CNM, especially comparing micro-PTC and macro-PTC.

METHODS

One hundred and eighty-six patients were recruited. All the patients had cN0 clinically unifocal PTC and underwent total thyroidectomy and bilateral prophylactic central neck dissection. Risk factors for occult CNM in micro- and macro-PTC patients were evaluated.

RESULTS

Eighty-two patients showed CNM. The rate of CNM did not differ among different sizes cut off (≤20 mm, ≤10 mm, ≤5 mm P = NS). Significantly more pN1a than pN0 patients had pT3 tumors (35/82 vs. 26/104) (P < 0.05), extracapsular invasion (35/82 vs. 22/104) (P < 0.01) and microscopic multifocal disease (50/82 vs. 47/104) (P < 0.05). Independent risk factors for CNM were extracapsular invasion and multifocality at multivariate analysis. Risk factors for CNM in 77 micro-PTC were extracapsular invasion (16/31 pN1 vs. 10/46 pN0, P < 0.05) and multifocality (21/31 pN1 vs. 16/46 pN0, P < 0.01). Among 109 macro-PTC, risk factors for CNM were angioinvasion (15/51 pN1 vs. 7/58 pN0, P < 0.05) and classic PTC at the final histology (PTC vs. tall cell variant vs. follicular variant PTC) (P < 0.05).

CONCLUSIONS

Risk factors for CNM can differ between micro- and macro-PTC, but no preoperatively known clinical parameter is predictor of CNM in cN0 clinically unifocal PTC.

Updated guidelines on the preoperative staging of thyroid cancer

Recent studies have provided prognostic information and recommendations for staging thyroid cancers that have changed the staging and management guidelines for the disease. Consequently, minimal extrathyroidal extension (ETE) was removed from the T3 stage classification in the eighth edition of the TNM staging system by the American Joint Committee on Cancer. New T categories have been subsequently added, including T3a, defined as a tumor >4 cm in its greatest dimension, limited to the thyroid gland, and T3b, defined as a tumor of any size with gross ETE invading only the strap muscles. In this article, the author reviews the changes in the TNM staging system for thyroid cancer, with an emphasis on ultrasonography in preoperative staging.

Nonanaplastic follicular cell-derived thyroid carcinoma: mitosis and necrosis in long-term follow-up

Nonanaplastic follicular cell-derived thyroid carcinoma (NAFCTC) includes differentiated- (DTC) and poorly differentiated thyroid carcinoma (PDTC). DTC has an excellent prognosis, while PDTC is situated between DTC and anaplastic carcinomas. Short-term studies suggest that PDTC patients diagnosed only on tumor necrosis and/or mitosis have a prognosis similar to those diagnosed according to the TURIN proposal. The purpose of this study was to evaluate prognosis for NAFCTC based on long-term follow-up illuminating the significance of tumor necrosis and mitosis. A cohort of 225 patients with NAFCTC was followed more than 20 years. Age, sex, distant metastasis, histology, tumor size, extrathyroidal invasion, lymph node metastasis, tumor necrosis and mitosis were examined as possible prognostic factors. Median follow-up time for patients alive was 28 years (range 20-43 years). Age, distant metastasis, extrathyroidal invasion, tumor size, tumor necrosis and mitosis were independent prognostic factors in multivariate analysis for overall survival (OS). In disease specific survival (DSS) age was not significant. Using only necrosis and/or mitosis as criteria for PDTC the 5-, 10- and 20-year OS for DTC was 87, 79 and 69%, respectively. In DSS it was 95, 92 and 90%. For PDTC the 5-, 10- and 20-year OS was 57, 40 and 25%, respectively. In DSS it was 71, 55 and 48%. Tumor necrosis and mitosis are highly significant prognostic indicators in analysis of long time survival of nonanaplastic follicular cell-derived thyroid carcinoma indicating that a simplification of the actually used criteria for poorly differentiated carcinomas may be justified.

Papillary thyroid carcinoma in Denmark, 1996-2008: outcome and evaluation of established prognostic scoring systems in a prospective national cohort

BACKGROUND

Regional as well as national series show an increasing incidence of thyroid cancer largely small size papillary thyroid carcinoma (PTC). Prognostic scoring systems have been developed, but these do not take into account the rapidly changing case mix, and adjustments may be required. The purposes of this study were to evaluate treatment outcomes and to analyze the value of older prognostic scoring systems tested on a relatively new, unselected national cohort of PTC patients.

