Factors influencing extrathyroidal extension of papillary thyroid cancer and evaluation of ultrasonography for its diagnosis: a retrospective analysis

Pathologists usually explore extrathyroidal extensions (ETEs) in thyroid cancer; however, sonographers are often not concerned with ETEs. We investigated factors influencing ETEs and the efficacy of ultrasound evaluation of thyroid capsule invasion. We retrospectively analysed 1933 papillary thyroid carcinoma patients who underwent thyroidectomy during 2018-2021. Patients were divided into three groups: no ETE, minor ETE (mETE), and gross ETE. Clinical characteristic differences were assessed using binary logistic regression analysis to identify ETE predictors, and the kappa test was performed to analyse consistency between ultrasonographic and pathological diagnoses of ETE. The mETE group was more likely to have larger tumour diameters and more extensive lymph node metastasis (LNM) than the no ETE group and more likely to be diagnosed in the isthmus. In the multivariate logistic regression analysis, longest tumour diameter, lesion site, LNM extent, and thyroglobulin concentration were significant mETE predictors. Minimal consistency existed between pathological and ultrasonographic examinations for neighbouring tissue invasion. Many clinical differences were observed between the no ETE and mETE groups, suggesting the importance of considering mETE. Therefore, sonographers should pay more attention to relationships between nodules and capsule and indicate these on ultrasound reports to provide more accurate preoperative ETE information for surgeons.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

The complementary value of intraoperative fluorescence imaging and Raman spectroscopy for cancer surgery: combining the incompatibles

A clear margin is an important prognostic factor for most solid tumours treated by surgery. Intraoperative fluorescence imaging using exogenous tumour-specific fluorescent agents has shown particular benefit in improving complete resection of tumour tissue. However, signal processing for fluorescence imaging is complex, and fluorescence signal intensity does not always perfectly correlate with tumour location. Raman spectroscopy has the capacity to accurately differentiate between malignant and healthy tissue based on their molecular composition. In Raman spectroscopy, specificity is uniquely high, but signal intensity is weak and Raman measurements are mainly performed in a point-wise manner on microscopic tissue volumes, making whole-field assessment temporally unfeasible. In this review, we describe the state-of-the-art of both optical techniques, paying special attention to the combined intraoperative application of fluorescence imaging and Raman spectroscopy in current clinical research. We demonstrate how these techniques are complementary and address the technical challenges that have traditionally led them to be considered mutually exclusive for clinical implementation. Finally, we present a novel strategy that exploits the optimal characteristics of both modalities to facilitate resection with clear surgical margins.

Microscopic Extrathyroidal Extension Results in Increased Rate of Tumor Recurrence and Is an Independent Predictor of Patient’s Outcome in Middle Eastern Papillary Thyroid Carcinoma

Background

Papillary Thyroid Cancer (PTC) is the most common endocrine malignancy, with recurrence rate as high as 30%. A great deal of controversy surrounds the significance of microscopic extrathyroidal extension (m-ETE) as a prognostic factor. The most recent edition (8^th) of American Joint Committee on Cancer (AJCC) staging system has removed m-ETE from the definition of pT3, which suggests that m-ETE may lack prognostic impact in PTC patients. Moreover, data about m-ETE prevalence and clinical impact on Middle Eastern PTC remains unknown. We therefore investigate the prevalence of m-ETE and its clinico-pathological correlation and prognostic impact in Middle Eastern PTC. We also compared the AJCC 7^th and 8^th staging systems and their prognostic performance.

Methods

PTCs from 1430 consecutive adult (> 18 years) patients from single tertiary care hospital were included in this study. A retrospective analysis of PTC patients’ survival and recurrence were compared between AJCC 8^th and AJCC 7^th staging systems using Proportion of Variation Explained (PVE) and Harrell’s C-index.

