What Is Medullary Thyroid Cancer?

Medullary thyroid cancer is not actually thyroid cancer. It is derived from the thyroid follicular cells (also called C cells) that secrete calcitonin. It is a neuroendocrine cell and has nothing to do with thyroid follicular cells. It was first proposed by Hazand et al in 1959 as an independent clinicopathological type. It only accounts for a small portion of thyroid tumors (about 3-12%), and its pathogenesis, diagnosis, and treatment are unique.

Chen Xiaohong

(Deputy Chief Physician)

Department of Otorhinolaryngology Head and Neck Surgery, Beijing Tongren Hospital

The main cause of medullary thyroid cancer is mutation of RET proto-oncogene. When unilateral or bilateral goiter masses, poor breathing, difficulty swallowing, hoarseness, hand and foot twitches, carcinoid syndrome and other symptoms should be alert to the occurrence of medullary thyroid cancer. Women who are between 30 and 60 years of age and have a family history of parathyroid and adrenal tumors are susceptible to medullary thyroid cancer, and precautions should be taken.

Western Medicine Name: Medullary thyroid carcinoma
English name: medullary thyroid carcinoma, MTC
Affiliated Department: surgical-
Disease site: thyroid
The main symptoms: Unilateral or bilateral goiter mass, difficulty breathing, difficulty swallowing, cervical side mass, hoarseness, hand and foot convulsions, carcinoid syndrome

Main cause: RET proto-oncogene mutation, inherited
Multiple groups: Female, aged 30 to 60 years, with a family history of MEN syndrome

Introduction to Medullary Thyroid Cancer Diseases

Medullary thyroid cancer is not actually thyroid cancer. It is derived from the thyroid follicular cells (also known as C cells) that secrete calcitonin. It is a neuroendocrine cell and has nothing to do with thyroid follicular cells. It was first proposed by Hazand et al in 1959 as an independent clinicopathological type. It only accounts for a small part of thyroid tumors (about 3-12%), and its pathogenesis, diagnosis and treatment are unique.

Classification of medullary thyroid cancer diseases

According to whether it is hereditary, MTC can be divided into two categories: sporadic and hereditary:

1. Sporadic MTC: most commonly seen clinically, accounting for about 75-80% of MTC, mostly middle-aged and elderly, slightly more women;

2. Hereditary MTC: It is rare in clinical practice, accounting for about 20-25% of MTC. The age of onset is about 10-20 years earlier than sporadic MTC. There is no difference in incidence between men and women. There can be multiple people in a family at the same time or in succession. Sick. Subdivided into the following 3 types:

Multiple endocrine adenoma 2A (MEN2A): 80% of all hereditary MTC, this type will occur MTC, pheochromocytoma, and parathyroid hyperplasia simultaneously

Multiple endocrine adenoma 2B (MEN2B): no parathyroid disease, characterized by mucosal multiple neuroma with MTC and / or adrenal pheochromocytoma, is the most malignant type of hereditary MTC;

Familial non-multiple endocrine adenomatic MTC (FMTC): This type is considered to be a variant type of MEN2A. MTC is its only characteristic and it is the least malignant type of hereditary MTC.

Causes of medullary thyroid cancer

1. The main cause of MTC is mutation of RET proto-oncogene;

2. About 95% of hereditary MTC and 70% of sporadic MTC are caused by RET mutations in the 10q11.2 proto-oncogene.

Pathogenesis of medullary thyroid cancer

1. The main pathogenesis is the mutation of the RET proto-oncogene, which causes the protein conformation of the thyroid C cells to change, which induces excessive cell proliferation and canceration;

2. The RET proto-oncogene is located on the long arm of chromosome 10, contains 21 exons, and encodes a transmembrane protein belonging to the tyrosine kinase receptor superfamily;

3. At present, there are more than 20 RET gene mutation sites related to MTC. These mutations can lead to changes in the protein conformation of the extracellular region and the intracellular region, respectively. Such conformational changes can enhance the transformation ability of RET and stimulate casein. The amino acid kinase is automatically phosphorylated, which induces excessive cell proliferation and carcinogenesis.

