Overview and management of dermatologic events associated with targeted therapies for medullary thyroid cancer

A Proposed Modified Staging System for Medullary Thyroid Cancer: A SEER Analysis With Multicenter Validation

BACKGROUND

The 8th edition of the American Joint Committee on Cancer (AJCC) staging system for medullary thyroid cancer (MTC) was implemented in 2018. However, its ability to predict prognosis remains controversial.

PATIENTS AND METHODS

Patient data were obtained from the Surveillance, Epidemiology, and End Results (SEER) database and multicenter datasets. Overall survival was the primary end-point of the present study. The concordance index (C-index) was used to assess the efficacy of various models to predict prognostic outcomes.

RESULTS

A total of 1450 MTC patients were selected from the SEER databases and 349 in the multicenter dataset. According to the AJCC staging system, there were no significant survival differences between T4a and T4b categories (P = .299). The T4 category was thus redefined as T4a' category (≤3.5 cm) and T4b' category (>3.5 cm) based on the tumor size, which was more powerful for distinguishing the prognosis (P = .003). Further analysis showed that the T category was significantly associated with both lymph node (LN) location and count (P < .001). Therefore, the N category was modified by combining the LN location and count. Finally, the above-mentioned novel T and N categories were adopted to modify the 8th AJCC classification using the recursive partitioning analysis principle, and the modified staging system outperformed the current edition (C-index, 0.811 vs. 0.792).

CONCLUSIONS

The 8th AJCC staging system was improved based on the intrinsic relationship among the T category, LN location, and LN count, which would have a positive impact on the clinical decision-making process and appropriate surveillance.

Six-Membered Aromatic Nitrogen Heterocyclic Anti-Tumor Agents: Synthesis and Applications

Cancer stands as a serious malady, posing substantial risks to human well-being and survival. This underscores the paramount necessity to explore and investigate novel antitumor medications. Nitrogen-containing compounds, especially those derived from natural sources, form a highly significant category of antitumor agents. Among these, antitumor agents with six-membered aromatic nitrogen heterocycles have consistently attracted the attention of chemists and pharmacologists. Accordingly, we present a comprehensive summary of synthetic strategies and clinical implications of these compounds in this review. This entails an in-depth analysis of synthesis pathways for pyridine, quinoline, pyrimidine, and quinazoline. Additionally, we explore the historical progression, targets, mechanisms of action, and clinical effectiveness of small molecule inhibitors possessing these structural features.

A meta-analysis of the efficacy and toxicity of tyrosine kinase inhibitors in treating patients with different types of thyroid cancer: how to choose drugs appropriately?

PURPOSE OF REVIEW

Because the high risk of death and poor prognosis of patients with refractory thyroid cancer (TC), studies related to tyrosine kinase inhibitors (TKIs) in treating different types of refractory TC have gradually attracted attention. Thus, we conducted a meta-analysis of published randomized controlled trials and single-arm trials to evaluate tyrosine kinase inhibitors' efficacy and safety profile treatment in TC patients.

RECENT FINDINGS

The studies of 29 in 287 met the criteria, 9 were randomized controlled trials and 20 were single-arm trials, involving 11 TKIs (Apatinib, Anlotinib, Cabozantinib, Imatinib, Lenvatinib, Motesanib, Pazopanib, Sorafenib, Sunitinib, Vandetanib, Vemurafenib). Treatment with TKIs significantly improved progression-free survival [hazard ratio [HR] 0.34 (95% confidence interval [CI]: 0.24, 0.48), P < 0.00001] and overall survival [OS] [HR 0.76, (95% CI: 0.64, 0.91), P = 0.003] in randomized controlled trials, but adverse events (AEs) were higher than those in the control group (P < 0.00001). The result of the objective response rate (ORR) in single-arm trials was statistically significant [odds ratio [OR] 0.49 (95% CI: 0.32, 0.75), P = 0.001].

