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.

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 RET Gene Expression Levels Do Not Represent anAlternative RET Activation Mechanism in Medullary Thyroid Carcinoma

This study was designed to investigate whether RET (rearranged during transfection) mRNA over-expression could be considered an alternative driver event for the development of medullary thyroid carcinoma (MTC), and if different RET isoforms could play a role in MTC tumorigenesis. Eighty-three MTC patients, whose mutational profile was previously identified by next-generation sequencing (NGS) IONS5, were included in this study. Expression analysis was performed by the quantitative reverse transcription-polymerase chain reaction technique. RET expression levels were found to be significantly higher in cases with RET somatic mutations than in cases that were negative for RET somatic mutations (p = 0.003) as well as in cases with a somatic mutation, either in RET or RAS than in cases negative for both these mutations (p = 0.01). All cases were positive for the RET51 isoform expression while only 72/83 (86.7%) were positive for RET9 isoform expression. A statistically significant higher expression of the RET51 isoform was found in cases positive for RET somatic mutation than in cases either positive for RAS mutation (p = 0.0006) or negative for both mutations (p = 0.001). According to our data, RET gene over-expression does not play a role in MTC tumorigenesis, neither as an entire gene or as an isoform. At variance, the RET gene, and in particular the RET51 isoform, is expressed higher in RET mutated cases. On the basis of these results we can hypothesize that the overexpression of RET, and in particular of RET51, could potentiate the transforming activity of mutated RET, making these cases more aggressive.

Prevalence and Risk Factors of Developing Fistula or Organ Perforation in Patients Treated with Lenvatinib for Radioiodine-Refractory Thyroid Cancer

INTRODUCTION

Tyrosine kinase inhibitors represent a better treatment in patients with radioiodine-refractory differentiated thyroid cancer (RAI-R DTC). Lenvatinib is usually well-tolerated, but sometimes, it is associated with serious and even life-threatening side effects. The aim of this study was to evaluate the prevalence of and the potential risk factors for fistula and/or organ perforation in RAI-R DTC patients treated with lenvatinib.

METHODS

This study included data from advanced and progressive RAI-R DTC patients treated with lenvatinib from February 2011 to February 2020 who were followed up at a single center. The clinical-pathological features and the biochemical and morphological results of the patients were collected at the time of starting lenvatinib and during the follow-up.

RESULTS

Fourteen of 95 (14.7%) locally advanced or metastatic RAI-R DTC patients treated with lenvatinib developed a fistula or organ perforation. Nine of 14 (64.3%) patients had tumor infiltration of the trachea, bronchus, esophagus, pleura, or bladder. Five of 14 (35.7%) had a bowel perforation, but only 2 had preexisting diverticulosis. Evaluation of the risk factors for developing a fistula or organ perforation showed that the presence of tumor infiltration and the tumor histology (papillary and poorly differentiated vs. follicular and Hurthle thyroid cancer) were significantly correlated with the development of a fistula or organ perforation (p = 0.003 and p = 0.02, respectively). In the subgroup of patients with tumor infiltration, we found that the papillary thyroid cancer histotype was the only potential predictor of fistula development. External beam radiation therapy (EBRT), the starting dose of lenvatinib, and the duration of treatment were not relevant for the development of fistula.

CONCLUSIONS

In metastatic thyroid cancer patients treated with lenvatinib, the presence of tumor infiltration and histological type should be considered as potential risk factors for the development of fistula or organ perforation, although they do not represent an absolute contraindication. Although EBRT and the presence of diverticulosis were not significantly associated with the development of fistula and organ perforation, they should be regarded as potential additional reasons for the development of these complications. According to our findings, there is no reason to start lenvatinib at a lower daily dose when tumor infiltration is present.

Thyroid cancer and COVID-19: experience at one single thyroid disease referral center

PURPOSE

Severe acute respiratory syndrome coronavirus 2 (SARS-Cov-2) is challenging health systems all over the world. Cancer patients have a higher risk of being infected by SARS-Cov-2 and higher coronavirus disease 2019 (COVID-19) severity and mortality. Up to date, there were no data about COVID-19 in patients with thyroid cancer (TCs). The aim of the study was to describe the prevalence of COVID-19 in a well-characterized series of TC patients evaluated for the persistence of the neoplastic disease from March to September 2020; as secondary objective, we looked for the COVID-19 disease severity in a subgroup of multimetastatic TC patients.

