Timing and Ideal Patient for an Appropriate Search for Somatic RET Mutation in Medullary Thyroid Cancer

RET somatic mutation analysis in sporadic MTC should be guided by postoperative evaluation results.

Poorly differentiated thyroid carcinoma: molecular, clinico-pathological hallmarks and therapeutic perspectives

Poorly differentiated thyroid carcinoma (PDTC) is a rare and extremely aggressive tumor, accounting for about 2-15% of all thyroid cancer. PDTC has a distinct biological behavior compared to well-differentiated and anaplastic thyroid carcinoma and, in last years, it has been classified as a separate entity from both anatomopathological and clinical points of view. Nevertheless, there is still a lack of consensus among clinicians regarding inclusion criteria and definition of PDTC that affects its diagnosis and clinical management. Due to its rarity and difficulty in classification compared to other tumors, very few studies are available to date and series often include different histotypes in addition to PDTC. This review focuses on main studies concerning PDTC summarizing the evolution in the definition of its diagnosis criteria, clinicopathological features, management, and outcome. The data available confirm that the pathological evaluation and classification of PDTC are crucial and should therefore be standardized. Since the clinical presentation and prognosis of PDTC may vary widely depending on the different stage of the disease at diagnosis, the patient's management may differ in treatment and should be tailored to each patient. Finally, this review discusses advances in molecular insights of PDTC that, together with the implementation of both in vitro and in vivo models, will provide valuable insights into biological mechanisms of progression, metastasis, and invasion of this aggressive thyroid carcinoma. Further studies on larger, carefully selected series are needed to better assess the peculiar features of PDTC and to better define its management by focusing on the best diagnostic and therapeutic approaches.

Usefulness of second 131I treatment in biochemical persistent differentiated thyroid cancer patients

Background

Second 131I treatment is commonly performed in clinical practice in patients with differentiated thyroid cancer and biochemical incomplete or indeterminate response (BiR/InR) after initial treatment.

Objective

The objective of the is study is to evaluate the clinical impact of the second 131I treatment in BiR/InR patients and analyze the predictive factors for structural incomplete response (SiR).

Patients and methods

One hundred fifty-three BiR/InR patients after initial treatment who received a second 131I treatment were included in the study. The clinical response in a short- and medium- long-term follow-up was evaluated.

Results

After the second 131I treatment (median 8 months), 11.8% patients showed excellent response (ER), 17% SiR, while BiR/InR persisted in 71.2%. Less than half (38.5%) of SiR patients had radioiodine-avid metastases. Patients who, following the second 131I treatment, experienced SiR had larger tumor size and more frequently aggressive histology and vascular invasion than those experienced BiR/InR and ER. Also, the median values of thyroglobulin on levothyroxine therapy (LT4-Tg), Tg peak after recombinant human TSH stimulation (rhTSH-Tg) and thyroglobulin antibodies (TgAb) were significantly higher in patients who developed SiR. At last evaluation (median: 9.9 years), BiR/InR persisted in 57.5%, while 26.2% and 16.3% of the patients showed ER and SiR, respectively. About half of BiR/InR patients (71/153 (46.4%)) received further treatments after the second 131I treatment.

Conclusions

Radioiodine-avid metastatic disease detected by the second 131I is an infrequent finding in patients with BiR/InR after initial treatment. However, specific pathologic and biochemical features allow to better identify those cases with higher probability of developing SiR, thus improving the clinical effectiveness of performing a second 131I treatment.

BRAF K601E Mutation in Oncocytic Carcinoma of the Thyroid: A Case Report and Literature Review

BACKGROUND

Thyroid carcinoma (TC) is the most common endocrine cancer, with papillary thyroid carcinoma (PTC) being the most common subtype. BRAF and RAS oncogene were characterized as the most frequently altered genes in PTC, with a strong association between genotype and histotype. The most common mutation in BRAF gene is V600E and is prevalent in classic and aggressive variants of PTC, while BRAF K601E mutation is the most common among the other rare BRAF mutations. BRAF K601E mutated thyroid carcinomas are usually characterized by low aggressiveness, except for anecdotal cases of poorly differentiated TC.

CASE PRESENTATION

We described a case of oncocytic carcinoma of the thyroid (OCA) with an aggressive clinical course, including widespread metastasis and resistance to radioiodine treatment. Molecular analysis revealed the exclusive presence of the BRAF K601E mutation in both primary tumor and metastatic lesions. Accordingly, a revision of the literature about aggressive TC cases carrying BRAF K601E mutation was performed.

CONCLUSION

Although rare, this case emphasizes the relevance of considering BRAF K601E mutation in advanced non-PTC thyroid carcinomas, since it can be considered an actionable mutation for target therapies.

Ultrasound features and risk stratification system in NIFT-P and other follicular-patterned thyroid tumors

OBJECTIVE

Noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFT-P) is an encapsulated follicular variant of papillary thyroid carcinoma (PTC) with nonaggressive clinical behavior. However, since its diagnosis is exclusively possible after surgery, it represents a clinical challenge. Neck ultrasound (US) shows good sensitivity and specificity in suggesting malignancy in thyroid nodules. However, little information is available about its ability in identifying NIFT-P.