SUMMARY

TKIs significantly prolonged progression-free survival and OS or improved ORR in patients with different types of TC (P < 0.01). Our recommendation is to select appropriate TKIs to treat different types of TC patients, and to prevent and manage drug-related AEs after using TKIs.

Management of adverse events associated with cabozantinib plus nivolumab in renal cell carcinoma: A review

Tyrosine kinase inhibitors have been successfully developed in combination with immune checkpoint inhibitors to treat advanced renal cell carcinoma (RCC), further advancing treatment. While safety profiles are generally manageable with combination regimens, overlapping adverse events (AEs) and immune-related AEs can make treatment more complex. The CheckMate 9ER study evaluated the tyrosine kinase inhibitor cabozantinib in combination with the anti-programmed cell death protein-1 antibody nivolumab in patients with previously untreated advanced RCC. Cabozantinib + nivolumab demonstrated superiority over sunitinib for progression-free survival, overall survival, and objective response rate. These outcomes supported the approval of cabozantinib + nivolumab as a first-line therapy for advanced RCC. The safety profile was manageable with prophylaxis, supportive care, dose holds and reductions for cabozantinib, and dose holds and immunosuppressive therapy for nivolumab. This review discusses the safety results of CheckMate 9ER and provides guidance on managing some of the more clinically relevant AEs with a focus on overlapping AEs, including diarrhea, elevated amylase/lipase, hepatotoxicity, dermatologic reactions, fatigue, endocrine disorders, and nephrotoxicity. We discuss AE management strategies (prophylaxis, supportive care, dose modification, and immunosuppressive therapy), and provide recommendations for identifying the causative agent of overlapping AEs and for consulting specialists about organ-specific immune-related AEs. Optimizing AE management can maintain tolerability and should be a priority with cabozantinib + nivolumab treatment.

Management of Apatinib-Related Adverse Events in Patients With Advanced Osteosarcoma From Four Prospective Trials: Chinese Sarcoma Study Group Experience

Four prospective trials have reported apatinib-related efficacy in osteosarcoma, with a high response rate of 43.2%. Currently, Adverse Events (AEs) have increasingly gained attention, as treatment with multiple tyrosine kinase inhibitors (TKIs) is potentially lifelong. For this reason, a consensus meeting of the Chinese Sarcoma Study Group (CSSG), which is a multidisciplinary panel composed of pediatric, medical and surgical oncologists specializing in sarcoma, nurse specialists, oncological senior pharmacists and gastroenterologists, was held to develop comprehensive guidelines on AEs emerging due to apatinib treatment to better assist in the prevention, management, and understanding of AE development. We summarized all AEs that arose in ≥10% of the participants as well as rare AEs that required extra caution to prevent that were observed in these four published prospective trials and arranged these AEs into 14 disorder systems according to CTCAE 5.0. In this review, we discuss strategies for the management of AEs in patients with advanced osteosarcoma, with the aim of maximizing treatment benefits and minimizing the need for apatinib treatment discontinuation. We also focus on providing recommendations for the prophylaxis and treatment of advanced osteosarcoma using apatinib to achieve optimal outcomes.

LINC01816 promotes the migration, invasion and epithelial‑mesenchymal transition of thyroid carcinoma cells by sponging miR‑34c‑5p and regulating CRABP2 expression levels