METHODS

We evaluated 1464 patients affected by persistent TC: 67 patients who were taking multikinase inhibitors (MKIs) and 1397 under active surveillance for a persistent but stable disease. During the clinical evaluation, all patients were specifically investigated about a positive history of Sars-Cov-2 infection.

RESULTS

SARS-Cov-2 infection was identified in 4/1464 (0.3%) cases of patients affected by TC. We identified three cases among patients under active surveillance (0.2%), and one case among patients treated with MKI systemic therapy (1/67, 1.5%). This patient was taking vandetanib for metastatic medullary thyroid cancer (MTC), when he came to our attention referring severe fatigue, dyspnea for light physical activities. He presented a mild COVID-19 and he received exclusively supportive care. After a multidisciplinary consultation, we decided against the discontinuation of vandetanib. After 2 months from the infection, he did not present any signs of active infection, and the MTC metastatic disease was stable.

CONCLUSIONS

We showed that COVID-19 is not more frequent in TC patients than in general population, although a relatively higher prevalence in the group of TC patients treated with MKIs. A single patient with advanced TC and SARS-Cov-2 infection during MKIs treatment had a mild COVID-19 and did not require the discontinuation of MKI therapy. In cases of more severe COVID-19, an accurate evaluation from a multidisciplinary team would consider risks and benefits in taking the decision to continue or stop MKI treatment.

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.

RET mutated C-cells proliferate more rapidly than non-mutated neoplastic cells

A statistically significant higher prevalence of the RET p.Met918Thr somatic mutation, identified by direct sequencing, was previously reported in MTC > 2 cm than in smaller tumors. Aim of this study was to correlate the full RET and RAS mutation profile, identified by a Next Generation Sequencing approach, with the growth rate, proliferation and tumor size of MTC. Data of 149 sporadic MTC patients were correlated with RET mutations and Ki67 positivity. Eighty-one cases had a somatic RET mutation, 40 had a RAS mutation and 28 were negative. A statistically significant higher prevalence of RET mutations was found in MTC > 2 cm. A higher prevalence of RET more aggressive mutations, higher allelic frequencies and, higher percentage of Ki67 positive cells were found in larger tumors which had also a worse outcome. Our study highlights the predominant role of RET somatic mutations in MTC tumorigenesis. We demonstrate that RET mutation prevalence and allelic frequency (AF) are significantly higher in larger tumors. Based on these results, we can conclude that RET mutated C-cells's growth and proliferation are more rapid than those of non-mutated cells and give origin to bigger and more aggressive MTC.

Proteinuria is a late-onset adverse event in patients treated with cabozantinib

PURPOSE

The use of tyrosine kinase inhibitors (TKIs) in thyroid cancer patients is often limited by toxicities. Some have a long-term onset and potentially could impact patients' survival. Among them, there is the nephrotoxicity, mainly represented by proteinuria. The aim of the study was to evaluate the prevalence of proteinuria in medullary thyroid cancer patients treated with cabozantinib, to examine whether it could be a marker for treatment monitoring and to evaluate histological kidney alterations.

METHODS

We collected data of 31 medullary thyroid cancer patients enrolled in the EXAM trial. Proteinuria was defined and evaluated using the National Cancer Institute's Common Terminology Criteria for Adverse Events. In two symptomatic cases with high-grade proteinuria, a kidney biopsy was performed.

RESULTS

Proteinuria was observed in 4/18 patients (22.2%) and occurred after a mean period of 38 months (median: 35.5 months). It was significantly associated with previous chemotherapy (p = 0.005) and/or treatment with other TKIs (p = 0.04), a prolonged use of cabozantinib (p = 0.0004), and a better radiological response at the end of follow-up (p = 0.002). The kidney biopsy showed pathognomonic features of thrombotic microangiopathy in both cases and a focal amyloid deposit in one.

CONCLUSION

Proteinuria is a quite frequent adverse event during cabozantinib treatment. It is relatively well manageable with the early detection and correction of risk factors, the temporary discontinuation of cabozantinib and/or its dose reduction, and the use of anti-proteinuric and renoprotective drugs in patient with hypertension. The histological findings confirmed some typical features of the anti-VEGF inhibition injury, already described for other TKIs.