Results

Median follow up of the study cohort was 9.3 years. 31.2% (446/1430) of patients had m-ETE. In the overall cohort, m-ETE was associated with multiple adverse features such as older age (p < 0.0001), male sex (p = 0.0245), tall cell variant (p < 0.0001), bilateral tumors (p < 0.0001), multifocality (p < 0.0001), lymphovascular invasion (p < 0.0001), lymph node metastasis (p < 0.0001), distant metastasis (p = 0.0166), tumor recurrence (p < 0.0001), radioactive iodine refractoriness (p < 0.0001), BRAF mutation (p < 0.0001) and reduced recurrence-free survival (RFS; HR = 1.75; 95% CI = 1.30 – 2.35; p < 0.0001) irrespective of tumor size. Of the 611 patients with T3 disease based on AJCC 7^th edition, 359 (58.8%) were down-staged in AJCC 8^th edition classification. Overall, the prognostic performance of AJCC 8^th edition was inferior to AJCC 7^th on the basis of lower PVE (3.04% vs. 3.73%) and lower C-index (0.40 vs. 0.48).

Conclusions

In Middle Eastern PTC, m-ETE is significantly associated with compromised survival and acts as an independent predictor of RFS. Given these findings, m-ETE should be included in the thyroid cancer treatment guidelines.

Minimal Extrathyroidal Extension in Predicting 1-Year Outcomes: A Longitudinal Multicenter Study of Low-to-Intermediate-Risk Papillary Thyroid Carcinoma (ITCO#4)

Background: The role of minimal extrathyroidal extension (mETE) as a risk factor for persistent papillary thyroid carcinoma (PTC) is still debated. The aims of this study were to assess the clinical impact of mETE as a predictor of worse initial treatment response in PTC patients and to verify the impact of radioiodine therapy after surgery in patients with mETE. Methods: We reviewed all records in the Italian Thyroid Cancer Observatory database and selected 2237 consecutive patients with PTC who satisfied the inclusion criteria (PTC with no lymph node metastases and at least 1 year of follow-up). For each case, we considered initial surgery, histological variant of PTC, tumor diameter, recurrence risk class according to the American Thyroid Association (ATA) risk stratification system, use of radioiodine therapy, and initial therapy response, as suggested by ATA guidelines. Results: At 1-year follow-up, 1831 patients (81.8%) had an excellent response, 296 (13.2%) had an indeterminate response, 55 (2.5%) had a biochemical incomplete response, and 55 (2.5%) had a structural incomplete response. Statistical analysis suggested that mETE (odds ratio [OR] 1.16, p = 0.65), tumor size >2 cm (OR 1.45, p = 0.34), aggressive PTC histology (OR 0.55, p = 0.15), and age at diagnosis (OR 0.90, p = 0.32) were not significant risk factors for a worse initial therapy response. When evaluating the combination of mETE, tumor size, and aggressive PTC histology, the presence of mETE with a >2 cm tumor was significantly associated with a worse outcome (OR 5.27 [95% confidence interval], p = 0.014). The role of radioiodine ablation in patients with mETE was also evaluated. When considering radioiodine treatment, propensity score-based matching was performed, and no significant differences were found between treated and nontreated patients (p = 0.24). Conclusions: This study failed to show the prognostic value of mETE in predicting initial therapy response in a large cohort of PTC patients without lymph node metastases. The study suggests that the combination of tumor diameter and mETE can be used as a reliable prognostic factor for persistence and could be easily applied in clinical practice to manage PTC patients with low-to-intermediate risk of recurrent/persistent disease.

Outcomes of Tracheal Resections in Well-Differentiated Thyroid Cancer-A case series and meta-analysis

BACKGROUND

Tracheal invasion in thyroid cancer is a well-known form of advanced disease. There is an ongoing controversy over outcomes of tracheal shaving in this situation. The aim of this study was to compare the results of tracheal shaving to radical resections in patients with low-volume tracheal involvement.

METHODS

An institutional case series and a meta-analysis was conducted. All studies that included patients diagnosed with well-differentiated thyroid cancer (WDTC) and tracheal invasion were analyzed. Patients with low-volume tracheal invasion (according to the Shin classification) were extracted from the various studies and subsequently included in this study. The outcomes of tracheal shaving and radical resection were consolidated and compared. All recurrences and mortality over 10 years of follow-up were calculated using the Kaplan-Meier method.