Thyroid carcinoma (THCA) is a common type of endocrine system cancer and its current clinical treatment method is surgical resection. Long non-coding RNAs (lncRNAs) have been revealed to serve important roles in a variety of complex human diseases. Therefore, determining the association between lncRNAs and diseases may provide novel insight into disease-related lncRNAs, with the aim of improving disease treatments and diagnoses. Long intergenic non-protein coding RNA 1816 (LINC01816) was identified to be associated with the survival of patients with colorectal cancer using the IDHI-MIRW method. The present study aimed to investigate the role and molecular mechanism of LINC01816 in THCA. Analysis of datasets from The Cancer Genome Atlas database revealed that the upregulation of LINC01816 expression levels was associated with a variety of cancer types. Reverse transcription-quantitative PCR analysis demonstrated that compared with the normal thyroid tissues, the expression levels of LINC01816 were upregulated in THCA tissues. The results of wound healing and Transwell assays, and western blotting demonstrated that the overexpression of LINC01816 could strengthen the invasive and migratory abilities of THCA cells and enhance epithelial-mesenchymal transition progression. Analysis using the starBase website and dual-luciferase reporter assays identified that microRNA (miR)-34c-5p was a target of LINC01816. The overexpression of miR-34c-5p could inhibit the invasive and migratory abilities of THCA cells, in addition to inhibiting the cellular retinoic acid binding protein 2 (CRABP2) overexpression-induced effects on invasion, migration and EMT processes. In conclusion, the findings of the present study indicated that LINC01816 may be capable of sponging miR-34c-5p to upregulate CRABP2 expression levels, which subsequently promoted the invasion, migration and EMT of THCA cells. Therefore, targeting the LINC01816/miR-34c-5p/CRABP2 pathway may be an effective therapeutic approach for patients with THCA.

Management of skin adverse reactions in oncology

Chemo and targeted anticancer therapies present significant skin adverse reactions, which impair the patients' quality of life. Cutaneous toxicities lead to poor treatment adherence, drug cessation, and psychosocial distress. This review aims to summarize the current knowledge concerning the prevention and management of skin toxicity arising from these therapies. A systematic literature search on online databases was conducted. The categorization of the main preventive and treatment measures was performed according to the level of evidence. Management of skin adverse reactions of oncology treatments is very heterogeneous, which can be explained by the lack of sound evidence-based treatments. The most studied adverse effects are papulopustular eruption, xerosis, and hand-foot syndrome. Prevention of xerosis stands out as the strategy most supported by level II studies. With respect to treatment, the use of antibiotics in papulopustular eruption resulting from anti-epidermal growth factor receptor agents is the most evidence-based approach. In general, the number of studies published in the literature classified with a level II of evidence (52%) is similar to the ones classified as level IV (33%), making clear the need of more randomized controlled trials regarding the effectiveness of preventive and treatment measures of skin adverse reactions of chemo and targeted anticancer therapies.

Management of adverse events associated with tyrosine kinase inhibitors: Improving outcomes for patients with hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the most common form of primary liver cancer. Sorafenib, regorafenib, lenvatinib and cabozantinib are tyrosine kinase inhibitors (TKIs) that target, in part, vascular endothelial growth factor receptors, and are approved in various regions of the world for the treatment of advanced HCC. All these agents are associated with a range of adverse events (AEs) that can have a substantial impact on patients' health-related quality of life. Fatigue, diarrhoea, hand-foot skin reaction, nausea, vomiting, decreased appetite, hypertension and weight loss are among the most common AEs experienced with these four TKIs. In this review, we discuss strategies for the management of these AEs in patients with advanced HCC, with the aim of maximizing treatment benefits and minimizing the need for TKI treatment discontinuation. We also consider potential TKI-drug interactions and discuss the use of TKIs in patients with liver dysfunction or who have experienced tumour recurrence after liver transplantation. Use of appropriate AE management strategies and avoidance of contraindicated drugs should help patients with advanced HCC to achieve optimal outcomes with TKIs.

Safety of Tyrosine Kinase Inhibitors in Patients With Differentiated Thyroid Cancer: Real-World Use of Lenvatinib and Sorafenib in Korea