METHODS

This was a national prospective cohort study conducted in Denmark, which has a population of 5.5 million.

RESULTS

A total of 1350 patients were diagnosed with PTC during 1996-2008, and the median follow-up time was 7.9 years. The 10-year recurrence-free survival rate was 90.2%, and the 10-year crude and cause-specific survival (CSS) rates were 83.7% and 93.8% respectively. By multivariate Cox regression, it was possible to confirm age, metastases (distant and nodal), extrathyroidal extension, and tumor size as predictors of mortality, whereas only nodal metastases, extrathyroidal extension, and tumor size were predictors of recurrence. In analyses of older prognostic scoring systems, a significant correlation between the risk group ranks was found for survival as well as recurrence. The c-index for CSS was highest for MACIS (0.92) and lowest for AMES (0.80). In the TNM, MACIS, and EORTC systems, most patients were classified as stage 1, and for these patients, the 10-year CSS rate was approximately 99.5%, confirming the generally excellent survival.

CONCLUSION

This national study provides further evidence that a favorable prognosis is to be expected for patients diagnosed with PTC. Also, it was possible to confirm age, metastases, extrathyroidal extension, and tumor size as predictors of mortality, whereas only nodal metastases, extrathyroidal extension, and tumor size were predictors of recurrence. All the scoring systems evaluated were able to produce a highly significant risk group stratification, showing that in spite of the changes in the case mix of PTC, these systems are still applicable, and in fact contain valuable prognostic information useable for treatment planning.

Preoperative ultrasonographic features of papillary thyroid carcinoma predict biological behavior

BACKGROUND

Although ultrasound (US) features of papillary thyroid carcinoma (PTC) are well established, little is known regarding biological behavior according US features. We investigated whether there was a difference in biological behavior between PTCs that did and did not meet malignant US criteria.

PATIENTS AND METHODS

We retrospectively reviewed clinical records and histological and US findings of the index tumors in 488 patients who underwent surgery for PTC. Benign-looking PTC (B-PTC) was defined as showing none of the accepted US criteria for malignancy. Malignant-looking PTCs (M-PTCs) and B-PTCs were compared in terms of patients' age, sex, tumor size, histological subtype, multifocality, lymph node (LN) metastasis, extrathyroidal extension, stage, recurrence, and distant metastasis.

RESULTS

B-PTCs accounted for 74 (15%) of all 488 PTCs. Mean tumor size was not significantly different between the groups, with 1.10 cm for M-PTC and 1.11 cm for B-PTC (P = .947). Univariate and multivariate analysis indicated that M-PTC more frequently had LN metastasis, extrathyroidal extension, and a higher stage than B-PTC (all P < .05). The results were significant in tumors ≥1.0 cm, whereas there were no significant differences in tumors <1 cm. As the number of malignant US features increased, multifocality, extrathyroidal extension, LN metastasis, and a higher stage were more likely.

CONCLUSION

PTCs that did not meet malignant US criteria had better prognostic indicators than PTCs that met US criteria. Therefore, US features at the time of diagnosis can serve as a useful tool for predicting biological behavior in PTC.

Influence of lymphocitic thyroiditis on prognostic outcome differentiated thyroid carcinoma