RESULTS

Institutional case series included 22 patients diagnosed with WDTC and tracheal invasion that underwent resection. There was one case of recurrence (4.5%) during the follow-up period and no mortality. The meta-analysis yielded a total of 284 patients from six studies who met the inclusion criteria. The 10-year overall survival was 82.4% for the shave group and 80.8% for the resection group. The combined Kaplan-Meier curves revealed no statistically significant difference between the two techniques (hazard ratio [HR] = 0.86, P = .768). The combined 10-year local control rate of the shave group was 90.2%.

CONCLUSIONS

The outcomes of tracheal shaving in low-volume invasion are similar to more aggressive forms of tracheal resections. Shave resection is oncologically safe in carefully selected WDTC patients demonstrating minimal tracheal invasion.

Microscopic positive surgical margins in thyroid carcinoma: a proposal for thyroid oncology teams

PURPOSE

In the case of well-differentiated thyroid cancer, the importance of microscopic margin status remains controversial. We discuss the relevance of the effect of microscopic positive surgical margins in the early stages of differentiated thyroid cancer.

METHODS

A comprehensive literature search and review of available evidence in English literature was undertaken.

RESULTS

A previous meta-analysis did not find an association between microscopic positive surgical margins and local recurrence. Heterogeneity of definitions and differences between microscopic surgical margins and extrathyroid extension are discussed. Impact on clinical decision-making is explored.

CONCLUSION

The finding of microscopic positive surgical margins in a patient with a thyroid tumor without intraoperative evidence of macroscopic invasion to adjacent structures, with complete resection made by the surgeon and without pathological report of extrathyroid extension, does not have a worse prognostic effect. We present a classification of surgical margins that may help thyroid oncology teams to tailor further management in patients with thyroid cancer.

Current surgical treatment of intermediate risk differentiated thyroid cancer: a systematic review

Introduction: Surgical treatment of thyroid cancer has become less aggressive but for many patients, the threshold for performing total thyroidectomy (TT), as opposed to thyroid lobectomy (TL), has remained unclear. Current American Thyroid Association (ATA) guidelines encourage more individualization of treatment options, which necessitates explicit review of the pros and cons of the different options with patients.Areas covered: This review focuses on the extent of surgery for treatment of intermediate-risk differentiated thyroid cancer, restricted to relevant literature available after publication of the 2015 ATA guidelines.Expert opinion: Dynamic risk-stratification facilitates a tailored approach when deciding on the extent of surgery for thyroid cancer. Treatment with TT allows for a lower recurrence risk, a simpler follow-up regimen, and treatment with adjuvant post-operative radioactive iodine. Treatment with TL has a lower associated risk of complications and avoidance of lifelong thyroid hormone replacement but has a significant risk of requiring a completion thyroid lobectomy (CT). Overall, treatment with TL and TT have comparable survival outcomes, but TL is the more cost-effective option. Larger cancer size is correlated with worse clinical outcomes, and numerous subgroup analyses have shown poorer outcomes for cancers with a diameter that is 2-4 cm compared to 1-2 cm.

Effects of the Minimal Extrathyroidal Extension on Early Response Rates after (Adjuvant) Initial Radioactive Iodine Therapy in PTC Patients

Simple Summary

The aim of our retrospective study was to evaluate the impact of minimal extrathyroidal extension on early response rate after (adjuvant) initial radioactive iodine therapy in patients with papillary thyroid cancer (PTC). We found that response rates after radioactive iodine (RAI) therapy in PTC patients were achieved irrespective of minimal extrathyroidal extension (mETE). Nonetheless, the risk of lymph node metastases involvement was significantly higher in the mETE patient group.

