Recurrent Medullary Thyroid Cancer Research Articles

Surgical De-Escalation in Medullary Thyroid Cancer: A Commentary.

This commentary remarks on the results of a recent study that investigated patterns and outcomes of recurrent medullary thyroid cancer to inform decision making on the optimal management of lateral neck lymph node compartments in medullary thyroid cancer.

Radioactive iodine in the management of medullary carcinoma of the thyroid.

Although it is generally accepted that medullary thyroid cancer (MTC) cells do not take up iodine, there are reports indicating that this can occur. Additionally, the potential for radioactive iodine (RAI) to reduce the risk of recurrence within the thyroid bed following thyroid remnant ablation in MTC is uncertain. A systematic review was therefore undertaken. Studies of patients with MTC of any age or stage receiving RAI, either as adjuvant postoperative treatment or primary treatment for unresectable disease, or as treatment for recurrent or metastatic disease were eligible for inclusion. Randomised and non-randomised studies were identified by electronic searching of Medline and Embase databases. A risk of bias assessment (ROBINS-I) was carried out for each study. Outcome measures sought included overall survival, locoregional relapse-free survival, rates of locoregional recurrence, and changes in serum calcitonin. A protocol was registered with PROSPERO before the systematic review was undertaken. There were no randomised studies. Ten non-randomised studies (525 patients) and ten case reports (21 patients) met the inclusion criteria, with all studies containing a high risk of bias. There were case reports reporting responses to RAI, both as adjuvant treatment and for recurrent/metastatic disease. The proportion of metastatic or recurrent MTC which take up iodine remains unknown. A possible role of RAI ablation for patients with localised MTC and raised calcitonin post-thyroidectomy should be explored. Although there is insufficient data to recommend changes to current treatment policies, this review suggests avenues for further research.

The Role of 18F-FDOPA PET/CT in Recurrent Medullary Thyroid Cancer Patients with Elevated Serum Calcitonin Levels.

To evaluate the diagnostic performance of 18F-dihydroxyphenylalanine (FDOPA) positron emission tomography/computed tomography (PET/CT) in the detection of medullary thyroid carcinoma (MTC) recurrence in patients with elevated calcitonin levels. The patients who had undergone 18F-FDOPA PET/CT imaging for elevated calcitonin levels after primary surgery of MTC were included in the study. addition, if available 18F-fluorodeoxyglucose (FDG) PET/CT and Gallium-68 (68Ga)- DOTATATE PET/CT images of the patients were evaluated retrospectively. The sensitivity and diagnostic performance of 18F-DOPA PET/CT were investigated. A total of 14 patients (9 F and 5 M; median age: 45) were included in the analysis. Three patients had MEN IIA syndrome and 1 patient had MEN IIB syndrome, 10 patients had a diagnosis of sporadic MTC. Median calcitonin levels of the patients were calculated as 757.5 (min-max: 28.5-7911) pg/mL. Nine patients and 5 patients had undergone ultrasound and contrast-enhanced computed tomography (ceCT) of the neck, respectively, before 18F-FDOPA PET/CT imaging. 18F-FDOPA PET/CT revealed pathological uptake in the thyroid bed, lymph nodes, and distant organs in three, five and two patients, respectively. Median maximum standardized uptake value for the recurrent or metastatic lesions were calculated as 6.4 (min-max: 1.9-18.4). The sensitivity of 18F-FDOPA PET/CT in the detection of recurrent disease was calculated as 64%. Eight patients had 68Ga-DOTATATE PET/CT and 7 of them had 18F-FDG PET/CT within 3 months period before 18F-FDOPA PET/CT. 18F-FDOPA PET/CT revealed recurrent disease in 4 of 5 and 2 of the 5 patients who had negative 18F-FDG PET/CT and negative 68Ga- DOTATATE PET/CT, respectively. 18F-FDOPA PET/CT can detect recurrence in about two- thirds of patients with elevated calcitonin levels after primary surgery for MTC. Due to variable differentiation degree, different receptor status, and clinical behavior of MTC, all three radiopharmaceuticals can be beneficial and are complementary to each other in patient management.