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.

RET Copy Number Alteration in Medullary Thyroid Cancer Is a Rare Event Correlated with RET Somatic Mutations and High Allelic Frequency

Copy number variations (CNV) of the RET gene have been described in 30% of Medullary Thyroid Cancer (MTC), but no information is available about their role in this tumor. This study was designed to clarify RET gene CNV prevalence and their potential role in MTC development. RET gene CNV were analyzed in 158 sporadic MTC cases using the ION Reporter Software (i.e., in silico analysis) while the multiplex ligation-dependent probe amplification assay (i.e., in vitro analysis) technique was performed in 78 MTC cases. We identified three categories of RET ploidy: 137 in 158 (86.7%) cases were diploid and 21 in 158 (13.3%) were aneuploid. Among the aneuploid cases, five out of 21 (23.8%) showed an allelic deletion while 16 out of 21 (76.2%) had an allelic amplification. The prevalence of amplified or deleted RET gene cases (aneuploid) was higher in RET positive tumors. Aneuploid cases also showed a higher allelic frequency of the RET driver mutation. The prevalence of patients with metastatic disease was higher in the group of aneuploid cases while the higher prevalence of disease-free patients was observed in diploid tumors. A statistically significant difference was found when comparing the ploidy status and mortality. RET gene CNVs are rare events in sporadic MTC and are associated with RET somatic mutation, suggesting that they could not be a driver mechanism of tumoral transformation per se. Finally, we found a positive correlation between RET gene CNV and a worse clinical outcome.

No difference in the outcome of metastatic thyroid cancer patients when using recombinant or endogenous TSH

OBJECTIVE

At present, recombinant TSH cannot be used for the treatment of metastatic differentiated thyroid cancer patients. The aim of this study was to evaluate if the type of TSH stimulation, recombinant or endogenous, had an impact on the outcome of these patients.

DESIGN AND METHODS

We compared the outcome of two propensity score-matched groups of metastatic patients, stimulated by either only recombinant TSH (n = 43) or only endogenous TSH (n = 34).

RESULTS

As expected from the matching procedure, the clinical-pathological features and the cumulative 131-I activities administered to the two groups were very similar. After 4 years of follow-up, 4% of patients were cured, 3% had biochemical disease and 93% had structural disease. However, 91% of patients obtained a clinical benefit from this therapy in terms of stabilization of the disease or complete remission or partial response. When considering the two groups separately, we did not find any difference in their outcome. When considering the response to 131-I therapy of the single type of metastases, 8% of lymph node metastases and 8% of lung metastases disappeared but none of the bone metastases. The response to 131-I therapy of the single type of metastases was similar when we looked at the two groups separately.

CONCLUSIONS

This study shows (i) an overall clinical benefit of the 131-I therapy, since the majority of patients remained affected but with a stable disease, and (ii) that the preparation with either recombinant or endogenous TSH has no impact on the 131-I therapy efficacy and the outcome of our two groups of patients.

Nonthyroidal second primary malignancies in differentiated thyroid cancer patients: Is the incidence increased comparing to the general population and could it be a radioiodine therapy consequence?

The long-term survival of differentiated thyroid cancer (DTC) patients and the need to perform several treatments with radioiodine (131-I) lead to the question if the lifetime risk of developing a nonthyroidal second primary cancer (NTSPC) is increased in these patients. In our study, we assessed the prevalence of NTSPCs in thyroid cancer population and evaluated the possible causative role of 131-I treatment. We analyzed 1096 consecutive patients followed at our institution from 1964 to 1998. A total of 101 NTSPCs were observed in 92/1096 patients (8.4%) among which 17/101 (16.8%) diagnosed before DTC and 84/101 (83.2%) diagnosed after. The most frequent tumor sites observed were breast and bladder/urinary tract in the post-DTC group and breast and hematological system in the pre-DTC group. Regarding 131-I treatment, we did not observe any significant differences regarding either the number of treatments or the cumulative activity. The only significant parameter associated with an increased incidence of NTSPC was follow-up (P = .02): a longer follow-up period was associated with a higher number of NTSPCs. The mean latency between 131-I and NTSPC was 10.52 ± 7.69 years. Comparing with the general Italian population, independent of radioiodine treatment, the standard incidence ratio in our cohort was similar to that of the general population (SIR 1.07) and this result was confirmed by analyzing only the treated group. In conclusion, these results show that the risk of NTSPCs in the DTC patients' population is similar to that in the general population and 131-I treatment was not associated with an increased risk.