Abstract

Background: Extrathyroidal extension of differentiated thyroid cancer is a poor outcome factor but seems to be less significant in minimal extrathyroidal extension (mETE). However, the impact of mETE on response rate after (adjuvant) initial radioactive iodine (RAI) therapy remains unclear. We therefore compared response rates of patients with classical and follicular variants of papillary thyroid cancer (PTC) according to the updated eighth tumor-node-metastasis (TNM) classification to a control group. Methods: 455 patients with T3 (primary tumor > 4 cm) PTC according to the seventh classification who underwent total thyroidectomy followed by RAI therapy were screened. Patients formerly classified as T3 PTC solely due to mETE were reclassified into patients with T1 (primary tumor ≤ 2 cm) or T2 (primary tumor > 2 cm but ≤ 4 cm) +mETE and compared to a control group of T1/T2 −mETE PTC patients. Results: 138/455 patients were reclassified as T1/2 +mETE and compared to 317/455 T1/T2 −mETE control patients. At initial presentation, +mETE patients showed significantly higher rates of cervical lymph node metastases (p-value 0.001). Response rates were comparable in both groups (p-value n.s.). N1a/N1b-stage (Hazard ratio, HR 0.716; 95% CI 0.536–0.956, p-value 0.024) was identified as an independent prognostic factor for lower response rates. Conclusion: Response rates after RAI therapy were comparable in PTC patients irrespective of mETE but with higher rates of lymph node metastases.

Hemithyroidectomy for Thyroid Cancer: A Review

Thyroid cancer incidence is on the rise; however, fortunately, the death rate is stable. Most persons with well-differentiated thyroid cancer have a low risk of recurrence at the time of diagnosis and can expect a normal life expectancy. Over the last two decades, guidelines have recommended less aggressive therapy for low-risk cancer and a more personalized approach to treatment of thyroid cancer overall. The American Thyroid Association (ATA) and National Comprehensive Cancer Network (NCCN) thyroid cancer guidelines recommend hemithyroidectomy as an acceptable surgical treatment option for low-risk thyroid cancer. Given this change in treatment paradigms, an increasing number of people are undergoing hemithyroidectomy rather than total or near-total thyroidectomy as their primary surgical treatment of thyroid cancer. The postoperative follow-up of hemithyroidectomy patients differs from those who have undergone total or near-total thyroidectomy, and the long-term monitoring with imaging and biomarkers can also be different. This article reviews indications for hemithyroidectomy, as well as postoperative considerations and management recommendations for those who have undergone hemithyroidectomy.

Data set for reporting carcinoma of the thyroid: recommendations from the International Collaboration on Cancer Reporting

Thyroid cancer therapy is increasingly tailored to patients' risk of recurrence and death, placing renewed importance on pathologic parameters. The International Collaboration on Cancer Reporting (ICCR), an organization promoting evidence-based, internationally agreed-upon standardized pathology data sets, is the ideal conduit for the development of a pathology reporting protocol aimed at improving the care of patients with thyroid carcinomas. An international expert panel reviewed each element of thyroid pathology reporting. Recommendations were made based on the most recent literature and expert opinion.The data set uses the most recent World Health Organization (WHO) classification for the purpose of a more clinically and prognostically relevant nomenclature. One example is the restriction of the term minimally invasive follicular carcinoma to tumors with capsular invasion only. It reinforces the already established criteria for blood vessel invasion adopted by the most recent WHO classification and Armed Forces Institute of Pathology fascicle. It emphasizes the importance of the extent of blood vessel invasion and extrathyroid extension to better stratify patients for appropriate therapy. It is the first data set that requires pathologists to use the more recently recognized prognostically powerful parameters of mitotic activity and tumor necrosis. It highlights the importance of assessing nodal disease volume in predicting the risk of recurrence.The ICCR thyroid data set provides the tools to generate a report that will guide patient treatment in a more rational manner aiming to prevent the undertreatment of threatening malignancies and spare patients with indolent tumors the morbidity of unnecessary therapy. We recommend its routine use internationally for reporting thyroid carcinoma histology.

An impact of microscopic positive margin on incomplete response after I-131 treatment in differentiated thyroid cancer

OBJECTIVE

To find an impact of microscopic positive margin on incomplete response after initial I-131 therapy in differentiated thyroid cancer.

METHODS

We retrospectively recruited patients with differentiated thyroid cancer who underwent total thyroidectomy and received the first dose of radioiodine during January 2014-February 2018. Patients with grossly incomplete tumor resection or distant metastasis at the time of radioiodine therapy were excluded. Thyroid specimens were re-evaluated by one pathologist who was blinded to clinical information to determine microscopic margin status. Treatment response was evaluated at 6-12 months after therapy and was categorized according to the 2015 American Thyroid Association guidelines. Univariable and multivariable analyses were used to find an association between microscopic positive margin and incomplete response.

