Recurrence after treatment of micropapillary thyroid cancer

ATA risk stratification in papillary thyroid microcarcinoma has low positive predictive value when identifying recurrence

BACKGROUND

Rising incidence of papillary thyroid microcarcinomas (PTMC) has raised concerns for overdiagnosis. Utility of the American Thyroid Association Risk Stratification System (ATA-RSS) 2015 in predicting risk of disease recurrence in patients with PTMC was assessed.

METHODS

Electronic health records of patients who underwent total thyroidectomy were queried. ATA-RSS 2015 risk stratification was performed on those with PTMC, and validity for predicting disease recurrence was calculated.

RESULTS

With 10-year median follow up, recurrence was higher in PTMC patients with high/intermediate vs low ATA risk (33 ​% vs 4 ​%, p ​= ​0.002). Sensitivity of ATA-RSS for detecting recurrence was 60 ​%, specificity 90 ​%, PPV 33.3 ​%, NPV 96.6 ​%, and accuracy 88 ​%. When microscopic extrathyroidal extension (ETE) was excluded as an intermediate risk criterion, PPV improved to 50 ​% and accuracy improved to 92.5 ​% CONCLUSIONS: ATA-RSS 2015 predicts recurrence in PTMC with high NPV but low PPV. Exclusion of microscopic ETE improved PPV, which may help prevent overtreatment.

Impact of radioiodine therapy on recurrence and survival outcomes in intermediate-risk papillary thyroid carcinoma -A systematic review and meta-analysis

OBJECTIVE

The utility of radioiodine (RAI) therapy in intermediate-risk papillary thyroid carcinoma (PTC) remains a topic of ongoing discussion. This systematic review and meta-analysis aimed to consolidate existing evidence on the impact of postoperative RAI therapy on recurrence and survival outcomes in intermediate-risk PTC.

METHODS

A literature search was performed using relevant keywords in PubMed, Scopus, and EMBASE. Articles from January 2008 to March 2023 were included. Odds ratios (ORs) and hazard ratios (HRs) were extracted from the individual articles, and pooled estimates were generated using meta-analysis.

RESULTS

Eleven articles comprising 56,266 intermediate-risk PTC patients were included. 41,530 (73.8%) patients underwent postoperative RAI therapy, while 14,736 (26.2%) patients were kept on no-RAI (NOI) follow-up. No significant reduction in rates of structural disease recurrence was noted with RAI therapy in comparison to NOI follow-up (pooled univariate OR, 0.73, 95% confidence interval [CI], 0.29-1.87, I2  = 75%). RAI therapy was not a significant predictor of better recurrence-free survival (pooled multivariate HR, 0.21; 95% CI, 0.01-3.74, I2  = 94%). Interestingly, RAI therapy was associated with an overall survival benefit compared to NOI follow-up (pooled multivariate HR, 0.63; 95% CI, 0.48-0.82, I2  = 79%).

CONCLUSIONS

This meta-analysis did not establish a conclusive benefit of RAI therapy in preventing structural disease recurrence or improving recurrence-free survival in intermediate-risk PTC. However, these results need to be interpreted with caution owing to significant heterogeneity in the existing literature. A prospective, randomised clinical trial is the need of the hour to better understand the effect of RAI therapy on long-term outcomes.

Retrospective comparison of individual risk factors hemithyroidectomy and thyroidectomy in patients with papillary carcinoma of the thyroid gland in combination with autoimmune thyroiditis

Introduction. Papillary thyroid carcinoma is the most common subtype of thyroid cancer as it comprises 95 % of cases. Frequently, this pathology develops in the presence of autoimmune thyroiditis (Hashimoto’s thyroiditis) which is the main cause of hypothyroidism in various rich in iodine regions. Papillary thyroid carcinoma is characterized by good prognosis, however some patients experience recurrence which depends on the volume of surgical intervention.

Aim. To compare clinical outcomes and complications after hemithyroidectomy (HE) and thyroidectomy (TE) in patients with papillary thyroid carcinoma secondary to autoimmune thyroiditis.

Materials and methods. The retrospective study included 2031 patients with papillary thyroid carcinoma. Considering individual risk factors, 67 patients were excluded from the HE group, and 588 patients were excluded from the TE group. Each group included 688 patients for whom data were matched. Such individual factors as age, sex, primary tumor size, extrathyroidal invasion, multifocal tumor and cervical lymph node metastasis were taken into account.

Results. During 10‑year follow-up, recurrence was diagnosed in 26 (3.8 %) patients of the HE group and 11 (1.6 %) patients of the TE group. Relative risk of recurrence was significantly lower after TE than after HE (risk ratio (RR) 0.41; 95 % confidence interval (CI) 0.21–0.81; р = 0.01). In the HE group, for the majority of patients recurrence was observed in the contralateral lobe of the thyroid (84.6 %). In the TE group, there were no recurrences in all patients. There were no significant differences between the groups after exclusion of recurrence in the contralateral thyroid lobe (RR 2.75; 95 % CI 0.08–8.79; р = 0.08). In the TE group, the number of patients with transient and permanent hypothyroidism in the TE group was significantly higher than in the HE group (р <0.001).

Conclusion. Hemithyroidectomy is appropriate for the majority of patients with papillary thyroid carcinoma in the absence of extrathyroidal invasion in the neighboring tissues per preoperative examination. For patients after HE, preoperative and postoperative diagnostic examinations are important as most recurrences develop in the contralateral thyroid lobe.

Pathological multifocality is not a prognosis factor of papillary thyroid carcinoma: a single-center, retrospective study

INTRODUCTION

Non-total thyroidectomy (non-TTx) is a widely accepted operative procedure for low-risk papillary thyroid carcinoma (PTC). PTC patients preoperatively diagnosed with unifocal disease are often revealed as having multifocal foci by microscopy. The present study determined whether or not patients with clinically unifocal, but pathologically multifocal non-high-risk PTC treated with non-TTx have an increased risk of a poor prognosis compared to those with pathologically unifocal PTC.

MATERIALS AND METHODS

PTC patients diagnosed as unifocal preoperatively who underwent non-TTx were multifocal in 61 and unifocal in 266 patients microscopically. Oncologic event rates were compared between pathologically multifocal and unifocal PTC patients.

RESULTS

Pathological multifocality was associated with positive clinical lymph node metastasis (cN1) (odds ratio [OR] 4.01, 95% confidence interval [CI]: 1.91-8.04) and positive pathological lymph node metastasis (pN1) in > 5 nodes (OR 3.68, 95% CI: 1.60-8.49). No patients died from PTC. There was no significant difference in the disease-free survival rate, remnant thyroid disease-free survival rate, lymph node disease-free survival rate, or distant disease-free survival rate between the two groups. Recurrence in pathologically multifocal PTC patients was locoregional in all cases and able to be salvaged by reoperation. Cox proportional hazard model analyses showed no significant difference in recurrence rates with regard to pathological multifocality and cN or number of pNs.

CONCLUSION

The prognosis of PTC with pathological multifocality treated by non-TTx was not inferior to that of unifocal PTC. Immediate completion thyroidectomy is not necessary when microscopic foci are proven.

Radioactive Iodine Ablation Can Reduce the Structural Recurrence Rate of Intermediate-Risk Papillary Thyroid Microcarcinoma: A Meta-Analysis

Background

The incidence of papillary thyroid microcarcinoma (PTMC) has significantly increased in recent years, and the decision to use radioactive iodine (RAI) ablation in low-risk (LR) and intermediate-risk (IR) patients is controversial. The aim of this study was to evaluate whether RAI ablation can reduce the recurrence rate in LR-IR PTMC patients.

Methods

A comprehensive literature search of the PubMed, Embase, Cochrane Library, and Web of Science was conducted according to the PRISMA statement.

Results

There were 8 studies in English that fit our search strategy, and a total of 2847 patients were evaluated. The results of the meta-analysis showed RAI ablation in LR-IR PTMC patients did not reduce cancer recurrence (risk radio (RR) 0.56, 95% CI 0.19-1.70, P = 0.31). Nevertheless, we further performed data analysis and found that IR PTMC patients without RAI ablation had a higher rate of cancer recurrence than those who underwent RAI ablation (RR 0.23, 95% CI 0.11-0.49, P = 0.0001). Furthermore, patients with risk factors for lymph node metastasis (RR 0.16, 95% CI 0.06-0.42, P = 0.0002), microscopic extrathyroidal extension (RR 0.19, 95% CI 0.06-0.60, P = 0.005), and multifocality (RR 0.13, 95% CI 0.04-0.45, P = 0.001) in the absence of RAI ablation were more likely to have recurrence.

Conclusions

Based on our current evidence, RAI ablation can reduce the cancer recurrence rate over 5 years in IR PTMC patients, especially when patients have some risk factors, such as lymph node metastasis, microscopic extrathyroidal extension, and multifocality.