LBODP095 Radiofrequency Ablation Performed By Endocrinologists Is A Viable Treatment Option For Recurrent Thyroid Cancer In The Outpatient Community Setting In The United States

Abstract Objective To determine if radiofrequency ablation (RFA) performed by endocrinologists for recurrent thyroid cancer in the neck is a treatment option in the outpatient community setting in the USA. Methods A review of 9 patients with 12 recurrent thyroid cancer lesions in the neck who were treated with RFA was conducted (July 2020 to November 2021). Recurrence was defined as biochemical and structural identification of disease. Recurrence was confirmed with ultrasound guided fine needle aspiration (US-FNA) cytology and measurement of thyroglobulin (Tg) washout concentration in cases of papillary thyroid cancer (PTC) and calcitonin washout concentration in medullary thyroid cancer (MTC). Informed consent was obtained. RFA was done in the outpatient setting with standard aseptic techniques, conscious sedation, and local anesthesia. Real time US imaging was used to perform hydro-dissection and a limited "moving shot" technique with a medial to lateral approach. Node volume in mL (length x depth x width×0.525) and tumor markers were recorded before at 6 to 12 weeks and at 6 months (m) after RFA. The volume reduction percentage (VRP) for each nodule was calculated using the following equation: VRP = {[baseline volume in mL - final volume in mL]/baseline volume in mL}×100 A VRP of more than 50% was considered a significant response, and VRP of 100% was considered complete response. Results A total of 9 patients with 12 nodes were included in the study. 7 patients had nodal recurrence of PTC in the neck. RFA was recommended for 1 patient as palliative treatment while on treatment with chemotherapy. 1 patient had recurrent MTC. There were no serious complications. 6 m data was unavailable for 2 patients. 9 of 10 (90%) nodes for which data is available had a volume decrease of at least 50% at 6 m. The only patient without at least a partial response to therapy was on chemotherapy. 4 of the 10 (40%) metastatic nodes of papillary thyroid cancer had a complete response. Mean volume reduction for all lesions at 6 mos was 0.339 mL, P = 0. 012. Median change in Tg level at 6 months was 0.4 IU/ml with a downward trend in 4/5 (80%) of patients with recurrent papillary thyroid cancer who were not receiving chemotherapy. Discussion Complete response may be expected in about 40% of patients after RFA at 6 m, however, this may potentially be improved with extended follow up time or multiple RFA sessions. Patients who are not surgical candidates, refuse surgery, or require palliative treatment may be potential candidates for this procedure. Therefore, RFA appears to be a viable treatment option in selected patients with recurrent thyroid carcinoma. Presentation: No date and time listed

Chimeric Anterolateral Thigh Flap for One-stage Reconstruction after Cervical Exenteration with Anterior Mediastinal Tracheostomy

Summary:Cervical exenteration with anterior mediastinal tracheostomy is rarely performed for extensive cervicothoracic malignancies. Although it provides effective palliation and occasional cure, reconstruction remains a formidable challenge owing to its complexity and high mortality. The resultant defects usually require an intestinal flap or tubed skin flap to restore the alimentary tract, soft-tissue interposition to separate the relocated trachea from the innominate artery, and another tubed or fenestrated skin flap to create a tension-free tracheocutaneous anastomosis and provide coverage for the exposed vessels, hopefully in one stage. We report a case involving a 60-year-old woman with recurrent medullary thyroid cancer who developed dyspnea and dysphagia. Salvage cervical exenteration and anterior mediastinal tracheostomy were complicated by tissue fibrosis caused by previous surgical and radiation therapies, resulting in complex defects with segmental loss of the esophagus, a short stump of trachea incapable of tracheocutaneous anastomosis, and great-vessel exposure. We used a chimeric anterolateral thigh flap consisting of a tubed skin flap for pharyngoesophageal reconstruction, a fenestrated skin flap for tracheostomy and neck coverage, and a vastus lateralis muscle bulk to separate the innominate artery from the relocated trachea. To our knowledge, this is the first report describing the reconstruction of such a complex defect with a single skin flap in a single stage.

Calcitonin levels in washout samples vs. cytology in the detection of malignant lymph node metastasis in recurrent medullary thyroid cancer