RESULTS

A total of 101 patients (78 females; mean age 50.3 years) were enrolled. Ninety-four patients (93.1%) had papillary thyroid carcinoma. Microscopic positive margin was found in 27 patients (26.7%). After the median follow-up time of 10.3 months, incomplete response was observed in 13 patients (48.5%) and 17 patients (23.0%) with positive and negative margins, respectively. Multivariable analysis showed a significant association between microscopic positive margin and incomplete response after adjusting for tumor size, ETE, and cervical lymph node metastasis with adjusted odds ratio of 3.04 (95% CI 1.05-8.75, p value = 0.04). Moreover, after adding pre-ablative Tg as a covariate in 69 patients with negative TgAb, positive margin had a trend toward being associated with incomplete response with adjusted odds ratio of 3.43 (95% CI 0.73-16.07, p value = 0.118).

CONCLUSIONS

Microscopic positive margin was found to be significantly associated with incomplete response after I-131 therapy in patients with differentiated thyroid cancer after adjusting for tumor size, ETE, and cervical lymph node metastasis and also had a trend toward being associated with incomplete response after adjusting for pre-ablative Tg.

Microscopic Positive Tumor Margin Increases Risk for Disease Persistence but Not Recurrence in Patients with Stage T1-T2 Differentiated Thyroid Cancer

Introduction

Differentiated thyroid cancer (DTC) has an overall excellent prognosis. Patients who develop recurrent disease have a more unfavorable disease course than those with no recurrence. Higher recurrence rates are seen with incomplete surgical resection and gross positive margins. It is unclear whether microscopic positive margin affects disease recurrence rates as much as grossly positive margin. Aim of the Study. To assess whether microscopic positive margin is an independent predictor of disease recurrence in patients with overall low-risk DTC. Patients and Methods. We conducted a retrospective single-center institutional review of 1,583 consecutive patients' charts from 1995–2013 using the Canadian Thyroid Cancer Consortium Registry. We included adult patients with nonmetastasizing T1 and T2 DTC with a minimum of three years follow-up. Univariate and multivariate analyses were used to study factors that may influence the risk of persistent/recurrent disease. Strict definitions of persistent versus recurrent disease were applied.

Results

963 patients (152 men and 811 women) were included in the study with a mean age of 46 years. Microscopic positive margins were present in 12% of the specimens and were associated with an increased rate of persistent disease (8% versus 2% in the controls) but not with an increased risk of recurrent disease (1% in both groups). T2 tumors had a significantly higher incidence of positive margins than T1 tumors (48% versus 36%) and significantly higher nodal staging.

Conclusions

Microscopic positive margin in the histopathology report in patients with low-risk DTC was associated with a higher rate of persistent disease but did not increase the risk of disease recurrence. A close follow-up of biomarkers and occult residual cancerous lesions is needed, especially in the first year. Further studies are needed to determine whether additional therapeutic measures to prevent recurrence are indicated in T1 and T2 DTC with positive microscopic surgical margins.

Critical Prognostic Parameters in the Anatomic Pathology Reporting of Differentiated Follicular Cell-Derived Thyroid Carcinoma

In the past decades, pathology reporting on thyroid carcinoma has evolved from a narrative approach to structured synoptic reports. Many histologic variables are present in the current synoptic reports that are crucial elements for initial risk stratification and clinical management. In this review, we compare and summarize the key prognostic pathologic characteristics utilized by the most influential clinical and pathologic guidelines from the American Thyroid Association (ATA), the National Comprehensive Cancer Network (NCCN), the current World Health Organization (WHO) classification of endocrine tumors (fourth edition), the current American Joint Committee on Cancer (AJCC) staging system (eighth edition), the College of American Pathologists (CAP) protocol, and the International Collaboration on Cancer Reporting (ICCR) dataset. The aim is to provide a comprehensive review focused on the definitions and prognostic impacts of these crucial pathologic parameters.

Microscopically positive surgical margins and local recurrence in thyroid cancer. A meta-analysis

BACKGROUND

Microscopically positive surgical margins are a prognostic factor of recurrence in advanced thyroid carcinoma. However, information on early and completely resected thyroid tumors is scarce. Some studies do not identify any association between positive margin and local recurrence. The objective of this study was to perform a meta-analysis to measure the association of microscopically positive surgical margins and local recurrence in patients who underwent total thyroidectomy.