OR21-01 Pre-Operative Calcitonin Value as a Predictive Factor of Cancer Related Death in Sporadic Medullary Thyroid Carcinoma

Introduction: Medullary thyroid carcinoma (MTC) is a rare tumor, it originates from the C cells producing calcitonin (CT) and can occur as sporadic or associated to germline RET mutation. The initial treatment is represented by total thyroidectomy associated with central compartment lymph nodes dissection and possible extension to the laterocervical compartment. CT is the main marker of follow-up of MTC, conversely its pre-operative role as diagnostic and prognostic factor is still debated. The aim of the present study was to evaluate several predictive factors of cancer related death in a large series of sporadic MTCs. Patients and Methods: We evaluated 537 consecutive patients surgically treated for sporadic MTC, from 2000 to 2019, and followed at the Operative Unit of Endocrinology 1 of the University of Pisa. We evaluated epidemiological, clinical and pathological data and pre and post-operative CT values, and their correlation with cancer related death. Results: At the end of the follow-up (average 75 months), 300/537 (55.9%) pts were cured, 100/537 (18.6%) pts showed biochemical disease, 88/537 (16.4%) pts showed metastatic disease and 49/537 (9.1 %) pts died for the disease. The factors significantly correlated with the cancer related death to the univariate analysis were the male gender, dimension of the primary tumor> 4 cm, the presence of lymph node metastasis to histology (N1) and/or distant metastasis (M1) at the time of diagnosis, multifocality, minimal extrathyroidal extension (mETE), initial staging, pre-operative CT values> 500 pg/ml and post-operative> 20 pg/ml. At multivariate analysis, statistical significance persisted only for pre- and post-operative CT and for the staging. Conclusions: 1) In our study we observed a significant improvement in the outcome and survival in the medium-long term of sporadic CMT patients, compared to the previous studies. 2) A more advanced staging at the time of diagnosis has been confirmed as a negative prognostic factor and it is evident that an early diagnosis is an essential requirement for improving cancer related death. 3) This is the first study that showed, in a large monocentric series of sporadic MTCs, as pre-operative CT represents a prognostic factor associated with cancer related death, as well as the value of post-operative CT.

MON-537 Primary Adrenal Insufficiency During Tyrosine Kinase Inhibitors Treatment in Advanced Thyroid Cancer Patients

Objective: Tyrosine kinase inhibitors (TKIs) are used for the treatment of metastatic differentiated (DTC), poorly differentiated (PDTC) and medullary (MTC) thyroid cancer. Several adverse events (AEs) have been reported in almost all patients (pts) treated with TKIs. One of the less known AE related to the use of these drugs is the primary adrenal insufficiency (PAI).

Methods: We analyzed the basal and stimulated adrenal function, ACTH levels, adrenal antibodies and electrolytes levels in 82 thyroid cancer pts treated with TKIs (vandetanib and cabozantinib in MTC pts, lenvatinib and sorafenib in DTC and PDTC pts) and we correlated these results with the clinical-pathological features of our pts.

Results: In our series, 25/82 (30.5%) pts showed a PAI after stimulation test with a progressive ACTH increase in 14/25 (56%) pts. Thirteen/25 (52%) pts with PAI were DTC, 8/25 (32%) pts were MTC and 4/25 (16%) pts were PDTC. Sixteen/25 (64%) pts were treated with lenvatinib, 8/25 (32%) were treated with vandetanib and 1/25 (4%) was treated with cabozantinib at the time of stimulation test. In 5/25 (20%) pts PAI occurred within 12 months from the TKIs treatment initiation, in 9/25 (36%) within 36 months and in 11/25 (44%) after 36 months of treatment. Eighteen/25 pts with PAI were older than 55 years. Twenty/25 (80%) of these pts were treated with cortisone acetate replacement therapy with the improvement of fatigue in a small part of these while other 5 pts were untreated due to the mild degree of PAI and the absence of specific symptoms (i.e fatigue). Moreover, in our pts the evaluation of adrenal antibodies was negative and the electrolytes levels were in the normal range. We also correlated the presence of PAI with the clinical-pathological features of our pts but we didn’t observe any significant correlation.