Calcitonin level in fine-needle aspirate washout fluid (Ct-FNA) was extensively studied for thyroid nodules and lymph nodes (LN). However, the data was scarce for neck recurrences/metastases of medullary thyroid cancer (MTC). Thus, the diagnostic accuracy of Ct-FNA and cytology in the detection of neck LN metastases of recurrent MTC cases were assessed. The database of MTC patients between 2010 and 2021 was retrospectively reviewed. A total of 32 patients with recurrent MTC and suspicious LN who underwent FNA and Ct measurement from washout samples were included in this study. Preoperative serum Ct (sCt), Ct-FNA, Ct-FNA/sCt ratio, cytology data were recorded for all participants. Median sCt of 32 patients and Ct-FNA washout fluid levels of operated suspicious 44 LNs were 723 (54–9000) pg/mL and 1800 (151–9500) pg/mL, respectively. The diagnostic accuracy of Ct-FNA washout fluid was greater than cytology (95.4% vs. 86%, respectively). Using a cut-off level of >638.5 pg/mL, the Ct-FNA predicted the diagnosis of LN metastasis of recurrent MTC with a sensitivity of 80% and specificity of 94.9%. Furthermore, using a cut-off level of >1.16, the Ct-FNA/sCt ratio well predicted the diagnosis of LN metastasis of recurrent MTC with a sensitivity of 92.3% and specificity of 100%. As Ct-FNA has greater diagnostic accuracy in our study, it would be complementary to cytology results to localize metastatic LNs in recurrent MTC. Furthermore, for the first time, we demonstrated that the Ct-FNA/sCt ratio was a better predictor of metastatic LNs in recurrent MTC than a particular cut-off for Ct-FNA alone.

Comparison of Simultaneous calcitonin washout and cytology procedure success in recurrent medullary thyroid cancer

Comparison of Simultaneous calcitonin washout and cytology procedure success in recurrent medullary thyroid cancer

The role of 68Ga-DOTATATE PET/CT and 18F-FDG PET/CT in the follow-up of patients with medullary thyroid cancer.

Medullary thyroid cancer (MTC) is an aggressive form of thyroid malignancy with local metastasis in 30%-50% of the cases and distant metastasis predominantly to lung, liver and skeleton in 13%-15% of patients. Identification of the lesion using imaging modalities is of crucial importance for disease management in the recurrent or metastatic MTC. In this study, we aimed to determine the efficacy of fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) and gallium-68 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid tyrosine-3-octreotate (68Ga-DOTATATE) PET/CT imaging in patients with MTC and to evaluate the relationship between imaging findings and serum tumor markers. The records of MTC patients, who were treated and followed-up in our department between the years 2005 and 2018 were retrospectively analyzed. Seventy-three patients with MTC, who underwent either 68Ga-DOTATATE PET/CT (n=61) and/or 18F-FDG PET/CT (n=59) together with serum calcitonin (Ctn) and/or carcinoembryogenic antigen (CEA) measurement within 6 months period were included in the study. Gallium-68-DOTATATE PET/CT and 18F-FDG PET/CT scans performed within 6 months on the same patient (n=38) were analyzed separately for comparison of the efficacy of both modalities. The overall sensitivity of 18F-FDG PET/CT and 68Ga-DOTATATE PET/CT were 72.4% and 88.1%, respectively in detecting recurrent or metastatic disease. In the group of patients, who had both 18F-FDG PET/CT and 68Ga-DOTATATE PET/CT within 6 months interval (median: 1.14 months; range: 0.03 - 5.7 months), no significant difference was found in the overall sensitivity of both imaging modalities, however 68Ga-DOTATATE PET/CT was found to be more sensitive in detection of bone lesions compared to 18F-FDG PET/CT (P=0.005). Both 18F-FDG PET/CT and 68Ga-DOTATATE PET/CT are efficient imaging modalities in detection of recurrent or metastatic disease in MTC patients. Gallium-68-DOTATATE PET/CT could be more beneficial in detection of bone metastases with respect to 18F-FDG PET/CT.

A novel combined transoral and transcervical surgical approach for recurrent metastatic medullary thyroid cancer to the parapharyngeal space

Medullary thyroid cancer (MTC) represents less than 1% of all thyroid cancers. Complete surgical resection remains the mainstay of treatment for locoregional disease. Unfortunately, patients with recurrence may present with metastasis to challenging anatomic locations. We describe the first case of a recurrent MTC metastatic to the parapharyngeal space (PPS) that was managed using a combined transoral robotic surgery (TORS) and transcervical (TC) approach. We review the presentation, natural history, diagnosis and management of recurrent MTC, and describe a novel combined TORS-TC surgical approach for the treatment of PPS metastasis. A 66-year-old male with history of MTC treated with total thyroidectomy in 2000 and a liver resection in 2011 for metastatic MTC was referred to our Head and Neck Surgery Clinic in October 2016 due to increased calcitonin and CEA levels. Exam was significant for mild right tonsillar/pharyngeal bulging and induration. Imaging with PET-CT and MRI showed an enlarging ovoid mass centered within the right PPS without the presence of another systemic metastasis. FNA was consistent with MTC. The patient was taken to the operating room for a combined TORS-TC approach. Final pathology was consistent with metastatic MTC. Until recently, PPS tumors have been managed using highly morbid and cosmetically disfiguring open surgical approach. TORS provides a safe and effective alternative.