Predictive Factors for Bilateral Disease in Papillary Microcarcinoma: A Retrospective Cohort Study

Background: Based on risk stratification, the therapeutic options in papillary microcarcinoma (PTMC) can be active surveillance or surgery. Multifocal tumor occurrence can be decisive in determining the treatment strategy. The objective of this study was to identify risk factors for bilateral tumor occurrence in PTMC to enable individual therapy planning. Methods: A total of 545 PTMC patients who underwent thyroidectomy from 2008 to 2020 were retrieved. Univariate and multivariate analyses were performed to evaluate risk factors for bilateral PTMC. Results: 25.1% (n = 137) of all patients had multifocal PTMC, and 13.2% (n = 72) bilateral PTMC, respectively. In contrast to the maximum tumor size, the total tumor size significantly influenced a bilateral tumor manifestation (median total tumor size 5 mm versus 8.5 mm for bilateral PTMC, p < 0.001). A cut-off level for the total tumor size of >10 mm resulted in a sensitivity and specificity of 29.2% and 94.7%, respectively, in predicting a bilateral tumor manifestation, AUC 0.680 (95% CI, 0.611−0.748, p < 0.001). A cut-off of >4 tumors showed a sensitivity of 99.4% and a specificity of 97.5%, AUC 0.897 (95% CI, 0.870−0.924, p < 0.001) in predicting bilaterality. Conclusion: We could demonstrate for the first time that a total tumor size of >10 mm and more than four tumors significantly increased the risk of bilateral PTMC tumor involvement. These findings enable a risk-adjusted patient treatment.

Differences in the clinical characteristics of papillary thyroid microcarcinoma located in the isthmus ≤5 mm and >5mm in diameter

Background

The optimal treatment of papillary thyroid microcarcinomas (PTMCs) located in the isthmus (iPTMCs) is still controversial. The purpose of this study was to compare the clinicopathologic features of patients with iPTMCs ≤5 mm and >5 mm in diameter after total thyroidectomy, and to identify the risk factors for recurrence in patients with iPTMCs.

Methods

A total of 102 iPTMC patients who underwent total thyroidectomy were reviewed retrospectively. The clinicopathologic characteristics of iPTMCs ≤5 mm group (n = 29) have been compared with a group >5 mm (n = 73). Univariate and multivariate Cox proportional hazard models served to identify risk factors associated with recurrence-free survival (RFS).

Results

Gender (p = 0.033), multifocality (p = 0.041), and central lymph node metastasis (CLNM) (p = 0.009) of patients in the ≤5 mm and >5 mm groups differed significantly. iPTMC patients with age <55 years, male, multiple tumor, and extrathyroidal extension showed comparatively more frequent of CLNM in >5 mm groups. Of the 102 patients, nine (8.8%) developed recurrence during follow-up (median: 49.5 months). The patients with recurrences had comparatively high rates of CLNM (p = 0.038), extranodal invasion (p = 0.018), and more MNCND (Metastasis Nodes for Central Neck dissection) (p = 0.020). A cutoff of MNCND >2.46 was established as the most sensitive and specific level for the prediction of recurrence based on receiver operating characteristic (ROC) curve analyses. Multivariate analysis showed that the number of MNCND ≥3 was an independent predictor of poor RFS (p = 0.028).

Conclusion

We have found that the recurrence rates are similar in patients with iPTMCs ≤5 mm and >5 mm. The iPTMCs >5 mm were more likely to be associated with pathological features such as multifocality and CLNM. The male gender, extrathyroidal extension, and CLNM were associated with recurrence of iPTMCs except for tumor size and multifocality. Higher risk of CLNM should be considered in iPTMC >5 mm when it reaches some risk factors. The numbers of MNCND ≥3 may be an independent predictor for recurrence, which could help clinicians for the decision of radioiodine administration and the modulation of follow-up modalities.

Is thyroglobulin a reliable biomarker of differentiated thyroid cancer in patients treated by lobectomy? A systematic review and meta-analysis

OBJECTIVES

The prognostic role of thyroglobulin in predicting recurrence in differentiated thyroid cancer (DTC) patients treated by lobectomy is controversial. This systematic review with meta-analysis aimed to update the current evidence deepening the reliability of circulating thyroglobulin in assessing the early response and in predictive recurrence.

METHODS

The methodology was registered in the PROSPERO database under the protocol number CRD42021288189. A systematic search was carried out on PubMed, Embase, Web of Science, and Scopus from September to November 2021 without time and language restrictions. The literature search strategy was based on the following keywords: Thyroglobulin AND (Lobectomy OR Hemithyroidectomy).

RESULTS

After screening 273 articles, seven studies were included in the systematic review, and only six of them were included in the meta-analysis for a total of 2,455 patients. Circulating thyroglobulin was found non-reliable in assessing early response and predicting recurrence in patients with hemithyroidectomy, especially those with a low initial ATA classification.

CONCLUSIONS

Our study does not support serum thyroglobulin levels for monitoring patients with low-risk DTC treated with lobectomy, and weak evidence supports its role for intermediate- or high-risk patients. Studies with longer follow-up, different study designs, and stringent inclusion/exclusion criteria are needed to evaluate the role of thyroglobulin in recurrence prediction.

Optimal Surgical Extent in Patients with Unilateral Multifocal Papillary Thyroid Carcinoma

Multifocality increases the risk of recurrence in patients with papillary thyroid carcinoma (PTC); however, it is unclear whether multifocality justifies more extensive or aggressive surgical treatment. Here, we evaluated the effect of the operative extent on the recurrence-free survival (RFS) of patients with multifocal PTC. Between 2010 and 2019, 718 patients with unilateral multifocal PTC were enrolled; 115 patients (16.0%) underwent ipsilateral thyroid lobectomy, and 606 patients (84.0%) underwent total thyroidectomy. With a mean follow up of 5.2 years, RFS was comparable between the total thyroidectomy and lobectomy groups (p = 0.647) after adjusting for potential confounders. Multivariable Cox regression analysis also demonstrated that the operative extent was not an independent predictor of recurrence (HR 1.686, 95% CI: 0.321-8.852). Subgroup analyses further indicated that both total thyroidectomy and thyroid lobectomy resulted in comparable RFS for multifocal PTC patients with other high-risk factors, including tumor size > 1 cm (p = 0.711), lymph node metastasis (p = 0.536), and intermediate ATA risk of recurrence (p = 0.682). In conclusion, thyroid lobectomy was not associated with the risk of recurrence in patients with multifocal PTCs. Multifocality in PTC may not always require aggressive surgery.

A New Dynamic Response to Therapy Assessment in Postoperative Patients With Low-Risk Differentiated Thyroid Cancer Treated Without Radioactive Iodine

Background

Total thyroidectomy (TT) or lobectomy without radioactive iodine (RAI) is becoming a common management for patients with low-risk differentiated thyroid cancer (DTC). However, the assessment of response to therapy for these patients remains controversial. The aim of this study was to propose and validate a new dynamic evaluation strategy to assess the response to therapy in patients with low-risk DTC treated with TT or lobectomy but without RAI.

Methods

We performed a retrospective analysis of 543 adult patients with low-risk DTC who underwent TT or lobectomy without RAI therapy. Follow-up consisted of trends of serum thyroglobulin (Tg), anti-thyroglobulin antibody (TgAb) levels and neck ultrasonography (US) were conducted every 6-24 months. Response to therapy assessments were defined as excellent response, biochemical incomplete response, structural incomplete response, and indeterminate response according to the follow-up findings.

Results

At a median follow-up of 51 months (range 33-66 months), 517 (95%) had excellent response, while the other 26 had either biochemical incomplete response (an increasing trend of suppressed serum Tg levels, n=9; an increasing trend of TgAb levels, n=3) or indeterminate response (a stable or decreasing trend of suppressed serum Tg levels, but a stable positive trend of TgAb levels, n=14). No patients had structural incomplete response or no deaths related to thyroid cancer. The risk of incomplete response was significantly higher in lobectomy than in TT (p<0.001).

Conclusion

Our study proposed and validated a new dynamic response to therapy assessment depending on trends of suppressed serum Tg, TgAb levels, and neck US findings which could be an appropriate tool for postoperative follow-up in low-risk DTC patients without RAI therapy. Our findings provided further evidence to support no routine recommendation of RAI after surgery in low-risk DTC.

Predictive Factors of Recurrence of Papillary Thyroid Microcarcinomas: Analysis of 2,538 Patients

Introduction  The incidence of papillary thyroid microcarcinoma (PTMC) has increased, and its treatment remains controversial.

Objective  To identify the clinical and pathological factors predictive of tumor recurrence.

Methods  We retrospectively analyzed 2,538 consecutive patients treated for PTMC, most submitted to total thyroidectomy (98%) followed by radioactive iodine (RAI) ablation (51.7%) at a cancer center from 1996 to 2015. The patients were stratified according to the American Thyroid Association (ATA) risk categories (low, intermediate, or high), and the clinicopathological features were evaluated by multivariate Cox regression analysis to identify independent prognostic factors for recurrence.

Results  After a mean follow-up of 58 months (range: 3 to 236.5 months), tumor recurrence was diagnosed in 63 (2.5%) patients, mostly in the lymph nodes. Distant metastasis occurred in 2 (0.1%) patients. There were no cancer-related deaths. The multivariate analysis showed that age < 55 years ( p  = 0.049; hazard ratio [HR]: 2.54; 95% confidence interval [95%CI]: 0.95 to 0.99), multifocality ( p  = 0.032; HR: 1.76; 95%CI: 1.05 to 2.96), and the presence of lymph-node metastasis ( p  < 0.001; HR: 3.69; 95%CI: 2.07–6.57) were independent risk factors for recurrence. Recurrence was observed in 29 (1.5%) out of 1,940 low-risk patients, 32 (5.4%) out of 590 intermediate-risk patients, and in 2 (25%) out of 8 high-risk patients.