DESIGN

The aim of this study was to evaluate the US features of NIFT-P, comparing them with other follicular-patterned thyroid tumors, and to test the ability of the main US risk stratification system (RSS) in identifying NIFT-P.

METHODS

We retrospectively evaluated 403 consecutive patients submitted to thyroid surgery, with positive histology for at least 1 nodule being NIFT-P, follicular variant of PTC (FV-PTC), follicular thyroid carcinoma (FTC), or follicular adenoma (FA).

RESULTS

The US features of NIFT-P (n = 116), FV-PTC (n = 170), FTC (n = 76), and FA (n = 90) were reported. Follicular variant of PTC and FTC more frequently showed irregular margins, presence of calcifications, "taller than wide" shape, and the absence of halo compared with NIFT-P. Furthermore, FTC and also FA were larger and more frequently hypoechoic than NIFT-P. Most cases (77%) showed an indeterminate cytology. Regardless of the US RSS considered, NIFT-P and FA were less frequently classified in the high-suspicious category compared with FV-PTC and FTC.

CONCLUSIONS

Ultrasound features of NIFT-P are frequently superimposable to those of nodules with low suspicion of malignancy. The NIFT-P is almost never classified in the high-suspicious category according to the main US RSS. Therefore, although the preoperative identification of NIFT-P remains a challenge, neck US can be integrated in the algorithm of management of nodules with indeterminate cytology, suggesting a possible conservative approach in those with low-suspicious features.

Effect of Pregnancy and Menopause on Micropapillary Thyroid Carcinomas During Active Surveillance

Background

The effect of estrogen and beta-human chorionic gonadotropin on micropapillary thyroid carcinoma (mPTC) is not defined. Pregnancy and menopause could represent critical moments during active surveillance (AS) for women with mPTC.

Objective

To evaluate the effect of either pregnancy or menopause on growth of mPTCs on AS.

Patients and Methods

Women with mPTC on AS who became pregnant or underwent menopause during AS were evaluated in this retrospective observational study. The primary outcome was disease progression according to the AS protocol. The secondary outcome was the shrinkage of mPTCs. We compared the menopause group of patients with 2 unmatched control groups: (1) the pre-menopause group of patients on AS who had not experienced menopause yet and (2) the post-menopause group of patients who started AS while already in menopause.

Results

Five patients who became pregnant and 9 who underwent menopause during AS were enrolled. No patient from either group had a disease progression, and all pregnant patients showed stable disease after pregnancy. Four patients of the menopause group (44%) experienced mPTC shrinkage. The percentage of patients with mPTC shrinkage was significantly higher in the menopause group than in the 2 control groups.

Conclusions

mPTC AS appears to be safe and feasible in patients who become pregnant or undergo menopause during surveillance. Our data suggest a possible association between menopause and mPTC shrinkage during AS.

Chromosomal alterations in sporadic medullary thyroid carcinoma and correlation with outcome

Somatic Copy Number Alterations (SCNA) involving either a whole chromosome or just one of the arms, or even smaller parts have been described in about 88% of human tumors. This study investigated the SCNA profile in 40 well-characterized sporadic medullary thyroid carcinomas by comparative genomic hybridization array. We found that 26/40(65%) cases had at least one SCNA. The prevalence of SCNA, and in particular of chromosome 3 and 10, was significantly higher in cases with a RET somatic mutation. Similarly, SCNA of chromosomes 3, 9, 10 and 16 were more frequent in cases with a worse outcome and an advanced disease. By the pathway enrichment analysis, we found a mutually exclusive distribution of biological pathways in metastatic, biochemically persistent and cured patients. In particular, we found gain of regions involved in the intracellular signaling and loss of regions involved in DNA repair and TP53 pathways in the group of metastatic patients. Gain of regions involved in cell cycle and senescence were observed in patients with biochemical disease. Finally, gain of regions associated to the immune system and loss of regions involved in the apoptosis pathway were observed in cured patients suggesting a role of specific SCNA and corresponding altered pathways in the outcome of sporadic MTC.

NF1 Gene Inactivation Acts as Tumor Driver in RET/RAS Negative Medullary Thyroid Carcinomas

OBJECTIVE

20% of sporadic MTC has no RET/RAS somatic alterations or other known gene alterations. Aim of this study was to investigate RET/RAS negative MTC for the presence of NF1 alterations.

METHODS

we studied 18 sporadic RET/RAS negative MTC cases: Next generation sequencing of tumoral and blood DNA was performed using a custom panel including the entire coding region of the NF1 gene. The effect of NF1 alterations on the transcripts were characterized by RT-PCR and the loss of heterozygosity of the other NF1 allele was investigated with Multiplex Ligation-dependent Probe Amplification.