Histology-proven recurrence in the lateral or central neck after systematic neck dissection for medullary thyroid cancer.

To delineate risk factors for, and examine temporal patterns of, histology-proven recurrent medullary thyroid cancer (MTC) after compartment-oriented surgery. Multivariate Cox regression on overall, node, and soft tissue infiltrate recurrence per previously dissected neck compartment. Mean follow-up for the 203 (and 158) patients with central (and ipsilateral lateral) neck dissection was 56.1 months. On multivariate Cox regression, tumor size > 20 mm predicted overall and node recurrence in the central neck, whereas extranodal growth predicted overall and node recurrence in the ipsilateral lateral neck. Extrathyroidal extension alone predicted soft tissue infiltrate recurrence in the central neck, and extranodal growth alone soft tissue infiltrate recurrence in the ipsilateral lateral neck. When analyses were restricted to patients not biochemically cured after initial surgery, only extranodal growth predicted overall and node recurrence in the dissected neck compartments. Patients not biochemically cured, specifically those with extranodal growth at the initial operation, carry greater risks of node recurrence.

Prostate-specific Membrane Antigen Imaging in Recurrent Medullary Thyroid Cancer: A New Theranostic Tracer in the Offing?

Prostate-specific membrane antigen (PSMA) expression has been shown in neovasculature of various malignancies. Recurrent medullary thyroid cancer (MTC) is difficult to treat. We present the findings on PSMA-positron emission tomography/computed tomography (PET/CT) of a 68-year-old man with MTC, who presented with a recurrent left paratracheal mass and rising calcitonin. The scan revealed significant uptake on PSMA imaging but not on 68Ga-DOTANOC PET/CT. 177Lu-PRRT is one of the therapeutic options in patients with recurrent MTC, but in this case was not possible due to lack of somatostatin receptor expression. Imaging evidence of PSMA expression alerts us to the potential use of 177Lu-DKFZ-PSMA-617 therapy in such patients.

SPECT-CT Modality for Imaging of Medullary Thyroid Cancer (MTC)

Medullary thyroid cancer (MTC) is a neuroendocrine tumor that arises from the parafollicular Calcitonin-producing C-cells of the thyroid. Typically the MTC is an extremely slow-growing cancer; however, it has a tendency of spreading distant metastases fairly early. Systemic chemotherapy and external been radiotherapy have not shown to give a good MTC response. As of date radical thyroidectomy is the main method of choice for therapy. New compounds like tyrosine kinase inhibitors (TKIs) targeting signaling pathways may have a positive outcome and be of great clinical benefits in patients with advanced and metastatic MTC. Somatostatin receptor are over expressed in MTC and thus allows the use of radiolabeled somatostatin analogues for scintigraphic imaging before and after treatment for proper staging and follow-up of these patients. SPECT-CT is used to optimize somatostatin-receptor scintigraphic protocols for MTC imaging. We have presented a case report of a patient who underwent total thyroidectomy with bilateral lymphadenectomy in August 2006 due to the diagnosed MTC. This patient was treated by chemotherapy and surgery during the period between January/2007- December/2014 because of the recurrent disease. In December 2014 the calcitonin level reached 56 000 pg/ml; whole body scan with 740 MBq 99mTc-EDDA/HYNIC-TOC, followed by target SPECT-CT showed a total disease progression with advanced metastatic dissemination into the body. The assigned therapy was with Caprelsa®(Vandetanib) 300 mg/d orally which was initialized from March 2015 until present. In June 2016 a control SPECT-CT somatostatinreceptor scintigraphy with 740 MBq 99mTc-Tektrotyd was performed from which was reported a partial disease response with a reduction of about 60% in size and a decrease in the number of metastatic lesions shown to correlated with the decreased calcitonin level up to 1560 pg/ml. It can be concluded that SPECT-CT with 99mTc- Tektrotyd has important clinical role for re-staging and follow-up of patients with recurrent and metastatic MTC after target therapy.

