External beam radiation therapy for recurrent or residual thyroid cancer: What is the best treatment time and the best candidate for long-term local disease control?

INTRODUCTION

Cervical disease control might be challenging in advanced thyroid cancer (DTC). Indications for cervical external beam radiation therapy (EBRT) are controversial.

PURPOSE

To identify clinical and molecular factors associated with control of cervical disease with EBRT.

METHODS

Retrospective evaluation and molecular analysis of the primary tumor DTC patients who underwent cervical EBRT between 1995 and 2022 was performed.

RESULTS

Eighty adults, median age of 61 years, were included. T4 disease was present in 43.7%, lymph node involvement in 42.5%, and distant metastasis in 47.5%. Those with cervical progression were older (62.5 vs. 57.3, p = 0.04) with more nodes affected (12.1 vs. 2.8, p = 0.04) and had EBRT performed later following surgery (76.6 vs. 64 months, p = 0.05). EBRT associated with multikinase inhibitors showed longer overall survival than EBRT alone (64.3 vs. 37.9, p = 0.018) and better local disease control. Performing EBRT before radioiodine (RAI) was associated with longer cervical progression-free survival (CPFS) than was RAI before (67.5 vs. 34.5, p < 0.01). EBRT ≥2 years after surgery was associated with worse CPFS (4.9 vs. 34, p = 0.04). The most common molecular alterations were ERBB2, BRAF, FAT1, RET and ROS1 and TERT mutation was predictive of worse disease control after EBRT (p = 0.04).

CONCLUSION

Younger patients, with fewer affected nodes and treated earlier after surgery had better cervical disease control. Combination of EBRT with MKI improved OS. TERT mutation might indicate worse responders to EBRT; however, further studies are necessary to clarify the role of molecular testing in selecting candidates for cervical EBRT.

Serum anti-Müllerian hormone is lower in patients with multiple radioiodine dose for treatment of pediatric thyroid cancer

Introduction

Treatment of patients with pediatric differentiated thyroid cancer (DTC) often involves radioiodine (RAI), which is associated with increased risks of short- and long-term adverse outcomes. The impact of RAI treatment on the female reproductive system remains uncertain. Anti-Müllerian hormone (AMH) is a marker of ovarian reserve and is related to fertility.

Objective

The aim was to analyze the association between RAI and serum AMH level in women treated with RAI.

Methods

We evaluated women with pediatric DTC treated with RAI at the age of ≤19 years. Serum AMH was measured.

Results

The study included 47 patients with a mean age of 25.1 years (12.4-50.8) at AMH measurement and follow-up of 11.8 ± 8.4 years. The mean RAI administered was 235 mCi (30-1150). Sixteen (34%) received multiple RAI doses (471 ± 215 mCi). Mean AMH level was 2.49 ng/mL (0.01-7.81); the level was 1.57 ng/mL (0.01-7.81) after multiple RAI doses and 2.99 ng/mL (0.01-6.63) after a single RAI dose (P = 0.01). Patients who received a cumulative RAI lower than 200 mCi had higher AMH levels (2.23 ng/mL, 0.39-7.81) than those who received more (1.0 ng/mL, 0.01-6.63; P = 0.02). In patients with similar cumulative RAI activities, administration of multiple RAI doses was significantly and independently associated with AMH level lower than the reference range for age (HR: 5.9, 1.55-52.2, P = 0.014) after age adjustments.

Conclusion

Levels of AMH were lower after multiple RAI doses, especially after a cumulative RAI dose above 200 mCi. More studies are needed to clarify the impact of RAI on fertility considering its cumulative activity and treatment strategy.

Increased Progression-Free Survival with Cabozantinib Versus Placebo in Patients with Radioiodine-Refractory Differentiated Thyroid Cancer Irrespective of Prior Vascular Endothelial Growth Factor Receptor-Targeted Therapy and Tumor Histology: A Subgroup Analysis of the COSMIC-311 Study

Background: Lenvatinib and sorafenib are standard of care first-line treatments for advanced, radioiodine-refractory (RAIR) differentiated thyroid cancer (DTC). However, most patients eventually become treatment-resistant and require additional therapies. The phase 3 COSMIC-311 study investigated cabozantinib in patients with RAIR DTC who progressed on lenvatinib, sorafenib, or both and showed that cabozantinib provided substantial clinical benefit. Presented in this study is an analysis of COSMIC-311 based on prior therapy and histology. Methods: Patients were randomized 2:1 (stratification: prior lenvatinib [yes/no]; age [≤65, >65 years]) to oral cabozantinib (60 mg tablet/day) or matched placebo. Eligible patients received 1-2 prior vascular endothelial growth factor receptor-targeting tyrosine kinase inhibitors for DTC (lenvatinib or sorafenib required), had a confirmed DTC diagnosis, and were refractory to or ineligible for radioiodine therapy. For this analysis, progression-free survival (PFS) and objective response rate (ORR) per Response Evaluation Criteria in Solid Tumors version 1.1 by a blinded independent radiology committee were evaluated by prior therapy (lenvatinib only, sorafenib only, both) and histology (papillary, follicular, oncocytic, poorly differentiated). Results: Two hundred fifty-eight patients were randomized (170 cabozantinib/88 placebo) who previously received sorafenib only (n = 96), lenvatinib only (n = 102), or both (n = 60). The median follow-up was 10.1 months. The median PFS (months) with cabozantinib/placebo was 16.6/3.2 (sorafenib only: hazard ratio [HR] 0.13 [95% confidence interval, CI, 0.06-0.26]), 5.8/1.9 (lenvatinib only: HR 0.28 [95% CI 0.16-0.48]), and 7.6/1.9 (both: HR 0.27 [95% CI 0.13-0.54]). The ORR with cabozantinib/placebo was 21%/0% (sorafenib only), 4%/0% (lenvatinib only), and 8%/0% (both). Disease histology consisted of 150 papillary and 113 follicular, including 43 oncocytic and 36 poorly differentiated. The median PFS (months) with cabozantinib/placebo was 9.2/1.9 (papillary: HR 0.27 [95% CI 0.17-0.43]), 11.2/2.5 (follicular: HR 0.18 [95% CI 0.10-0.31]), 11.2/2.5 (oncocytic: HR 0.06 [95% CI 0.02-0.21]), and 7.4/1.8 (poorly differentiated: HR 0.18 [95% CI 0.08-0.43]). The ORR with cabozantinib/placebo was 15%/0% (papillary), 8%/0% (follicular), 11%/0% (oncocytic), and 9%/0% (poorly differentiated). Safety outcomes evaluated were consistent with those previously observed for the overall population. Conclusions: Results indicate that cabozantinib benefits patients with RAIR DTC, regardless of prior lenvatinib or sorafenib treatments or histology. Clinical Trial Registration Number: NCT03690388.

Management of radioiodine refractory differentiated thyroid cancer: the Latin American perspective

Radioiodine (RAI) refractory differentiated thyroid cancer is an uncommon and challenging situation that requires a multidisciplinary approach to therapeutic strategies. The definition of RAI-refractoriness is usually a clear situation in specialized centers. However, the right moment for initiation of multikinase inhibitors (MKI), the time and availability for genomic testing, and the possibility of prescribing MKI and selective kinase inhibitors differ worldwide.Latin America (LA) refers to the territories of the world that stretch across two regions: North America (including Central America and the Caribbean) and South America, containing 8.5% of the world's population. In this manuscript, we critically review the current standard approach recommended for patients with RAI refractory differentiated thyroid cancer, emphasizing the challenges faced in LA. To achieve this objective, the Latin American Thyroid Society (LATS) convened a panel of experts from Brazil, Argentina, Chile, and Colombia. Access to MKI compounds continues to be a challenge in all LA countries. This is true not only for MKI but also for the new selective tyrosine kinase inhibitor, which will also require genomic testing, that is not widely available. Thus, as precision medicine advances, significant disparities will be made more evident, and despite efforts to improve coverage and reimbursement, molecular-based precision medicine remains inaccessible to most of the LA population. Efforts should be undertaken to alleviate the discrepancies between the current state-of-the-art care for RAI-refractory differentiated thyroid cancer and the present situation in Latin America.

Stimulated thyroglobulin and diagnostic 131-iodine whole-body scan as a predictor of distant metastasis and association with response to treatment in pediatric thyroid cancer patients

INTRODUCTION

Differentiated thyroid carcinoma (DTC) is a rare oncological disease in the pediatric population, presenting with a more aggressive form. Stimulated thyroglobulin (sTg) and the 131-iodine whole-body scans (WBSs) are known adult markers related to the presence of distant metastasis. Little is known about their roles in the pediatric population.

PURPOSE

To evaluate sTg levels and diagnostic WBS (DxWBS) as predictors of distant metastasis after thyroidectomy and to correlate with the response to treatment at the end of follow-up in pediatric DTC.

MATERIALS AND METHODS

Patients under 19 years old diagnosed with DTC from 1980 to 2022 were retrospectively evaluated. sTg values and WBS were assessed after thyroidectomy and prior radioiodine treatment (RIT) and correlated with the possibility of finding distant metastasis and response to treatment at the end of follow-up.

RESULTS

In a total of 142 patients with a median age of 14.6 (4-18) years who were followed for 9.5 ± 7.2 years and classified according to the ATA risk of recurrence as low (28%), intermediate (16%), and high risk (56%), 127 patients had their sTg evaluated. A sTg value of 21.7 ng/dl yielded a sensitivity of 88% compared to 30% for DxWBS in predicting distant metastasis. Specificity was 60% and 100% respectively. 42% of patients obtained discordant results between DxWBS and RxWBS. In high-risk patients, sTg levels were particularly able to differentiate those who would have distant metastasis with better diagnostic accuracy than the WBSs.

CONCLUSIONS

The sTg level had better performance in detecting distant metastases in pediatric DTC than the DxWBS. DxWBS's low performance suggests that caution should be taken in interpreting their findings in terms of the underdiagnosis for metastatic disease, especially when the sTg level already suggests distant disease.

Guidelines from the Brazilian society of surgical oncology regarding indications and technical aspects of neck dissection in papillary, follicular, and medullary thyroid cancers

Objective

The purpose of these guidelines is to provide specific recommendations for the surgical treatment of neck metastases in patients with papillary, follicular, and medullary thyroid carcinomas.

Materials and methods

Recommendations were developed based on research of scientific articles (preferentially meta-analyses) and guidelines issued by international medical specialty societies. The American College of Physicians' Guideline Grading System was used to determine the levels of evidence and grades of recommendations. The following questions were answered: A) Is elective neck dissection indicated in the treatment of papillary, follicular, and medullary thyroid carcinoma? B) When should central, lateral, and modified radical neck dissection be performed? C) Could molecular tests guide the extent of the neck dissection?