Conclusions  The prognosis of PTMC is excellent, favoring a conservative treatment for most patients. Age < 55 years, multifocality, and node metastasis at diagnosis, as well the ATA staging system effectively predict the risk of recurrence. The presence of these risk factors can help identify patients who should be considered for more aggressive management and more frequent follow-up.

Clinical predictors of I-131 therapy failure in differentiated thyroid cancer by machine learning: A single-center experience

Well-differentiated thyroid carcinoma is predominantly a slow-growing malignancy, amendable to treatment, and has an excellent prognosis following thyroidectomy and radioiodine (RAI) therapy. However, patients who fail the initial RAI treatment attempt may require repeated RAI or other treatments and with this, comes an associated impact on patient quality of life. Therefore, the anticipation of patients in whom there is a higher risk of RAI failure may help in patient risk stratification and subsequent management. We conducted a retrospective review to determine the factors associated with initial RAI therapy failure in well-differentiated thyroid cancer patients. Using scikit-learn from Python, we implemented a machine-learning algorithm to determine the clinical patient factors associated with a higher likelihood of treatment resistance. We found that clinical factors such as tumor focality (P = 0.026) and lymph node invasion at surgical resection (P = 0.0135) were significantly associated with initial treatment failure following RAI. Elevated serum thyroglobulin (Tg) and Tg antibody levels following surgery but before RAI were also associated with treatment resistance (P < 0.0001 and P = 0.011 respectively). Less expected factors such as decreased time from surgery to RAI were also associated with treatment failure, however not to a statistically significant degree (P > 0.064). Clinical outcomes following RAI can be stratified by identifying factors that are associated with initial treatment failure. These findings can help restratify patients for RAI treatment and change patient management in certain cases. Such stratification will ultimately help to optimize successful treatment outcomes and improve patient quality of life.

Negative Histopathological Prognostic Factors Affecting Morbidity in T1 Differentiated Thyroid Carcinoma

Background: The aim was to evaluate (i) if multifocality is a negative prognostic factor, (ii) the association of diameter of the largest tumor, total tumor diameter, and the ratio of the largest tumor diameter to total tumor diameter (DR) with histopathological and clinical outcome parameters in T1 differentiated thyroid carcinoma (DTC). Methods: In 1014 T1N0/1Mx patients, correlation between multifocality, contralateral lobe involvement, capsular-vascular invasion, diameter of the largest tumor, total tumor diameter, DR, and follow-up results were investigated. Results: Persistent/recurrent disease and necessity for additional radioiodine treatment (RAIT) were more frequent in cases with multifocality and contralateral lobe involvement (p = 0.035, p = 0.015, p = 0.021, and p = 0.04). Persistence/recurrence, reoperation in the neck, and additional RAIT were more frequent in patients with the size of the largest tumor focus >1 cm (p = 0.024, p < 0.001, and p = 0.002) and N1 status (p < 0.001, p < 0.001, and p < 0.001). Mean total tumor diameter was higher in patients with capsular invasion, contralateral lobe, and lymph node involvement (p = 0.001, p = 0.003, and p = 0.013). Conclusion: Multifocality, contralateral lobe involvement, diameter of the largest tumor >1 cm, and N1 status are related with increased risk of disease persistence, recurrence, reoperation, and additional RAIT. Sum of diameter of all tumor foci are associated with capsular invasion.

Can Age at Diagnosis and Sex Improve the Performance of the American Thyroid Association Risk Stratification System for Prediction of Structural Persistent and Recurrent Disease in Patients With Differentiated Thyroid Carcinoma? A Multicenter Study

OBJECTIVE

Although the age at diagnosis has been suggested as a major determinant of disease-specific survival in the recent TNM staging system, it is not included in the recent American Thyroid Association (ATA) guidelines to estimate the risk of recurrence. Nevertheless, the effect of sex on differentiated thyroid carcinoma (DTC) recurrence is controversial. Therefore, this multicenter study was conducted to assess whether age at diagnosis and sex can improve the performance of the ATA 3-tiered risk stratification system in patients with DTC with at least 5 years of follow-up.

METHODS

In this study, the computer-recorded data of the patients diagnosed with DTC between January 1985 and January 2016 were analyzed. Only patients with proven structural persistent/recurrent disease were selected for comparisons.

RESULTS

This study consisted of 1691 patients (female, 1367) with DTC. In Kaplan-Meier analysis, disease-free survival (DFS) was markedly longer in females only in the ATA low-risk category (P = .045). Nevertheless, a markedly longer DFS was observed in patients aged <45 years in the ATA low- and intermediate-risk categories (P = .004 and P = .009, respectively), whereas in patients aged <55 years, DFS was markedly longer only in the ATA low-risk category (P < .001). In the Cox proportional hazards model, ages of ≥45 and ≥55 years at diagnosis and the ATA risk stratification system were all independent predictors of persistent/recurrent disease.

CONCLUSION

Applying the age cutoff of 45 years in the ATA intermediate- and low-risk categories may identify patients at a higher risk of persistence/recurrence and may improve the performance of the ATA risk stratification system, whereas sex may improve the performance of only the ATA low-risk category.

Total thyroidectomy can be overtreatment in cN1a papillary thyroid carcinoma patients whose tumor is smaller than 1 cm

BACKGROUND

The 2015 American Thyroid Association (ATA) guidelines recommend pursuing total thyroidectomy with therapeutic central lymph-node dissection (CND) in patients with clinically apparent nodal disease (cN1a), regardless of tumor size. The aim of this study was to investigate whether total thyroidectomy is necessary for thyroid papillary microcarcinoma (PTMC) patients with preoperative unilateral cN1a.

METHODS

This study included 295 papillary thyroid microcarcinoma patients who underwent total thyroidectomy with bilateral CND from January 2012 to June 2015.

RESULTS

The median follow-up time was 42.5 months. Locoregional recurrence (LRR) was observed in only two (0.9%) patients. Among 70 cN1a patients, only 19 (27.1%) were at intermediate risk for disease recurrence and required total thyroidectomy per the ATA guidelines. Lobectomy can be considered as a treatment option for the remaining patients (72.9%).

CONCLUSIONS

Our study showed that more than two-thirds of PTMC patients with clinical nodal disease who underwent total thyroidectomy and CND were actually lobectomy candidates. Total thyroidectomy as the first surgical option for cN1a, especially in PTMC patients, should be reconsidered.

[Pathological and Molecular Features of Lung Micropapillary Adenocarcinoma]

肺微乳头腺癌作为高级别肺腺癌，具频发转移、淋巴结浸润、复发率高和总体生存率低的临床特征。该亚型肿瘤中存在特征致癌因子通路的激活和肿瘤免疫微环境的建立。本文拟对近年来微乳头腺癌的病理学表现及分子学特征研究进展作一综述，旨在加深对微乳头型病变的认识，进而为制定特异性治疗策略奠定基础。

A UK based two-centre review of multifocality and its role in the treatment of papillary thyroid cancer

INTRODUCTION

Multifocality is increasingly observed in papillary thyroid carcinoma (PTC) due to improvements in imaging and histopathological analysis. However, its significance in management, particularly as a sole risk-factor, remains controversial. This study aimed to investigate the prognostic value of multifocality in predicting recurrence following thyroid lobectomy in a contemporary group of PTC patients managed in the UK.

METHODS

Patients with PTC in NHS Lothian (2009-19) and Guys and St Thomas NHS Foundation Trust (2012-19) were identified. Categorical variables were compared using Chi-squared or Fisher's exact test. Five-year recurrence free survival (RFS) were analysed using Kaplan-Meier method and compared using log-rank.

RESULTS

Of 828 patients; 492 (59%) had unifocal and 336 (41%) multifocal disease on final pathology. A higher rate of pathological nodal disease (22%v36%,p < 0.001), total thyroidectomy (TT) (78%v92%,p < 0.001) and radioactive iodine (RAI) (57%v75%,p < 0.001) was demonstrated in patients with multifocality. With a median follow-up of 50 months, overall 5-year RFS was 96.5%; 96.5% for unifocal versus 96.6% for multifocal disease (p = 0.695). Recurrence was not shown to be associated with multifocality on either univariate or multivariate analysis. Amongst patients with T1/2N0M0 disease (n = 341), more patients were treated with TT and RAI with multifocal compared to unifocal disease (<0.001). Only two patients within this group recurred during follow up, both of whom had multifocal disease and were treated with TT and RAI (5yRFS100%v98.1%,p = 0.051).

CONCLUSION

Multifocality is a common feature of PTC but does not appear to be an independent predictor of outcome. Therefore, treatment intensification on the basis of multifocality alone seems unwarranted.

Is Postoperative Adjuvant Radioactive Iodine Ablation Therapy Always Necessary for Intermediate-Risk Papillary Thyroid Cancer Patients With Central Neck Metastasis?

BACKGROUND

Papillary thyroid cancer (PTC) is commonly associated with neck lymph node metastasis (LNM), and recurrence does occur after radioactive iodine (RAI) ablation therapy. This study aimed to analyze the effectiveness of RAI ablation with regard to disease recurrence in intermediate-risk PTC patients with neck LNM. In addition, the study identified possible predisposing risk factors that might benefit from RAI ablation and analyzed common RAI therapy complications among these patients.

