Prognostic impact of tumour multifocality in thyroid papillary microcarcinoma based on a series of 160 cases

The Impact of Total Tumor Diameter on Lymph Node Metastasis and Tumor Recurrence in Papillary Thyroid Carcinomas

(1) Introduction: The impact of multifocality/bilaterality on the prognosis of papillary thyroid carcinoma (PTC) is a matter of debate. In order to clarify this debate, several studies have attempted to identify additional parameters associated with poor prognosis, including total tumor diameter (TTD), in the context of multifocal PTCs. In this context, this study was carried out to investigate the impact of TTD on tumor recurrence and lymph node metastasis (LNM) in PTCs. (2) Materials and Methods: The sample of this single-center retrospective study consisted of 706 patients diagnosed with PTC. TTD was calculated as the sum of the largest diameters of tumor foci in multifocal tumors. The resulting TTDs were grouped into TTDs ≤ 10 mm, TTDs > 10 mm, TTDs ≤ 20 mm, and TTDs > 20 mm, using 10 mm and 20 mm as cutoff values. (3) Results: There was no significant difference between multifocal papillary microcarcinomas (PTMCs) with a TTD of >10 mm and unifocal PTCs with a primary tumor diameter (PTD) of >10 mm except for advanced age and lymphovascular invasion (LVI). In addition, perineural invasion (PNI) and TTD > 10 mm were found to be significant risk factors for LNM, and PNI, TTD > 10 mm, TTD > 20 mm, and bilaterality were found to be significant risk factors for recurrence. LVI, and TTD > 10 mm were found to be independent significant predictors for recurrence, and LVI and extrathyroidal extension (ETE) were found to be independent significant predictors for LNM. (4) Conclusions: Considering TTD > 10 mm in recurrence risk categorization models and adopting a clinical approach that takes into account multifocal PTMCs with TTD > 10 mm along with unifocal PTCs with PTD > 10 mm may be more useful in terms of clinical management of the disease.

Recent Advances in the Surgical Management of Thyroid Cancer

A growing incidence of differentiated thyroid cancer (DTC) has been reported in most developed countries, corresponding mainly to incidentally discovered small papillary thyroid carcinomas. Given the excellent prognosis of most patients with DTC, optimal therapeutic management, minimizing complications, and preserving patient quality of life are essential. Thyroid surgery has a central role in both the diagnosis, staging, and treatment of patients with DTC. Thyroid surgery should be integrated into the global and multidisciplinary management of patients with DTC. However, the optimal surgical management of DTC patients is still controversial. In this review article, we discuss the recent advances and current debates in DTC surgery, including preoperative molecular testing, risk stratification, the extent of thyroid surgery, innovative surgical tools, and new surgical approaches.

The relationship between lipotoxicity and risk of extrathyroidal extension in papillary thyroid microcarcinoma

OBJECTIVE

To explore the relationship between triglyceride (TG) levels and aggressive pathological characteristics in papillary thyroid microcarcinoma (PTMC) patients, especially the relationship between TG, BMI, age, and extrathyroidal extension (ETE).

METHODS

A retrospective analysis of 9663 patients with PTMC in a single center from 2010 to 2017 was included in this study. Binary logistic regression was used to analyze the relationship between serum TG and aggressive pathological characteristics of PTMC in different genders. Further analyzing the risk of high TG in different ages and BMI groups.

RESULTS

Even after adjustment for confounding factors, high TG is still a risk factor for ETE in women with PTMC, but not a risk factor for men. Compared with the group with lower than 0.90 mmol/L, when the TG level is higher than 1.93 mmol/L, the risk of ETE in women increased by about 1.35-fold. The remaining two variables (BMI, age) as risk factors for ETE are analyzed. In the normal BMI group, high TG is still a risk factor for ETE. The risk of ETE in women more than 55 years old is significantly increased by 1.96-fold (1.34-fold in less than 55 years).

CONCLUSION

High TG in women is positively correlated with the risk of ETE in PTMC. PTMC with high TG in elderly women (more than 55 years) has a higher risk of ETE. TG is a potential serological index for predicting the risk of ETE in women with normal BMI.

Influence of Tumor Number on Clinicopathologic Features and Outcomes of Patients With Papillary Thyroid Carcinoma

OBJECTIVES

The purpose of this study was to investigate the significance of tumor number on clinicopathologic factors and outcomes of patients with papillary thyroid carcinoma (PTC).

METHODS

We retrospectively analyzed 667 patients with PTC. We compared clinicopathologic features of patients with a different tumor number. Cox proportional hazards model was used to analyze risk factors of recurrence.