METHODS

Clinical trials assessing the association between microscopically positive surgical margin and local recurrence in patients with early-stage, well-differentiated thyroid carcinoma who underwent total thyroidectomy were evaluated. The outcome measured was local recurrence in the thyroid bed. A systematic review and meta-analysis was done using a random-effects model.

RESULTS

Six studies with 7696 patients were identified. Methodological quality was good, and we did not identify statistical heterogeneity or publication bias. The risk difference for microscopically positive surgical margin and local recurrence was 0% (95% CI 0 to 1).

CONCLUSION

Meta-analysis did not find a statistically significant association between microscopically positive surgical margin and local recurrence in this population. A finding of microscopically positive surgical margin in the absence of other adverse factors is not an indication for adjuvant treatment.

Predictive factors determining incomplete response to radioiodine therapy in patients with differentiated thyroid cancer

BACKGROUND

Although differentiated thyroid cancer (DTC) has relatively favorable course, factors predicting the course of the disease are intensively searched. The aim of the study was to identify the clinical factors determining incomplete response to radioiodine therapy in patients with DTC.

METHODS

We retrospectively analyzed 385 consecutive patients with DTC treated and followed-up at a single tertiary reference center. We investigated clinical factors detectable during first hospitalization 3-6 months following total thyroidectomy due to DTC, which may serve as prognostic factors determining response to DTC therapy in a long-term follow-up.

RESULTS

Stimulated thyroglobulin (sTg) was the only parameter significantly correlated with the cumulative radioiodine activity (r=0.247, P<0.001). The need for repeated radioiodine administration (≥3 doses) was best predictable on the basis of sTg concentration assessed at the moment of qualification to radioiodine therapy (P=0.003). Predictive value of the sTg for incomplete response to radioiodine has been confirmed with the ROC curve analysis and the best proposed cut-off value was 8.17 ng/mL (sensitivity 55%, specificity 77%, positive predictive value 42.1%, negative predictive value 84.7%); sTg over 8.17 ng/mL increases the risk of incomplete response to therapy 2.5-folds (P=0.002).

CONCLUSIONS

sTg, assessed at the moment of qualification to radioiodine therapy, as the most important factor determining incomplete response to radioiodine therapy in patients with DTC, should be particularly taken into consideration in predicting the future course of the disease as well as treatment and follow-up planning. Radical thyroidectomy may help to increase the effectiveness of treatment.

Small papillary thyroid carcinoma with minimal extrathyroidal extension should be managed as ATA low-risk tumor

PURPOSE

According to American Thyroid Association (ATA) guideline, papillary thyroid cancer (PTC) with minimal extrathyroidal extension (mETE) is classified at "intermediate risk" of persistent/recurrent disease. However, the impact of mETE per se on patients' outcome is not fully understood. The aim of our study was to evaluate the prognostic significance of mETE in patients with PTC not submitted to therapeutic or prophylactic lymph node dissection, according to tumor size and other prognostic factors.

PATIENTS AND METHODS

We retrospectively evaluated a total of 514 PTC patients: 127 (24.7%) had mETE (pT3Nx) and 387 (75.3%) had negative margins (pT1-2Nx). At a median follow-up of 9.1 years, patients were divided in two groups: patients with "good outcome" (no evidence of disease) and patients with "poor outcome" (persistent structural disease or recurrent disease or tumor-related death).

RESULTS

The rate of patients with "poor outcome" was significantly higher in patients with mETE compared with patients with negative margins (11.8 versus 5.1%; OR 2.4576, 95% CI 1.2178-4.9594, p = 0.01). However, mETE was significantly associated with poor outcome only in patients with tumors larger than 1.5 cm.

CONCLUSIONS

mETE is an unfavorable prognostic factor in tumors larger than 1.5 cm, suggesting that, in the absence of other unfavorable characteristics, smaller tumors with mETE should be classified and managed as "low risk" tumors.