RESULTS

Two cases showed bi-allelic inactivation of NF1 with a prevalence of about 11% of RET/RAS negative cases. In a patient affected by neurofibromatosis there was a somatic intronic point mutation determining the transcript alteration in one allele and a germline loss of heterozygosity (LOH) in the other. In the other case described both the point mutation and the LOH were somatic events; this latter finding shows, for the first time, a driver role of NF1 inactivation in MTC independent of RET/RAS alterations and the presence of neurofibromatosis.

CONCLUSIONS

About 11% of our series of sporadic RET/RAS negative MTC harbor biallelic inactivation of NF1 suppressor gene also regardless neurofibromatosis status. According to our results, NF1 alterations should be searched in all RET/RAS negative MTC as possible driver. Moreover, this finding reduces the number of negative sporadic MTCs and may have important clinical implications in the management of these tumors.

Clinical evolution of sporadic medullary thyroid carcinoma with biochemical incomplete response after initial treatment

CONTEXT

The clinical response after surgery is a determinant in the management of patients with medullary thyroid carcinoma (MTC). In case of excellent or structural incomplete response, the follow-up strategies are well designed. Conversely, in case of biochemical incomplete response (BiR) the management is not clearly defined.

PURPOSE

To evaluate the overall and per-site prevalence of structural disease detection in sporadic MTC patients with BiR and to assess the predictive value of various clinical, biochemical, and genetics features.

METHODS

We evaluated data of 599 consecutive patients surgically treated for sporadic MTC (2000-2018) and followed-up at Endocrine Unit of the University Hospital of Pisa.

RESULTS

After a median of 5 months from surgery, 145/599 (24.2%) patients were classified as BiR. Structural disease was detected in 64/145 (44.1%), after a median time of 3.3 years. In 73.6% structural disease was detected at a single site, prevalently cervical lymph nodes. Among several others, at the time of first evaluation after surgery, only basal calcitonin (bCTN) and stage IVa/b were independent predictive factors. Also, structural disease was more frequent in patients with shorter CTN doubling time and somatic RET mutation.

CONCLUSIONS

In sporadic MTC patients with BiR the risk of detection of structural disease was about 50% at 10 years. Higher bCTN levels and staging predicted the risk of detecting structural disease. According to these findings, a stricter follow-up should be reserved to MTC with BiR and elevated values of bCTN and to those with an advanced stage. Long follow-up should anyway be considered for all BiR patients since 50% of them develop structural disease within 10 years.

Active surveillance in differentiated thyroid cancer: a strategy applicable to all treatment categories response

Currently, the differentiated thyroid cancer (DTC) management is shifted toward a tailored approach based on the estimated risks of recurrence and disease-specific mortality. While the current recommendations on the management of metastatic and progressive DTC are clear and unambiguous, the management of slowly progressive or indeterminate disease varies according to different centers and different physicians. In this context, active surveillance (AS) becomes the main tool for clinicians, allowing them to plan a personalized therapeutic strategy, based on the risk of an unfavorable prognosis, and to avoid unnecessary treatment. This review analyzes the main possible scenarios in treated DTC patients who could take advantage of AS.

Chylous effusions in advanced medullary thyroid cancer patients treated with selpercatinib

OBJECTIVE

Selpercatinib is a highly selective RET-inhibitor drug, approved for the treatment of RET-altered lung and thyroid cancers. So far, RET-altered medullary thyroid cancer (MTC) patients treated with selpercatinib showed a remarkable objective response rate and safety profile. However, new treatment emerging adverse events (TEAEs) have been recently reported. The aim of this study was to evaluate the prevalence, features, and clinical management of effusions that are one of these TEAEs.

DESIGN

Around 10 of 11 patients with advanced MTC enrolled in the LIBRETTO-201 clinical trial at Endocrinology Unit of the Pisa University Hospital were evaluated for the presence and management of effusions.

METHODS

We retrospectively evaluated MTC patients treated with selpercatinib. The presence of pleural, pericardial, abdominal, and/or pelvic effusions was evaluated by reviewing the computerized tomography scan performed during the study protocol and up to 24 months of observation.

RESULTS

All but one MTC patient experienced previous multikinase inhibitors treatment. Three patients already had effusions before starting selpercatinib treatment. New effusions appeared in eight of ten (80%) patients during the treatment. A chylous nature was documented in patients who underwent fluid aspiration. Whenever a dose reduction was performed, a significant positive effect was observed.

CONCLUSIONS

Chylous effusions are a new TEAE of selpercatinib treatment. They can appear or worsen at any time during the treatment. For cases with asymptomatic and mild effusions, active surveillance may be appropriate and safe. In symptomatic and/or moderate/severe cases, aspiration of the fluid and a dose reduction can improve this AE, strongly supporting a cause-effect correlation with selpercatinib.

SIGNIFICANCE STATEMENT

Effusions, particularly of chylous nature, represent emergent and quite frequent adverse events in the management of patients affected by advanced MTC on treatment with the highly selective inhibitor selpercatinib. In this study, we evaluated, in a series of MTC patients treated with selpercatinib, the prevalence of pleural, pericardial, abdominal, and/or pelvic effusions. Insights into the diagnosis and treatment of the effusions are provided as well as suggestions for clinical management.