Background: Thyroid cancer has become the most common cancer in Korea. Generally, thyroid cancer patients have a good prognosis; however, 15-20% of patients experience recurrence or distant metastasis or are refractory to standard treatment. We assessed the safety of sorafenib and lenvatinib in patients with advanced or metastatic radioactive iodine-refractory differentiated thyroid cancers (DTC) consecutively treated at a tertiary center in South Korea. Methods: We retrospectively reviewed the charts of all consecutive patients with DTC treated during ≥6 months with lenvatinib (February 2016-April 2018) and sorafenib (January 2014-April 2018) at Gangnam Severance Hospital. Patients were treated according to the prescribing information of each drug and were followed up for 2 months. We evaluated the adverse events (AEs) reported with each drug. Results: A total of 71 medical records (lenvatinib, n = 23; sorafenib, n = 48) were reviewed. The most common histological types were papillary thyroid cancer (69.0%) and follicular thyroid cancer (22.5%). All patients (n = 23) started lenvatinib at a dose of 20 mg; 41.7% of sorafenib-treated patients received an initial dose of 800 mg daily. Four (17.4%) lenvatinib-treated patients and 26 (54.2%) sorafenib-treated patients required treatment discontinuation. The most common AEs of any grade in the lenvatinib group were diarrhea (82.6%), hypertension (78.3%), hand-foot skin reaction (56.5%), weight loss (52.2%), proteinuria (47.8%), and anorexia (43.5%). In the sorafenib group, these were hand-foot skin reaction (87.5%), diarrhea (62.5%), anorexia (60.4%), alopecia (56.3%), mucositis (52.1%), weight loss and generalized weakness (each, 50%), and hypertension (43.8%). The incidence of hand-foot skin reaction, alopecia, and rash of any grade was significantly lower (P = 0.003, P = 0.017, and P = 0.017) in patients treated with lenvatinib compared with those treated with sorafenib. The incidence of hypertension, QT prolongation, and proteinuria of any grade was significantly higher (P = 0.006, P = 0.038, and P < 0.001) in patients treated with lenvatinib compared with those treated with sorafenib. Seven deaths occurred, which were attributed to disease progression. Conclusions: No new safety concerns were identified for either drug. Most AEs were managed with dose modification and medical therapy. AEs such as hypertension and proteinuria warrant close monitoring.

Skin adverse events in recently approved targeted therapies in solid malignancies

Targeted anticancer therapies are an important weapon in the fight against cancer. Targeted therapies interfere with specific molecules necessary for tumor growth and cancer progression. They are divided mainly to either monoclonal antibodies or small molecules inhibitors. Their primary objective is to target directly and precisely the cancer cells leading to a minimal side-effects profile. The dermatologic adverse reactions of these targeted therapies is different from those seen with classical cytotoxic chemotherapy. Rashes, xerosis, hand-foot-skin reaction and mucositis are the most frequent side effects. In this paper, we aim to present a comprehensive review of the dermatologic side effects of targeted therapies including, specific side effects related to recently, approved targeted therapies.

Managing the adverse events associated with lenvatinib therapy in radioiodine-refractory differentiated thyroid cancer

Lenvatinib is a multikinase inhibitor of vascular endothelial growth factor (VEGF) receptors 1-3, fibroblast growth factor receptors 1-4, RET, KIT, and platelet-derived growth factor receptor-α. Lenvatinib is approved as a monotherapy for the treatment of radioiodine-refractory differentiated thyroid cancer and in combination with everolimus for the second-line treatment of advanced renal cell carcinoma. Lenvatinib is also under investigation for the treatment of several malignancies including unresectable hepatocellular carcinoma. Although lenvatinib is associated with favorable efficacy, it is associated with adverse events (AEs) that the clinician will have to closely monitor for and proactively manage. Most of these AEs are known class effects of VEGF-targeted therapies, including hypertension, diarrhea, fatigue or asthenia, decreased appetite, and weight loss. This review summarizes the safety profile of lenvatinib and offers guidance for the management of both frequent and rare AEs. We discuss the potential mechanisms underlying these AEs and present practical recommendations for managing toxicities. The development of treatment plans that include prophylactic and therapeutic strategies for the management of lenvatinib-associated AEs has the potential to improve patient quality of life, optimize adherence, minimize the need for dose reductions, treatment interruptions, or discontinuations, and maximize patient outcomes.