Backgraund/aim. Thyroid carcinoma is rare malignant tumors. They are typically presented with slow progression and clinical course. Lymphocytic infiltration, including fagocytosis of neoplastic cells by macrophage plays an important role in preventing development of distant metastases. This paper sets the following objectives: Establish whether presence or absence of Hashimoto thyroiditis in differentiated thyroid carcinoma (DTC) is a favourable prognostic factor. Methods. The group under examination here are all newly diagnosed patients with differentiated thyroid carcinoma surgically treated at the Surgery Clinic in Podgorica from 2003. to 2010. A total of 125 patients, aged 11 to 79, were included in this research. The patients were divided in two groups, those with and those without lymphocytic infiltration. Both groups were mutually compared for their prognostic factors. For the identification of T and B lymphocytes, anti-CD 3 and anti-CD 20 antibodies were used. Student t-test was used for comparison of clinical and pathological parameters among groups, Hi square test for comparison of frequency, and Coxs regression model for time dependant variables as frequency of recurrence among groups with various stages of disease. Survival curve (Kaplan-Meier) is used for comparison of time dependant variables (survival, recurrence, death). The follow-up time ranges from 10 to 70 months in both groups of patients. Results are as follows: presence of lymphocytic infiltration in thyroid tissue in patients with differentiated thyroid carcinoma is significant prognostic factor (P<0.0001). But, absence of lymphocytic infiltration is a poor prognostic factor in patients with invasive extra thyroid tumours (P<0.0001). Also, absence of lymphocytic infiltration is a poor prognostic factor for development of lymphogenic and hematogenic metastases. The presence of T or B lymphocytes and varying degree of their presence is not a significant prognostic factor (P<0.0046). Patients without lymphocytic infiltration are significantly more numerous in the fourth stage of disease (P<0.0001). There is no statistically significant difference in terms of the presence of T or B lymphocytes in the tissue. Chronic lymphocytic thyroidis hahshimoto is a favourable prognostic factor in our examined group (P<0.0001). Local invasiveness and extrathyroid expansion is significantly smaller in the group of patients with the presence of lymphocytic infiltration (P<0.0001). By means of univariate analysis, we found that factors with a significant impact on survival rate include age (P<0.0001), size of tumour (P<0.018), extrathyroid invasiveness (P<0.0001), hematogenic metastases (P<0.049). Lymphocytic infiltration is present in 81% of patients in their thyroid gland, and in 19% patients there are no lymphocytes in tissue. Limphocitic infiltration has a favourable influence on tumor variables. Conclusion.This research has shown that lymphocytes in tissue as part of Hashimoto thzroiditis have an effect on certain prognostic factors of differentiated thyroid carcinoma as size, smaller invasiveness and extrathyroid tumour growth and incidence of hematogenic metastases.

Prognostic factors and therapeutic strategies for differentiated carcinomas of the thyroid

Differentiated thyroid carcinoma originates from thyroid follicular cells and is the most prominent malignancy of the endocrine organs. There are two histological types of differentiated carcinoma, namely, papillary and follicular carcinoma. According to reports from Western countries, papillary carcinoma comprises 85.3% of thyroid malignancies in whites, and 72.3% in blacks. In Japan, a previous study showed that the prevalence of papillary carcinoma was 78.4% based on material registered between 1977 and 1986, but according to recent findings reported in 2004 by Japanese Society of Thyroid Surgeons (JSTS), papillary carcinoma accounted for as much as 93% of all thyroid carcinomas. Papillary carcinoma frequently metastasizes to the regional lymph node and shows multicentricity in the thyroid gland. It usually shows a typical ultrasonographic appearance and can be rather easily diagnosed by fine needle aspiration biopsy (FNAB). Follicular carcinoma accounts for 10.9-20.5% of the patients in the United States. In Japan, the prevalence of follicular carcinoma was reported to be 17.2%, but it decreased to 5% in a report by JSTS in 2004. This carcinoma is only occasionally diagnosed preoperatively, because it is hard to discriminate follicular carcinoma from benign adenoma on imaging studies and cytologic findings. In contrast to papillary carcinoma, follicular carcinoma more often metastasizes to distant organs than regional lymph nodes. In Japan, the prevalence of papillary carcinoma increased and that of follicular carcinoma decreased between reports from 1977 to 1986 and that in 2004, which may be because follicular variant of papillary carcinoma was classified into follicular carcinoma in the previous results. Generally, these carcinomas show an indolent character, but when the lesion dedifferentiates and becomes undifferentiated carcinoma, it displays very rapid growth with an adverse prognosis and is regarded even as the most aggressive malignancy among human solid carcinomas. Furthermore, cases showing certain characteristics are likely to be constantly progressive and even become life-threatening. Such cases should be regarded as "high-risk" requiring careful and extensive surgical treatment and postoperative follow-up. Indeed, it is most important for physicians to correctly distinguish high-risk cases from those with an indolent character, although how to evaluate the biological characteristics of thyroid carcinoma and how to identify high-risk cases remains highly controversial. In this review, the methods of distinguishing high-risk cases and the appropriate therapeutic strategies for papillary and follicular carcinomas predominantly based on our experience are emphasized and our proposals for therapies including surgical treatment are demonstrated.