Pre- and Post-operative Circulating Tumoral DNA in Patients With Medullary Thyroid Carcinoma

CONTEXT

Measurement of driver mutations in circulating tumoral DNA (ctDNA) obtained by liquid biopsy has been shown to be a sensitive biomarker in several human tumors.

OBJECTIVE

The aim of this study was to evaluate the clinical relevance of pre- and post-operative ctDNA in sporadic medullary thyroid cancer (sMTC).

METHODS

We studied pre- and post-operative ctDNA in 26 and 23 sMTC patients, respectively. ctDNA results were correlated to serum calcitonin (Ct), carcinoembryonic antigen (CEA), and other clinical/pathological features.

RESULTS

Twenty-six of 29 (89.7%) sMTCs were mutated either for RET or RAS and 3/29 (10.3%) were negative. Four of 26 (15.4%) cases showed positive pre-operative ctDNA with a significantly higher presence of RET M918T mutation (P = 0.0468). Patients with positive pre-operative ctDNA showed a higher variation allele frequency value of the somatic driver mutation (P = 0.0434) and a higher frequency of persistent disease (P = 0.0221). Post-operative ctDNA was positive only in 3/23 (13%) sMTCs and no one was positive for pre-operative ctDNA. Higher values of both Ct (P = 0.0307) and CEA (P = 0.0013) were found in positive ctDNA cases. Finally, the 7 cases harboring either pre- or post-operative positive ctDNA had a persistent disease (P = 0.0005) showing a higher post-operative serum Ct when compared with cases with negative ctDNA (P = 0.0092).

CONCLUSIONS

Pre-operative ctDNA in medullary thyroid cancer is not useful for diagnostic purposes, but it can be useful for predicting the outcome of the disease. In our series, post-operative ctDNA showed a potential for monitoring the response to therapies, but further studies are required to confirm our results.

Somatic RET Indels in Sporadic Medullary Thyroid Cancer: Prevalence and Response to Selpercatinib

CONTEXT

Although the majority of RET alterations are single nucleotide variants (SNV), small deletions and/or insertions have been reported at variable prevalence. No information about the efficacy of RET-specific inhibitors in patients harboring RET indels has been provided.

OBJECTIVE

We present an update on the prevalence of RET indels in medullary thyroid cancer (MTC) and describe the efficacy of selpercatinib in patients with advanced MTC with RET indels.

METHODS

The MTC tissues of 287 patients were analyzed using an Ion S5 targeted sequencing. The functional role of the reported indels have been evaluated by MutationTaster. Clinical and pathological data of MTC patients harboring a RET indel were collected and analyzed. Two patients with a RET indel were treated with selpercatinib.

RESULTS

Among 178 RET-positive cases, 147 (82.6%) harbored a SNV and 31 (17.4%) a RET in-frame indel. Nine indels were not previously reported and were found to be disease causing by MutationTaster. Patients harboring an indel were found to have an aggressive disease and 2 of them were treated with selpercatinib, experiencing a good response to the treatment.

CONCLUSION

These data show that RET indels are not infrequent and correlate with an aggressive disease. Two RET indel-positive patients showed a partial response to the treatment with a highly selective RET inhibitor; thus, these RET indels can be considered actionable mutations. In order to not miss these alterations, the analysis of the full gene is recommended.

Sporadic Medullary Thyroid Carcinoma: Towards a Precision Medicine

Medullary thyroid carcinoma (MTC) is a neuroendocrine malignant tumor originating from parafollicular C-cells producing calcitonin. Most of cases (75%) are sporadic while the remaining (25%) are hereditary. In these latter cases medullary thyroid carcinoma can be associated (multiple endocrine neoplasia type IIA and IIB) or not (familial medullary thyroid carcinoma), with other endocrine diseases such as pheochromocytoma and/or hyperparathyroidism. RET gene point mutation is the main molecular alteration involved in MTC tumorigenesis, both in sporadic and in hereditary cases. Total thyroidectomy with prophylactic/therapeutic central compartment lymph nodes dissection is the initial treatment of choice. Further treatments are needed according to tumor burden and rate of progression. Surgical treatments and local therapies are advocated in the case of single or few local or distant metastasis and slow rate of progression. Conversely, systemic treatments should be initiated in cases with large metastatic and rapidly progressive disease. In this review, we discuss the details of systemic treatments in advanced and metastatic sporadic MTC, focusing on multikinase inhibitors, both those already used in clinical practice and under investigation, and on emerging treatments such as highly selective RET inhibitors and radionuclide therapy.

Active Surveillance in RET Gene Carriers Belonging to Families with Multiple Endocrine Neoplasia

Simple Summary

MEN2 has a very high penetrance for the development of medullary thyroid cancer. However, intra- and inter-familial variabilities have been described. Accordingly, in this precision medicine era, a personalized approach should be adopted in subjects harboring RET mutations. In these subjects, we showed that thyroid surgery could be safely timed according to basal and stimulated calcitonin, especially in children who can reach adulthood, avoiding the risks of thyroid surgery and decreasing the period of a long-life hypothyroidism treatment.