METHODS

A retrospective analysis of 349 intermediate-risk PTC patients with neck LNM who underwent thyroidectomy with neck dissection was performed. The oncologic results and clinicopathologic characteristics of these patients together with the incidence of postoperative RAI therapy complications were evaluated.

RESULTS

Of the 349 patients, disease recurrence after treatment occurred for 27 patients (8%) during a mean follow-up period of 58.7 months (range 7-133 months). The recurrence-free survival curve of the patients who received postoperative RAI therapy (n = 208) did not differ significantly from that of the patients who did not receive it (n = 141) (P = 0.567). Nine patients without adjuvant RAI therapy (6%, 9/141) had recurrence. The recurrence rate for the central LNM patients without RAI therapy was only 2% (2/106). Both of these patients with recurrence had pathologic extranodal spread (ENS) and a high number (> 5) of metastatic central LNs. Postoperative RAI-related complications were observed in 24 patients (12%).

CONCLUSIONS

Postoperative RAI is not necessary for intermediate-risk papillary thyroid cancer patients with central LNM, especially for patients with negative ENS and low number (< 5) of metastatic lymph nodes.

Microcarcinoma papilar de tiroides: ¿es adecuada la selección para protocolo de vigilancia activa?

Introducción. Los microcarcinomas papilares de tiroides son tumores de hasta 10 mm en su diámetro mayor. Su tratamiento es sujeto de debate y se propone, desde seguimiento clínico, hasta intervención quirúrgica temprana. Este estudio buscó identificar factores de riesgo relacionados con compromiso ganglionar, que permitan una mejor selección de los pacientes en nuestro medio, en quienes se propone manejo quirúrgico inmediato o vigilancia activa, en consonancia con la clasificación del riesgo de progresión. Métodos. Estudio de cohorte analítica ambispectiva que incluyó pacientes con microcarcinoma papilar de tiroides llevados a tiroidectomía más vaciamiento central. Se caracterizó la población y se realizó un análisis de regresión logística multivariado para definir factores preoperatorios asociados al compromiso ganglionar. Adicionalmente, se evaluó de manera retrospectiva la eventual asignación a grupos de riesgo de progresión, según los criterios de Miyauchi, y su comportamiento respecto al estado nodal. Resultados. Se incluyeron 286 pacientes. El 48,9 % presentó compromiso ganglionar, y de estos, el 33,5 % presentó compromiso ganglionar significativo, que modificó su clasificación de riesgo de recaída. De estos últimos, el 59,5 % hubiesen sido manejados con vigilancia activa, según los criterios propuestos por Miyauchi. Se identificó que la edad menor de 55 años, los ganglios sospechosos en la ecografía y los nódulos mayores de 5 mm, se relacionan con compromiso ganglionar significativo. Discusión. El manejo quirúrgico inmediato parece ser una opción adecuada para pacientes con sospecha de compromiso ganglionar en ecografía preoperatoria, pacientes menores de 55 años y nódulos mayores de 5 mm. Es posible que los actuales criterios para definir vigilancia activa no seleccionen adecuadamente a los pacientes en nuestro medio.

The influence of nodule size on the aggressiveness of thyroid carcinoma varies with patient's age

Background

Thyroid nodule size is one of the key parameters that determines the operative approach for thyroid carcinoma. It is necessary to evaluate the influence of nodule size on the aggressiveness of thyroid carcinoma. The eighth edition of staging system has updated the prognostic age cutoff from 45 to 55 years old. It is needed to re-evaluate the difference in aggressiveness of thyroid carcinoma between younger (<55 years old) and older (≥55 years old) patients. Importantly, whether the influence of nodule size on the aggressiveness of thyroid carcinoma varies according to the new age stratification remains to be explored.

Methods

Medical records from patients were retrospectively reviewed. Patients with a documented thyroid ultrasonography (US), US-guided fine needle aspiration (FNA) and histopathology were included. The risks of unfavorable events such as central-compartment neck lymph node (CLN) metastasis, lateral-compartment neck lymph node (LLN) metastasis and gross extrathyroidal extension (ETE) were analyzed in four subsets of patients according to size and age.

Results

Large nodule size (≥10 mm) significantly increased the frequencies of CLN metastasis, LLN metastasis and gross ETE (P<0.05). The frequency of CLN metastasis was significantly higher in younger patients compared with that in older ones. Logistic regression analysis recognized large nodule size as an independent risk factor for all CLN metastasis (OR: 3.304, 95% CI: 2.473-4.415), LLN metastasis (OR: 9.673, 95% CI: 4.542-20.597), and gross ETE (OR: 2.430, 95% CI: 1.508-3.916). Secondly, in younger patients, frequencies of all CLN metastasis, LLN metastasis and gross ETE were significantly higher in nodules ≥10 mm than in nodules <10 mm (P<0.001). However, in older patients, no significant difference was found in the frequencies of LLN metastasis or gross ETE between nodules <10 mm and ≥10 mm. Logistic regression analysis showed, in younger patients, large nodule size was an independent risk factor for all CLN metastasis (OR: 3.241, 95% CI: 2.393-4.389), LLN metastasis (OR: 12.495, 95% CI: 5.281-29.562), and gross ETE (OR: 2.591, 95% CI: 1.519-4.419), while in older patients large nodule size was recognized as an independent risk factor for CLN metastasis (OR: 3.924, 95% CI: 1.413-10.899) but not for LLN metastasis or gross ETE.

Conclusions

Large nodule size is significantly related to high aggressiveness of thyroid carcinoma. The correlation between large nodule size and high aggressiveness varies according to patient's age, indicating that the presence of unfavorable events has different clinical significance for patients of varied ages. These findings contribute to accurately assessing the prognosis of individual patient and developing a better management strategy.

The clinical importance of multifocality on tumor recurrence in papillary thyroid carcinoma

Background

Although the origin of the multifocality of papillary thyroid carcinoma (PTC) is unclear, it is not unusual and has not been considered as an independent prognostic factor from several tumor staging systems. This study aims to evaluate whether the presence of multifocality is associated with PTC recurrence.

Methods

We reviewed retrospectively detailed histological reports of PTC patients who underwent thyroidectomy from January 2000 through December 2010 at a single institution. We assessed the relationship between multifocality and other possible prognostic factors using binary logistic regression analysis. We compared recurrence by the Kaplan-Meier method (the log-rank test). We analyzed a prognostic factor for recurrence using Cox's proportional hazard model (the stepwise forward method).

Results

We enrolled a total of 434 PTC patients (380 women and 54 men; mean age, 48 years). The median follow-up period was 10.2 years. Of all PTC patients enrolled, 135 patients (31%) had multifocal PTC. There was a significant association between multifocality and cervical lymph node (CLN) metastasis (P=0.01). Multivariate analyses showed a significant association between multifocality and CLN metastasis (P<0.001). Multifocal PTC patients had higher CLN metastasis and tumor recurrence than those with single PTC. There was a significant association between multifocality and tumor recurrence (P=0.03 by log-rank test), but it disappeared in multivariate analysis.

Conclusions

Multifocality of PTC might be related to CLN metastasis and tumor recurrence.

Value of thyroglobulin post hemithyroidectomy for cancer: a literature review

BACKGROUND

An increasing number of patients with low and moderate risk differentiated thyroid cancer (DTC) are now managed with lobectomy alone. The value of serum thyroglobulin (Tg) in the follow up of these patients remains poorly defined.

METHODS

A review of the MEDLINE and EMBASE databases was performed to assess the utility of Tg in the follow up of patients undergoing thyroid lobectomy for DTC.

RESULTS

A total of five retrospective reviews were identified including 1136 patients undergoing hemithyroidectomy with or without prophylactic central neck dissection. The overall locoregional recurrence rate was 3.7%. Changes in serum Tg following hemithyroidectomy for cancer were found to be clinically useful in one study only. The proposed cut-off value of 30 ng/mL following hemithyroidectomy as a predictor of recurrent disease was not validated by any study.

CONCLUSION

Serum Tg values are not useful in the follow up of DTC patients managed with lobectomy alone. Good quality neck ultrasound appears to be an effective modality in the detection of locoregional recurrence in these patients while research efforts continue to identify and validate novel biomarkers.

The De Novo Detection of Anti-Thyroglobulin Antibodies and Differentiated Thyroid Cancer Recurrence

Background: The prevalence and clinical significance of de novo detection of anti-thyroglobulin antibodies (TgAbs) during the follow-up of patients with differentiated thyroid cancer (DTC) is unknown. Methods: We utilized the National Thyroid Cancer Treatment Cooperative Study registry (1987-2012). Patients registered after 1996 (n = 3318) were analyzed. We identified 1545 subjects who had available TgAb status (TgAb cohort) between years 1996 and 2012, of whom 1325 were TgAb negative at first postoperative follow-up testing. From this initial TgAb-negative group, we excluded 513 patients: 423 patients who had less than 3 years of follow-up and/or fewer than three follow-up visits, 86 patients with persistent disease after initial treatment, and 4 patients with data entry errors. The remaining 812 patients were included for analysis, comprising the TgAb persistently negative group (defined as TgAb negative for at least 3 consecutive follow-up visits and at least 3 years of follow-up) (n = 772) and the de novo TgAb-positive group in whom TgAbs became detectable (n = 40). We then assessed whether de novo appearance of TgAb was associated with DTC structural recurrence by using the Kaplan-Meier method. Results: The de novo detection of TgAb occurred in 5% of DTC patients. Recurrence of DTC in the TgAb persistently negative group compared with the de novo TgAb-positive group did not differ significantly (9.6% vs. 15.0%, p = 0.23). Baseline characteristics, histology, history of radiation exposure, staging, and median duration of follow-up were similar between the two groups. Interestingly, in all six patients who suffered a recurrence in the de novo TgAb-positive group, the TgAbs were negative at the time of recurrence detection and became positive at a median of 2.1 (0.7-8.7) years after the structural recurrence. Conclusions: Utilizing a large North American DTC registry, we found the prevalence of de novo TgAb detection to be 5% among initially TgAb-negative patients. We did not find a statistically significant association between de novo TgAb development and DTC structural recurrence. Larger prospective studies are required to confirm these findings and further assess the significance of de novo TgAb detection in the follow-up of DTC.