Results and conclusion

Recommendation 1: Elective central neck dissection is not indicated in patients with cN0 well-differentiated thyroid carcinoma or in those with noninvasive T1 and T2 tumors but may be considered in T3-T4 tumors or in the presence of metastases in the lateral neck compartments. Recommendation 2: Elective central neck dissection is recommended in medullary thyroid carcinoma. Recommendation 3: Selective neck dissection of levels II-V should be indicated to treat neck metastases in papillary thyroid cancer, an approach that decreases the risk of recurrence and mortality. Recommendation 4: Compartmental neck dissection is indicated in the treatment of lymph node recurrence after elective or therapeutic neck dissection; "berry node picking" is not recommended. Recommendation 5: There are currently no recommendations regarding the use of molecular tests in guiding the extent of neck dissection in thyroid cancer.

Neutrophil-to-lymphocyte ratio as an independent factor for worse prognosis in radioiodine refractory thyroid cancer patients

PURPOSE

This study aimed to evaluate neutrophil to lymphocyte ratio (NLR) as a laboratory biomarker in radioactive iodine-refractory (RAIR) locally advanced and/or metastatic differentiated thyroid cancer (DTC) and determine its correlation with overall survival (OS).

METHODS

We retrospectively included 172 patients with locally advanced and/or metastatic RAIR DTC admitted between 1993 and 2021 at INCA. Age at diagnosis, histology, presence of distant metastasis (DM), DM site, neutrophil-to- lymphocyte ratio (NLR), imaging studies such as PET/CT results, progression free survival (PFS) and overall survival (OS) data were analyzed. NLR was calculated at the time of locally advanced and/or metastatic disease diagnosis and the cutoff value was 3. Survival curves were established using the Kaplan-Meier method. The confidence interval is 95%, and a p-value of less than 0.05 was considered statistically significant RESULTS: Out of 172 patients, 106 were locally advanced, and 150 presented DM at some point during follow-up. Regarding NLR data, 35 had NLR over 3 and 137 had NLR under 3. Higher NLR at was associated with shorter OS (6 vs. 10; p = 0.05) and with highest SUV on FDG PET-CT (15.9 vs. 7.7, p = 0.013). We found no association between higher NLR and age at diagnosis, DM or final status.

CONCLUSION

NLR higher than 3 at the time of locally advanced and/or metastatic disease diagnosis is an independent fator for shorter OS in RAIR DTC patients. Noteworthy higher NLR was also associated with highest SUV on FDG PET-CT in this population.

An Undetectable Postoperative Calcitonin Level Is Associated with Long-Term Disease-Free Survival in Medullary Thyroid Carcinoma: Results of a Retrospective Cohort Study

Background: Calcitonin measurement is widely used in the diagnosis, prognosis, and follow-up of patients with medullary thyroid carcinoma (MTC). The prognostic value of undetectable postoperative calcitonin (POCal) in long-term disease outcomes remains uncertain. Objective: The aim of this study is to evaluate POCal as a prognostic marker for long-term MTC disease status. Methods: A retrospective cohort study was carried out. We collected data from the medical records of patients with MTC attending two tertiary teaching hospitals. Patients were divided according to POCal into two groups: undetectable (below the detection limit) or detectable. The outcome was determined at the last medical visit and defined as disease free (undetectable calcitonin and no evidence of disease on imaging), persistent disease (detectable calcitonin with or without structural disease), or disease-related death. Results: Three hundred thirty-four MTC patients were included in the study. The mean age at diagnosis was 41.1 ± 18.6 years; 202 patients (60.5%) were women; and 167 patients (50.0%) had sporadic MTC. The median tumor size was 2.0 cm (1.1-3.5 cm); 164 patients (49.1%) had lymph node metastasis and 63 patients (18.9%) had distant metastasis. At the first postoperative evaluation (3-6 months after surgery), 141 patients had undetectable POCal (mean age = 37.9 years, 70.9% women, median tumor size 1.5 cm [0.7-2.5 cm]; 28 [19.9%] had lymph node metastasis and none had distant metastasis). After a median follow-up of 7.7 years (2.1-13.2 years), 127 (90.1%) of these patients were free of disease, whereas 14 (9.9%) had persistent biochemical disease with stable calcitonin levels. No patient with undetectable POCal died of the disease. In the detectable POCal group (mean age = 42.9 years, 52.8% women, median tumor size 3.0 cm [1.8-4.2 cm]; 136 [70.5%] had lymph node metastasis and 63 [32.6%] had distant metastasis), 18 (9.2%) patients achieved disease-free status, 51 (26.6%) had biochemical disease, and 61 (31.6%) had persistent structural disease. Sixty-three (32.6%) patients died of disease-related events. Further analysis using a multivariate model identified undetectable POCal as an independent prognostic variable for disease-free status (HR = 5.33, CI = 2.86-9.94; p < 0.001). Conclusions: POCal is a strong prognostic marker for long-term disease-free survival and might help define follow-up strategies for MTC patients.

Cabozantinib for previously treated radioiodine-refractory differentiated thyroid cancer: Updated results from the phase 3 COSMIC-311 trial

BACKGROUND

At an interim analysis (median follow-up, 6.2 months; n = 187), the phase 3 COSMIC-311 trial met the primary end point of progression-free survival (PFS): cabozantinib improved PFS versus a placebo (median, not reached vs. 1.9 months; p < .0001) in patients with previously treated radioiodine-refractory differentiated thyroid cancer (RAIR-DTC). The results from an exploratory analysis using an extended datacut are presented.

METHODS

Patients 16 years old or older with RAIR-DTC who progressed on prior lenvatinib and/or sorafenib were randomized 2:1 to oral cabozantinib tablets (60 mg/day) or a placebo. Placebo patients could cross over to open-label cabozantinib upon radiographic disease progression. The objective response rate (ORR) in the first 100 randomized patients and the PFS in the intent-to-treat population, both according to Response Evaluation Criteria in Solid Tumors version 1.1 by blinded, independent review, were the primary end points.

RESULTS

At the data cutoff (February 8, 2021), 258 patients had been randomized (cabozantinib, n = 170; placebo, n = 88); the median follow-up was 10.1 months. The median PFS was 11.0 months (96% confidence interval [CI], 7.4-13.8 months) for cabozantinib and 1.9 months (96% CI, 1.9-3.7 months) for the placebo (hazard ratio, 0.22; 96% CI, 0.15-0.32; p < .0001). The ORR was 11.0% (95% CI, 6.9%-16.9%) versus 0% (95% CI, 0.0%-4.1%) (p = .0003) with one complete response with cabozantinib. Forty placebo patients crossed over to open-label cabozantinib. Grade 3/4 treatment-emergent adverse events occurred in 62% and 28% of the cabozantinib- and placebo-treated patients, respectively; the most common were hypertension (12% vs. 2%), palmar-plantar erythrodysesthesia (10% vs. 0%), and fatigue (9% vs. 0%). There were no grade 5 treatment-related events.

CONCLUSIONS

At extended follow-up, cabozantinib maintained superior efficacy over a placebo in patients with previously treated RAIR-DTC with no new safety signals.

Neutrophil to lymphocyte ratio as a prognosis biomarker of PRRT in NET patients

PURPOSE

Peptide Receptor Radionuclide Therapy (PRRT) with 177Lu-DOTATATE is a palliative therapeutic option for advanced Neuroendocrine Tumors (NETs). Prognostic factors can predict long-term outcomes and determine response to therapy. Among those already explored, biomarkers from full blood count, including neutrophil to lymphocyte ratio (NLR) and platelet to lymphocyte ratio (PLR) has shown value for other solid tumors and for NETs patients submitted to other forms of therapy. However, its relation to PRRT response and patients' prognosis is still to be determined.

METHODS

Medical records from 96 patients submitted to PRRT between 2010 and 2017 were reviewed, median NLR and PLR were calculated from baseline flood blood count and dichotomized as high or low. Progression-free survival (PFS) and Overall Survival (OS) were calculated.

RESULTS

NLR and PLR median values were 1.8 and 123, respectively. Patients with low NLR had a significantly longer OS (estimated median of 77.5 months, 95% CI: 27.3-127.7) when compared to patients with high NLR (estimated median of 47.7 months, 95% CI: 34.7-60.8); p = 0.04. Patients with low NLR had a trend toward a longer median PFS when compared to patients with high NLR [estimated medians of 77 months (95% CI: 27.3-127.7), and 47.7 months, (95% CI: 34.7-60.7)], respectively, p = 0.08.

CONCLUSION

Patients with advanced-stage NET with NLR higher than 1.8 have worse long term clinical outcomes after PPRT. Larger studies are needed to validate the optimal cutoff for this biomarker.

Treatment strategies for low-risk papillary thyroid carcinoma: a position statement from the Thyroid Department of the Brazilian Society of Endocrinology and Metabolism (SBEM)

Increasingly sensitive diagnostic methods, better understanding of molecular pathophysiology, and well-conducted prospective studies have changed the current approach to patients with thyroid cancer, requiring the implementation of individualized management. Most patients with papillary thyroid carcinoma (PTC) are currently considered to have a low risk of mortality and disease persistence/recurrence. Consequently, current treatment recommendations for these patients include less invasive or intensive therapies. We used the most recent evidence to prepare a position statement providing guidance for decisions regarding the management of patients with low-risk PTC (LRPTC). This document summarizes the criteria defining LRPTC (including considerations regarding changes in the TNM staging system), indications and contraindications for active surveillance, and recommendations for follow-up and surgery. Active surveillance may be an appropriate initial choice in selected patients, and the criteria to recommend this approach are detailed. A section is dedicated to the current evidence regarding lobectomy versus total thyroidectomy and the potential pitfalls of each approach, considering the challenges during long-term follow-up. Indications for radioiodine (RAI) therapy are also addressed, along with the benefits and risks associated with this treatment, patient preparation, and dosage. Finally, this statement presents the best follow-up strategies for LRPTC after lobectomy and total thyroidectomy with or without RAI.

Selumetinib Plus Adjuvant Radioactive Iodine in Patients With High-Risk Differentiated Thyroid Cancer: A Phase III, Randomized, Placebo-Controlled Trial (ASTRA)

PURPOSE

Selumetinib can increase radioactive iodine (RAI) avidity in RAI-refractory tumors. We investigated whether selumetinib plus adjuvant RAI improves complete remission (CR) rates in patients with differentiated thyroid cancer (DTC) at high risk of primary treatment failure versus RAI alone.