Abstract

Multiple Endocrine Neoplasia 2 (MEN2) is a hereditary cancer syndrome for developing medullary thyroid cancer (MTC) due to germline mutations of RET gene. Subjects harboring a germline RET mutation without any clinical signs of MTC are defined as gene carriers (GCs), for whom guidelines propose a prophylactic thyroid surgery. We evaluate if active surveillance of GCs, pursuing early thyroid surgery, can be safely proposed and if it allows safely delaying thyroid surgery in children until adolescence/adulthood. We prospectively followed 189 GCs with moderate or high risk germline RET mutation. Surgery was planned in case of: elevated basal calcitonin (bCT) and/or stimulated CT (sCT); surgery preference of subjects (or parents, if subject less than 18 years old); other reasons for thyroid surgery. Accordingly, at RET screening, we sub-grouped GCs in subjects who promptly were submitted to thyroid surgery (Group A, n = 67) and who were not (Group B, n = 122). Group B was further sub-grouped in subjects who were submitted to surgery during their active surveillance (Group B1, n = 22) and who are still in follow-up (Group B2, n = 100). Group A subjects presented significantly more advanced age, bCT and sCT compared to Group B. Mutation RET^V804M was the most common variant in both groups but it was significantly less frequent in Group A than B. Analyzing age, bCT, sCT and genetic landscape, Group B1 subjects differed from Group B2 only for sCT at last evaluation. Group A subjects presented more frequently MTC foci than Group B1. Moreover, Group A MTCs presented more aggressive features (size, T and N) than Group B1. Accordingly, at the end of follow-up, all Group B1 subjects presented clinical remission, while 6 and 12 Group A MTC patients had structural and biochemical persistent disease, respectively. Thank to active surveillance, only 13/63 subjects younger than 18 years at RET screening have been operated on during childhood and/or adolescence. In Group B1, three patients, while actively surveilled, had the possibility to reach the age of 18 (or older) and two patients the age of 15, before being submitted to thyroid surgery. In Group B2, 12 patients become older than 18 years and 17 older than 15 years. In conclusion, we demonstrated that an active surveillance pursuing an early thyroid surgery could be safely recommended in GCs. This patient-centered approach permits postponing thyroid surgery in children until their adolescence/adulthood. At the same time, we confirmed that genetic screening allows finding hidden MTC cases that otherwise would be diagnosed much later.

Higher baseline TSH levels predict early hypothyroidism during cancer immunotherapy

BACKGROUND AND PURPOSE

Immune checkpoint inhibitors (ICIs) are monoclonal antibodies that enhance the immune response against cancer cells. ICIs are generally well tolerated, although endocrine immune-related adverse events (irAEs) are common. We investigated the risk factors for thyroid irAEs in patients treated with ICIs. Moreover, we evaluated the clinical outcome of subjects who became hypothyroid compared to euthyroid patients.

PATIENTS AND METHODS

We retrospectively analyzed a series of 195 consecutively subjects treated with ICIs for metastatic tumors at the University of Naples "Federico II" between January 2014 and March 2020. Only subjects tested for thyroid function before and during the treatment with ICIs were included.

RESULTS

In the 96 patients treated with ICIs who were included [66 males, median age: 62 years (27-87)], thyroid irAEs occurred in 36 (37.5%), 16 (16.7%) a transient thyrotoxicosis, and 20 (20.8%) an hypothyroidism (in nine subjects hypothyroidism was preceded by a transient thyrotoxicosis). Only baseline TSH levels above 1.67 mIU/L and positive anti-thyroid antibodies (Ab-T) were associated with a higher risk of hypothyroidism. Patients with hypothyroidism during ICI treatment showed an improved 2-year PFS (HR = 0.82 CI 0.47-1.43; p = 0.0132) and OS (HR = 0.38 CI 95% 0.17-0.80; p = 0.011) compared to euthyroid patients.

CONCLUSIONS

Baseline TSH levels above 1.67 mIU/L and presence of Ab-T are risk factors for the development of thyroid irAEs. Patients affected by thyroid irAEs showed a longer survival than patients who remained euthyroid.

Ultrasound features and risk stratification systems to identify medullary thyroid carcinoma

OBJECTIVE

Recently, several scientific societies designed ultrasound (US) risk stratification systems (RSS) to guide the workup of thyroid nodules and decide which nodules should undergo fine-needle aspiration cytology (FNAC). However, these systems have been developed against papillary thyroid carcinoma, and scanty data on their role in identifying medullary thyroid carcinoma (MTC) are available. The aims of this study are to describe the US features of MTC and evaluate the performance of RSS in identifying MTC.

METHODS

Data of 152 consecutive patients with MTC was evaluated. The results of the pre-operative neck US of all patients were collected. Ultrasound features of each MTC were evaluated and classified according to the five main RSS available.