Unilateral Multifocality and Bilaterality Could Be Two Different Multifocal Entities in Patients with Papillary Thyroid Microcarcinoma

OBJECTIVE

Multifocality within an affected lobe (unilateral multifocality) or two lobes (bilaterality) is commonly denoted as multifocality without differentiation. Recently, there has been molecular evidence indicating that unilateral multifocality and bilaterality could be two different entities. However, few studies concerning the comparison between these two different multifocality entities have been reported.

DESIGN

A retrospective cohort study.

METHODS

From 2010 to 2013, in total, 949 consecutive patients with papillary thyroid microcarcinoma (PTMC) were enrolled and further divided into four groups based on multifocality status. Unilateral multifocality and bilaterality were analyzed by binary logistic regression along with other clinicopathological factors.

RESULTS

Unilateral multifocality, instead of bilaterality, was correlated with central neck metastasis (CNM) in both univariate and multivariate analyses. Group IV (unilateral multifocality and bilaterality coexist) had the highest CNM rate. Group III (unilateral multifocality) had a higher CNM rate than group II (bilaterality, single lesion in each lobe), with a significant difference (p = 0.032). Similar lateral neck metastasis tendency was observed among the four groups. In the multivariate analysis, only unilateral multifocality and bilaterality which coexisted were correlated with CNM. Moreover, 9 cases had a recurrence, with the recurrence rate ranking top in group IV (3.6%), second in group III (2.8%), and third in group II (1.2%). The difference was significant (p = 0.021).

CONCLUSION

Unilateral multifocality and bilaterality could be two different multifocal entities in patients with PTMC. Unilateral multifocality serving as a prognostic factor indicated a worse prognosis than bilaterality on neck metastasis. When the two factors coexisted in PTMC, patients had the highest risk of CNM and possibly local recurrence compared with those with either risk factor alone.

New paradigms in the treatment of low-risk thyroid cancer

INTRODUCTION

Thyroid cancer is the most common endocrine malignancy. Multiple different staging systems have been introduced and used for differentiated thyroid carcinoma (DTC).

AREAS COVERED

In this literature review we provide an overview of the standard options for management of patients with low risk differentiated thyroid cancer.

EXPERT OPINION

Surgery is considered the first and most important step in managing DTC with goal to remove all the malignant foci in order to achieve cure and increase the survival with least chance of recurrence. Many studies have been conducted to determine the best surgical approaches and how aggressive surgeries should be in order to achieve the best outcomes regarding efficacy as well as safety. Radioactive iodine (RAI) therapy has also been a part of the treatment regimen and is used for different purposes with three main goals: post-surgical ablation, adjuvant therapy and persisted/recurrent disease treatment. Radiation therapy, on the other hand, is still not recommended to be used routinely in DTC because of the conflicting data of its benefit.

Association between Thyroiditis and Multifocality in Papillary Thyroid Carcinoma

Introduction  Hashimoto thyroiditis (HT) shares many characteristics with papillary thyroid carcinoma (PTC), and some studies show that, when associated, PTC is diagnosed mostly with smaller lesions and multifocal pattern.

Objective  To evaluate the relationship between HT and PTC.

Methods  A retrospective study of 155 patients who underwent total thyroidectomy from 2009 to 2015. Demographical, clinical and ultrasonographical data, as well as anatomopathological findings were evaluated.

Results  There were signs of thyroidits in 35 patients, and 114 patients had a unifocal disease. There was no statistical significance between the variables studied and thyroiditis. However, when compared with the occurrence of unifocal or multifocal lesions, there was statistical significance regarding age ( p  = 0.038) and mass ( p  = 0.031). There was no direct relationship between thyroiditis and multifocality ( p  = 0.325) nor between thyroiditis and cervical extension of the disease ( p  = 0.300 e p  = 0.434).

Conclusion  There was no relationship between thyroiditis and multifocality in cases of PTC.

Total thyroidectomy versus lobectomy for papillary thyroid cancer: A systematic review and meta-analysis

BACKGROUND

This systematic review and meta-analysis collected data for evaluating the effect of surgical extent on overall survival (OS) and recurrence-free survival (RFS) in patients with papillary thyroid cancer (PTC).

METHODS

We searched the PubMed, Embase, and Cochrane Library databases. The included studies compared two groups of patients with PTC: the total thyroidectomy (TT) group and the lobectomy (LT) group. The combined hazard ratio (HR) was calculated.

RESULTS

Thirteen studies were included in the present study. The TT and LT groups had similar OS results (HR = 1.04; 95% CI: 0.90-1.21; P = .60). In the subgroup analysis, the combined HR of the ≤1 cm group and the 1.0 to 2.0 cm group showed that TT had no advantage with regard to OS compared to LT. In the 2.0 to 4.0 cm group, TT provided better OS than LT (HR = 0.88; 95% CI: 0.79-0.99; P = .03). Patients who underwent TT had a better RFS outcome than those who underwent LT (HR = 0.56; 95% CI: 0.41-0.77; P < .0001). In the subgroup analysis, both the ≤1 cm group and >1 cm group that underwent TT were associated with better RFS.

CONCLUSIONS

Our meta-analysis suggested that LT increased the risk of recurrence in PTC patients with tumors ≤1.0 cm and in PTC patients with tumors >1.0 cm. More importantly, LT was associated with higher mortality in PTC patients with 2.0 to 4.0 cm tumors. Caution is warranted when LT is performed in this group of patients.

Clinical features and therapeutic outcomes of patients with papillary thyroid microcarcinomas and larger tumors

OBJECTIVE

The aim of this study was to identify clinical features and therapeutic outcomes of patients with papillary thyroid cancer (PTC) according to tumor diameter and evaluate the correlation of neck lymph node (LN) involvement of papillary thyroid microcarcinoma (PTMC) according to patients' age.

PATIENTS AND METHODS

We divided 467 patients into two groups according to tumor diameter: PTMC group (≤1 cm) and non-PTMC group (>1 cm). The clinical data were analyzed retrospectively. Thereafter, we divided the PTMC patients into three subgroups according to age: young subgroup (<45 years), middle subgroup (45-54 years), and old subgroup (≥55 years). A further study about clinical features, especially the neck LN involvement in three subgroups, was analyzed.

RESULTS

All patients received radioiodine ablation at least once. There were more patients with a single cancer lesion and cancer in the unilateral lobe, less number of neck LN involvement, fewer patients with neck lymph node metastasis (LNM), and more patients with Hashimoto's thyroiditis in PTMC group than in non-PTMC group. At the further evaluation, 58.03% patients maintained clinical remission, which was more in the PTMC group than in non-PTMC group. There was no significant difference in recurrence, but the disease-free survival rate of patients in the PTMC group was higher than in the non-PTMC group. In the PTMC group, the radioactive iodine curative ratio in younger patients is lower than that in the other two subgroups. Both the LNM and central LNM (CLNM) rates were significantly higher in young patients compared with older patients. In addition, the LNM-positive group had more male patients, larger tumor size, and higher thyroglobulin antibody level. Both LNM and the CLNM rates were significantly higher in the young subgroup than in the older subgroup. Young and middle age and extrathyroid extension were independent risk factors for neck LNM. Unlike LNM, young age, extrathyroid extension, and male sex were independent risk factors for CLNM.

CONCLUSION

Some PTMCs were less aggressive and the therapeutic outcomes of them were better than non-PTMC. Moreover, PTMCs in young patients were more aggressive, especially in LNM. Hence, clinicians should consider an individualized treatment according to tumor characteristics and age to achieve better therapeutic efficacy.

Predictive factors for non-small-volume central lymph node metastases (more than 5 or ≥ 2 mm) in clinically node-negative papillary thyroid carcinoma

The benefits of prophylactic central neck dissection (pCND) for treating patients with clinical node-negative (cN0) papillary thyroid carcinoma (PTC) remain controversial. Lymph node metastases have been strongly associated with local recurrence and low survival, especially in PTC patients with 5 or more or ≥2 mm metastatic lymph nodes. The following study investigates the incidence and risk factors of more than 5 or ≥2 mm metastatic lymph nodes in the central compartment.A total of 611 patients with cN0 PTC were retrospectively analyzed. Cervical lymph nodes were harvested, and the size of metastatic lymph nodes was consequently analyzed.Non-small-volume central lymph node metastases (NSVCLNM), defined as more than 5 or ≥2 mm metastatic lymph nodes) were detected in 67 (11.0%) patients. Male gender, age ≤36 years, multifocal lesions, extrathyroidal extension, and tumor size > 0.85 cm were independent risk factors for NSVCLNM in cN0 PTC. The sensitivity and specificity of having ≥3 risk factors for predicting NSVCLNM was 46.3% and 86.8%, respectively.These findings suggest that pCND is a suitable treatment strategy for cN0 PTC patients with 3 or more risk factors for NSVCLNM.