METHODS

ASTRA (ClinicalTrials.gov identifier: NCT01843062) is an international, phase III, randomized, placebo-controlled, double-blind trial. Patients with DTC at high risk of primary treatment failure (primary tumor > 4 cm; gross extrathyroidal extension outside the thyroid gland [T4 disease]; or N1a/N1b disease with ≥ 1 metastatic lymph node(s) ≥ 1 cm or ≥ 5 lymph nodes [any size]) were randomly assigned 2:1 to selumetinib 75 mg orally twice daily or placebo for approximately 5 weeks (no stratification). On treatment days 29-31, recombinant human thyroid-stimulating hormone (0.9 mg)-stimulated RAI (131I; 100 mCi/3.7 GBq) was administered, followed by 5 days of selumetinib/placebo. The primary end point (CR rate 18 months after RAI) was assessed in the intention-to-treat population.

RESULTS

Four hundred patients were enrolled (August 27, 2013-March 23, 2016) and 233 randomly assigned (selumetinib, n = 155 [67%]; placebo, n = 78 [33%]). No statistically significant difference in CR rate 18 months after RAI was observed (selumetinib n = 62 [40%]; placebo n = 30 [38%]; odds ratio 1.07 [95% CI, 0.61 to 1.87]; P = .8205). Treatment-related grade ≥ 3 adverse events were reported in 25/154 patients (16%) with selumetinib and none with placebo. The most common adverse event with selumetinib was dermatitis acneiform (n = 11 [7%]). No treatment-related deaths were reported.

CONCLUSION

Postoperative pathologic risk stratification identified patients with DTC at high risk of primary treatment failure, although the addition of selumetinib to adjuvant RAI failed to improve the CR rate for these patients. Future strategies should focus on tumor genotype-tailored drug selection and maintaining drug dosing to optimize RAI efficacy.

Cabozantinib (C) versus placebo (P) in patients (pts) with radioiodine-refractory (RAIR) differentiated thyroid cancer (DTC) who have progressed after prior VEGFR-targeted therapy: Outcomes in prespecified subgroups based on prior VEGFR-targeted therapy

6083

Background: Based on the results of the phase 3 COSMIC-311 trial, the multikinase inhibitor C was recently approved by the FDA for the treatment of RAIR DTC pts who progress after prior VEGFR-targeted therapies, such as lenvatinib (L) or sorafenib (S), and for whom there was no standard of care (Brose et al. Lancet Oncol. 2021). In an extended follow-up of the intent-to-treat (ITT) population, C-treated pts achieved a median (m) progression-free survival (PFS) of 11 months (mo) vs 1.9 mo with P (HR 0.22, 96% CI 0.15–0.32, P <.0001); here we present outcomes for prespecified subgroups who received prior L, S, or both. Methods: Pts were randomized 2:1 to C (60 mg QD) or P. P pts could cross over to open-label C upon disease progression per confirmation by blinded independent radiology committee (BIRC). The primary endpoints were PFS (ITT) and objective response rate (first 100 randomized pts), per RECIST v1.1 by BIRC. Pts must have received L or S and progressed during or after 1–2 prior VEGFR inhibitors. Results: After a median follow-up of 10.1 mo, 258 pts (170 C, 88 P) had been randomized (data cutoff 8 Feb 2021); 96 (̃37%) had received prior S (no L), 102 (̃40%) prior L (no S), and 60 (̃23%) prior S and L. Median PFS was 16.6 for C vs 3.2 mo for P in prior S (no L) (HR 0.13, 95% CI 0.06–0.26); 5.8 vs 1.9 mo in prior L (no S) (HR 0.28, 95% CI 0.16–0.48), and 7.6 vs 1.9 mo in prior S and L (HR 0.27, 95% CI 0.13–0.54). In the C arm, 21% of pts in prior S (no L), 3% in prior L (no S), and 8% in S and L subgroups had confirmed partial response, and 1 pt had a confirmed complete response in prior L (no S); there were no responses with P. Stable disease as best response was 67% for C vs 45% for P in prior S (no L), 68% vs 32% in prior L (no S), and 74% vs 38% in prior S and L. Median duration of C-exposure was 7.0 mo in prior S (no L), 5.6 mo in prior L (no S) and 5.9 mo in prior S and L. Grade 3/4 treatment-emergent adverse events (TEAE) occurred in 63% pts in prior S (no L), 57% in prior L (no S), and 69% in prior S and L. Discontinuations of C due to TEAE occurred in 16% of pts in prior S (no L), 13% in prior L (no S), and 23% in prior S and L. There were no treatment-related deaths. Conclusions: In the extended follow-up, C maintained its superior PFS vs P irrespective of prior L and/or S. AEs in each subgroup were consistent with that of the overall population. This is also the first phase 3 study demonstrating a clinical benefit with C after prior L in RAIR DTC pts. Clinical trial information: NCT03690388.

Cabozantinib versus placebo in patients (pts) with radioiodine-refractory (RAIR) differentiated thyroid cancer (DTC) who progressed after prior VEGFR-targeted therapy: Outcomes in prespecified subgroups based on histology subtypes

6081

Background: DTC comprises multiple histology subtypes, the most common being papillary and follicular. Based on results of the phase 3 COSMIC-311 trial, the multikinase inhibitor cabozantinib was recently approved by FDA for the treatment of pts with RAIR DTC who progressed after prior VEGFR-targeted therapy (Brose et al. 2021). In an extended follow-up, median (m) progression-free survival (PFS) was 11 months (mo) for cabozantinib vs 1.9 mo for placebo (HR 0.22, 96% CI 0.15–0.32, P<.0001) in the intent-to-treat (ITT) population (Capdevila et al. ESMO 2021. Abstr LBA67). Here we present outcomes for prespecified subgroups based on the baseline histology subtypes of papillary and follicular thyroid cancers. Methods: Pts were randomized 2:1 to cabozantinib (60 mg QD) or placebo. Placebo pts could cross over to open-label cabozantinib upon disease progression per blinded independent radiology committee (BIRC). Primary endpoints were PFS (ITT) and objective response rate (ORR, first 100 randomized pts), per RECIST v1.1 assessed by BIRC. Results: After a median follow-up of 10.1 mo, 258 pts (170 cabozantinib, 88 placebo) had been randomized (data cutoff 8 Feb 2021); 150 pts (96 cabozantinib, 54 placebo) had papillary thyroid cancer (PTC) and 113 pts (78 cabozantinib, 35 placebo) had follicular thyroid cancer (FTC), with the PTC and FTC subgroups each including 5 pts with both PTC and FTC. Sixty-three pts (̃56%) within the FTC subgroup had Hurthle cell and poorly differentiated variants. mPFS was 9.2 mo for cabozantinib vs 1.9 mo for placebo in the PTC subgroup (HR 0.27, 95% CI 0.17–0.43) and 11.2 mo vs 2.6 mo in the FTC subgroup (HR 0.18, 95% CI 0.10–0.31). The mPFS was 11.1 mo for cabozantinib and 1.9 mo for placebo for pts with Hurthle cell and poorly differentiated variants (HR 0.12, 95% CI 0.05–0.27). The ORR was 15% for cabozantinib vs 0% for placebo in the PTC subgroup and 8% vs 0% in the FTC subgroup. Median duration of cabozantinib exposure was 5.5 mo for the PTC subgroup and 7.3 mo for FTC. Grade 3/4 treatment-emergent adverse events (TEAE) in the cabozantinib arm occurred in 59% of pts in the PTC subgroup and 68% of pts in the FTC subgroup; discontinuations due to TEAE occurred in 17% and 15% of pts, respectively. Conclusions: In the extended follow-up, cabozantinib maintained superior efficacy vs placebo irrespective of histology subtype, including the aggressive Hurthle cell and poorly differentiated variants. The moderately higher rates of grade 3/4 TEAE in the FTC vs the PTC subgroup could be attributed to the longer median duration of exposure of cabozantinib in the FTC subgroup. Clinical trial information: NCT03690388.

Puberty and sex in pediatric thyroid cancer: could expression of estrogen and progesterone receptors affect prognosis?

OBJECTIVE

A sharp increase in pediatric thyroid cancer incidence is observed during adolescence, driven mainly by girls. Differences in disease presentation across sexual maturity stages raise the question of whether sex steroids have a role in the heterogeneity. The aims of this study were to analyze the influence of puberty and sex on clinical presentation and prognosis and to evaluate the correlation between the expression of sex hormone receptors.

DESIGN AND METHODS

Clinical records and immunohistochemical of specimens from 79 patients were analyzed. Puberty was analyzed by two criteria: end of puberty and beginning, in which the age of 10 was the cutoff.

RESULTS

Postpubertal were more frequently classified as having low-risk disease and a lower frequency of persistent disease, especially when the completion of puberty was used as the criteria. Male sex was associated with a higher risk of persistent disease at the end of the observation period. Estrogen receptor α positivity was low in the entire sample, while progesterone receptor positivity was positive in 30% of the cases. Female hormone receptor expression was not associated with sex, American Thyroid Association risk score, persistent structural disease, or pubertal status.

CONCLUSION

Our study showed that the completion of puberty correlated best with the clinical behaviour of pediatric thyroid cancer. It was also shown that postpubertal patients have a less aggressive initial presentation and better outcomes. However, this observation could not be explained by the expression of estrogen and progesterone receptors in the primary tumors.

Pregnancy has no significant impact on the prognosis of differentiated thyroid cancer

OBJECTIVE

To evaluate the impact of pregnancy on differentiated thyroid carcinomas (DTC) behavior.

METHODS

Retrospective study of patients diagnosed with DTC before or during pregnancy and treated with standard therapy. In women diagnosed with DTC before pregnancy, we evaluated the occurrence of progression according to categories of response to therapy based on imaging and non-stimulated thyroglobulin (TG) levels.

RESULTS

Of 96 analyzed patients, 76 became pregnant after DTC treatment and 20 were diagnosed with DTC during pregnancy. Among women who became pregnant after a DTC diagnosis, no difference was observed regarding response to therapy before and after pregnancy. Disease progression after pregnancy was documented in six of these patients, while seven of them presented progression before pregnancy but were only treated after delivery. Patients with DTC diagnosed during pregnancy had a higher rate of distant metastases at diagnosis (30%) compared with the patients who became pregnant after DTC diagnosis (9.2%, p = 0.01).

CONCLUSION

Pregnancy had no impact on the natural course of DTC. Disease progression after pregnancy was limited and probably related to more aggressive disease and higher risk stratification at diagnosis. Still, mild disease progression may have occurred asymptomatically in some patients.