RESULTS

Median MTC dimension was 1.3 cm. Most of the nodules showed solid composition, hypoechoic pattern, and regular margins. About half of them showed the presence of calcifications, but only a subgroup had microcalcifications. A minority of the nodules showed a 'taller than wide' shape. Only 7.9% of all MTC showed the simultaneous presence of at least four US features suggestive of malignancy. Ultrasonographic high-risk of malignancy of the MTC included in the five RSS, varied from 45.4 to 47.4%, and performing FNAC was suggested in only 48.7 to 63.8% of all MTC.

CONCLUSIONS

In this series, neither single nor the association of US features are specific for MTC. The five main RSS correctly identify less than 50% of MTC and do not suggest performing FNAC in about half of them with potentially missed or delayed diagnosis.

Thyroid Cancers: From Surgery to Current and Future Systemic Therapies through Their Molecular Identities

Differentiated thyroid cancers (DTC) are commonly and successfully treated with total thyroidectomy plus/minus radioiodine therapy (RAI). Medullary thyroid cancer (MTC) is only treated with surgery but only intrathyroidal tumors are cured. The worst prognosis is for anaplastic (ATC) and poorly differentiated thyroid cancer (PDTC). Whenever a local or metastatic advanced disease is present, other treatments are required, varying from local to systemic therapies. In the last decade, the efficacy of the targeted therapies and, in particular, tyrosine kinase inhibitors (TKIs) has been demonstrated. They can prolong the disease progression-free survival and represent the most important therapeutic option for the treatment of advanced and progressive thyroid cancer. Currently, lenvatinib and sorafenib are the approved drugs for the treatment of RAI-refractory DTC and PDTC while advanced MTC can be treated with either cabozantinib or vandetanib. Dabrafenib plus trametinib is the only approved treatment by FDA for BRAFV600E mutated ATC. A new generation of TKIs, specifically for single altered oncogenes, is under evaluation in phase 2 and 3 clinical trials. The aim of this review was to provide an overview of the current and future treatments of thyroid cancer with regards to the advanced and progressive cases that require systemic therapies that are becoming more and more targeted on the molecular identity of the tumor.

Impact of Advanced Age on the Clinical Presentation and Outcome of Sporadic Medullary Thyroid Carcinoma

Simple Summary

The clinical behavior of medullary thyroid carcinoma is heterogeneous and can be influenced by several clinical, biochemical and molecular factors. The role of age as a prognostic factor remains controversial. In our cohort of 432 sporadic medullary thyroid carcinoma, no differences in histologic features at diagnosis and in number and type of therapies performed during the follow-up were detected when dividing the patients according to age (< and ≥ 65 years). Younger patients had a longer follow-up and survival time, compared to the older patients. However, in dead patients, no differences in the aggressiveness of the disease at presentation and treatments performed during the follow-up were found between the two age groups.

Abstract

Sporadic medullary thyroid carcinoma (MTC) is a rare malignancy with a heterogeneous clinical course. Several potential prognostic factors have been investigated, but the impact of some of these is controversial, such as age at diagnosis. We evaluated the data of 432 sporadic MTC patients followed-up for a median of 7.4 years. Patients were divided and compared according to their age at diagnosis in group A (<65 years—n = 338, 78.2%) and group B (≥65 years—n = 94, 21.8%). No differences were detected between the two groups. Median follow-up time was significantly longer in patients <65 than ≥65 years. We observed 41 (9.5%) cancer-related death events. The death rate was similar between the two age groups. However, the Kaplan Meier curve showed a longer survival time for younger patients compared to older patients [HR 2.5 (CI 95%: 1.27–4.94), p < 0.01]. Nevertheless, no differences in the aggressiveness of the disease at presentation and in the number and type of treatments performed were found in the two subgroups of dead patients. In patients with sporadic MTC, age at diagnosis did not correlate with any clinical and pathological features. Cancer-related death events are similar in older and younger patients, but survival time is longer in the younger.

Thyroglobulin Changes are Highly Dependent on TSH in Low-risk DTC Patients not Treated with Radioiodine

INTRODUCTION

Low-risk differentiated thyroid cancer (DTC) is currently rarely treated with radioiodine (131I) to ablate the postoperative remnant. Therefore, the interpretation of the serum thyroglobulin (Tg) values should be reconsidered. The aim of our study was to evaluate the changes in Tg values during follow-up with regard to the changing values in thyroid stimulating hormone (TSH).

MATERIALS AND METHODS

We evaluated 271 low-risk DTC patients, treated with total thyroidectomy but not 131I. To be included, patients had to be negative for Tg antibodies and have at least 3 evaluations in our department. All patients were on levothyroxine (L-T4) therapy.

RESULTS

After a median follow-up of 73 months, the overall Tg values were stable, while TSH values slightly increased. Therefore, we pooled data of Tg and TSH from all evaluations and a significant positive correlation was demonstrated (R = 0.2; P < 0.01), and was also demonstrated when we performed the analysis using time-weighted values (R = 0.14; P = 0.02). Moreover, when dividing patients into 3 groups according to first postoperative Tg (Group A [Tg < 0.2 ng/ml], Group B [Tg 0.2-1 ng/ml], and Group C [Tg > 1 ng/ml]) most patients showed stable values of Tg at the end of follow-up but TSH variations had a clear impact on the changes in Tg among the groups.