Recurrence after low-dose radioiodine ablation and recombinant human thyroid-stimulating hormone for differentiated thyroid cancer (HiLo): long-term results of an open-label, non-inferiority randomised controlled trial

BACKGROUND

Two large randomised trials of patients with well-differentiated thyroid cancer reported in 2012 (HiLo and ESTIMABL1) found similar post-ablation success rates at 6-9 months between a low administered radioactive iodine (¹³¹I) dose (1·1 GBq) and the standard high dose (3·7 GBq). However, recurrence rates following radioactive iodine ablation have previously only been reported in observational studies, and recently in ESTIMABL1. We aimed to compare recurrence rates between radioactive iodine doses in HiLo.

METHODS

HiLo was a non-inferiority, parallel, open-label, randomised controlled factorial trial done at 29 centres in the UK. Eligible patients were aged 16-80 years with histological confirmation of differentiated thyroid cancer requiring radioactive iodine ablation (performance status 0-2, tumour stage T1-T3 with the possibility of lymph-node involvement but no distant metastasis and no microscopic residual disease, and one-stage or two-stage total thyroidectomy). Patients were randomly assigned (1:1:1:1) to 1·1 GBq or 3·7 GBq ablation, each prepared with either recombinant human thyroid-stimulating hormone (rhTSH) or thyroid hormone withdrawal. Patients were followed up at annual clinic visits. Recurrences were diagnosed at each hospital with a combination of established methods according to national standards. We used Kaplan-Meier curves and hazard ratios (HRs) for time to first recurrence, which was a pre-planned secondary outcome. This trial is registered with ClinicalTrials.gov, number NCT00415233.

RESULTS

Between Jan 16, 2007, and July 1, 2010, 438 patients were randomly assigned. At the end of the follow-up period in Dec 31, 2017, median follow-up was 6·5 years (IQR 4·5-7·6) in 434 patients (217 in the low-dose group and 217 in the high-dose group). Confirmed recurrences were seen in 21 patients: 11 who had 1·1 GBq ablation and ten who had 3·7 GBq ablation. Four of these (two in each group) were considered to be persistent disease. Cumulative recurrence rates were similar between low-dose and high-dose radioactive iodine groups (3 years, 1·5% vs 2·1%; 5 years, 2·1% vs 2·7%; and 7 years, 5·9% vs 7·3%; HR 1·10 [95% CI 0·47-2·59]; p=0·83). No material difference in risk was seen for T3 or N1 disease. Recurrence rates were also similar among patients who were prepared for ablation with rhTSH and those prepared with thyroid hormone withdrawal (3 years, 1·5% vs 2·1%; 5 years, 2·1% vs 2·7%; and 7 years, 8·3% vs 5·0%; HR 1·62 [95% CI 0·67-3·91]; p=0·28). Data on adverse events were not collected during follow-up.

INTERPRETATION

The recurrence rate among patients who had 1·1 GBq radioactive iodine ablation was not higher than that for 3·7 GBq, consistent with data from large, recent observational studies. These findings provide further evidence in favour of using low-dose radioactive iodine for treatment of patients with low-risk differentiated thyroid cancer. Our data also indicate that recurrence risk was not affected by use of rhTSH.

FUNDING

Cancer Research UK.

Persistent/Recurrent Differentiated Thyroid Cancer: Clinical and Radiological Characteristics of Persistent Disease and Clinical Recurrence Based on Computed Tomography Analysis

BACKGROUND

The natural course of persistent/recurrent differentiated thyroid cancer (DTC) has not been fully elucidated. The purpose of this study was to assess the relative incidence and clinico-radiological characteristics of persistent disease and clinical recurrence based on computed tomography (CT) analysis in patients with persistent/recurrent DTC.

METHODS

From January 2005 to December 2016, this retrospective study included 107 patients (M:F = 28:79; M_age = 53.5 years) with surgically proven cervical locoregional recurrence of DTC. Two neck CT examinations (median interval 1.92 years; range 0.17-7.58 years) before the last thyroid cancer surgery within the study period were reevaluated. Based on the presence of the lesion on the first CT and its progression on the second CT, the locoregional recurrence was classified into the following categories: stable persistence (decrease, no change, or increase by <2 mm in short dimension on the second CT), progressive persistence (increase by ≥2 mm), and clinical recurrence (newly appeared on the second CT). Clinical and radiological characteristics of the three groups were compared using univariate and multivariate logistic regression analyses.

RESULTS

The relative incidences of stable persistence, progressive persistence, and clinical recurrence were 56.1% (60/107), 15.0% (16/107), and 29.0% (31/107), respectively. Multivariate analysis between the clinical recurrence (29.0%) and persistence (71.0%) groups revealed various independent factors for prediction of clinical recurrence. These included longer interval between the two CT examinations (median 2.67 vs. 1.79 years; p = 0.021), a smaller number of thyroid surgeries (1.16 ± 0.45 vs. 1.55 ± 0.81; p = 0.002), and a history of neck dissection at the location of the largest locoregional recurrence (70.0% vs. 31.4%; p < 0.001). There was no significant independent factor for differentiation between the stable persistence (78.9%; 60/76) and progressive persistence (21.1%; 16/76) groups. The results may have been influenced by selection bias because this study included only surgically proven cases.

CONCLUSIONS

With regard to cervical locoregional recurrence of DTC, active surveillance may be favored because more than a half of the cases are structurally persistent and stable. However, meticulous evaluation is necessary to detect progressive persistence and clinical recurrence, considering various clinical factors.

Retrospective analysis of prognostic factors in patients of papillary thyroid microcarcinoma

We performed a retrospective chart review of 245 patients with papillary thyroid microcarcinoma (PTMC) to define factors linked to central lymph node metastasis and thus prognosis. Univariate and multivariate analyses showed that being male (p < 0.001), age <45 years at diagnosis (p = 0.045), maximum tumor size > 5 mm (p = 0.030), multifocal tumor (p = 0.040) and tumor envelope invasion (p < 0.001) were all independent risk factors for central compartment lymph node metastasis. Unifocal lesions at the thyroid gland’s upper pole, middle and lower pole, had lymph node metastasis rates of 22.7%, 14.0% and 35.0%, respectively (p = 0.048). The rate of central lymph node metastasis was much higher when there was bilateral thyroid involvement than with multifocal unilateral lesions (58.6% vs 37.5%; p = 0.040). These results suggest that for patients at low risk of central lymph node metastasis, unilateral thyroid lobe and isthmus resection is sufficient. However, for patients at high risk of central lymph node metastasis, central lymph node dissection increases the likelihood of complete tumor excision.

Long-term oncologic outcomes of papillary thyroid microcarcinoma according to the presence of clinically apparent lymph node metastasis: a large retrospective analysis of 5,348 patients

Purpose

Active surveillance (AS) of low-risk papillary thyroid microcarcinoma (PTMC) may reduce the risk of overtreatment of clinically insignificant cancer. However, the absence of predictor for the progression of PTMC resulted in treatment delay and potentially compromising cure of aggressive disease. Therefore, to anticipate potential damage of delayed surgery, we investigated the oncologic outcomes of patients with low-risk PTMC initially eligible for AS except clinically apparent lymph node metastasis (LNM), imitating delayed surgery with neck dissection.

Materials and methods

A total of 5,348 patients, enrolled between 1987 and 2016, with low-risk PTMC initially eligible for AS were included regardless of LNM. We classified our study patients into two groups: Group I, lobectomy with prophylactic central cervical node dissection; Group II, total thyroidectomy with modified radical neck dissection for LNM. In addition, we investigated the oncological outcomes of patients with second-wave surgery due to lateral lymph node recurrence (Group III, subgroup of Group I).

Results

Group I showed more favorable clinicopathological characteristics compared with Group II. In Group I, only 29 (0.58%) of 4,927 patients underwent second-wave surgery with neck dissection for lateral lymph node recurrences, whereas in Group II, all 22 (5.23%) of 421 patients underwent second-wave selective node dissection because of nodal recurrence. Disease-free survival rates were significantly different between Groups I and II (P<0.05). Of note, the recurrence rate of Group II was still significantly higher than that of Group III (5.2% vs 0%, respectively; P=0.021). In addition, Kaplan–Mayer survival analysis indicated poor disease-free survival rates in Group II compared with Group III (P<0.05).

Conclusion

The long-term treatment outcome of PTMC without LNM was favorable even if the recurrence occurs during follow-up period compared with that of PTMC with LNM. It should be noted that AS might be able to cause poor prognosis due to clinically apparent LNM.

Changes in Serum Thyroglobulin Levels After Lobectomy in Patients with Low-Risk Papillary Thyroid Cancer

BACKGROUND

Low-risk patients with differentiated thyroid cancer can be treated with thyroid lobectomy. Serial measurements of serum thyroglobulin (Tg) are recommended for surveillance, but the cutoff values indicating recurrence are not known. This study documented the natural course of serum Tg levels during follow-up after lobectomy for low-risk papillary thyroid carcinoma (PTC) and evaluated whether changes in serum Tg levels predict disease recurrence.