Prognostic factors in patients with advanced differentiated thyroid cancer treated with multikinase inhibitors - a single Brazilian center experience

OBJECTIVE

The aim of this study was to describe the real-world experience multikinase inhibitors (MKI) in the treatment advanced differentiated thyroid carcinoma (DTC) refractory to radioactive iodine (RAIR) therapy.

METHODS

We reviewed the records of all patients with MKI-treated DTC from 2010 to 2018. Progression free survival (PFS), response rates (RR) and adverse events (AE) profiles were assessed. Clinical parameters were compared between groups with different outcomes (disease progression and death) to identify possible prognostic factors and benefit from treatment.

RESULTS

Forty-four patients received MKI for progressive RAIR DTC. Median PFS was 24 months (10.2-37.7) and median overall survival (OS) was 31 months. Best overall response was complete response in one patient (4.5%), partial response in nine (20.4%), stable disease in twenty-two (50%), and progressive disease (PD) in twelve (27.3%). Seventy-two point 7 percent patients had clinical benefit and AE were mild in most cases (82.7%). Progressive patients were more likely to have FDG positive target lesion than those who did not progress (p = 0.033) and higher maximum SUV on target lesions (p = 0.042). Presence of lung-only metastasis and lower thyroglobulin (Tg) during treatment was associated with stable disease (p = 0.015 and 0,049, respectively). Patients with shorter survival had larger primary tumor size (p = 0.015) and higher maximum SUV on target lesions (p = 0.023).

CONCLUSION

Our findings demonstrate safety and effectiveness of MKI in patients with advanced RAIR DTC. We were able to identify as possible prognostic markers of better outcomes: absence of FDG uptake on target lesions, lower maximum SUV on PET-CT, presence of lung-only metastasis and lower Tg during treatment.

Choosing Wisely for Thyroid Conditions: Recommendations of the Thyroid Department of the Brazilian Society of Endocrinology and Metabolism

OBJECTIVE

Choosing Wisely (CW) is an initiative that aims to advance the dialogue between physicians and patients about low-value health interventions. Given that thyroid conditions are frequent in clinical practice, we aimed to develop an evidence-based list of thyroid CW recommendations.

METHODS

The Thyroid Department of the Brazilian Society of Endocrinology and Metabolism (SBEM) named a Task Force to conduct the initiative. The Task Force work was based on an electronic Delphi approach. The 10 recommendations that received the highest scores by the Task Force were submitted for voting by all SBEM associates. The 5 recommendations that received the highest scores by SBEM associates are presented herein.

RESULTS

The Task Force was composed of 14 thyroidologists from 10 tertiary-care, teaching-based Brazilian institutions. The brainstorming/ideation phase resulted in 69 recommendations. After the removal of duplicates and recommendations that did not adhere to the initiative's scope, 35 remained. Then the Task Force voted to attribute a grade (0 [lowest agreement] to 10 [highest agreement]) for each recommendation. The 10 recommendations that received the highest scores by the Task Force were submitted to all SBEM associates. A total of 683 associates voted electronically, attributing a grade (0 to 10) for each recommendation. The 5 recommendations that received the highest scores by the SBEM associates compose our final list.

CONCLUSION

A set of recommendations to avoid unnecessary medical tests, treatments, or procedures for thyroid conditions are offered with a transparent methodology. This initiative aims to foster productive interactions between physicians and patients, stimulating shared decision-making.

High thyroglobulin and negative whole-body scan: no long-term benefit of empiric radioiodine therapy

PURPOSE

Around 10-27% of patients will present elevated thyroglobulin (Tg) levels and negative diagnostic whole-body scan (dxWBS) during differentiated thyroid cancer (DTC) follow-up. Empiric radioactive iodine (RAI) therapy in this context is controversial due to the lack of good quality studies in the context. The main purpose of this study is to compare long-term response to therapy status and overall survival between empiric RAI treated and untreated DTC patients.

METHODS

A retrospective study comparing differentiated thyroid cancer patients with negative diagnostic whole-body scan and elevated thyroglobulin levels submitted or not to empiric radioactive iodine therapy in a thyroid cancer referral center. The main outcome measures were ATA Response to Therapy Stratification at 6-12 months after RAI ablative dose, at 6-18 months after negative dxWBS and last follow-up visits.

RESULTS

Overall, 120 DTC patients with stimulated Tg >10 ng/ml and negative dxWBS were included in this study. Overall, 53 patients were submitted to empiric RAI and 67 were in the control group. No difference was observed in ATA Response to Therapy Stratification after RAI ablation or at the end of follow-up between groups. Also, no difference was found in terms of Tg changes response. After more than 10 years of follow-up, 17 patients died (13 from treated and 4 from untreated group).

CONCLUSIONS

Empiric RAI treatment was not associated with better long-term ATA response to therapy status or overall survival.

Cabozantinib for radioiodine-refractory differentiated thyroid cancer (COSMIC-311): a randomised, double-blind, placebo-controlled, phase 3 trial

BACKGROUND

Patients with radioiodine-refractory differentiated thyroid cancer (DTC) previously treated with vascular endothelial growth factor receptor (VEGFR)-targeted therapy have aggressive disease and no available standard of care. The aim of this study was to evaluate the tyrosine kinase inhibitor cabozantinib in this patient population.

METHODS

In this global, randomised, double-blind, placebo-controlled, phase 3 trial, patients aged 16 years and older with radioiodine-refractory DTC (papillary or follicular and their variants) and an Eastern Cooperative Oncology Group performance status of 0 or 1 were randomly assigned (2:1) to oral cabozantinib (60 mg once daily) or matching placebo, stratified by previous lenvatinib treatment and age. The randomisation scheme used stratified permuted blocks of block size six and an interactive voice-web response system; both patients and investigators were masked to study treatment. Patients must have received previous lenvatinib or sorafenib and progressed during or after treatment with up to two VEGFR tyrosine kinase inhibitors. Patients receiving placebo could cross over to open-label cabozantinib on disease progression confirmed by blinded independent radiology committee (BIRC). The primary endpoints were objective response rate (confirmed response per Response Evaluation Criteria in Solid Tumours [RECIST] version 1.1) in the first 100 randomly assigned patients (objective response rate intention-to-treat [OITT] population) and progression-free survival (time to earlier of disease progression per RECIST version 1.1 or death) in all patients (intention-to-treat [ITT] population), both assessed by BIRC. This report presents the primary objective response rate analysis and a concurrent preplanned interim progression-free survival analysis. The study is registered with ClinicalTrials.gov, NCT03690388, and is no longer enrolling patients.

FINDINGS

Between Feb 27, 2019, and Aug 18, 2020, 227 patients were assessed for eligibility, of whom 187 were enrolled from 164 clinics in 25 countries and randomly assigned to cabozantinib (n=125) or placebo (n=62). At data cutoff (Aug 19, 2020) for the primary objective response rate and interim progression-free survival analyses, median follow-up was 6·2 months (IQR 3·4-9·2) for the ITT population and 8·9 months (7·1-10·5) for the OITT population. An objective response in the OITT population was achieved in ten (15%; 99% CI 5·8-29·3) of 67 patients in the cabozantinib group versus 0 (0%; 0-14·8) of 33 in the placebo (p=0·028) but did not meet the prespecified significance level (α=0·01). At interim analysis, the primary endpoint of progression-free survival was met in the ITT population; cabozantinib showed significant improvement in progression-free survival over placebo: median not reached (96% CI 5·7-not estimable [NE]) versus 1·9 months (1·8-3·6); hazard ratio 0·22 (96% CI 0·13-0·36; p<0·0001). Grade 3 or 4 adverse events occurred in 71 (57%) of 125 patients receiving cabozantinib and 16 (26%) of 62 receiving placebo, the most frequent of which were palmar-plantar erythrodysaesthesia (13 [10%] vs 0), hypertension (11 [9%] vs 2 [3%]), and fatigue (ten [8%] vs 0). Serious treatment-related adverse events occurred in 20 (16%) of 125 patients in the cabozantinib group and one (2%) of 62 in the placebo group. There were no treatment-related deaths.

INTERPRETATION

Our results show that cabozantinib significantly prolongs progression-free survival and might provide a new treatment option for patients with radioiodine-refractory DTC who have no available standard of care.

FUNDING

Exelixis.

Abstract 2035: Alterations in nuclear DNA organization in sporadic pediatric Papillary Thyroid Carcinoma (PTC)

Pediatric papillary thyroid carcinoma (PTC) present a more aggressive disease than adults, with higher risk of malignancy, higher rates of metastasis, multifocality and larger tumor sizes. We described AGK-BRAF fusion in 19% of sporadic pediatric PTC, which is associated with lung metastasis and younger age (mean 10.67 y.o.). Super-resolved three-dimensional structured illumination microscopy (3D-SIM) allows the visualization of the DNA structure inside the interphase nucleus at microscopic length scales. 3D-SIM has shown that cancer cell nuclei exhibit chromatin remodeling, with increased amount of DNA-poor spaces, which indicates a disrupted pattern in the DNA and has been associated with aggressive behavior in other tumor subtypes. In order to understand the underlying causes of the aggressiveness of pediatric PTC, we here aimed to analyze, for the first time, the DNA organization from 13 pediatric PTC patients (≤18 y.o.), using super-resolved 3D-SIM technology. A granulometry-based measurement method quantified the size distribution of DNA structure (DNA packaging) and DNA-poor spaces. We compared the granulometry for: tumor vs normal tissues; AGK-BRAF fusion (positive vs negative tumors); distant metastasis (presence vs absence); multifocal vs unifocal tumors; age at diagnosis (≤ 10 y.o. vs &gt; 10 y.o.); tumor size ( ≤ 2 cm vs &gt; 2 cm) and extra-thyroidal (ET) extension (presence vs absence). Nuclei from tumor cells exhibited larger DNA structures (p=0.0001) and more DNA-poor spaces (p&lt;0.0001) than normal cells. In relation to the clinicopathological features, patients that presented distant metastasis (p=0.001), multifocal tumors (p=0.002) and &gt; 2 cm tumors (p=0.0029), exhibited more DNA-poor spaces in their nuclei. Regarding the analyses of the AGK-BRAF fusion, borderline results were observed for both DNA structure (p=0.058) and DNA-poor spaces (p=0.053). Similar results were observed in PTC cases with age ≤10 y.o. for DNA structure (p=0.068) and DNA-poor spaces (p=0.06). No significant difference was observed for ET extension. Our preliminary data corroborate with previous studies, where tumor cell nuclei present more DNA-poor spaces than normal cells; and suggest a progressive disruption and remodeling of the chromatin in malignant cells. Interestingly, tumor cells from patients with features of poor prognosis (distant metastasis, multifocality and tumor size) can exhibit a more disrupted DNA organization, which can be related to a more aggressive behavior of the tumor. Moreover, can also observe a trend to a more disrupted chromatin organization in AGK-BRAF tumors and tumors from &lt;10 y.o. patients, which can be associated with the aggressiveness of the disease in these cases. Further analysis are needed to better understand wether AGK-BRAF fusion is associated with poor prognosis in pediatric PTC and if it could be related to a high genomic instability caused by this fusion.