Conclusions: We observed that PAI, mainly subclinical, can occur during TKIs treatment in thyroid cancer pts. The appearance of fatigue, the typical symptom of PAI, could be multifactorial in these pts due also to the direct effect of TKIs treatment. Thus, in these cases is very difficult to recognize the cause of fatigue and to decide the appropriate treatment (cortisone acetate replacement therapy vs TKIs dose reduction). Moreover, the time of PAI appearance is variable since it can be early (<12 months) or late (>36 months) after TKIs treatment initiation and the adrenal function must be monitored during all TKIs treatment period. More studies are needed to know the pathophysiology of this “adverse event” during TKIs treatment and to improve the acknowledgments regarding the differential diagnosis and treatment of these pts, regardless of symptoms.

Active Surveillance in Papillary Thyroid Microcarcinomas is Feasible and Safe: Experience at a Single Italian Center

CONTEXT

The dramatic rise in the incidence of thyroid cancer over the last 30 years is largely attributable to the increasing diagnosis of papillary microcarcinomas (mPTCs). Current guidelines endorse an observational management approach in properly selected cases.

OBJECTIVE

To evaluate the feasibility of active surveillance in mPTC in Italy, its impact on real life, and to identify risk factors of progression.

DESIGN AND SETTING

In 2014 we started a prospective-observational study of active surveillance in mPTC patients.

PATIENTS

Included patients demonstrated a single Thy4 or Thy5 thyroid nodule, with largest diameter ≤1.3 cm, and no suspicious laterocervical lymph nodes by neck ultrasonography. Of 185 eligible subjects, 50.3% (93/185) enrolled in the observational management protocol while the others opted for surgery and were excluded from this analysis.

INTERVENTION

Enrolled patients were followed with neck ultrasound at 6- to 12-month intervals. Disease progression was defined as the appearance of abnormal lymph nodes or nodule enlargement during follow-up. In these cases, patients were directed to surgery.

RESULTS

Three patients (3/93, 3%) showed clinical progression and required surgery. Another 19 patients (19/93, 20%) decided to transition to surgical intervention even though there was no evidence of disease progression. All operated patients had excellent response to initial treatment despite the delayed surgery.

CONCLUSIONS

Within an Italian medical context, active surveillance appears to be a feasible and safe alternative to immediate surgery in healthy mPTC patients. Only 3% of mPTC demonstrated disease progression during a median follow-up of 19 months (range 6-54) and importantly demonstrated excellent outcomes after surgical intervention in a short-term follow-up.

Medullary thyroid cancer treated with vandetanib: predictors of a longer and durable response

Vandetanib is an important treatment option for advanced metastatic medullary thyroid cancer. The aims of this study were to evaluate the predictors of both a longer response to vandetanib and the outcome. Medical records of 79 medullary thyroid cancer patients treated with vandetanib at our center were analysed. Twenty-five patients were treated for <12 months, 54 were treated for ≥12 months and 24 of these latter were treated for ≥48 months (short-, long- and very long-term). The median progression free survival of the long and very long-term treated patients was significantly longer than in the ZETA trial. When comparing the groups of short - and long-term treated patients the only significant difference was that these latter were less frequently previously treated with a tyrosine kinase inhibitor. However, the long-term treated patients had a younger age, both at diagnosis and enrolment, which was statistically significant in the very long-term treated patients. In the long-term treated group, younger age, enrolment for symptoms and development of adverse events were significantly correlated with a better outcome. The enrolment for symptoms remained the only statistically significant predictor of a good outcome in the very long-term treated patients. In conclusion, early treatment with vandetanib, when patients are younger, with a good ECOG performance status and symptomatic disease, not necessarily progressing for RECIST, seem to be the best predictors of a longer and durable response. Further studies are needed to confirm these results

Genetic Landscape of Somatic Mutations in a Large Cohort of Sporadic Medullary Thyroid Carcinomas Studied by Next-Generation Targeted Sequencing

Sporadic Medullary Thyroid Carcinoma (sMTC) is a rare but aggressive thyroid tumor. RET and RAS genes are present in about 50%-80% of cases, but most of the remaining cases are still orphan of a genetic driver. We studied the largest series of sMTC by deep sequencing to define the mutational landscape. With this methodology we greatly reduced the number of RET- or RAS-negative cases and we confirmed the central role of RET and RAS mutations. Moreover, we highlighted the bad prognostic role of RET mutations in sMTC and consolidated the favorable prognostic role of RAS mutations. For the first time, we showed that the variant allele frequency represents an additional prognostic marker inside the group of RET-mutated sMTC.