METHODS

This historical cohort study included 208 patients with low-risk PTC who underwent lobectomy but did not require hormone replacement. Postoperative serum Tg levels and Tg/thyrotropin (TSH) ratios and neck ultrasound were evaluated during a follow-up period with a median of 6.9 years.

RESULTS

The serum Tg levels increased gradually, and the proportion of patients with levels >10 ng/dL increased annually by 13.9%, 18.8%, 22.1%, 21.9%, 28.4%, and 28.9% during the six-year follow-up period (β = 0.574, p = 0.027). The relative serum Tg levels increased by 10% annually (β = 0.105, p < 0.001), and the levels of Tg and Tg/TSH ratios in 19 patients with recurrent disease did not differ significantly (β = 0.150, p = 0.090). Patients without recurrent disease were more likely to have serum Tg levels increased by >20% (p = 0.022). There were no significant differences in the proportions of patients with serum Tg levels increased by ≥50% or ≥100% in terms of the disease recurrence.

CONCLUSIONS

Serum Tg levels and the Tg/TSH ratio increased gradually after lobectomy in patients with and without recurrences, without any significant differences. Periodic measurements of serum Tg levels seem to have limited value in predicting recurrent PTCs after lobectomy.

Too Much of a Good Thing: Radioactive Iodine Ablation Use for Micropapillary Thyroid Carcinoma

Radioactive iodine (RAI) is not routinely recommended for the adjuvant treatment of micro-papillary thyroid carcinoma (MPTC). We aimed to report on clinical and pathologic factors associated with the use of RAI in these patients. We queried the Surveillance, Epidemiology, and End Results database for patients who underwent surgery for MPTC (tumor size ≤1 cm) from 1988 to 2009. We excluded patients without a biopsy-proven diagnosis, those diagnosed at autopsy, and patients with documented extra-thyroidal extension. Multivariate logistic regression models predicted the use of RAI based on patient, tumor, and treatment-related factors. We identified 24,076 patients with MPTC that were eligible for study inclusion. Of these, 6,172 (25.6%) received RAI. Lymph node metastases were present in 23.8 per cent of those for whom lymph node status was known. On multivariate analysis, an increasing number of positive nodes, increasing tumor size, Asian race, and male gender predicted the use of RAI. RAI use was less likely in those with advancing age, an increasing number of lymph nodes examined and patients that received less than a total thyroidectomy. Among node-negative patients, Asian race and increasing tumor size predicted the use of RAI. Factors predicting decreased use of RAI were an increasing number of lymph nodes examined, unknown race, less than a total thyroidectomy, and advancing age. A significant number of MPTC patients receive potentially unnecessary RAI.

Are Evidence-Based Guidelines Reflected in Clinical Practice? An Analysis of Prospectively Collected Data of the Italian Thyroid Cancer Observatory

OBJECTIVES

The goal of evidence-based practice guidelines is to optimize the management of emerging diseases, such as differentiated thyroid cancer (DTC). The aim of this study was to assess therapeutic approaches for DTC in Italy and to see how closely these practices conformed to those recommended in the 2009 American Thyroid Association (ATA) guidelines.

METHODS

The Italian Thyroid Cancer Observatory was established to collect data prospectively on thyroid cancers consecutively diagnosed in participating centers (uniformly distributed across the nation). Data on the initial treatment of all pathologically confirmed DTC cases present in the database from January 1, 2013 (database creation) to January 31, 2016, were analyzed.

RESULTS

A total of 1748 patients (77.2% females; median age 48.1 years [range 10-85 years]) were enrolled in the study. Most (n = 1640; 93.8%) were papillary carcinomas (including 84 poorly differentiated/aggressive variants); 6.2% (n = 108) were follicular and Hürthle cell carcinomas. The median tumor diameter was 11 mm (range 1-93 mm). Tumors were multifocal in 613 (35%) and presented extrathyroidal extension in 492 (28%) cases. Initial treatments included total thyroidectomy (involving one or two procedures; n = 726; 98.8%) and lobectomy (n = 22; 1.2%). A quarter of the patients who underwent total thyroidectomy had unifocal, intrathyroidal tumors ≤1 cm (n = 408; 23.6%). Neck dissection was performed in 40.4% of the patients (29.5% had central compartment dissection). Radioiodine remnant ablation (RRA) was performed in 1057 (61.2%) of the 1726 patients who underwent total thyroidectomy: 460 (41.2%) of the 983 classified by 2009 ATA guideline criteria as low-risk, 570 (87.1%) of the 655 as intermediate-risk, and 82 (93.1%) of the 88 as high-risk patients (p < 0.001). RRA was performed in 44% of the cases involving multifocal DTCs measuring ≤1 cm.

CONCLUSIONS

The treatment approaches for DTCs used in Italy display areas of inconsistency with those recommended by the 2009 ATA guidelines. Italian practices were characterized by underuse of thyroid lobectomy in intrathyroidal, unifocal DTCs ≤1 cm. The use of RRA was generally consistent with risk-stratified recommendations. However, its frequent use in small DTCs (≤1 cm) that are multifocal persists, despite the lack of evidence of benefit. These data provide a baseline for future assessments of the impact of international guidelines on DTC management in Italy. These findings also illustrate that the dissemination and implementation of guideline recommendations, and the change in practice patterns, require ongoing education and time.

Defining Papillary Carcinoma of the Thyroid: A Short Review and Analysis

OBJECTIVES

To review how changes in the pathologic definitions for papillary tumors of the thyroid during recent decades have affected outcomes for patients with these tumors.

METHODS

Forty-nine previous reports or studies involving collectively 53,606 patients were reviewed, and new analyses were performed on the data to include analyses of agreement, incidence, survival, and diagnostic categories.

RESULTS

The past emphasis on cytologic features to define papillary tumors has not resulted in ideal pairwise agreement between pathologists and has produced incidence and survival data suggesting overdetection and overdiagnosis. Most recently, tissue patterns have been reemphasized.

CONCLUSIONS

With the recent reemphasis on diagnostic tissue patterns (over cytologic criteria), agreements between pathologists for the diagnosis of papillary tumors should improve, and the incidence of papillary carcinoma should decline. Nevertheless, updated survival analyses demonstrate excellent long-term survival for most of those diagnosed with papillary carcinomas.

Controversies in the Management of Low-Risk Differentiated Thyroid Cancer

Controversy exists over optimal management of low-risk differentiated thyroid cancer. This controversy occurs in all aspects of management, including surgery, use of radioactive iodine for remnant ablation, thyroid hormone supplementation, and long-term surveillance. Limited and conflicting data, treatment paradigm shifts, and differences in physician perceptions contribute to the controversy. This lack of physician consensus results in wide variation in patient care, with some patients at risk for over- or undertreatment. To reduce patient harm and unnecessary worry, there is a need to design and implement studies to address current knowledge gaps.

Lack of Efficacy of Radioiodine Remnant Ablation for Papillary Thyroid Microcarcinoma: Verification Using Inverse Probability of Treatment Weighting

BACKGROUND

Most of the increase in thyroid cancer in recent decades has been due to papillary thyroid microcarcinoma (PTMC). We evaluated the efficacy of radioiodine remnant ablation (RRA) in patients with PTMC.

METHODS

This historical cohort study included 1932 PTMC patients without lateral cervical lymph node (LN) or distant metastasis who underwent total thyroidectomy (TT) during the median 8.3 years of follow-up. The clinical outcomes of patients with or without RRA were compared using weighted logistic regression models with the inverse probability of treatment weighting (IPTW) method and considering risk factors, including age, sex, primary tumor size, extrathyroidal extension, multifocality, and central cervical LN metastasis.

RESULTS

The median primary tumor size of the RRA group was significantly larger than that of the no-RRA group (0.7 vs. 0.5 cm, P < 0.001). There were significantly more patients with multifocality, extrathyroidal extension, and cervical LN metastasis in the RRA group compared with the no-RRA group. There was no significant difference in recurrence-free survival between the two groups (P = 0.11). Cox proportional-hazard analysis with IPTW by adjusting for clinicopathological risk factors demonstrated no significant difference in recurrence of PTMC according to RRA treatment (hazard ratio [HR] 2.02; 95% confidence interval [CI] 0.65-6.25; P = 0.2).

CONCLUSIONS

RRA had no therapeutic effect on the clinical outcomes of patients with PTMC who underwent TT. Surgical treatment without RRA could be applicable for patients with PTMC if there is no evidence of lateral cervical LN metastasis or distant metastasis.

Active Surveillance for Patients With Papillary Thyroid Microcarcinoma: A Single Center's Experience in Korea

CONTEXT

Papillary thyroid microcarcinoma (PTMC) usually has an excellent prognosis.

OBJECTIVE

To evaluate the three-dimensional structures of PTMCs, using serial neck ultrasonography (US) in patients under active surveillance.

DESIGN AND SETTING

A retrospective cohort study.

PARTICIPANTS

In total, 192 patients diagnosed with PTMC under active surveillance for >1 year were included in a median 30-month follow-up. Changes in tumor size were evaluated not only using the maximal tumor diameter but also the tumor volume.