CONCLUSION

We demonstrated that in low-risk DTC not treated with 131I, serum Tg remains substantially stable over time, and the variations observed were correlated with the concomitant variations of TSH levels, mainly due to the modification of LT-4 therapy performed according to the ongoing risk stratification.

Management and follow-up of differentiated thyroid cancer not submitted to radioiodine treatment: a systematic review

INTRODUCTION

The treatment of differentiated thyroid cancer (DTC) has been changing. In low (LR) and intermediate (IR) risk DTC, surgery is becoming more conservative and the usefulness of radioiodine (¹³¹I) has been questioned. An increasing number of patients are treated with lobectomy or total thyroidectomy (TTx), but without ¹³¹I. Consequently, the management and the follow-up of these patients need to be revised.

EVIDENCE ACQUISITION

We reviewed the available data about the management of these growing categories of patients. We focused on the emerging roles of the conventional tools in the follow-up [thyroglobulin (Tg), thyroglobulin antibodies (TgAb) and neck ultrasound (US)]. Moreover, we evaluated the changes in the use of levothyroxine (L-T4) therapy, and the role of the ongoing risk re-stratification.

EVIDENCE SYNTHESIS

Tg, TgAb and neck US continue to represent the cornerstone of the follow-up, however, a change in their interpretation is needed. In particular, the absolute value of Tg and TgAb lost their clinical meaning, while their trend over time acquired a greater value. At variance, the diagnostic role of neck US is becoming very relevant for the early identification of the local recurrences. In addition, L-T4 therapy should be personalized according with the type of surgery, the age of patients and their comorbidities.

CONCLUSIONS

Management of DTC treated with lobectomy or TTx but without ¹³¹I is worldwide changing. The evidences suggest that in this setting of patients with LR or IR of recurrences, a relaxed surveillance could represent the most reasonable choice.

Potential Impact of BMI on the Aggressiveness of Presentation and Clinical Outcome of Differentiated Thyroid Cancer

BACKGROUND

Obesity is a risk factor for several cancers, including differentiated thyroid cancer (DTC). Moreover, it has also been investigated as a potential risk factor for aggressiveness of DTC, but the data gathered so far are conflicting. The aim of our study was to evaluate the relationship between body mass index (BMI), aggressiveness of DTC at diagnosis, and clinical outcome.

METHODS

We evaluated 1058 consecutive DTC patients treated with total thyroidectomy and enrolled at the time of first radioactive iodine (131I) treatment. Patients were divided into 4 groups based on their BMI: underweight (< 18.5 kg/m2), normal weight (18.5-24.9 kg/m2), overweight (25-29.9 kg/m2), and obese (≥ 30 kg/m2). Histological aggressiveness of DTC at the time of diagnosis and clinical outcome according to 2015 American Thyroid Association (ATA) guidelines were evaluated.

RESULTS

No differences in histological features, ATA risk of recurrence, activity of 131I administered and prevalence of 131I avid metastatic disease after first131I treatment, have been demonstrated among the groups. Furthermore, at the end of follow up (median = 5.7 years), no differences were evident in the number of further treatments performed as well as in the clinical response.

CONCLUSIONS

In our study group of Caucasian subjects, we could not demonstrate any association between BMI and aggressiveness of DTC, neither at the time of diagnosis nor during follow-up. These data indicate that postsurgical assessment and therapeutic attitude for treatment and follow-up of DTC should be based on the class of risk applied to the general population, with no concern for BMI.

DELAYED 131-I FIRST TREATMENT AFTER SURGERY HAS NO IMPACT ON THE MEDIAN TERM OUTCOME OF PATIENTS WITH INTERMEDIATE RISK DIFFERENTIATED THYROID CANCER

Objective: In intermediate risk (IR) differentiated thyroid cancer (DTC) patients, selective use of radioiodine (131-I) for remnant ablation and/or as adjuvant therapy (RRA) is advocated. The recently suggested postoperative evaluation could delay the use of RRA. The aim of this study was to evaluate if a delayed RRA can worsen the clinical outcome of IR-DTC patients. Methods: Four hundred and fourteen consecutive IR-DTC patients were divided according to the time elapsed from surgery to RRA, <6 months (group A, 186/414 [44.9%]), or ≥6 months (group B, 228/414 [55.1%]). Clinical and biochemical data were collected, and clinical outcome was analyzed at the first evaluation (EV) after RRA (first-EV) and after a median of 6 years of follow-up (last-EV). Results: No difference in the clinical outcome of group A and B was found. Since a different activity of 131-I could have an impact on the outcome, we separately analyzed the groups according to the 131-I activity (low-activity group: 1,110 MBq/30 mCi [n = 320], and high-activity group: 3,700 MBq/100 mCi [n = 94]), further subdivided according to the time elapsed from surgery to RRA. No major differences were found in both the low- and high-activity groups when comparing the features of their subgroups A and B, as far as in their clinical outcome. Conclusion: The time elapsed between surgery and the first 131-I treatment does not influence the clinical outcome of IR-DTC patients. This finding allows a more relaxed attitude in the decision making process whether to perform the RRA in IR-DTC cases in which a selective use of 131-I is recommended. Abbreviations: ATA = American Thyroid Association; DTC = differentiated thyroid cancer; EV = evaluation; HR = high risk; 131-I = radioiodine; IR = intermediate risk; LR = low risk; rhTSH = recombinant human thyroid-stimulating hormone; RRA = radioiodine for remnant ablation; Tg = thyroglobulin; TgAb = thyroglobulin autoantibody; US = ultrasound.