RESULTS

In papillary thyroid microcarcinoma (PTMC), the increase in the number of tumor foci was related to a higher risk of minimal extrathyroidal extension (ETE) and lymphovascular invasion (P < .05). Patients with PTMC with four or more foci had a significantly higher risk of central lymph node metastasis (CLNM) and lateral lymph node metastasis (LLNM) than patients with solitary tumors (P < .05). Patients with macro-PTC with four or more foci and with three foci had a higher risk of gross ETE and lymphovascular invasion than patients with solitary tumors (P < .05). The increase in the tumor number was related to a higher risk of CLNM in macro-PTC (P < .05). The number of foci was the independent predictor of recurrence in patients with macro-PTC (P < .05).

CONCLUSIONS

An increase in the number of tumors was associated with an increased risk of aggressive clinicopathologic features in PTMC and macro-PTC. The number of tumor foci could influence risk of recurrence in macro-PTC.

Radioiodine remnant ablation in papillary thyroid microcarcinoma: a meta-analysis

BACKGROUND

The incidence of papillary thyroid microcarcinoma (PTMC) has been increasing sharply, the current statement about whether PTMC patients should undergo radioactive iodine (RAI) remnant ablation is still controversial, mainly because it is uncertain whether RAI treatment can reduce the recurrence rate.

OBJECTIVE

To evaluate the effectiveness of RAI remnant ablation for thyroid cancer-related outcomes of PTMC patients.

METHODS

We comprehensively searched PubMed, Cochrane Library, Scopus and Science Direct for studies that compared the effectiveness after total-thyroidectomy or near total-thyroidectomy, with or without RAI remnant ablation treatment. Random and fixed-effects meta-analytical models were used where indicated, and between-study heterogeneity was assessed.

RESULTS

Twenty-two studies, which included 8724 patients, met our search criteria and were assessed. For PTMC patients treated by total thyroidectomy or near-total thyroidectomy, the locoregional recurrence rates were 1.92 and 7.36% [risk ratio (RR)=0.45; 95% confidence interval (CI)=0.18-1.11; P=0.08] for patients with or without RAI treatment respectively, the distant metastasis rates were 1.39 and 2.46% (RR=0.64; 95% CI=0.28-1.48; P=0.30), and the thyroid cancer-related mortality rates were 0.98 and 1.76% (RR=0.68; 95% CI=0.22-2.09; P=0.50).

CONCLUSION

For PTMC patients who have already treated by total thyroidectomy or near-total thyroidectomy, incremental RAI remnant ablation may significantly improve thyroid cancer-related outcomes.

Low-Dose Radioiodine Ablation in Patients with Low-Risk Differentiated Thyroid Cancer

AIM

Based on the response criteria of the 2015 American Thyroid Associations guidelines, our objectives were to -determine the response rate when using a low dose of -131-I GBq in patients with low-risk differentiated thyroid cancer (LRDTC) and the influence of clinical and analytical variables on the prediction of complete response.

METHODS

We performed a multicentre and longitudinal study, including patients who were operated for LRDTC and who underwent radioiodine remnant ablation with a low-dose of 131-I. All patients were assessed at 6-12 months, and their status was classified as complete (excellent response) or incomplete response (structural incomplete, biochemical incomplete or indeterminate response). Various factors including age, gender, histology, tumour focality and size, stage, time from surgery to treatment, type of thyroid-stimulating hormone (TSH) stimulation, preablation serum thyroglobulin (pTg), antiTg antibodies (pAntiTgAb) and TSH (pTSH) levels were also analysed in order to predict the complete response rate.

RESULTS

Of 108 patients, 79.6$ achieved complete response and the remaining showed incomplete response (2.9, 5.5 and 12$ due to biochemical incomplete, structural incomplete and indeterminate response respectively). Six patients received a new dose of 131-I. Tumour size and pAntiTgAb were the only factors related to therapeutic response (p = 0.03 and p < 0.01, respectively). However, pAntiTgAb was the only independent factor related to complete -response. Patients with complete response showed lower pTg than those with incomplete response (5.1 ± 12.9 vs. 11.2 ± 25 ng/mL) although without statistical significance (p = 0.14). There was no significant difference in the response rate depending on the thyrotropin stimulation methods.

CONCLUSIONS

A low dose of 131-I was sufficient for reaching a complete response at 6-12 months of follow-up in the majority of patients with LRDTC. Tumour size and pAntiTgAb variables were related to therapeutic response.