Fifty Years After the First Description, MEN 2B Syndrome Diagnosis Is Still Late: Descriptions of Two Recent Cases

BACKGROUND

Multiple endocrine neoplasia type 2B (MEN 2B) is a very rare syndrome characterized by a very peculiar phenotype with mucosal neuromas, marfanoid habitus, and bumpy lips associated with medullary thyroid cancer (MTC) and pheochromocytoma (PHEO). Although the syndrome was first described 50 years ago, it is still diagnosed too late, when the MTC is metastatic and frequently when the PHEO has already developed.

CASE PRESENTATIONS

We report on two cases of MEN 2B that were diagnosed too late, preventing a cure. The cases involve two females who were 25 and 12 years old. Both were previously treated for congenital skeletal abnormalities; however, despite their bumpy lips and mucosal neuromas, MEN 2B syndrome was not recognized. When they arrived at our center for both the presence of thyroid nodules and elevated serum calcitonin values, the MTC was already metastatic, and the older patient had already developed a bilateral PHEO. After 3 years and 1 year of follow-up, the two patients are still alive but with persistent structural and biochemical disease.

DISCUSSION

These two cases show that knowledge of this syndrome is still insufficient and that the lack of knowledge impairs the ability to obtain an early diagnosis and cure. Because most patients with MEN 2B have no familial history, the only way to ensure a timely diagnosis is to recognize the MEN 2B phenotype on a clinical basis.

Clinical, pathological and genetic features of anaplastic and poorly differentiated thyroid cancer: A single institute experience

Anaplastic (ATC) and poorly differentiated thyroid cancer (PDTC) are very aggressive cancers whose histological diagnosis is not always straightforward. Clinical, pathological and genetic features may be useful to improve the identification of these rare histotypes. In the present study the clinical, pathological and genetic features of two groups of ATC (n=21) and PDTC (n=21) patients were analyzed. Clinical data were retrieved from a computerized database. The oncogenic profiles were studied using the Sanger sequencing method of a selected series of oncogenes and/or tumor suppressor genes known to be altered in these tumors. The presence of macrophages in both series of tissues was evaluated by immunohistochemistry. Patients with ATC were older and affected by a more advanced disease at diagnosis than those with PDTC. The median survival was significantly shorter in ATC compared with PDTC patients (P=0.0014). ATC showed a higher prevalence of TP53 and TERT mutations (10/21, 47.6% and 9/21, 42.8%, respectively) while TERT and BRAF mutations were the most prevalent in the PDTC group (7/21, 33.3% and 4/23, 19% respectively). Genetic heterogeneity (i.e., >2 mutations) was more frequent in ATC (10/21, 28.6%) compared with in PDTC (3/21, 4.7%) (P=0.03). Macrophages were more frequently present in ATC, particularly in those cases with TP53 mutations. In conclusion, these data indicate that ATC and PDTC may be characterized by different clinical, pathological and genetic profiles. In particular ATC, but not PDTC, were positive for TP53 and PTEN alterations. Complex mutations were also found in ATC but not in PDTC. Moreover, genetic heterogeneity was more frequent in ATC than PDTC. Finally, TP53 mutation and the accumulation of several mutations correlated with a shorter survival time.

Calcitonin receptor expression in medullary thyroid carcinoma

Background

Calcitonin expression is a well-established marker for medullary thyroid carcinoma (MTC); yet the role of calcitonin receptor (CTR), its seven-transmembrane G-protein coupled receptor, remains to be established in C-cells derived thyroid tumors. The aim of this work was to investigate CTR expression in MTC and to correlate such expression with clinicopathological features in order to evaluate its possible role as a prognostic indicator of disease aggressiveness and outcome.

Methods

Calcitonin receptor expression was analyzed in a series of 75 MTCs by immunohistochemistry, and by qPCR mRNA quantification in specimens from four patients. Statistical tests were used to evaluate the correlation between CTR expression and the clinicopathological and molecular characteristics of patients and tumors.