Crucial parameters in thyroid carcinoma reporting - challenges, controversies and clinical implications

In the modern era, a pathology report of thyroid carcinoma requires the inclusion of numerous prognostically relevant histopathological features, e.g. the presence and extent of vascular and capsular invasion, extrathyroidal extension, the surgical margin status and the characteristics of nodal metastasis. These pathological features are crucial components of the initial risk stratification to determine the need for completion thyroidectomy and/or postoperative radioactive iodine ablation therapy. The current review aims to summarise the diagnostic criteria, the controversies, the prognostic impacts and the challenges of these pathological characteristics, focusing specifically on the parameters that are incorporated into the American Joint Committee on Cancer (AJCC) staging system, the College of American Pathologists (CAP) reporting template, the American Thyroid Association (ATA) and the National Comprehensive Cancer Network (NCCN) guidelines.

Papillary thyroid microcarcinoma: characteristics at presentation, and evaluation of clinical and histological features associated with a worse prognosis in a Latin American cohort

Objective We aimed to describe the presentation of papillary microcarcinoma (PTMC) and identify the clinical and histological features associated with persistence/recurrence in a Latin American cohort. Subjects and methods Retrospective study of PTMC patients who underwent total thyroidectomy, with or without radioactive iodine (RAI), and who were followed for at least 2 years. Risk of recurrence was estimated with ATA 2009 and 2015 classifications, and risk of mortality with 7th and 8th AJCC/TNM systems. Clinical data obtained during follow-up were used to detect structural and biochemical persistence/recurrence. Results We included 209 patients, predominantly female (90%), 44.5 ± 12.6 years old, 183 (88%) received RAI (90.4 ± 44.2 mCi), followed-up for a median of 4.4 years (range 2.0-7.8). The 7th and 8th AJCC/TNM system classified 89% and 95.2% of the patients as stage I, respectively. ATA 2009 and ATA 2015 classified 70.8% and 78.5% of the patients as low risk, respectively. Fifteen (7%) patients had persistence/recurrence during follow-up. In multivariate analysis, only lymph node metastasis was associated with persistence/recurrence (coefficient beta 4.0, p = 0.016; 95% CI 1.3-12.9). There were no PTMC related deaths. Conclusions Our series found no mortality and low rate of persistence/recurrence associated with PTMC. Lymph node metastasis was the only feature associated with recurrence in multivariate analysis. The updated ATA 2015 and 8th AJCC/TNM systems classified more PTMCs than previous classifications as low risk of recurrence and mortality, respectively.

Microscopic positive margins in papillary thyroid cancer do not impact disease recurrence

BACKGROUND

The prognostic significance of microscopic positive margins in papillary thyroid carcinoma (PTC) remains unclear. The aim of this study was to determine if microscopic positive margins are associated with increased risk of disease recurrence.

METHODS

This is a retrospective analysis of 610 patients with PTC using multivariate Cox regression to evaluate the association between microscopic positive margins and disease-free survival.

RESULTS

Microscopic positive margins were found in 67 (11%) patients and associated with extrathyroidal extension (P < 0.001), multifocality (P < 0.001), nodal metastases (P < 0.001), lymphovascular invasion (P < 0.001), age ≥55 years (P = 0.048), administration of radioactive iodine (RAI) therapy (P = 0.001) and a trend towards larger tumour size (18 versus 15 mm; P = 0.074). After a median follow-up of 3.4 years, there were 83 recurrences. Although involved margins were associated with increased risk of recurrence on univariate analysis (hazard ratio 2.6, 95% confidence interval 1.5-4.6; P = 0.001), there was no association after adjusting for age, nodal metastases, tumour size and extrathyroidal extension on multivariate analysis (hazard ratio 1.5, 95% confidence interval 0.8-2.9; P = 0.242). Similar results were obtained after adjusting for RAI and if margins were analysed as focal versus widely positive. In our study cohort, patients with involved margins generally had other indications for RAI. However, in the nine patients who did not receive RAI, there was no recurrence in the thyroid bed.

CONCLUSION

Despite a strong association between microscopic positive margins and other adverse prognostic factors in PTC, there is no independent association with disease recurrence on multivariate analysis. Microscopic positive margins are rare (1.1%) in the absence of other indications for RAI.