Independent predictors and lymph node metastasis characteristics of multifocal papillary thyroid cancer

The multifocal papillary thyroid cancer (PTC), with more aggressive and poorer prognosis, is not rare in papillary histotype. Few studies evaluated risk factors and lymph node metastasis in multifocal PTC. The aim of this present study focusing on risk factors and lymph node metastasis characteristics in multifocal PTC was excepted to assist clinical decisions regarding surgery.It was a retrospective study. The 1249 consecutive patients with PTC were reviewed. Of these, 570 patients who met the criteria were selected: 285 with solitary papillary thyroid cancer and 285 with multifocal PTC. The risk factors and lymph node metastasis in multifocal PTC were investigated by univariate and multivariate analysis.Multifocal PTC showed a higher positive rate of capsular invasion, extrathyroidal extension, tumor size >10 mm, pathological T classification, N+ stage, local recurrence, and radioactive iodine ablation (RAI). Capsular invasion (hazard ratio [HR], 1.589; 95% confidence interval [CI],1.352-1.984), advanced pathological T classification (HR, 3.582; 95% CI, 2.184-5.870), and pathological N+ stage (HR, 1.872; 95% CI, 1.278-2.742) were related to increased risk of multifocality and there was a significant increased HR for central neck compartment involvement in male sex (HR, 2.694; 95% CI, 1.740-4.169), advanced pathological T classification (HR, 2.403; 95% CI, 1.479-3.907) and multifocality (HR, 1.988; 95% CI, 1.361-2.906).There is a significant association between capsular invasion, advanced pathological T classification, N+ stage, and multifocal PTC. Total thyroidectomy plus prophylactic bilateral central lymph node dissection should be recommended during surgery due to a stronger predilection for level VI lymph node metastasis in multifocal PTC.

Multifocality as a prognostic factor in thyroid cancer: A meta-analysis

BACKGROUND

Thyroid cancer is one of the most common endocrine cancers whose incidence has been steadily increasing. Previous studies have suggested that multifocality in thyroid cancer is associated with poor prognosis. The present study aims to quantify the data on multifocality as a factor indicating poor prognosis by meta-analysis.

METHODS

A systematic search was carried out using the electronic databases PubMed and Medline. We searched for articles containing keywords of multifocality and thyroid cancer, as well as risk factors and prognostic factors for thyroid cancer (Lymph node metastases, extrathyroidal extension, distant metastases, disease recurrence, Age, tumour size. and gender). Data sets containing hazard ratios and odds ratios were then compared.

RESULTS

The meta-analysis was performed using a total of 21 articles, showed that multifocality is associated with an increased risk of development of LNM (12 Studies: OR = 1.87; 95% CI = 1.51-2.32; I2 = 49.11; p-value = .03), Extrathyroidal extension (15 Studies: OR = 3.18; 95% CI = 0.69-14.71; I2 = 95.62; p-value <.001), Tumour Size > 1 cm (3 Studies: OR = 2.75; 95% CI = 1.95-3.89; I2 = 0.00 and p-value = .88) and disease recurrence (5 Studies: HR = 2.81; 95% CI = 1.07-7.36; I2 = 95.85; p-value < .001). Risk factors that did not significantly contribute to a higher incidence of multifocality include Age >45, Male Gender.

CONCLUSIONS

Multifocality in thyroid cancer is a significant risk factor for disease progression and increases the risk of disease recurrence. The present study suggests that patients who have multifocal disease should therefore be managed more aggressively from an operative and post-operative perspective.

Active Surveillance for Papillary Thyroid Microcarcinoma: Challenges and Prospects

Active surveillance (AS) can be considered as an alternative to immediate surgery in low-risk papillary thyroid microcarcinoma (PTMC) without clinically apparent lymph nodes, gross extrathyroidal extension (ETE), and/or distant metastasis according to American Thyroid Association. However, in the past AS has been controversial, as evidence supporting AS in the management of PTMC was scarce. The most prominent of these controversies included, the limited accuracy and utility of ultrasound (US) in the detection of ETE, malignant lymph node involvement or the advent of novel lymph node malignancy during AS, and disease progression. We summarized publications and indicated: (1) US, performer-dependent, could not accurately diagnose gross ETE or malignant lymph node involvement in PTMC. However, the combination of computed tomography and US provided more accurate diagnostic performance, especially in terms of selection sensitivity. (2) Compared to immediate surgery patients, low-risk PTMC patients had a slightly higher rate of lymph node metastases (LNM), although the overall rate for both groups remained low. (3) Recent advances in the sensitivity and specificity of imaging and incorporation of diagnostic biomarkers have significantly improved confidence in the ability to differentiate indolent vs. aggressive PTMCs. Our paper reviewed current imagings and biomarkers with initial promise to help select AS candidates more safely and effectively. These challenges and prospects are important areas for future research to promote AS in PTMC.