Risk factors contributing to a poor prognosis of papillary thyroid carcinoma: validity of UICC/AJCC TNM classification and stage grouping

BACKGROUND

In 2002, the UICC/AJCC TNM classification for papillary thyroid carcinoma was revised. In this study, we examined the validity of this classification system by investigating the predictors of disease-free survival (DFS) and cause-specific survival (CSS) in patients.

METHODS

We examined various clinicopathological features, including the component of the TNM classification, for 1,740 patients who underwent initial and curative surgery for papillary carcinoma between 1987 and 1995.

RESULTS

Clinical and pathological T4a, clinical N1b in the TNM classification, and patient age were recognized as independent predictors of not only DFS, but also CSS of patients. Tumor size, male gender, and central node metastasis independently affected DFS only. There were 1,005 pathological N1b patients, but pathological N1b did not independently affect either DFS or CSS. Regarding the stage grouping, clinical stage IVA including clinical N1b more clearly affected DFS and CSS than pathological stage IVA including pathological N1b.

CONCLUSION

Clinical stage grouping was more useful than pathological stage grouping for predicting the prognosis of papillary carcinoma patients possibly because pathological stage overestimates the biological characteristics of many pathological N1b tumors.

Extranodal tumor extension to adjacent organs predicts a worse cause-specific survival in patients with papillary thyroid carcinoma

BACKGROUND

We previously reported that massive extrathyroid extension has an independent prognostic value in patients with thyroid papillary carcinoma. However, tumor extension to adjacent organs can be observed not only in primary tumor but also in metastatic nodes. In this study we investigated the clinical significance of extranodal tumor extension to adjacent organs (nodal ex) in papillary thyroid carcinoma.

METHODS

We classified all cases into three categories based on the degree of nodal ex: nodal ex0, no apparent extranodal tumor extension; nodal ex1, hard metastatic nodes with perinodal growth extending to adjacent organs, which require separation of the nodes from the organs; and nodal ex2, metastatic nodes with perinodal growth completely invading the adjacent organs and requiring excision of nodes together with these organs. We investigated the clinical significance of each grade in 1,692 patients who underwent initial surgery for papillary carcinoma between 1987 and 1995.

RESULTS

The presence of nodal ex was significantly linked to various clinicopathological features such as male gender, N1b, large number of metastatic nodes, pT4a, and distant metastasis. On univariate analysis, patients with either nodal ex1 or ex2 showed significantly worse disease-free and cause-specific survival rates, although these rates did not differ between patients with nodal ex1 and those with nodal ex2. Furthermore, multivariate analysis demonstrated that nodal ex independently predicts worse cause-specific survival of these patients.

CONCLUSIONS

Presence of nodal ex significantly reflects the biologically aggressive behaviors of papillary carcinoma and has a prognostic value, especially for cause-specific survival of patients.

Histological aggressiveness of fluorodeoxyglucose positron-emission tomogram (FDG-PET)-detected incidental thyroid carcinomas

BACKGROUND

We previously reported a high incidence of primary thyroid cancer in fluorodeoxyglucose positron-emission tomogram (FDG-PET)-detected incidental thyroid abnormalities. The aim of our study was to determine if these FDG-PET-detected thyroid malignancies represent a more-aggressive variant of primary thyroid carcinoma.

MATERIALS AND METHODS

All patients that underwent operative intervention for FDG-PET-detected incidental thyroid abnormalities were identified (June 2003 to April 2006). Patients with a diagnosis of primary thyroid carcinoma on final histopathology were included in the study. The patient demographics and histopathological findings were analyzed to identify adverse prognostic features.

RESULTS

In 11,500 patients, 17,250 FDG-PET scans were performed; 377 of these patients (3.2% of patients and 2.1% of FDG-PET scans) had findings positive for thyroid abnormality. Of the 32 patients that underwent operative intervention, 22 patients with a final diagnosis of primary thyroid malignancy were included in the study. A greater number of patients [12 patients, (54%)] were noted to harbor poor prognostic variants of primary thyroid carcinoma on final histopathology [tall-cell variant: 11 patients (50%) and poorly differentiated thyroid carcinoma: 1 patient (4%)]. Extra-thyroidal extension (ETE) was noted in the majority of patients [14 patients (63%)]. In patients with tall cell variant on final histopathology, the rate of ETE was even higher [10 patients (90%)].

CONCLUSION

Thyroid malignancies incidentally detected on FDG-PET scan harbor a high rate of unfavorable prognostic features and may represent a more-aggressive variant of primary thyroid carcinoma. These patients need to be subjected to further investigation with a view to possible operative intervention.