Citation Format: Luiza Sisdelli, Maria I. Cordioli, Fernanda Vaisman, Osmar Monte, Carlos Longui, Adriano N. Cury, Aline Rangel-Pozzo, Sabine Mai, Janete M. Cerutti. Alterations in nuclear DNA organization in sporadic pediatric Papillary Thyroid Carcinoma (PTC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2035.

Cabozantinib versus placebo in patients with radioiodine-refractory differentiated thyroid cancer who have progressed after prior VEGFR-targeted therapy: Results from the phase 3 COSMIC-311 trial

6001

Background: Cabozantinib (C), an inhibitor of VEGFR2, MET, AXL, and RET, showed clinical activity in patients (pts) with radioiodine (RAI)-refractory differentiated thyroid cancer (DTC) in phase 1/2 studies (Cabanillas 2017; Brose 2018). This phase 3 study (NCT03690388) evaluated the efficacy and safety of C vs placebo (P) in pts with RAI-refractory DTC who had progressed during/after prior VEGFR-targeted therapy for whom there is no standard of care. Methods: In this double-blind, phase 3 trial, pts were randomized 2:1 to receive C (60 mg QD) or P, stratified by prior lenvatinib treatment (L; yes, no) and age (≤65, > 65 yr). Pts with RAI-refractory DTC must have received L or sorafenib for DTC and progressed during or following treatment with ≤ 2 prior VEGFR inhibitors. Pts randomized to P could cross over to open-label C upon disease progression per blinded independent radiology committee (BIRC). The primary endpoints were objective response rate (ORR) in the first 100 randomized pts and progression-free survival (PFS) in all randomized pts. PFS and ORR were assessed by BIRC per RECIST v1.1. The study was designed to detect an ORR for C vs P (2-sided α = 0.01) and a hazard ratio (HR) for PFS of 0.61 (90% power, 2-sided α = 0.04). A prespecified interim PFS analysis was planned for the ITT population at the time of the primary ORR analysis. Results: As of 19 Aug 2020,125 vs 62 pts had been randomized to the C and P arms, respectively; median age was 66 yr, 55% were female and 63% received prior L. Median (m) follow-up was 6.2 months (mo). At the planned interim analysis, the trial met the primary endpoint of PFS with C demonstrating significant improvement over P (HR 0.22, 96% CI 0.13–0.36; p < 0.0001). mPFS was not reached for C vs 1.9 mo for P; PFS benefit was observed in all prespecified subgroups including prior L (yes, HR 0.26; no, HR 0.11) and age (≤65 yr, HR 0.16; > 65 yr, HR 0.31). ORR was 15% for C vs 0% for P (p = 0.0281) but did not meet the prespecified criteria for statistical significance (p < 0.01). A favorable OS trend was observed for C vs P (HR 0.54, 95% CI 0.27–1.11). Treatment-emergent adverse events (AEs) of any grade with higher occurrences in the C vs P arm included diarrhea (51% vs 3%), hand-foot skin reaction (46% vs 0%), hypertension (28% vs 5%), fatigue (27% vs 8%), and nausea (24% vs 2%); grade 3/4 AEs were experienced by 57% of pts with C vs 26% with P. Dose reductions due to any grade AEs occurred in 57% of pts with C vs 5% with P. Treatment discontinuations due to AEs not related to disease progression occurred in 5% of pts with C vs 0% with P. No treatment-related deaths occurred in either arm. Conclusions: C showed a clinically and statistically significant improvement in PFS over P in pts with RAI-refractory DTC after prior VEGFR-targeted therapy with no unexpected toxicities. C may represent a new standard of care in pts with previously treated DTC. Clinical trial information: NCT03690388.

Management of thyroid disorders during the COVID-19 outbreak: a position statement from the Thyroid Department of the Brazilian Society of Endocrinology and Metabolism (SBEM)

This position statement was prepared to guide endocrinologists on the best approach to managing thyroid disorders during the coronavirus disease (COVID-19) pandemic. The most frequent thyroid hormonal findings in patients with COVID-19, particularly in individuals with severe disease, are similar to those present in the non-thyroidal illness syndrome and require no intervention. Subacute thyroiditis has also been reported during COVID-19 infection. Diagnosis and treatment of hypothyroidism during the COVID-19 pandemic may follow usual practice; however, should avoid frequent laboratory tests in patients with previous controlled disease. Well-controlled hypo and hyperthyroidism are not associated with an increased risk of COVID-19 infection or severity. Newly diagnosed hyperthyroidism during the pandemic should be preferably treated with antithyroid drugs (ATDs), bearing in mind the possibility of rare side effects with these medications, particularly agranulocytosis, which requires immediate intervention. Definitive treatment of hyperthyroidism (radioiodine therapy or surgery) may be considered in those cases that protective protocols can be followed to avoid COVID-19 contamination or once the pandemic is over. In patients with moderate Graves' ophthalmopathy (GO) not at risk of visual loss, glucocorticoids at immunosuppressive doses should be avoided, while in those with severe GO without COVID-19 and at risk of vision loss, intravenous glucocorticoid is the therapeutic choice. Considering that most of the thyroid cancer cases are low risk and associated with an excellent prognosis, surgical procedures could and should be postponed safely during the pandemic period. Additionally, when indicated, radioiodine therapy could also be safely postponed as long as it is possible.

A Multifocal Pediatric Papillary Thyroid Carcinoma (PTC) Harboring the AGK-BRAF and RET/PTC3 Fusion in a Mutually Exclusive Pattern Reveals Distinct Levels of Genomic Instability and Nuclear Organization

Simple Summary

Genetic alterations, such as RET/PTC and AGK-BRAF fusions, are frequent events in pediatric papillary thyroid carcinoma (PTC). However, their role as prognostic markers in pediatric PTC is still under investigation. In this study, we present a patient harboring three tumor foci with distinct genetic alterations (AGK-BRAF, RET/PTC3 and an absence of canonical alterations) that were investigated for DNA structure and telomere-related genomic instability. These preliminary results highlight that AGK-BRAF fusion likely affects nuclear architecture, which might explain a more aggressive disease outcome observed in pediatric PTC cases with AGK-BRAF fusion.

Abstract

The spectrum and incidence of gene fusions in papillary thyroid carcinoma (PTC) can differ significantly depending on the age of onset, histological subtype or radiation exposure history. In sporadic pediatric PTC, RET/PTC1-3 and AGK-BRAF fusions are common genetic alterations. The role of RET/PTC as a prognostic marker in pediatric PTC is still under investigation. We recently showed that AGK-BRAF fusion is prevalent in young patients (mean 10 years) and associated with specific and aggressive pathological features such as multifocality and lung metastasis. In this pilot study, we report a unique patient harboring three different foci: the first was positive for AGK-BRAF fusion, the second was positive for just RET/PTC3 fusion and the third was negative for both rearrangements. To investigate whether AGK-BRAF and RET/PTC3 are associated with genomic instability and chromatin modifications, we performed quantitative fluorescence in situ hybridization (Q-FISH) of telomere repeats followed by 3D imaging analysis and 3D super-resolution Structured Illumination Microscopy (3D-SIM) to analyze the DNA structure from the foci. We demonstrated in this preliminary study that AGK-BRAF is likely associated with higher levels of telomere-related genomic instability and chromatin remodeling in comparison with RET/PTC3 foci. Our results suggest a progressive disruption in chromatin structure in AGK-BRAF-positive cells, which might explain a more aggressive disease outcome in patients harboring this rearrangement.

Genetic Landscape of Papillary Thyroid Carcinoma and Nuclear Architecture: An Overview Comparing Pediatric and Adult Populations

Thyroid cancer is a rare malignancy in the pediatric population that is highly associated with disease aggressiveness and advanced disease stages when compared to adult population. The biological and molecular features underlying pediatric and adult thyroid cancer pathogenesis could be responsible for differences in the clinical presentation and prognosis. Despite this, the clinical assessment and treatments used in pediatric thyroid cancer are the same as those implemented for adults and specific personalized target treatments are not used in clinical practice. In this review, we focus on papillary thyroid carcinoma (PTC), which represents 80-90% of all differentiated thyroid carcinomas. PTC has a high rate of gene fusions and mutations, which can influence the histologic subtypes in both children and adults. This review also highlights telomere-related genomic instability and changes in nuclear organization as novel biomarkers for thyroid cancers.

Cholestatic syndrome as initial manifestation of pancreatic metastasis of papillary thyroid carcinoma: case report and review

Most papillary thyroid carcinomas (PTC) harbor excellent prognosis. Although rare, distant metastases normally occur in lungs and/or bones. Here we describe a rare case of pancreatic metastasis presenting with rapid onset cholestatic syndrome. A literature review was also performed. A 73-year-old man with a high risk PTC was submitted to total thyroidectomy (TT) followed by radioiodine therapy. After initial therapy, he persisted with progressive rising serum thyroglobulin levels but with no evidence of structural disease. Recently, the patient presented with a rapid onset and progressive cholestatic syndrome. A 4 cm lesion in pancreas was identified, with echoendoscopy fine-needle aspiration biopsy (FNAB) confirming a pancreatic metastasis from PTC. The patient was submitted to a successful pancreaticoduodenectomy. Pancreatic metastases of PTC are rare and few long-term follow-up data are available to guide management. Fourteen cases were former reported, mean age was 65.7 years-old with mean time between PTC and pancreatic metastasis diagnosis of 7.9 years. Nine of them had another distant metastasis, nine were diagnosed by FNAB and just two received sorafenib.