BRAF mutation in papillary thyroid carcinoma (PTC) and its association with clinicopathological features and systemic inflammation response index (SIRI)

The aim of the present research was to investigate the association between the BRAF mutation and papillary thyroid carcinoma (PTC), and further explore the relationship between the systemic inflammation response index (SIRI) and BRAF mutation in patients with PTC. The clinicopathological data were extracted from the patients' medical records from June 2012 to June 2014 in our hospital. We enrolled 95 patients with PTC that have received the total or near-total thyroidectomy and pretracheal and paratracheal lymph node dissection. The blood samples were obtained before surgery. According to the BRAF mutation analysis, the patients were divided into two groups: BRAF mutation positive group and BRAF mutation negative group. The receiver operating characteristic curve (ROC) for the presence of BRAF mutation was used to evaluate the optimal cutoff value of SIRI. The ratio closest to the point with maximum sensitivity and specificity was defined as the optimal cutoff value. Univariate and multivariate logistic regression model were used to confirm the independent factors and compare observed and predicted outcomes. The BRAF mutation rates were 62.1% (59/95). The results indicated that BRAF mutation was significantly correlated with pathological TNM stage, monocyte, SIRI and Galectin-3. The pathological TNM stage, monocyte, SIRI and Galectin-3 were the significant risk factors associated with the presence of BRAF mutation. Moreover, we found that patients with low SIRI had higher BRAF mutation percentage than those with high SIRI, and patients with low monocyte had higher percentage than those with high monocyte. BRAF mutation is associated with the pathological TNM stage, monocyte, SIRI and Galectin-3, and SIRI was the significant risk factor with the BRAF mutation and patients with low SIRI have higher BRAF mutation.

Optimal use of lenvatinib in the treatment of advanced thyroid cancer

The development of orally active, multitargeted kinase inhibitors (MKIs) represents a significant advance in the treatment of progressive, metastatic thyroid cancer. Lenvatinib, an MKI targeting vascular endothelial growth factor receptor, fibroblast growth factor receptor, platelet-derived growth factor receptor, c-Kit, and RET, has shown efficacy in stabilizing previously progressive disease, with emerging evidence of a possible benefit in terms of overall survival. However, lenvatinib is associated with a side-effect profile similar to those of other MKIs that might affect the outcome of therapy. The aim of this review is to summarize the clinical efficacy and safety of MKIs in the treatment of advanced thyroid cancer in pivotal phase III trials. Common adverse events that may occur during lenvatinib therapy and their management are discussed, including conditions in which its administration should be temporarily withdrawn and resumed pending resolution of adverse events. We focus on data from a subanalysis of Japanese patients in the SELECT trial and in a post-marketing study in Japan. We suggest that lenvatinib is a valuable treatment option for advanced differentiated thyroid cancer. Monitoring and careful management of adverse events including supportive care are required to ensure continuation of therapy.

Treatment and surveillance of advanced, metastatic iodine-resistant differentiated thyroid cancer

PURPOSE OF REVIEW

This review will focus on the management and treatment of metastatic thyroid cancer that is radioactive iodine refractory and review the new drugs and their mechanism of actions as well as their adverse events.

RECENT FINDINGS

Until recently, there were no efficacious therapeutic modalities for these patients. With advancement in knowledge and research of the molecular aberrations and oncogenic mutations in thyroid cancer as well as further understanding the role of angiogenesis in tumor growth molecular pathogenesis, novel targeted therapies are available for these patients. Some of these drugs have successfully prolonged progression free survival and are now Food and Drug Administration approved. Additional agents are approved for the treatment of other types of cancers and are currently under investigation for differentiated thyroid cancer treatment.

SUMMARY

Differentiated thyroid cancer (papillary and follicular) is the most common endocrine malignancy. It is generally known to have an excellent prognosis and patients are usually cured with the conventional primary treatments including surgery, radioactive iodine, and thyroid stimulating hormone suppression. A minor proportion of patients do not fully recover mainly because they develop radioactive iodine-resistant disease. These patients have few treatment options, which we aimed to describe here.