Clinical significance of lymph node metastasis of thyroid papillary carcinoma located in one lobe

BACKGROUND

Previous studies have shown that lymph node metastasis can be of prognostic value. In this study, we investigated the clinical significance of node metastasis focusing on metastasis in the central compartment for patients with papillary carcinoma located in one lobe.

PATIENTS AND METHODS

We investigated the frequency of lymph node metastasis in 759 patients with papillary carcinoma to determine whether and how such metastasis affects disease-free survival (DFS).

RESULTS

Central node metastasis was observed in 63% of patients, and the frequency was increased in relation to tumor size. The frequency of lateral node metastasis was 62.0%, which was also directly related to tumor size. On multivariate analysis of cases showing tumor larger than 1 cm, central node metastasis was recognized as an independent prognostic factor of DFS. The frequency of metastasis to the paratracheal nodes contralateral to the tumor was drastically elevated for tumors larger than 1 cm, but metastasis to this region did not independently predict worse DFS.

CONCLUSION

Central node metastasis independently predicts a worse DFS for patients with papillary carcinoma larger than 1 cm.

Lymph node metastases in differentiated thyroid cancer under 2 cm

BACKGROUND

The goal of this study was to evaluate the presence of lymph node metastasis in patients with T1 differentiated thyroid cancer (DTC) and determine prognostic significance for tumor recurrence and cancer-related death.

METHODS

From a prospective tumor registry, we reviewed data from 551 patients with DTC who underwent total or subtotal thyroidectomy and who had primary tumor size </=2 cm. Patients received standard radioactive iodine ablation.

RESULTS

The proportion of patients with lymph node metastasis was 45%. This percentage remained the same in a comparison of tumors from 0 to 1 cm with tumors from 1 to 2 cm. Logistic regression analyses did not identify primary tumor size as a predictor of lymph node metastasis, but did show that histologic vascular invasion and soft tissue invasion correlated with positive lymph nodes. Multifocal disease approached significance. Actuarial estimates for first recurrence displayed a significant difference in patients who had positive cervical lymph nodes versus negative nodes: 56% versus 71% disease-free at 20 years. There was no difference in cancer-related death.

CONCLUSIONS

In T1 DTC, lymph node metastasis does not correlate with tumor size but does correlate with vascular/soft tissue invasion. Patients with positive lymph nodes have a higher recurrence risk, but no significant increase in death.

Prognostic significance of extrathyroid extension of papillary thyroid carcinoma: massive but not minimal extension affects the relapse-free survival

OBJECTIVES

Extrathyroid extension has been recognized as a prognostic factor in papillary thyroid carcinoma. In the most recent version of the UICC TNM classification system, extrathyroid extension has been classified into two grades, minimal extension (extension to sternothyroid muscle or perithyroid soft tissues) and massive extension (extension to subcutaneous soft tissue, larynx, trachea, esophagus, or recurrent laryngeal nerve). In this study, we investigated the prognostic significance of each of the two types of extension.

PATIENTS AND METHODS

One thousand and sixty-seven patients with papillary thyroid carcinoma without distant metastasis at surgery, who underwent surgical treatment in Kuma hospital between 1990 and 1995 and had been followed postoperatively for 60 months or more, were enrolled in this study. The grading of extrathyroid extension was based on both pathological findings and intraoperative surgical findings.

RESULTS

In univariate analysis, although patients with massive extension showed a significantly worse relapse-free survival (RFS) rate than those with no or minimal extension (P < 0.0001), there was no difference in the RFS rate between patients with no extension and those with minimal extension. Among patients with massive extension, the RFS rate tended to be worse in those with posterior extension than in those with anterior extension (P = 0.0562). Furthermore, the RFS rate of patients with massive posterior extension only to the recurrent nerve demonstrated a better RFS rate than those with extension to other posterior organs (P = 0.0052). Multivariate analysis demonstrated that massive extrathyroid extension is recognized as an independent prognostic factor for RFS (P = 0.0003).

CONCLUSIONS

These findings suggest that (1) upgrading of T category for tumors with massive extension is appropriate, whereas that for tumors with only minimal extension is not, and (2) careful surgical treatment and postoperative follow-up are required for tumors with massive extension to posterior organs other than the recurrent laryngeal nerve.