Association of tumor size and focality with recurrence/persistence in papillary thyroid cancer patients treated with total thyroidectomy along with radioactive-iodine ablation and TSH suppression

Locoregional recurrence is common in papillary thyroid cancer PTC and an optimal surgical treatment with respect to the multifocal nature of the disease stays controversial. It is a retrospective analytical study design. 209 diagnosed PTCs managed at our institute were grouped into macro-PTC with a size of dominant focus >1 cm (unifocal n = 106 and multifocal n = 64) and micro-PTMC if size of all foci was <1 cm; (unifocal n = 16 and multifocal PTMC n = 23). The primary endpoint is recurrence and tumor free survival in each of the four groups. Secondary endpoint is an assessment of a benefit of completion total thyroidectomy in terms of assignment of true focal status to an individual's PTC. The median follow-up was 4.1 years. Upon completion thyroidectomy, the tumor focality changed to multifocal in 31.4% of macro-PTC and 60% of micro-PTMC. Multifocality was an independent risk factor for recurrence, OR 2.41 for macro (CI 1.14-5.11), and 3.48 for micro-multifocal PTMC (CI 1.19-10.2). Disease free survival patterns on Kaplan-Meier's plots were alike for micro- and macro-unifocal groups, and similarly stayed comparable among the two multifocal groups. Our analysis showed that tumor multifocality rather than size is the significant factor determining prognosis; hence, total thyroidectomy is indicated for an optimal assessment of true focality in micro-PTC.

Predictors of incomplete response to therapy among Filipino patients with papillary thyroid cancer in a tertiary hospital

BACKGROUND

Although survival rate in papillary thyroid cancer (PTC) is high, the risk of persistence and recurrence together with the dramatic rise in its incidence cannot be overemphasized. Filipinos are considered to be at greater risk for negative outcomes. A paradigm shift in the management of PTC introduces re-stratification based on response to therapy which was reported to have better correlation with long-term outcome. The study aimed to identify predictors of incomplete response after thyroidectomy and radioiodine therapy among patients with PTC. The results of the study may have important implications in our understanding of the disease process allowing more aggressive treatment and monitoring of certain subgroups of patients.

METHODOLOGY

Retrospective review of 225 patients with PTC (59% ATA low risk, 30 % ATA intermediate risk and 11% ATA high risk) who underwent thyroidectomy and radioiodine therapy was performed. Thirteen variables were considered (age, gender, histopathological variant, stage, extent of disease, MACIS score, AMES score, primary tumour size, lymph node, lymphovascular invasion, bilaterality, multifocality and preoperative TSH level). Logistic regression analysis using Backward Wald algorithm was used to identify independent predictors of incomplete response to therapy after 24 months.

RESULTS

Of the 225 patients, 69 (31%) had incomplete response. Biochemical and structural (predominantly thyroid bed, lung and bone) incomplete response was observed in 6 and 63 patients, respectively. Incomplete response was documented in 8, 54 and 92% of low-, intermediate- and high-risk patients based on ATA recommendation. Incomplete response was significantly dependent on gender, lymph node involvement and location, extent of malignancy and multifocality taking into account the size of concurrent tumours (p < 0.05). The model was found to have high sensitivity (71%) and specificity (96%).

CONCLUSION

A significant fraction of PTC patients experienced incomplete response to therapy. Our data suggest that male gender, lateral or mediastinal lymph node involvement, class III extent of disease by De Groot and multifocality with concurrent tumour or tumours more than 1 cm are major predictors of incomplete response. Not all predictors of recurrence and mortality are consistent predictors of treatment response which may be equally important in a disease with low mortality but significant morbidity like PTC.

Multifocal Papillary Thyroid Cancer Increases the Risk of Central Lymph Node Metastasis

BACKGROUND

Papillary thyroid cancer (PTC) is the most common thyroid malignancy, with a strong predilection for lymph node metastasis, most commonly to the central neck compartment (level VI). Few studies have evaluated lymph node metastasis in multifocal PTC, and the role of level VI dissection in the management of PTC remains controversial. This retrospective analysis evaluated the rate of level VI lymph node positivity in multifocal PTC, as compared with unifocal disease, in order to inform surgical decision making better.

METHODS

Patients with PTC who underwent total or hemi-thyroidectomy plus level VI lymph node dissection at the authors' institution between January 2008 and June 2014 were included (N=227). The number and laterality of PTC foci, lymphovascular invasion (LVI), extrathyroidal extension (ETE), and positive/total number of level VI lymph nodes were recorded. Fisher's exact test was used to determine univariate associations, and multivariate analysis was done by logistical regression.