Management of tyrosine kinase inhibitors (TKI) side effects in differentiated and medullary thyroid cancer patients

Four tyrosine kinase inhibitors (TKIs) have been recently licensed in thyroid cancer (TC), sorafenib and lenvatinib for differentiated TC, vandetanib and cabozantinib for medullary TC. Others TKIs such as axitinib, pazopanib, sunitinib, have been tested within phase II trials. The toxicity burden associated to TKIs is not negligible. Drug reductions and interruptions are common, definitive drug withdrawals have also been reported as well as toxic deaths in more rare cases. In this context, the prevention of toxicities is mandatory to allow patients to stay on treatment as long as possible without dose and schedule modifications. Both physicians and patients should be educated to recognize drug-related toxicities in order to manage them in an early phase. Tools (e.g. toxicities summary booklet) for physicians and patients could be considered to improve the knowledge on side effects management. Guidelines, whenever available, should be followed.

Management of adverse events during treatment of gastrointestinal cancers with epidermal growth factor inhibitors

The epidermal growth factor receptor (EGFR) is involved in development and progression of some gastrointestinal cancers, and is targeted by monoclonal antibodies (mAbs) and tyrosine kinase inhibitors (TKIs) used to treat these conditions. Targeted agents are generally better tolerated than conventional chemotherapy, but have characteristic toxicities that can affect adherence, dosing, and outcomes. Skin conditions are the most common toxicities associated with EGFR inhibitors, particularly papulopustular rash. Other common toxicities include mucosal toxicity, electrolyte imbalances (notably hypomagnesaemia), and diarrhoea, while the chimaeric mAb cetuximab is also associated with increased risk of infusion reactions. With appropriate prophylaxis, the incidence and severity of these events can be reduced, while management strategies tailored to the patient and the degree of toxicity can help to ensure continuation of anti-cancer therapy. Here, we review the main toxicities associated with EGFR-inhibiting mAbs and TKIs in patients with gastrointestinal cancers, and provide recommendations for prophylaxis and treatment.

Managing tyrosine kinase inhibitors side effects in thyroid cancer

BACKGROUND

Tyrosine kinase inhibitors (TKIs) are a new group of drugs that show the activity against receptors of different growth factors leading to the inhibition of tumor cells growth and proliferation. To date, four different TKIs have been approved for RAI-refractory DTC or MTC: sorafenib, lenvatinib, vandetanib and cabozantinib.

METHODS

This review focuses on treatment toxicity related to above-mentioned TKIs administration in thyroid carcinoma.

RESULTS

TKIs cause a variety of side effects in nearly all treated patients, among them: hypertension, gastrointestinal disturbances (diarrhea, abdominal pain, nausea, vomiting), skin reactions (rashes, acne, hand-foot syndrome), fatigue and weight loss. Most of side effects are mild and moderate and manageable by dose adjustment (dose interruptions and dose reductions) and concomitant therapy. However, some complications although rare may be life-threatening or even fatal. Conclusion​: TKIs shows an acceptable toxicity profile in patients with advanced and progressive RAI refractory DTC and MTC but only in experienced hands familiar with TKIs, particularly with diagnostics and management of treatment-related complications and also with thyroid carcinoma, what is essential to safely care for the patients and keep them on kinase inhibitor therapy as long as the treatment is beneficial without an unfavorable impact on their quality of life.

Incorporating 131I into a PAMAM (G5.0) dendrimer-conjugate: design of a theranostic nanosensor for medullary thyroid carcinoma

We report the synthesis and purification of a targeting probe for Medullary Thyroid Carcinoma (MTC) by incorporating ¹³¹I into PAMAM (G5.0) dendrimers.