Results

Calcitonin receptor expression was detected in 62 out of 75 samples (82.7%), whereas 13 of the 75 samples (17.3%) were completely negative. CTR expression was significantly associated with expression of cytoplasmatic phosphatase and tensin homologue deleted on chromosome 10 and osteopontin, as well as with wild type RET/RAS genes and absence of tumor stroma, suggesting that CTR expression do not associate with clinicopathological signs of worse prognosis.

Discussion

Calcitonin receptor expression appears to be associated in MTC with more differentiated status of the neoplastic cells.

Protein kinase inhibitors for the treatment of advanced and progressive radiorefractory thyroid tumors: From the clinical trials to the real life

The last ten years have been characterized by the introduction in the clinical practice of new drugs named tyrosine kinase inhibitors for the treatment of several human tumors. After the positive conclusion of two international multicentric, randomized phase III clinical trials, two of these drugs, sorafenib and lenvatinib, have been recently approved and they are now available for the treatment of advanced and progressive radioiodine refractory thyroid tumors. We have been involved in most clinical trials performed with different tyrosine kinase inhibitors in different histotypes of thyroid cancer thus acquiring a lot of experience in the management of both drugs and their adverse events. Aim of this review is to give an overview of both the rationale for the use of these inhibitors in thyroid cancer and the major results of the clinical trials. Some suggestions for the management of treated patients in the real life are also provided.

Targeted Therapy in Thyroid Cancer: State of the Art

Thyroid cancer typically has a good outcome following standard treatments, which include surgery, radioactive iodine ablation for differentiated tumours and treatment with thyrotropine hormone-suppressive levothyroxine. Thyroid cancers that persist or recur following these therapies have a poorer prognosis. Cytotoxic chemotherapy or external beam radiotherapy has a low efficacy in these patients. 'Target therapy' with tyrosine kinase inhibitors (TKIs) represent an important therapeutic option for the treatment of advanced cases of radioiodine refractory (RAI-R) differentiated thyroid cancer (DTC), medullary thyroid cancer (MTC) and possibly for cases of poorly differentiated (PDTC) and anaplastic thyroid cancer (ATC). In the last few years, several TKIs have been tested for the treatment of advanced, progressive and RAI-R thyroid cancers and some of them have been recently approved for use in clinical practice: sorafenib and lenvatinib for DTC and PDTC; vandetanib and cabozantinib for MTC. The objective of this overview is to present the current status of the treatment of advanced DTC, MTC, PDTC and ATC with the use of TKIs by describing the benefits and the limits of their use. A comprehensive analysis and description of the molecular basis of these drugs and the new therapeutic perspectives are also reported. Some practical suggestions are also given for the management to the potential side-effects of these drugs.

Treatment of advanced thyroid cancer with targeted therapies: ten years of experience

Thyroid cancer is rare, but it is the most frequent endocrine malignancy. Its prognosis is generally favorable, especially in cases of well-differentiated thyroid cancers (DTCs), such as papillary and follicular cancers, which have survival rates of approximately 95% at 40 years. However, 15-20% of cases became radioiodine refractory (RAI-R), and until now, no other treatments have been effective. The same problems are found in cases of poorly differentiated (PDTC) and anaplastic (ATC) thyroid cancers and in at least 30% of medullary thyroid cancer (MTC) cases, which are very aggressive and not sensitive to radioiodine. Tyrosine kinase inhibitors (TKIs) represent a new approach to the treatment of advanced cases of RAI-R DTC, MTC, PDTC, and, possibly, ATC. In the past 10 years, several TKIs have been tested for the treatment of advanced, progressive, and RAI-R thyroid tumors, and some of them have been recently approved for use in clinical practice: sorafenib and lenvatinib for DTC and PDTC and vandetanib and cabozantinib for MTC. The objective of this review is to present the current status of the treatment of advanced thyroid cancer with the use of innovative targeted therapies by describing both the benefits and the limits of their use based on the experiences reported so far. A comprehensive analysis and description of the molecular basis of these therapies, as well as new therapeutic perspectives, are reported. Some practical suggestions are given for both the choice of patients to be treated and their management, with particular regard to the potential side effects.