RESULTS

There was an association between the number of PTC foci and level VI node positivity (p<0.001), with an odds ratio (OR) of 2.355 in patients with three or more tumor foci (p=0.026). The OR for central neck metastasis was 1.088 with each additional focus of PTC (p=0.018). The risk of level VI node positivity in the presence of one or two foci was only 19%, with no appreciable difference between one and two foci. This risk increased in the presence of between three and nine foci (38%), and 10 or more foci (88%). Level VI node positivity was associated with ETE (p<0.001), LVI (p<0.001), and size of the largest focus (p<0.001). There was no association between level VI lymph node positivity and male sex (p=0.089), bilaterality (p=0.276), or age (p=0.076).

CONCLUSIONS

There is a significant association between multifocal PTC and level VI lymph node positivity, increasing proportionally with the number of foci. These findings recognize multifocality as a sign of tumor aggressiveness, as evidenced by a higher propensity for lymph node metastasis.

Number of tumor foci predicts prognosis in papillary thyroid cancer

Background

Papillary thyroid cancer (PTC) often presents as multifocal. However, the association of multifocality with poor prognosis remains controversial. The aim of this retrospective study was to identify the characteristics of PTC with multiple foci and to evaluate the association between multifocality and prognosis.

Methods

We reviewed the medical records of 496 patients who underwent total thyroidectomy for PTC. Patients were classified as G1 (1 tumor focus), G2 (2 foci), and G3 (3 or more foci). We analyzed the clinicopathological features and clinical outcomes in each classification. A Cox regression model was used to assess the relationship between multifocality and recurrence or cancer mortality.

Results

The G1, G2 and G3 groups included 287, 141 and 68 patients, respectively. The mean age was 47.1 ± 16.1 yr in G1, 41.1 ± 18.4 yr in G2, and 35.5 ± 15.9 yr in G3 and differed significantly among the 3 groups (p = 0.001). The proportion of extrathyroidal extension, central lymph node metastasis (CLNM), and lateral lymph node metastasis (LLNM) in the G1 to G3 groups increased with increasing number of tumor foci. The Kaplan–Meier curves revealed that G3 had the shortest recurrence-free survival, and differences were significant among the 3 groups (p = 0.001, Log Rank test). Furthermore, cancer-specific survival rates decreased significantly with increasing number of tumor foci (p = 0.041). Independent predictors of recurrence by multivariate Cox analysis included >3 tumor foci [HR 2.60, 95% confidence interval (CI) 1.53-4.39, p = 0.001] and extrathyroidal extension (HR 1.95, CI 1.12-3.38, p = 0.018).

Conclusion

An increase in the number of tumors is associated with a tendency toward more aggressive features and predicts poor prognosis in PTC.

E-cadherin expression and cell proliferation in the primary tumor and metastatic lymph nodes of papillary thyroid microcarcinoma

Although papillary thyroid microcarcinoma (PTMC) has an excellent prognosis, certain cases exhibit aggressive clinical manifestations. In this study, we assessed the expression of E-cadherin and Ki-67 in primary PTMC tumors and metastatic lymph nodes, in order to investigate the mechanism underlying the mainly indolent but potentially malignant nature of PTMC. A total of 93 PTMC patients treated in our institute were included in this study. All primary tumors and 57 metastatic lymph nodes were immunohistochemically stained and a total of 73 tumors (78.5%) were positive for E-cadherin. E-cadherin expression was significantly less common at the invasive front (58.1%, P<0.01) compared to that at the center of the tumor. Tumors that had lost E-cadherin expression at the invasive front frequently presented with lymph node metastasis (70.6%). Small tumors (≤5 mm diameter) expressed E-cadherin significantly more frequently compared with larger tumors (P=0.04); however, no other particular characteristic was found to correlate with the status of E-cadherin expression in the primary tumors. E-cadherin expression was detected in 49 (86.0%) of the 57 metastatic foci and correlated significantly with the expression status at the invasive front of the tumor (P=0.02). The Ki-67 index was universally low and was not correlated with the clinicopathological characteristics or the E-cadherin expression of the tumors. These results suggested that cancer cells in the metastatic lymph nodes exhibit indolent characteristics, similar to those of the primary PTMC. However, the metastatic cancer cells may have already completed the process of epithelial-to-mesenchymal transition (EMT) and mesenchymal-to-epithelial transition (MET), suggesting an innate malignant potential.