Development of Photoonycholysis with Vandetanib Therapy

Vandetanib therapy is a novel once-daily oral multitargeted tyrosine kinase inhibitor, which is currently used in advanced or metastatic medullary thyroid cancer. Skin toxicities are among the most prevalent adverse events reported with this targeted therapy (e.g. acne-like rash, hand-foot skin reaction, hair changes, and paronychia). In addition, photosensitivity reactions may affect more than one third of treated patients. We report here 2 patients developing photosensitivity reactions with vandetanib therapy, including photoonycholysis. Our patients presented a wide range of phototoxic reactions with exaggerated sunburn reactions solely located to photoexposed areas or hyperpigmentation with visible blue dots. More importantly, both patients concomitantly developed nail changes consistent with type 1 photoonycholysis, which had never been reported so far neither with vandetanib therapy nor with other anticancer-targeted therapies. In addition, histopathologic findings and reflectance confocal microscopy imaging performed in one patient suffering from photodistributed skin hyperpigmentation both strengthen the likelihood of a postinflammatory mechanism. Clinicians should be aware of these underestimated but very characteristic photoinduced adverse events, which can lead to treatment interruption and require very strict photoprotective measures in treated patients.

New systemic therapies for locally advanced and metastatic thyroid cancer

Thyroid cancer affects one in 100 people over their lifetime. Differentiated and medullary thyroid cancer, refractory to traditional therapy, respond poorly to chemotherapeutic agents. However, tyrosine kinase inhibitors provide new hope for stabilizing disease in patients with advanced progressive disease. There are multiple tyrosine kinase inhibitors under study for thyroid cancer and currently four drugs that are US FDA approved. Nonetheless, use of these drugs should be selective given a significant adverse event profile and diseases with a typically indolent course. This review will cover molecular mechanisms in thyroid cancer as they are relevant to targeted therapies and review available evidence for the safety and efficacy of therapies currently approved and under study for thyroid cancer.

Cabozantinib for the treatment of progressive metastatic medullary thyroid cancer

Cabozantinib (XL-184) is a potent inhibitor of MET, VEGFR 2/KDR, RET and other receptor tyrosine kinases, such as KIT, AXL and FLT3. Its efficacy against MTC has been demonstrated in a prospective, randomized, placebo-controlled study (EXAM). Cabozantinib comparing to placebo significantly prolonged progression free survival both in hereditary and sporadic MTC, 11.2 vs 4.0 months, respectively. Final analysis showed no global differences in overall survival (OS) between cabozantinib and placebo. However, in a subgroup with RET M918T mutation the difference in OS was significant: 44.3 vs 18.9 months, respectively. Among the most frequent cabozantinib-related adverse events (AEs), observed in >30% of patients were diarrhea, palmar-plantar erythrodysesthesia, decreased weight, decreased appetite, nausea, fatigue, dysgeusia, hair color changes and hypertension. Expert Commentary: Cabozantinib constitutes an effective treatment option with acceptable toxicity in MTC patients showing either germinal or sporadic tumor RET M918T mutation as the drug prolonged OS in these subjects.

Selective use of vandetanib in the treatment of thyroid cancer

Vandetanib is a once-daily orally available tyrosine kinase inhibitor that works by blocking RET (REarranged during Transfection), vascular endothelial growth factor receptor (VEGFR-2, VEGFR-3), and epidermal growth factor receptor and to a lesser extent VEGFR-1, which are important targets in thyroid cancer (TC). It is emerging as a potentially effective option in the treatment of advanced medullary thyroid cancer (MTC) and in dedifferentiated papillary thyroid cancer not responsive to radioiodine. The most important effect of vandetanib in aggressive MTC is a prolongation of progression-free survival and a stabilization of the disease. Significant side effects have been observed with the vandetanib therapy (as fatigue, hypertension, QTc prolongation, cutaneous rash, hand-and-foot syndrome, diarrhea, etc), and severe side effects can require the suspension of the drug. Several studies are currently under way to evaluate the long-term efficacy and tolerability of vandetanib in MTC and in dedifferentiated papillary TC. The efficacy of vandetanib in patients with MTC in long-term treatments could be overcome by the resistance to the drug. However, the effectiveness of the treatment could be ameliorated by the molecular characterization of the tumor and by the possibility to test the sensitivity of primary TC cells from each subject to different tyrosine kinase inhibitor. Association studies are evaluating the effect of the association of vandetanib with other antineoplastic agents (such as irinotecan, bortezomib, etc). Further research is needed to determine the ideal therapy to obtain the best response in terms of survival and quality of life.