Management of one patient with oligoprogressive thyroid cancer during treatment with lenvatinib

Recent thyroid cancer guidelines found it reasonable to use local therapies during treatment with tyrosine kinase inhibitors (TKIs) in selected patients with oligoprogressive disease, namely, in the presence of a single progressing lesion in an otherwise TKI-responsive metastatic cancer. However, there is a lack of experience in the management of oligoprogressive thyroid cancers. This report illustrates the case of one patient with oligoprogressive thyroid cancer during therapy with lenvatinib. We found that the application of local ablative therapy in oligoprogressive disease prolonged the progression-free survival and thus extended the time to therapy interruption. However, the optimal care for TKI-treated oligoprogressive cancers remains unclear and needs to be investigated in prospective trials.

Changing Trend of Thyroglobulin Antibodies in Patients With Differentiated Thyroid Cancer Treated With Total Thyroidectomy Without 131I Ablation

BACKGROUND

Thyroglobulin (Tg) antibodies (TgAb) can interfere with Tg measurement and can be used as "Tg surrogate" in patients with differentiated thyroid cancer (DTC) treated with total thyroidectomy (TTx) and radioiodine remnant ablation (RRA). In contrast, few data, and in patients usually followed for a short-term follow-up, have been reported about the changes of TgAb levels in patients treated with TTx but without RRA. The aims of this study were to evaluate the changes of TgAb levels in DTC patients treated with TTx but not RRA and to identify the factors that influence these changes.

METHODS

The change in TgAb levels in 107 DTC (<1 cm) patients submitted to TTx but not RRA was evaluated. Patients were followed for a median of 6.3 years, and all had at least three determinations of TgAb and neck ultrasound (nUS).

RESULTS

TgAb levels showed a progressive decrease during follow-up. Initial TgAb levels and degree of lymphocytic infiltration influenced the time but not the rate of TgAb disappearance. No influence on time and rate of the decrease in TgAb was observed when the association with thyroperoxidase antibodies (TPOAb) levels were considered. A TgAb cutoff value of 61.9 IU/mL at first postoperative evaluation was a good indicator for disappearance of the TgAb within six years. No tumor recurrence was observed in the series. In one case, the progressive increase in TgAb anticipated the reappearance of benign thyroid tissue with lymphocytic infiltration.

CONCLUSIONS

TgAb levels decline in the majority of DTC patients treated with TTx but not ablated with radioiodine. The levels decrease rapidly after the surgical treatment and continue to decrease over time. The time of disappearance is influenced by the initial TgAb levels and the degree of lymphocytic infiltration. No influence of the actual TPOAb levels has been observed. An increase in TgAb levels should not be overlooked, since it can indicate the presence or reappearance of either normal thyroid tissue or tumor recurrence.

Postoperative Thyroglobulin and Neck Ultrasound in the Risk Restratification and Decision to Perform 131I Ablation

CONTEXT

There is much debate surrounding the choice of which patient should be submitted to postsurgical remnant radioiodine remnant ablation (RRA), particularly in low-risk (LR) and intermediate-risk (IR) differentiated thyroid cancer (DTC).

OBJECTIVE

The aim of this study was to evaluate the role of postoperative high-sensitive thyroglobulin (Tg) on L-thyroxine (LT4-HSTg) and postoperative neck ultrasound (US) in risk restratification and decision to perform RRA.

PATIENTS

We evaluated 505 patients with LR or IR DTC 3 to 4 months after total thyroidectomy (TTx). All patients underwent RRA and a posttherapeutic whole body scan (ptWBS).

RESULTS

After TTx, 29.7% DTC patients had LT4-HSTg <0.1 ng/mL (Group A) and could be restratified as cured: 1 of 150 had lymph node metastases (LN mets) detected by neck US but negative at ptWBS. 56.8% DTC patients had LT4-HSTg between 0.1 and ≤1 ng/mL (Group B) and could be restratified either as cured or not cured. In this group, 15 of 287 (5.2%) had metastases but only 7 were detected by ptWBS; 13.5% DTC patients had LT4-HSTg >1 ng/mL (Group C) and could not be considered as cured by definition. LN mets were present in 11 of 68(16.2%) cases, all detected by neck US. No correlation was found with the presence of metastases and serum LT4-HSTg values or with the level of risk.

CONCLUSIONS

LT4-HSTg measured 3 to 4 months after TTx is important in the risk restratification of DTC patients but is less relevant than neck US in the decision to perform RRA.