Cabozantinib (XL184) for the treatment of locally advanced or metastatic progressive medullary thyroid cancer

Cabozantinib (XL184) is an oral multiple receptor tyrosine kinase inhibitor manufactured by Exelixis Inc., CA, USA. It mainly inhibits three tyrosine kinase receptors: MET, VEGFR2 and RET. In both preclinical and clinical studies it has been shown to inhibit tumor angiogenesis, invasiveness and metastases. The most frequent side effects are fatigue, diarrhea, decreased appetite, nausea, weight loss and palmar-plantar erythrodysesthesia. A Phase III clinical trial (EXAM study) of XL184 versus placebo in advanced and progressive medullary thyroid cancer showed a 28 versus 0% overall response rate and a progression-free survival of 11.2 versus 4.0 months (hazard ratio: 0.28; 95% CI: 0.19-0.40; p < 0.0001) in patients treated with cabozantinib and placebo, respectively. The drug has been approved by the US FDA for the treatment of advanced/progressive metastatic medullary thyroid cancer in the USA. The EMA is now evaluating its approval in Europe.

The timing of total thyroidectomy in RET gene mutation carriers could be personalized and safely planned on the basis of serum calcitonin: 18 years experience at one single center

BACKGROUND

Medullary thyroid carcinoma (MTC) is a calcitonin (CT)-producing C-cell tumor. In hereditary cases, a germline RET mutation is found in 98% of families. Because MTC is cured only if intrathyroidal, prophylactic thyroidectomy is recommended in the gene carrier (GC).

AIMS

The aim was to determine whether thyroidectomy performed when stimulated CT becomes detectable is as safe as prophylactic thyroidectomy and to identify the serum CT cutoff able to distinguish intrathyroidal from extrathyroidal MTC.

PATIENTS

Eighty-four GC were prospectively enrolled; 53 of the 84 underwent total thyroidectomy, one refused surgery, and 30 with normal basal and stimulated CT were under surveillance. The follow-up ranged from 2 to 18 yr.

RESULTS

GC operated on for elevated stimulated CT included 27 GC with a positive peak CT at the screening and four cases who became positive after 4 yr. All of them had intrathyroidal MTC and no node metastases; all were cured after a mean follow-up of 7.5 yr. Among those operated on for detectable basal CT, intrathyroidal tumors were found when CT was below 60 pg/ml, whereas either node metastases or larger tumors were observed when CT was above 60 pg/ml. No correlation among serum CT, age, and type of RET mutation was observed. Thirty GC were still biochemically negative at the annual control.

CONCLUSIONS

The time of thyroidectomy in GC with negative CT could be personalized and safely planned when stimulated CT becomes positive, independent of the type of RET mutation and patient's age. In this series, a basal CT below 60 pg/ml was always associated to an intrathyroidal localization of MTC.

In silico and in vitro analysis of rare germline allelic variants of RET oncogene associated with medullary thyroid cancer

Germline and somatic RET oncogene mutations are found in 98% hereditary and 40% sporadic medullary thyroid carcinomas. Our aim was to analyse by in silico and in vitro assays the transforming activity of six rare RET mutations (T338I, V648I, M918V, A883T, S904F and M848T). Six known RET mutations were used as controls. The in silico analysis showed the highest score value (i.e. 65) for S904F, M848T, M918T and C634R, whereas L790F, G691S, T338I and V648I had 0 score. Intermediate score values were obtained by A883T (score=55), M918V, V804M and Y791F (score=15). The in vitro focus formation assay showed that cells transfected with S904F, M918T, M848T or C634R generated the largest number of focus formation units (FFU). Intermediate numbers of FFU were observed in cells transfected with M918V, V804M, Y791F or A883T, while cells transfected with L790F, G691S, T338I or V648I showed a number of FFU similar to control cells. A positive correlation between the in silico score and in vitro FFU was found (P=0.0005). Only cells transfected with M918T or C634R grew faster and generated higher number of colonies in soft agar than control cells. However, the cells that were transfected with V804M produced an intermediate number of colonies. In conclusion, two of the six rare RET mutations, S904F and M848T possessed a relatively high transforming activity but a low aggressiveness; the other four mutations T338I, V648I, M918V and A883T were low or non-transforming, and their ability to induce tumoural transformation might be related to particular genetic conditions.