Minimal extrathyroid extension does not affect the relapse-free survival of patients with papillary thyroid carcinoma measuring 4 cm or less over the age of 45 years

PURPOSE

In the most recent version of the UICC TNM classification system for thyroid carcinoma, tumors with minimal extrathyroid extension were classified as T3. In this study, we investigated whether this upgrading is appropriate for papillary thyroid carcinoma.

METHODS

We investigated the difference in the relapse-free survival (RFS) rate between patients with tumors having no, minimal, and massive extrathyroid extension in a series of 502 patients over the age of 45 years.

RESULTS

Patients with tumors showing massive extension showed a worse RFS rate except for those with tumors measuring 1 cm or less. However, there was no significant difference in RFS between tumors measuring 4 cm or less showing no or minimal extension. In an investigation of 409 patients without any clinically apparent node metastasis, the RFS of patients with tumors larger than 4 cm with massive extension was significantly worse than those with tumors measuring 4 cm or less, while the RFS of patients with tumors with either no or minimal extension did not depend on the tumor size.

CONCLUSIONS

These findings suggest that tumors with minimal extension should be classified to have the same T grade as those without such extension, and upstaging of such tumors is therefore not appropriate.

Needle tract implantation of papillary thyroid carcinoma after fine-needle aspiration biopsy

Although fine-needle aspiration biopsy (FNAB) is a useful tool for diagnosing thyroid carcinoma, there are some risks of complications. In this study, we investigated tumor implantation by FNAB of papillary carcinoma. We compared the characteristics of the main tumors and implanted tumors of patients showing FNAB implantations. Between 1990 and 2002, 4912 patients underwent FNAB and were diagnosed as having papillary carcinoma. We encountered 7 cases of needle tract implantation, which account only for 0.14%. We reviewed these 7 cases as well as 3 other patients who underwent FNAB in other hospitals. The intervals between FNAB and detection of the implanted tumor ranged from 2 to 131 months. For these 10 patients, the main tumors in 6 were diagnosed as poorly differentiated carcinoma, and 7 showed extrathyroid extension. Five showed the development of implanted tumor after comparatively shorter intervals (2-68 months), and we classified these as the short interval group. The remaining 5 were classified as the long interval group, because tumor development occurred after 87-131 months. All 5 cases in the short interval group involved preoperatively detectable lymph node metastasis; those in the long interval group did not. The MIB-1 labeling index of the implanted tumor was high in 4 cases in the short interval group, but it was low in all cases in the long interval group. The implanted tumors could be surgically removed without recurrence at the focal sites. These findings indicate that, although high growth activity in the metastatic lesions may be a risk factor of FNAB, inducing the growth of implanted tumors along the needle tract within a short interval after the procedure, FNAB remains the most useful technique for diagnosing thyroid carcinoma. The incidence of implantation was low, and when it did occur, the tumors could be surgically removed without recurrence.

Retrospective analysis of predictive factors for recurrence after curatively resected papillary thyroid carcinoma

PURPOSE

This retrospective study analyzes the predictive factors after curative surgery for papillary thyroid carcinoma (PTC).

METHODS

We analyzed 386 patients who underwent a curative operation for PTC in our hospital between 1977 and 1997, subject to the inclusion criteria.

RESULTS

According to univariate analysis, pathological lateral cervical lymph node involvement (P < 0.0001), dedifferentiation of the tumor (P < 0.002), male sex (P < 0.0001), a large tumor (P < 0.005), and an age of over 50 years (P < 0.05) were significant factors. Cox's proportional hazard model showed that a man (P < 0.05), aged over 50 years (P < 0.05), who had a large primary tumor (P < 0.05) with dedifferentiation (P < 0.05), and pathological lateral cervical lymph node metastasis (P < 0.005) was more likely to have recurrence of PTC.

CONCLUSIONS

Determining whether lymph node metastasis exists could be useful for predicting recurrence in patients who have undergone curative resection of PTC.