Breast Cancer After Treatment of Differentiated Thyroid Cancer With Radioiodine in Young Females: What We Know and How to Investigate Open Questions. Review of the Literature and Results of a Multi-Registry Survey

Published studies on the risk of radiation-induced second primary malignancy (SPM) after radioiodine treatment (RAI) of differentiated thyroid cancer (DTC) refer mainly to patients treated as middle-aged or older adults and are not easily generalizable to those treated at a younger age. Here we review available literature on the risk of breast cancer as an SPM after RAI of DTC with a focus on females undergoing such treatment in childhood, adolescence, or young adulthood. Additionally, we report the results of a preliminary international survey of patient registries from academic tertiary referral centers specializing in pediatric DTC. The survey sought to evaluate the availability of sufficient patient data for a potential international multicenter observational case-control study of females with DTC given RAI at an early age. Our literature review identified a bi-directional association of DTC and breast cancer. The general breast cancer risk in adult DTC survivors is low, ~2%, slightly higher in females than in males, but presumably lower, not higher, in those diagnosed as children or adolescents than in those diagnosed at older ages. RAI presumably does not substantially influence breast cancer risk after DTC. However, data from patients given RAI at young ages are sparse and insufficient to make definitive conclusions regarding age dependence of the risk of breast cancer as a SPM after RAI of DTC. The preliminary analysis of data from 10 thyroid cancer registries worldwide, including altogether 6,449 patients given RAI for DTC and 1,116 controls, i.e., patients not given RAI, did not show a significant increase of breast cancer incidence after RAI. However, the numbers of cases and controls were insufficient to draw statistically reliable conclusions, and the proportion of those receiving RAI at the earliest ages was too low.In conclusion, a potential international multicenter study of female patients undergoing RAI of DTC as children, adolescents, or young adults, with a sufficient sample size, is feasible. However, breast cancer screening of a larger cohort of DTC patients is not unproblematic for ethical reasons, due to the likely, at most slightly, increased risk of breast cancer post-RAI and the expected ~10% false-positivity rate which potentially produced substantial "misdiagnosis."

Thyroid nodules ≤ 1 cm and papillary thyroid microcarcinomas: Brazilian experts opinion

The indolent evolution of low-risk papillary thyroid microcarcinoma (mPTC) in adult patients and the consequences of thyroidectomy require a revision of the management traditionally recommended. Aiming to spare patients unnecessary procedures and therapies and to optimize the health system in Brazil, we suggest some measures. Fine-needle aspiration of nodules ≤ 1 cm without extrathyroidal extension on ultrasonography should be performed only in nodules classified as "very suspicious" (i.e., high suspicion according to ATA, high risk according to AACE, TI-RADS 5) and in selected cases [age < 40 years, nodule adjacent to the trachea or recurrent laryngeal nerve (RLN), multiple suspicious nodules, presence of hypercalcitoninemia or suspicious lymph nodes]. Active surveillance (AS) rather than immediate surgery should be considered in adult patients with low-risk mPTC. Lobectomy is the best option in patients with unifocal low-risk mPTC who are not candidates for AS because of age, proximity of the tumor to the trachea or RLN, or because they opted for surgery. The same applies to patients who started AS but had a subsequent surgical indication not due to a suspicion of tumor extension beyond the gland or multicentricity. Molecular tests are not necessary to choose between AS and surgery or, in the latter case, between lobectomy and total thyroidectomy. The presence of RAS or other RAS-like mutations or BRAFV600E or other BRAF V600E-like mutations should not modify the management cited above; however, the rare cases of mPTC exhibiting high-risk mutations, like in the TERT promoter or p53, are not candidates for AS.

CA19-9 as a Predictor of Worse Clinical Outcome in Medullary Thyroid Carcinoma

OBJECTIVE

Medullary thyroid carcinoma (MTC) is a rare disease, and its classic tumor marker is calcitonin. However, recently, very aggressive cases have been reported to also secrete carbohydrate antigen 19-9 (CA19-9), and its role as a marker of worse prognosis has been questioned. The aim of this study was to analyze the relationship between CA19-9 serum levels and MTC outcomes.

METHODS

We retrospectively reviewed 122 MTC patients followed in a tertiary cancer center from 1985 to 2017. Clinical-pathologic characteristics, therapeutic approaches, and outcomes were recorded and CA19-9 was collected.

RESULTS

Of the 122 patients included in the study, 48 had distant metastases, and at the end of follow-up 18.1% had structural persistent disease and 32.7% had progressive disease. CA19-9 was significantly higher in those who had disease progression than in those who had not (21.4 [14.3-110.9] vs. 7.27 [0.6-44.75] U/mL, p = 0.01) and was also higher in patients who died from MTC (18.4 [14.3-110.9] vs. 7.59 [0.6-67.8] U/mL, p < 0.001). Furthermore, using a ROC curve analysis, the cutoff point for CA19-9 in MTC patients was lower than that observed in pancreatic tumors.

CONCLUSION

CA19-9 might have a role as a prognostic factor in addition to calcitonin and carcinoembryonic antigen in metastatic MTC.

AGK-BRAF is associated with distant metastasis and younger age in pediatric papillary thyroid carcinoma

BACKGROUND

The incidence of thyroid carcinoma has increased in most populations, including pediatric patients. The increase is almost exclusively due to an increase in the incidence of papillary thyroid carcinoma (PTC). Genetic alterations leading to mitogen-activated protein kinase (MAPK) pathway activation are highly prevalent in PTC, with BRAF V600E mutation being the most common event in adult PTC. Although a lower prevalence of BRAF V600E had been reported among pediatric patients, a higher prevalence of BRAF fusion has been identified in both radiation-exposed and sporadic pediatric PTC. However, little is known about the prognostic implications of BRAF fusions in pediatric PTC.

PROCEDURE

In this study, we investigated the prevalence of BRAF alterations (AGK-BRAF fusion and BRAF V600E mutation) in a large set of predominantly sporadic pediatric PTC cases and correlate with clinicopathological features. Somatic AGK-BRAF fusion was investigated by RT-PCR and confirmed by FISH break-apart. The BRAF V600E mutation was screened using Sanger sequencing.

RESULTS

AGK-BRAF fusion, found in 19% of pediatric PTC patients, was associated with distant metastasis and younger age. Conversely, the BRAF V600E, found in 15% of pediatric PTC patients, was correlated with older age and larger tumor size.

CONCLUSION

Collectively, our results advance knowledge concerning genetic bases of pediatric thyroid carcinoma, with potential implications for diagnosis, prognosis, and therapeutic approaches.

Serum calcitonin nadirs to undetectable levels within 1 month of curative surgery in medullary thyroid cancer

OBJECTIVE

Because serum calcitonin (CT) is a reliable marker of the presence, volume, and extent of disease in medullary thyroid cancer (MTC), both the ATA and NCCN guidelines use the 2-3 month post-operative CT value as the primary response to therapy variable that determines the type and intensity of follow up evaluations. We hypothesized that the calcitonin would nadir to undetectable levels within 1 month of a curative surgical procedure.

SUBJECTS AND METHODS

This retrospective review identified 105 patients with hereditary and sporadic MTC who had at least two serial basal CT measurements done in the first three months after primary surgery.

RESULTS

When evaluated one year after initial surgery, 42 patients (42/105, 40%) achieved an undetectable basal calcitonin level without additional therapies and 56 patients (56/84, 67%) demonstrated a CEA within the normal reference range. In patients destined to have an undetectable CT as the best response to initial therapy, the calcitonin was undetectable by 1 month after surgery in 97% (41/42 patients). Similarly, in patients destined to have a normalize their CEA, the CEA was within the reference range by 1 month post-operatively in 63% and by 6 months in 98%. By 6 months after curative initial surgery, 100% of patients had achieved a nadir undetectable calcitonin, 98% had reached the CEA nadir, and 97% had achieved normalization of both the calcitonin and CEA.

CONCLUSION

The 1 month CT value is a reliable marker of response to therapy that allows earlier risk stratification than the currently recommended 2-3 month CT measurement.

Clinical Assessment and Risk Stratification in Differentiated Thyroid Cancer

Thyroid cancer management is rapidly evolving to a personalized management approach. Risk stratification systems are designed to assist in personalized management. Differentiating patients who may benefit from aggressive therapy and intense follow-up as opposed to those who can be successfully treated with minimalized initial management options and follow-up is crucial to the development of the right treatment plan for the right patient in order to optimize initial therapy and follow-up testing. This article aims to describe and discuss the risk stratification systems currently recommended for differentiated thyroid cancer.

Genotype and phenotype landscape of MEN2 in 554 medullary thyroid cancer patients: the BrasMEN study

Multiple endocrine neoplasia type 2 (MEN2) is an autosomal dominant genetic disease caused by RET gene germline mutations that is characterized by medullary thyroid carcinoma (MTC) associated with other endocrine tumors. Several reports have demonstrated that the RET mutation profile may vary according to the geographical area. In this study, we collected clinical and molecular data from 554 patients with surgically confirmed MTC from 176 families with MEN2 in 18 different Brazilian centers to compare the type and prevalence of RET mutations with those from other countries. The most frequent mutations, classified by the number of families affected, occur in codon 634, exon 11 (76 families), followed by codon 918, exon 16 (34 families: 26 with M918T and 8 with M918V) and codon 804, exon 14 (22 families: 15 with V804M and 7 with V804L). When compared with other major published series from Europe, there are several similarities and some differences. While the mutations in codons C618, C620, C630, E768 and S891 present a similar prevalence, some mutations have a lower prevalence in Brazil, and others are found mainly in Brazil (G533C and M918V). These results reflect the singular proportion of European, Amerindian and African ancestries in the Brazilian mosaic genome.

The Impact of Zoledronic Acid and Radioactive Iodine Therapy on Morbi-Mortality of Patients with Bone Metastases of Thyroid Cancer Derived from Follicular Cells

OBJECTIVE

Bone metastases bring greater morbi-mortality to patients with differentiated thyroid carcinoma (DTC). Treatment was limited to radioactive iodine (RAI) and local approaches. Currently, bisphosphonates are included in the therapeutic arsenal. The aim of this study is to evaluate the impact of bone metastases and their treatment with zoledronic acid (ZA) and RAI therapy.

METHODS

We retrospectively review 50 DTC patients with structurally evident bone metastases followed in a tertiary cancer center from 1994 to 2018. Clinical-pathologic characteristics, skeletal related events (SRE), and therapeutic approaches were recorded.

RESULTS

Among the 50 patients analyzed, 22 underwent ZA adjuvant therapy and 28 did not. Mortality rate was 44%. Those patients presented SREs more frequently (90.9 vs. 67.9% the survival group, p = 0.05) and also had a greater number of bone lesions (40.9 vs. 10.7% had more than 6 metastatic sites, p = 0.03). The same group of patients was analyzed before and after therapy with ZA and the incidence of SRE decreased from 1.81 (0-8) before therapy to 0.29 (0-7) after therapy (p = 0.006). Comparing similar groups of 22 patients treated with ZA with 28 patients not treated, there was a trend of better overall survival (OS) in the group that received this drug (147 vs. 119 months, p = 0.06) and significantly improvement when bone metastases were RAI avid 155 (125-185) versus 120 (85-157) months, p < 0.01. Conclusion : ZA can successfully diminish the chance of having new SRE and possibly affect OS in DTC patients with bone metastases. The positive impact of RAI adjuvant treatment on OS is directly associated with RAI uptake.