RESULTS

The median age of patients was 51.3 years and 145 patients (76%) were female. The median initial maximal tumor diameter and tumor volume were 5.5 mm and 48.8 mm3, respectively. The tumor size increased in 27 patients (14%); 23 patients showed a tumor volume increase >50% without a maximal diameter increase of ≥3 mm. The other four patients had both an increasing tumor volume and increasing maximal tumor diameter ≥3 mm. One patient (0.5%) had newly appeared cervical lymph node (LN) metastasis at 3 years after the initial diagnosis. There were no significant risk factors associated with increased tumor size, such as age, sex, or Hashimoto thyroiditis. Twenty-four patients (13%) underwent delayed thyroid surgery at a median of 31.2 months and seven (29%) had cervical LN metastasis on pathologic examination.

CONCLUSION

Some PTMCs could grow significantly after a relatively short period of active surveillance. We also found that the change in tumor volume was more sensitive to detect tumor progression than the change in the maximal tumor diameter.

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.

The Genetics of Papillary Microcarcinomas of the Thyroid: Diagnostic and Prognostic Implications

Papillary microcarcinoma of the thyroid (mPTC) is defined by the WHO as a papillary thy-roid cancer measuring 10mm or less in diameter and it is nowadays a topic of intense debate among the members of the medical community due to its apparent “epidemic” rise. Although these tumors follow almost always an indolent clinical course and carry an excellent prognosis, it is known that a small sub-set may display a potentially aggressive behavior. Nevertheless, we still lack an accurate way of predict-ing those which will cause significant disease. In an attempt to address this problem, a number of clini-co-pathologic features have been studied as poor prognostic markers in mPTC, and their association with known genetic alterations in thyroid cancer has been evaluated. Herein we review the present knowledge concerning mPTC’s genetic profile, namely the prevalence of BRAF (V600E), RAS and TERT promoter mutations and RET/PTC and PAX8-PPARG rearrangements and report the results of the evaluation in the putative prognostic value of these genetic alterations in mPTC.

A comparison of lobectomy and total thyroidectomy in patients with papillary thyroid microcarcinoma: a retrospective individual risk factor-matched cohort study

OBJECTIVE

Papillary thyroid microcarcinoma (PTMC) accounts for most of the increase in thyroid cancer in recent decades. We compared clinical outcomes and surgical complications of lobectomy and total thyroidectomy (TT) in PTMC patients.

DESIGN AND METHODS

In this retrospective individual risk factor-matched cohort study, 2031 patients with PTMC were initially included. Patients who underwent lobectomy or TT were one-to-one matched according to individual risk factors, including age, sex, primary tumor size, extrathyroidal extension, multifocality and cervical lymph node (LN) metastasis.

RESULTS

In total, 688 patients were assigned to each group. During the median 8.5 years of follow-up, 26 patients (3.8%) in the lobectomy group and 11 patients (1.6%) in the TT group had recurrences. The relative risk of recurrence was significantly less in the TT than that in the lobectomy group (hazard ratio (HR) 0.41; 95% confidence interval (CI) 0.21-0.81; P = 0.01). Most recurrences (84.6%) in the lobectomy group occurred in the contralateral lobe, and all patients were disease-free after completion of thyroidectomy. There were no significant differences in recurrence-free survival between the two groups after exclusion of contralateral lobe recurrences (HR, 2.75; 95% CI, 0.08-8.79; P = 0.08). There were significantly more patients with transient and permanent hypoparathyroidism in the TT than that in the lobectomy group (P < 0.001).

CONCLUSIONS

Lobectomy could be appropriate for most patients with PTMC when there is no evidence of extrathyroidal disease in the preoperative work-up. Preoperative and postoperative imaging studies are important for patients who undergo lobectomy for PTMC, because most recurrences are in the contralateral lobe.

Dynamic Risk Stratification for Predicting Recurrence in Patients with Differentiated Thyroid Cancer Treated Without Radioactive Iodine Remnant Ablation Therapy

BACKGROUND

Increased incidence of small differentiated thyroid cancer (DTC) has emphasized the need for risk stratification and individualized disease management for these low risk DTCs. The aim of this study was to validate a new dynamic risk stratification (DRS) system for the prediction of structural recurrent/persistent disease in patients with DTC treated without radioactive iodine (RAI) remnant ablation therapy.

METHODS

This historical cohort study included 357 patients with DTC treated with lobectomy or total thyroidectomy without RAI therapy. We stratified patient response to initial treatment as excellent, indeterminate, biochemical incomplete, and structural incomplete according to the DRS system.

RESULTS

During a median follow-up of 8.6 years, 3.6% patients had structural recurrent DTC. The response was excellent in 71.7% patients, indeterminate in 18.5%, biochemical incomplete in 8.4%, and structural incomplete in 1.4%. There were significant differences in DFS among the DRS groups (p < 0.001). The hazard ratio (HR) of recurrent/persistent disease was significantly higher in the biochemical incomplete group (HR = 20.8, p < 0.001) and structural incomplete group (HR = 243.3, p < 0.001) compared with the excellent group. However, the Tumor Node Metastasis staging system and the American Thyroid Association initial risk classification did not effectively predict recurrence of DTC.

CONCLUSIONS

The new DRS system was effective for predicting risk of recurrent/persistent disease in patients with DTC who underwent lobectomy or total thyroidectomy without RAI remnant ablation.

Prevalence of Contralateral Tumors in Patients with Follicular Variant of Papillary Thyroid Cancer

BACKGROUND

Thyroid lobectomy alone is being performed increasingly for patients with encapsulated follicular variant of papillary thyroid carcinoma (fvPTC). However, the prevalence of contralateral disease in these patients is unknown. We investigated the presence of synchronous disease in fvPTC to improve decision making about the extent of surgical resection and need for surveillance.

STUDY DESIGN

We performed a retrospective review of patients who underwent thyroid surgery from October 2009 to February 2013 with a diagnosis of fvPTC as their primary lesion. We collected information on patient demographics, nodule size, multifocality, fine-needle aspiration results, lymphovascular invasion, extrathyroidal extension, and lymph node metastasis. Tumors were divided into noninvasive and invasive/infiltrative fvPTC categories. Characteristics of solitary and bilateral fvPTC were compared.

RESULTS

We identified 124 patients with final pathology demonstrating fvPTC. The most common fine-needle aspiration diagnosis was "suspicious for malignancy" (n = 53). Sixty-five contralateral tumors were identified in 44 of 124 patients (35.5%) and included fvPTC (n = 40), classical PTC (n = 22), tall cell PTC (n = 2), and follicular carcinoma (n = 1). Fifty contralateral tumors were 1 to 5 mm, 10 measured 6 to 9 mm, and 5 were ≥10 mm. Contralateral disease correlated significantly with lymphovascular invasion (p = 0.037) and larger primary lesions (p = 0.020). There was no significant difference noted in extrathyroidal extension or lymph node metastasis. Both noninvasive and invasive/infiltrative fvPTC demonstrated similar rates of contralateral disease.

CONCLUSIONS

Bilateral disease is common in fvPTC, primarily in the form of papillary microcarcinomas. Future monitoring of the contralateral lobe should be discussed with fvPTC patients who do not undergo completion thyroidectomy.

Can ratio of the biggest tumor diameter to total tumor diameter be a new parameter in the differential diagnosis of agressive and favorable multifocal papillary thyroid microcarcinoma?

OBJECTIVES

In this study, we aimed to evaluate the usefulness of a new parameter -ratio of the biggest tumor diameter to total tumor diameter- for the differentiation of agressive and favorable papillary thyroid microcarcinomas (PTMC).

MATERIALS AND METHODS

The diameter of the biggest tumor focus was taken as the primary tumor diameter. Total tumor diameter was calculated as the sum of the maximal diameter of each lesion. Ratio of primary tumor diameter to total tumor diameter was defined as tumor diameter ratio (TDR). Positive and negative predictive value, sensitivity and specificity of TDR to predict capsular invasion, extrathyroidal extension (ETE) and lymph node metastasis (LNM) were determined.

RESULTS

Mean TDR was significantly lower in multifocal PTMC patients with capsular invasion, ETE, lymphovascular invasion and LNM compared to patients without these features. The sensitivities of TDR for the detection of LNM, ETE and capsular invasion were 100%, 100% and 94.2%, respectively. Specificity of TDR was 86.2% for LNM, 88% for ETE and 94.7% for capsular invasion. Best cut off values of TDR that can predict capsular invasion, ETE and LNM in multifocal PTMC were 0.62, 0.57 and 0.56, respectively. Multifocal papillary thyroid carcinoma patients with capsular invasion, ETE and LNM had significantly lower mean TDR when compared to ones without these features.

CONCLUSION

Decreased TDR was associated with capsular invasion, ETE and LNM in patients with multifocal PTMC and PTC. This new parameter might be particularly helpful for the detection of aggressive behavior in multifocal PTMCs.

Thyroid cancer

Thyroid cancer is the fifth most common cancer in women in the USA, and an estimated over 62 000 new cases occurred in men and women in 2015. The incidence continues to rise worldwide. Differentiated thyroid cancer is the most frequent subtype of thyroid cancer and in most patients the standard treatment (surgery followed by either radioactive iodine or observation) is effective. Patients with other, more rare subtypes of thyroid cancer-medullary and anaplastic-are ideally treated by physicians with experience managing these malignancies. Targeted treatments that are approved for differentiated and medullary thyroid cancers have prolonged progression-free survival, but these drugs are not curative and therefore are reserved for patients with progressive or symptomatic disease.