Ultrasonographically and anatomopathologically detectable node metastases in the lateral compartment as indicators of worse relapse-free survival in patients with papillary thyroid carcinoma

The recent prevalence of ultrasonography has made it easier to detect lymph node metastasis in the lateral compartment of patients with thyroid carcinoma. In this study, we investigated the prognostic impact of lateral node metastasis preoperatively detectable by ultrasonography (US) and metastasis diagnosed by pathology examination but not detected on preoperative US [anatomopathologically (AP)-detectable metastasis] in 560 patients with papillary carcinoma >1 cm in diameter, who underwent thyroidectomy with modified radical neck dissection at our hospital. Patients with US-detectable metastasis (US+ patients) showed a significantly worse relapse-free survival (RFS) rate than those with no metastasis (US-/AP- patients) or AP-detectable metastasis (US-/AP+ patients) regardless of tumor size. Furthermore, the RFS of US-/AP+ patients with tumors >2 cm was worse than that of US-/AP- patients with tumors >2 cm or US-/AP+ patients with tumors measuring 1.1-2.0 cm. There was no significant difference in RFS between US-/AP+ and US-/AP- patients with tumors measuring 1.1-2.0 cm. These findings suggest that US-detectable lateral metastasis predicts a worse RFS for patients regardless of tumor size, and AP-detectable metastasis affects the RFS of patients with tumors >2 cm.

Increased expression of valosin-containing protein (p97) is correlated with disease recurrence in follicular thyroid cancer

BACKGROUND

Valosin-containing protein (VCP) is involved in the ubiquitin/proteasome-degradation pathway, which works in proliferation and antiapoptosis in human cancer cells. Our previous study showed that VCP expression levels correlated with the recurrence and prognosis of several human cancers, such as hepatocellular carcinoma, gastric carcinoma, and colorectal carcinoma. In this study, the correlation of VCP expression with the prognosis of differentiated thyroid carcinoma was examined.

METHODS

VCP expression in 332 patients who underwent operation for differentiated thyroid carcinoma--257 with papillary thyroid carcinoma and 75 with follicular thyroid carcinoma (FTC)--was analyzed by immunohistochemistry. The staining intensity in tumor cells was categorized as weaker than (low expression), equal to (intermediate expression), or stronger than (high expression) that in endothelial cells in noncancerous tissue.

RESULTS

One hundred ten (33.5%) cases showed low VCP expression, 117 (28.0%) showed intermediate expression, and 101 (30.8%) showed high expression. VCP expression significantly correlated with histological subtype (P < .05) and lymph node metastasis (P < .01). However, it correlated with neither any clinicopathologic factor nor prognosis in papillary thyroid carcinoma. VCP expression correlated with extrathyroidal extension (P < .05), pT classification (P < .05), and lymph node metastasis (P < .01) in FTC. Patients with low VCP expressing FTC showed better disease-free and overall survival rates than those with intermediate or high expression (P < .01 and P < .05, respectively). Multivariate analysis revealed VCP expression and extracapsular extension to be independent prognostic factors for disease-free survival in cases of FTC.

CONCLUSIONS

The prognostic utility of VCP expression in FTC was demonstrated.

Video-assisted thyroidectomy for papillary thyroid carcinoma

BACKGROUND

In patients with small papillary thyroid carcinomas (PTC), we evaluated the operative feasibility and safety of video-assisted thyroidectomy (VAT) and the completeness of the surgical resection.

METHODS

Video-assisted thyroidectomy was attempted in 24 patients with thyroid malignancy. Total thyroid resection for PTC was achieved completely by VAT in 20 of them, who were included in this study.

RESULTS

In this study, 12 total thyroidectomies and 8 lobectomies followed by completion thyroidectomies were performed. Eight patients also underwent central neck lymph node dissection. Mean postoperative serum thyroglobulin was 0.2 ng/ml for patients receiving LT4 suppressive treatment and 4.2 ng/ml for patients after LT4 withdrawal. Postoperative ultrasonography showed no residual thyroid tissue. The mean radioiodine uptake at postoperative scintiscan was 2.2%.

CONCLUSIONS

In the case of PTC, VAT is feasible and safe. The completeness of the surgical resection seems comparable with that reported for conventional surgery. Nevertheless, larger series and longer follow-up evaluation are necessary for definitive conclusions to be drawn about its oncologic validity.