Three-dimensional Modeled T-tube Design and Insertion in a Patient With Tracheal Dehiscence

A 68-year-old man with recurrent medullary thyroid cancer underwent cervical tracheal resection and reconstruction. His course was complicated by tracheal anastomotic dehiscence, right carotid blowout, and ultimately cervical tracheoplasty with AlloDerm. Given the complex vascular interventions and upper-airway anatomy, a custom-designed Montgomery T-tube was designed for him. Three-dimensional digital reconstruction of his upper airways was obtained from a CT scan. The T-tube was designed and fabricated based on the digital trachea model and was subsequently placed successfully. Follow-up CT scan and bronchoscopy confirmed placement and revealed no granulation tissue at 4 weeks. The patient was discharged to home with the ability to phonate. To our knowledge, this is the first demonstration of three-dimensional modeling of an upper-airway defect with subsequent T-tube design using engineering software. The success of this case demonstrates a possible avenue for personalized airway prosthesis design and manufacturing in the future.

<sup>18</sup>F-DOPA and <sup>18</sup>F-FDG PET/CT, Scintigraphic Localization and Radioguided Surgery of Recurrent Medullary Thyroid Cancer: Two Case Reports

Medullary thyroid cancer (MTC) is considered as a rare thyroid cancer. Surgical approaches such as, total thyroidectomy and bilateral lymph node dissection, represent the first-line treatment. Persistent or increasing serum levels of tumor markers, such as CEA and calcitonin, imply residual or recurrent disease. An early and precise detection of recurrence is very important for guiding appropriate treatment. Recent developments in positron emission tomography (PET) imaging with different radiopharmaceuticals targeting specific hallmark of MTC, such as 18F-DOPA and 18F-FDG, have offered increased sensitivity for identifying recurrences. Moreover, the ability of conventional scintigraphic imaging to guide the surgical approach can be useful for the treatment of MTC recurrent patients. In the present work, we reported two cases of patients with recurrent MTC sending to surgical treatment guided by "nuclear medicine approaches".

Family medullary thyroid cancer: etiology, pathogenesis, diagnosis

Medullary thyroid cancer (MTC) represents 2-8 % of thyroid malignancies. Predominantly MTC have sporadic nature but 20-30% of cases are hereditary caused by germ line missense mutation in RET gene with autosomal dominant inheritance. There are precise genotype-phenotype correlations of RET mutation location (genotype) with tumor manifestation age, disease aggressiveness, presence of components of multiple endocrine neoplasia syndrome 2a and 2b types (phenotype). MTC is considering as slow-growing tumor but early metastasizing. Regional metastases frequently involve neck and mediastinal lymph nodes, distant — lungs, liver and bones. Calcitonin — highly sensitive biomarker of either primary or recurrent MTC.

18F-Fluorodihydroxyphenylalanine vs other radiopharmaceuticals for imaging neuroendocrine tumours according to their type

6-Fluoro-(18F)-L-3,4-dihydroxyphenylalanine (FDOPA) is an amino acid analogue for positron emission tomography (PET) imaging which has been registered since 2006 in several European Union (EU) countries and by several pharmaceutical firms. Neuroendocrine tumour (NET) imaging is part of its registered indications. NET functional imaging is a very competitive niche, competitors of FDOPA being two well-established radiopharmaceuticals for scintigraphy, 123I-metaiodobenzylguanidine (MIBG) and 111In-pentetreotide, and even more radiopharmaceuticals for PET, including fluorodeoxyglucose (FDG) and somatostatin analogues. Nevertheless, there is no universal single photon emission computed tomography (SPECT) or PET tracer for NET imaging, at least for the moment. FDOPA, as the other PET tracers, is superior in diagnostic performance in a limited number of precise NET types which are currently medullary thyroid cancer, catecholamine-producing tumours with a low aggressiveness and well-differentiated carcinoid tumours of the midgut, and in cases of congenital hyperinsulinism. This article reports on diagnostic performance and impact on management of FDOPA according to the NET type, emphasising the results of comparative studies with other radiopharmaceuticals. By pooling the results of the published studies with a defined standard of truth, patient-based sensitivity to detect recurrent medullary thyroid cancer was 70 % [95 % confidence interval (CI) 62.1–77.6] for FDOPA vs 44 % (95 % CI 35–53.4) for FDG; patient-based sensitivity to detect phaeochromocytoma/paraganglioma was 94 % (95 % CI 91.4–97.1) for FDOPA vs 69 % (95 % CI 60.2–77.1) for 123I-MIBG; and patient-based sensitivity to detect midgut NET was 89 % (95 % CI 80.3–95.3) for FDOPA vs 80 % (95 % CI 69.2–88.4) for somatostatin receptor scintigraphy with a larger gap in lesion-based sensitivity (97 vs 49 %). Previously unpublished FDOPA results from our team are reported in some rare NET, such as small cell prostate cancer, or in emerging indications, such as metastatic NET of unknown primary (CUP-NET) or adrenocorticotropic hormone (ACTH) ectopic production. An evidence-based strategy in NET functional imaging is as yet affected by a low number of comparative studies. Then the suggested diagnostic trees, being a consequence of the analysis of present data, could be modified, for some indications, by a wider experience mainly involving face-to-face studies comparing FDOPA and 68Ga-labelled peptides.