TERTp mutation is associated with a shorter progression free survival in patients with aggressive histology subtypes of follicular-cell derived thyroid carcinoma

PURPOSE

Evaluate the impact of TERTp mutation on the outcomes after initial treatment of 45 patients with thyroid carcinomas derived from follicular cells (TCDFC) with aggressive histology, in which the role of this mutation is not yet well defined.

METHODS

Analysis of the presence of TERTp (-124C > T and -146C > T), BRAF (V600E), and NRAS (Q 61R) mutations by Sanger sequencing and analysis of their correlation with the patient's outcomes.

RESULTS

Forty-five patients with aggressive histopathologic variants were included in the study. Of these, 68.9% had aggressive variants of papillary thyroid cancer (PTC), 22.2% had poorly differentiated thyroid carcinoma (PDTC)/insular carcinoma, and 8.9% had invasive follicular thyroid cancer (FTC) with Hurthle cell features (Hurthle cell carcinoma). Lymph node metastases were present in 46.7% and distant metastases in 54.6%. The response to the initial therapy was excellent in 45.5% and structurally incomplete in 50%. During the follow-up period (median of 56 months; 5-360 months), 47.7% presented with disease progression and 17.8% experienced disease-related death. In 53.3% of the cases at least one molecular alteration (TERTp in 33.4%, BRAF in 24.5%, RAS in 8.9%) was detected. In the multivariate analysis, TERTp mutation was the factor associated with the highest risk (6 times) of having structural disease after initial therapy (p = 0.01), followed by vascular invasion (p = 0.02), gross extrathyroidal extension (ETE) (p = 0.02) and distant metastasis (p = 0.04). Regarding mutational status, only TERTp mutation was associated with disease progression, and diminished disease progression-free survival (PFS). The presence of distant metastasis, vascular invasion and gross ETE were significantly associated with the risk of disease progression.

CONCLUSIONS

TERTp mutation appears be an indicator of both persistence and progression of structural disease after initial therapy in aggressive variants of TCDFC, and associates with a shorter progression free survival regardless of the therapy employed.

Clinical outcomes of low and intermediate risk differentiated thyroid cancer patients treated with 30mCi for ablation or without radioactive iodine therapy

OBJECTIVE

To retrospectively evaluate the outcomes of patients with low and intermediate risk thyroid carcinoma treated with total thyroidectomy (TT) and who did not undergo radioiodine remnant ablation (RRA) and to compare them to patients receiving low dose of iodine (30 mCi).

SUBJECTS AND METHODS

A total of 189 differentiated thyroid cancer (DTC) patients treated with TT followed by 30mCi for RRA or not, followed in two referral centers in Brazil were analyzed.

RESULTS

From the 189 patients, 68.8% was ATA low-risk, 30.6% intermediate and 0.6% high risk. Eighty-seven patients underwent RRA and 102 did not. The RRA groups tended to be younger and had a higher frequency of extra-thyroidal extension (ETE). RRA did not have and impact on response to initial therapy neither in low (p = 0.24) nor in intermediate risk patients (p = 0.66). It also had no impact on final outcome and most patients had no evidence of disease (NED) at final follow-up. Recurrence/persistence of disease was found in 1.2% of RRA group and 2% in patients treated only with TT (p = 0.59).

CONCLUSIONS

Our study shows that in low and intermediate-risk patients, RRA with 30 mCi seems to have no major advantage over patients who did not undergo RRA regarding response to initial therapy in each risk group and also in long term outcomes.

Somatostatin receptor subtype 1 might be a predictor of better response to therapy in medullary thyroid carcinoma

PURPOSE

Medullary thyroid carcinoma (MTC) is a malignant neoplasm of parafollicular cells. Because it is a neuroendocrine tumor, it has known somatostatin receptors (SSTRs). The actual frequencies of the SSTR subtypes and their potential influences (by binding with endogenous somatostatin) on MTC cell proliferation have not been fully elucidated to date. The present study evaluated the occurrence of SSTR subtypes 1, 2, 3 and 5 as well as the possible role that each subtype plays in the clinical evolution of patients with MTC.

METHODS

This retrospective, longitudinal study analyzed thyroid surgical material from 42 patients with MTC. Immunohistochemical staining was performed with monoclonal antibodies against subtypes 1, 2, 3 and 5 of SSTR. The histological material was classified as negative, focal positive or diffuse positive, in relation to each of the SSTR subtypes. The initial response to treatment, clinical course and patient mortality rate were assessed and related to the presence of SSTR subtypes.

RESULTS

The most prevalent SSTR subtype was SSTR 3, which was found in 81% of the patients, when considering any pattern of positivity. However, subtype 2 had the lowest number of positive patients, with 28.6% demonstrating any positive pattern. Subtypes 1 and 5 had an intermediate prevalence of positivity, with subtype 1 present in 45.2% of the patients and subtype 5 positive in 54.8% of the patients, when considering any pattern of positivity. The presence of STR 1, in the form of diffuse positivity, independently predicted a better response to the initial therapy, with a hazard ratio (HR) of 4.80 (p = 0.03).

CONCLUSION

This is the first study to show the correlation of the presence of SSTR1, detected by monoclonal immunohistochemical techniques, and better response to initial treatment and possibly better long-term clinical response in patients with MTC. In addition, these patients had low positivity rates for SSTR2, which might explain the low sensitivity of diagnostic and limited therapeutic response to octrotide based radioisotopes.

Metastatic lymph node characteristics as predictors of recurrence/persistence in the neck and distant metastases in differentiated thyroid cancer

OBJECTIVE

The aim of this study was to evaluate the association between this characteristic and outcomes in patients with lymph node metastasis in a Brazilian cohort.

SUBJECTS AND METHODS

This study examined a retrospective cohort of adult patients diagnosed with differentiated thyroid cancer and lymph node metastases from 1998 to 2015 in two referral centers. Number, location, size and extranodal extension (ENE) of metastatic lymph nodes were assessed and correlated with response to initial therapy.

RESULTS

A greater number of metastatic nodes, larger size, presence of lateral neck disease and ENE were all associated with a lower probability of achieving an excellent response to initial therapy (p ≤ 0.05 for all these parameters). Local recurrent disease had a significant association with lymph node number (6 in the recurrence/persistence group versus 4 in the non-recurrent group; p = 0.02) and ENE (19.2 versus 75%, p = 0.03). Lateral neck disease was the only characteristic associated with distant metastasis and was present in 52.1% of the group without metastasis and 70.4% of the group with metastasis (p = 0.001).

CONCLUSION

The lymph node characteristics were associated with response to initial therapy and neck recurrence/persistence, confirming the importance of the analysis of these factors in risk stratification in a Brazilian population and its possible use to tailor initial staging and long term follow-up.

Molecular Markers Involved in Tumorigenesis of Thyroid Carcinoma: Focus on Aggressive Histotypes

Thyroid cancer derived from follicular cells (TCDFC) comprises well-differentiated (papillary and follicular) carcinoma, poorly differentiated carcinoma, and anaplastic carcinoma. Papillary thyroid carcinoma is the most common endocrine cancer, and its incidence is steadily increasing. Lethality and aggressiveness of TCDFC is inversely correlated with differentiation degree. In this review, an emphasis has been put on molecular markers involved in tumorigenesis of thyroid carcinoma with a focus on aggressive histotypes and the role of such biomarkers in predicting thyroid cancer outcome. Genetic rearrangements in TCDFC (RET/PTC, PAX8/PPARG) and mutations in RAS, BRAF, TERT promoter (TERTp), TP53, PIK3CA, and AKT1 are discussed. The majority of the studies to date indicate that TERTp mutations can serve as a marker of more aggressive disease in all the subtypes of thyroid carcinoma, being the best current marker of poor prognosis, due to its independent association with distant metastases and increased disease-specific mortality. Some studies suggested that a more accurate prediction of thyroid cancer outcome may be possible through a more extensive genetic analysis. The same is true concerning the identification of other mutations that are only relatively frequent in advanced tumors (e.g., TP53, PIK3CA, or AKT1). A better understanding of the prognostic role of TERTp mutation (together with additional ones like BRAF, RAS, PIK3CA, AKT1, or TP53) and the clarification of their putative role in fine-needle aspiration biopsies are likely to allow, in the future, an early refinement of the stratification risk in patients with well-differentiated carcinomas. It is worth noting that, as with any categorical staging system, the risk evaluation within each category (low, intermediate, and high) varies depending on the specific clinicopathologic features of individual patients and the specific biological behavior of the tumor. Finally, besides the diagnostic and/or prognostic significance of the above-mentioned mutations, it is crucial to understand that the molecular pathways and epigenetic alterations will likely turn into interesting targets for new therapies.

Prognostic Factors for Early and Long-Term Remission in Pediatric Differentiated Thyroid Carcinoma: The Role of Sex, Age, Clinical Presentation, and the Newly Proposed American Thyroid Association Risk Stratification System

BACKGROUND

The incidence of pediatric differentiated thyroid carcinoma (DTC) has been rising in recent years, and the main risk factors for recurrence are lymph node and distant metastasis at diagnosis. Other clinical features remain unclear, such as the impact of age, sex, and puberty. Furthermore, until now, this population has been treated using the same strategies used to treat adults. In 2015, the American Thyroid Association (ATA) published the first guidelines targeted at this age group. The aims of this study were to investigate the prognostic factors for early and long-term remission and also to validate the ATA risk stratification proposal in a population outside the United States.

METHODS

Clinical records from 118 patients <18 years old followed in two referral centers were reviewed. The median age was 12 years (range 4-18 years), and 20.3% (24 patients) were <10 years old at diagnosis. The median follow-up was 9.1 years. The majority were female (72%) and received total thyroidectomy and radioiodine therapy (RAI), and 61.8% were treated with more than one dose of RAI. The majority were classified as high risk (48.3%) by the new ATA pediatric guidelines due to distant metastasis (30 patients) or extensive lymph node involvement (27 patients). The remained were classified as low risk (31.3%) and intermediate risk (20.4%).

RESULTS

Females with no lymph node or distant metastasis and low ATA pediatric risk were more likely to have no evidence of disease (p < 0.05) within the first year and also in the long term. In this study, age did not significantly predict outcomes. Furthermore, patients also benefitted from multiple doses of RAI, but when the cumulative activity was >400 mCi, this benefit was diminished.

CONCLUSIONS

This study shows that the ATA risk stratification proposal for pediatric patients is useful in predicting early and long-term outcomes in pediatric patients with DTC. In addition, it shows that sex and metastatic disease are important prognostic factors in pediatric populations.