Role of neck ultrasonography in the follow-up of children operated on for thyroid papillary cancer

The aim of this study was to evaluate the role of neck ultrasonography compared to (131)I whole-body scan (WBS) and circulating thyroglobulin (Tg) measurement after thyroid hormone withdrawal in the follow-up of children with thyroid papillary cancer, who had previously undergone total thyroidectomy for the diagnosis of neck lymph node metastases (LNM). Forty-five children were examined. Neck ultrasonography and diagnostic WBS were conclusive about the presence or absence of LNM in 35 patients. Diagnostic WBS revealed the presence of LNM in 6 cases not detected by neck ultrasonography; neck ultrasonography was positive in 3 cases that were negative at diagnostic WBS but confirmed by post-(131)I therapy WBS. One patient with suspicious neck lymphnodes at neck ultrasonography not confirmed by WBS was considered as a false-positive result of neck ultrasonography. Neck ultrasonography and thyroglobulin (Tg) were conclusive about the presence or absence of LNM in 29 patients. Tg was elevated in 10 subjects with negative neck ultrasonography (7 had also lung and/or mediastinic LNM). Tg was undetectable in 5 patients in whom the presence of LNM was confirmed by neck ultrasonography and WBS. In conclusion, our study in children demonstrates that neck ultrasonography can detect LNM that are not suspected by palpation, diagnostic WBS, or serum Tg determination. Furthermore, neck ultrasonography can pinpoint the anatomic site of the LNM.

Central neck lymph node removal during minimally invasive video-assisted thyroidectomy for thyroid carcinoma: a feasible and safe procedure

BACKGROUND AND PURPOSE

In 1998, we developed a technique for video-assisted thyroidectomy (VAT) which we proposed using also in patients with small low-risk papillary thyroid carcinomas (PTC). In some cases, enlarged lymph nodes are incidentally found at surgery for PTC. These nodes should be removed because of the risk of metastases. In this paper, we report on the patients in whom we removed enlarged central neck lymph nodes during VAT for PTC and discuss the feasibility and safety of video-assisted central neck lymph node dissection (VALD).

PATIENTS AND METHODS

The procedure is performed by a totally gasless video-assisted technique through a single 1.5-to 2.0-cm skin incision above the sternal notch. Dissection is performed under endoscopic vision using a technique very similar to that of conventional surgery. Only enlarged lymph nodes were removed and sent for frozen section examination (FS). No other dissection was performed in case of negative FS. Five patients underwent VALD during VAT for PTC.

RESULTS

The mean number of lymph nodes removed was 2.4. No metastases were found at FS or final histology examination. Postoperative complications included two transient postoperative hypocalcemias. No evidence of residual or recurrent disease was observed at postoperative follow-up. The cosmetic result was excellent.

CONCLUSION

Our experience demonstrates that removal of central compartment lymph nodes is feasible and safe. Perhaps also complete central neck lymph node dissection can be performed. Some doubts persist about the oncologic validity of this approach. For definitive conclusions, larger series and comparative studies are necessary.

Molecular detection of thyroglobulin mRNA transcripts in peripheral blood of patients with thyroid disease by RT-PCR

The sensitive detection of circulating tumour cells in patients with differentiated thyroid cancer may precede the detection of relapse by other diagnostic studies--such as serum thyroglobulin-and thus may have important therapeutic and prognostic implications. We performed reverse transcription-polymerase chain reaction (RT-PCR) on blood samples from patients diagnosed with thyroid disease using two different RT-PCR sensitivities. Additionally, tissue specificity of TG mRNA-expression was determined using RNA extracts from 27 different human tissues. The lower limit of detection was 50-100 TG mRNA producing cells/ml blood using a 'normal' RT-PCR sensitivity and 10-20 cells/ml blood using a 'high' sensitivity. With the normal sensitivity TG mRNA was detected in 9/13 patients with thyroid cancer and metastasis, 63/137 patients with a history of thyroid cancer and no metastasis, 21/85 with non-malignant thyroid disease and 9/50 controls. With the high sensitivity TG mRNA was detected in 11/13 patients with thyroid cancer and metastasis, 111/137 patients with a history of thyroid cancer and no metastasis, 61/85 with non-malignant thyroid disease and 41/50 controls. Interestingly, using the normal RT-PCR sensitivity TG mRNA transcripts are specific for thyroid tissue and detectable in the peripheral blood of controls and patients with thyroid disease, which correlates with a diagnosis of metastasized thyroid cancer. However, with a high RT-PCR sensitivity, TG mRNA expression was found not to be specific for thyroid tissue and was not correlated with a diagnosis of thyroid cancer in patients. As a consequence, to date TG mRNA detected by RT-PCR in the peripheral blood cannot be recommended as a tumour marker superior to TG serum-level.