Recurrent Medullary Carcinoma detected by Gallium-68 Positron Emission Tomography

ABSTRACT In this case, we would like to share our experience of a recurrent medullary thyroid cancer patient whose recurrence was detected by Ga-68 DOTATATE PET/CT. How to cite this article Soydal C, Ozkan E, Araz M, Kucuk ON, Demirer T. Recurrent Medullary Carcinoma detected by Gallium-68 Positron Emission Tomography. World J Endoc Surg 2013;5(2):59-60.

Evaluation of efficacy and clinical impact of 18F-FDG-PET in the diagnosis of recurrent medullary thyroid cancer with increased calcitonin and negative imaging test

AimTo evaluate the efficacy and clinical impact of the FDG-PET in the diagnosis of suspicion of recurrence of medullary thyroid cancer (MTC) in patients with elevated serum calcitonin and negative imaging test. Material and methodsWe performed a retrospective study of 31 consecutive cases from February 2001 to October 2007 of 17 women and 14 men, mean age 56.2 years (range: 26–88), with anatomical-pathology diagnosis of MTC and suspicion of recurrence due to abnormal elevation of calcitonin and negative imaging tests. All the patients underwent whole body FDG-PET scan with a dedicated PET or PET-CT 60min after intravenous injection of 333–434 MBq of 18F-FDG. Results were confirmed by pathology study in 45.2% of the patients and by clinical follow-up with a mean of 4 years (range: 16 months–8 years). ResultsSensitivity was 88%, specificity 84.6%, positive predictive value (PPV) 88%, negative predictive value (NPV) 84.6% and diagnostic accuracy 87%. The results of the FDG PET modified the therapeutic strategy in 14 cases (45.2%). A comparison was made of the mean values of calcitonin using the Student's t-test between positive PET studies for the disease and negative ones. No significant differences were found (p=0.3). ConclusionsIn patients with MTC and suspected recurrence with elevated calcitonin and negative imaging test, the FDG is the best test for the diagnosis of occult recurrence in MTC with elevated calcitonin and negative imaging techniques with elevated clinical impact. It facilitates the therapeutic management of the patients with MTC recurrence, and should be included in the diagnosis algorithm in these patients.

Medullary thyroid cancer--current treatment strategy, novel therapies and perspectives for the future.

Medullary thyroid cancer (MTC), an uncommon and slow-growing tumor, is difficult to eradicate when metastasis or recurrence develops. This review describes therapeutic approaches to patients with recurrent sporadic MTC, management of advanced cases of MTC, and future treatment options. A literature review of treatment of MTC in humans was conducted. Surgery is currently the only potentially curative treatment for MTC; complete tumor resection and removal of suspicious nodes is the most important initial treatment to prevent recurrence and metastasis. When recurrence or metastatic MTC develops, the decision for continued observation or initiation of systemic therapy is based on the degree of tumor aggressiveness. Lymph node involvement, calcitonin doubling time, types of RET mutation, and tumor stage are factors that help determine the need for further treatment. Therapeutic options for aggressive and inoperable MTC primarily include tyrosine kinase inhibitors, external beam radiation therapy, or other medications. Among tyrosine kinase inhibitors, vandetanib is the first drug that is FDA approved for treatment of MTC. Focused external beam radiation therapy can be reconsidered for patients with cervical node involvement. Although other targeted drug therapies have been tried, definitive clinical studies are lacking. In recurrent or advanced MTC, when systemic therapy is warranted, vandetanib is available for use in treatment; however, side effects of this drug can be problematic, and impact on overall survival is presently unknown. Newer therapeutics are being studied with the goal of balancing control of tumor growth with maintaining the patient's quality of life.

Progress in Molecular Targeted Therapy for Thyroid Cancer: Vandetanib in Medullary Thyroid Cancer

Progress in Molecular Targeted Therapy for Thyroid Cancer: Vandetanib in Medullary Thyroid Cancer