Dynamic Risk Stratification in Patients with Differentiated Thyroid Cancer Treated Without Radioactive Iodine

CONTEXT

Although response to therapy assessment is a validated tool for dynamic risk stratification in patients with differentiated thyroid cancer (DTC) treated with total thyroidectomy (TT) and radioactive iodine therapy (RAI), it has not been well studied in patients treated with lobectomy or TT without RAI. Because these responses to therapy definitions are heavily dependent on serum thyroglobulin (Tg) levels, modifications of the original definitions were needed to appropriately classify patients treated without RAI.

OBJECTIVE

This study aimed to validate the response to therapy assessment in patients with DTC treated with lobectomy or TT without RAI.

DESIGN AND SETTING

This was a retrospective study, which took place at a referral center.

PATIENTS

A total of 507 adults with DTC were treated with lobectomy (n = 187) or TT (n = 320) without RAI. They had a median age of 43.7 y, 88% were female, 85.4% had low risk, and 14.6% intermediate risk.

MAIN OUTCOME MEASURE

Main outcome measured was recurrent/persistent structural evidence of disease (SED) during a median followup period of 100.5 months (24-510).

RESULTS

Recurrent/persistent SED was observed in 0% of the patients with excellent response to therapy (nonstimulated Tg for TT < 0.2 ng/mL and for lobectomy < 30 ng/mL, undetectable Tg antibodies [TgAb] and negative imaging; n = 326); 1.3% with indeterminate response (nonstimulated Tg for TT 0.2-5 ng/mL, stable or declining TgAb and/or nonspecific imaging findings; n = 2/152); 31.6% of the patients with biochemical incomplete response (nonstimulated Tg for TT > 5 ng/mL and for lobectomy > 30 ng/mL and/or increasing Tg with similar TSH levels and/or increasing TgAb and negative imaging; n = 6/19) and all (100%) patients with structural incomplete response (n = 10/10) (P < .0001). Initial American Thyroid Association risk estimates were significantly modified based on response to therapy assessment.

CONCLUSIONS

Our data validate the newly proposed response to therapy assessment in patients with DTC treated with lobectomy or TT without RAI as an effective tool to modify initial risk estimates of recurrent/persistent SED and better tailor followup and future therapeutic approaches. This study provides further evidence to support a selective use of RAI in DTC.

An International Multi-Institutional Validation of Age 55 Years as a Cutoff for Risk Stratification in the AJCC/UICC Staging System for Well-Differentiated Thyroid Cancer

BACKGROUND

Age is a critical factor in outcome for patients with well-differentiated thyroid cancer. Currently, age 45 years is used as a cutoff in staging, although there is increasing evidence to suggest this may be too low. The aim of this study was to assess the potential for changing the cut point for the American Joint Committee on Cancer/Union for International Cancer Control (AJCC/UICC) staging system from 45 years to 55 years based on a combined international patient cohort supplied by individual institutions.

METHODS

A total of 9484 patients were included from 10 institutions. Tumor (T), nodes (N), and metastasis (M) data and age were provided for each patient. The group was stratified by AJCC/UICC stage using age 45 years and age 55 years as cutoffs. The Kaplan-Meier method was used to calculate outcomes for disease-specific survival (DSS). Concordance probability estimates (CPE) were calculated to compare the degree of concordance for each model.

RESULTS

Using age 45 years as a cutoff, 10-year DSS rates for stage I-IV were 99.7%, 97.3%, 96.6%, and 76.3%, respectively. Using age 55 years as a cutoff, 10-year DSS rates for stage I-IV were 99.5%, 94.7%, 94.1%, and 67.6%, respectively. The change resulted in 12% of patients being downstaged, and the downstaged group had a 10-year DSS of 97.6%. The change resulted in an increase in CPE from 0.90 to 0.92.

CONCLUSIONS

A change in the cutoff age in the current AJCC/UICC staging system from 45 years to 55 years would lead to a downstaging of 12% of patients, and would improve the statistical validity of the model. Such a change would be clinically relevant for thousands of patients worldwide by preventing overstaging of patients with low-risk disease while providing a more realistic estimate of prognosis for those who remain high risk.

Is radioactive iodine- 131 treatment related to the occurrence of non-synchronous second primary malignancy in patients with differentiated thyroid cancer?

OBJECTIVE

Much controversy relates to the risk of non-synchronous second primary malignancies (NSSPM) after radioactive iodine treatment (RAI-131) in differentiated thyroid cancer (DTC) patients. This study evaluated the relationship between RAI-131 and NSSPM in DTC survivors with long-term follow-up.

MATERIALS AND METHODS

Retrospective analysis of 413 DTC cases was performed; 252 received RAI-131 and 161 were treated with thyroidectomy alone. Exclusion criteria were: prior or synchronous non-thyroidal malignancies (within the first year), familial syndromes associated to multiple neoplasms, ionizing radiation exposure or second tumors with unknown histopathology.

RESULTS

During a mean follow-up of 11.0 ± 7.5 years, 17 (4.1%) patients developed solid NSSPM. Patients with NSSPM were older than those without (p = 0.02). RAI-131 and I-131 cumulative activity were similar in patients with and without NSSPM (p = 0.18 and p = 0.78, respectively). Incidence of NSSPM was 5.2% in patients with RAI-131 treatment and 2.5% in those without RAI-131 (p = 0.18). Using multivariate analysis, RAI-131 was not significantly associated with NSSPM occurrence (p = 0.35); age was the only independent predictor (p = 0.04). Under log rank statistical analysis, after 10 years of follow-up, it was observed a tendency of lower NSSPM-free survival among patients that received RAI-131 treatment (0.96 vs . 0.87; p = 0.06), what was not affected by age at DTC diagnosis.

CONCLUSION

In our cohort of DTC survivors, with a long-term follow-up period, RAI-131 treatment and I-131 cumulative dose were not significantly associated with NSSPM occurrence. A tendency of premature NSSPM occurrence among patients treated with RAI-131 was observed, suggesting an anticipating oncogenic effect by interaction with other risk factors.

A new appraisal of iodine refractory thyroid cancer

Thyroid cancer incidence is increasing all over the world - mostly due to an increase in the detection of small tumors that were previously undetected. A small percentage of these tumors lose the ability to uptake and/or to respond to radioiodine (RAI) therapy, especially in metastatic patients. There are several new therapeutic options that have emerged in the last 5 years to treat RAI refractory thyroid cancer patients, however, it is very important to properly identify RAI refractory patients and to clarify those appropriate for these treatments. In this review, we discuss the RAI refractory definitions and the criteria that have been suggested based on RAI uptake in the post therapy scan, as well as the response after RAI therapy and the possible molecular mechanisms involved in this process. We offer a review of the therapeutic options available at the moment and the therapeutic considerations based on a patient's individualized personal characteristics, primary tumor histology, tumor burden and location and velocity of lesion growth.

Survival from Differentiated Thyroid Cancer: What Has Age Got to Do with It?

BACKGROUND

In most staging systems, 45 years of age is used to differentiate low risk thyroid cancer from high risk thyroid cancer. However, recent studies have questioned both the precise 45 year age point and the concept of using a binary cut off as accurate predictors of disease specific mortality.

METHODS

A cohort of 3664 thyroid cancer patients that received surgery and adjuvant treatment at Memorial Sloan Kettering Cancer Center (MSKCC) from the years 1985 to 2010 were analyzed to determine the significance of age at diagnosis as a categorical variable at a variety of age cutoffs (5 year intervals between 30 and 70 years of age). The unadjusted and adjusted hazard ratio for the association between disease-specific survival and age was determined using a Cox proportional hazards model adjusted for other predictive variables sex, histology, and pathological T, N, and M status. Furthermore, predictive nomograms of disease-specific mortality were created and validated on an external dataset of 4551 patients to evaluate the impact of age at diagnosis as both a categorical and continuous variable.

RESULTS

In the MSKCC cohort, with a median follow-up time of 54 months (range 1-332), there were 59 deaths from thyroid cancer with a 10 year disease-specific survival of 96%. Adjusted hazard ratios for all age cutoffs from age 30 to age 70 years were significant. There was no specific cutoff age which risk stratifies patients with differentiated thyroid cancer (DTC). Categorizing age into five strata (<40, 40-49, 50-59, 60-69 and >70 years) showed a 37-fold increase in hazard ratio from age <40 years to age >70 years. A predictive nomogram using age as a continuous variable with other predictive variables had a high concordance index of 96%. Validation on the external cohort had a concordance index of 73%.

CONCLUSIONS

Mortality from DTC increases progressively with advancing age. There is no specific cutoff age which risk stratifies patients with DTC. A predictive nomogram using age as a continuous variable may be a more appropriate tool for stratifying patients with DTC and for predicting outcome.

Surgical approach and radioactive iodine therapy for small well-differentiated thyroid cancer

BACKGROUND

Management of small well-differentiated thyroid cancer (DTC) has generated much debate regarding the surgical approach and radioactive iodine treatment (RAI).

AIM

The aim of the study was to evaluate the impact of surgical extension and RAI on the outcome of DTC ≤2 cm.

METHODS

A retrospective analysis of 176 cases of DTC ≤2 cm was performed.

RESULTS

At diagnosis, tumor size was 1.38 ± 0.55 cm, age 40.2 ± 13.6 years. After a mean follow-up period of 14.1 ± 4.5 years, 15.9 % patients had recurrent/persistent structural disease, with cervical neck disease (thyroid gland area and/or cervical lymph nodes) in 11.9 % cases and distant metastasis in 5.1 %. Disease specific mortality was of 1.1 %. No difference in outcome was observed between patients submitted to total or subtotal thyroidectomy. After total and subtotal thyroidectomy, the rate of recurrent/persistent structural disease was 19.1 and 10.6 % (p = 1.00), respectively. Using the multivariate cox proportion hazards analysis, no difference in the clinical outcome was observed after total or subtotal thyroidectomy (p = 0.703) neither after RAI (p = 0.807). Similar results were observed after stratification by tumor size. Multifocal disease (p = 0.007), extra-thyroid extension (p = 0.007) and presence of lymph node metastasis (p = 0.000) were associated with unfavorable outcome.

CONCLUSIONS

Total thyroidectomy and RAI did not improve clinical outcomes of DTC ≤2.0 cm when compared with less extensive surgery and no RAI in selected patients. Therefore, in carefully selected patients with DTC ≤2.0 cm and no unfavorable risk factors (multifocal disease, extra-thyroid extension, lymph node and/or distant metastasis), less extensive surgery and no RAI may be acceptable treatment options.