Pathophysiology of Medullary Thyroid Carcinoma

1. MTC originates from thyroid C cells (belonging to neuroendocrine cells) and has strong biological activity. It synthesizes a variety of biological substances, including calcitonin (CT), adrenocorticotropic hormone (ACTH), histamine, and cancer embryos. Antigens and vasoactive peptides;

2. "C-cell hyperplasia" (CCH) is a multifocal C-cell cluster in the thyroid parenchyma;

3. CCH is an early stage of MTC. Patients may develop CCH first, then develop into early aggressive thyroid medullary thyroid carcinoma, and finally become MTC visible to the naked eye.

Clinical manifestations of medullary thyroid cancer

Clinical manifestations of medullary thyroid cancer:

1. Unilateral or bilateral goiter mass: SMTC mostly appears as a single thyroid tumor; hereditary MTC mostly manifests as a bilateral thyroid multicenter tumor;

2. Difficult breathing and difficulty swallowing: caused by a large lump and compression of the trachea and esophagus;

3. Cervical lateral mass: It is a swollen area that metastasizes to lymph nodes. The common metastases are the central cervical group and lateral lymph nodes. Clinicians can touch the mass of MTC patients, and the lymph node metastasis rate is above 75%;

4. Hoarseness: caused by tumor invasion of recurrent laryngeal nerve;

5. Hand and foot convulsions, caused by a decrease in blood calcium caused by calcitonin;

6. Facial flushing, palpitations, diarrhea, weight loss and other carcinoid syndromes: easily seen in patients with extensive liver metastases, caused by various peptides and peptide hormones secreted by tumor cells;

7. Liver, lung, and bone metastases: Tumors invade blood vessels, distant metastases occur, and up to 15% of patients have metastatic sites, which is the main cause of death in patients with MTC.

Diagnosis of medullary thyroid cancer

Differential diagnosis of medullary thyroid cancer

MTC is diagnosed with the following diseases:

1. Malignant thyroid tumors: such as undifferentiated thyroid cancer, follicular thyroid cancer, lymphoma and papillary cancer;

2. Non-cancerous thyroid tumors: such as thyroid adenoma.

Auxiliary examination of medullary thyroid cancer

If you need to identify these diseases, you need to undergo pathological, biochemical, and various imaging tests. The common methods are as follows:

Fine Needle Aspiration Cytology Examination (FNAC): It is used to determine the pathological type of MTC tumor tissue. It is one of the most effective methods for qualitative diagnosis before surgery. If DNA can be extracted, RET gene mutation analysis can also be performed;

Calcitonin test: can be used as MTC-specific tumor markers and is closely related to tumor burden;

Imaging examination methods: ultrasound, CT, MRI, nuclear medicine examination (thyroid imaging and PET / CT whole body scan) all play an important role in the diagnosis of MTC tumor localization and qualitative differential diagnosis.

First aid measures for medullary thyroid cancer

MTC is a slowly progressive disease and you should seek immediate medical assistance only if:

1. Large-scale local growth of the neck mass, which compresses the nearby trachea and esophagus;

2. Delayed treatment, obvious chest tightness, shortness of breath, and difficulty swallowing.

First aid measures are as follows:

1. The patient takes a semi-recumbent position;

2. Reduce active and passive activities;

3. Conditionally give oxygen;

4. Go to a regular hospital for a tracheotomy.

Medullary Thyroid Cancer Treatment

The doctor will determine the size of your thyroid nodule, the age at the time of diagnosis, and whether there is cervical lymph

Node metastasis and distant spread to choose one or more combination therapies that are right for you:

1. Surgery is currently the preferred treatment for MTC;

2. Other treatment methods include radiotherapy, chemotherapy and drug intervention;

3. Currently, radiotherapy and chemotherapy are only used as palliative treatment methods under ineffective control methods;

4. Novel molecular targeted therapy drugs for advanced (metastatic) MTC adult patients;

5. Radioimmunotherapy and vaccination treatments have recently developed. ^[1-2]

Medullary thyroid cancer disease prevention

The 10-year survival rate of MTC is above 50-90% on average

The following conditions indicate a poor prognosis:

1. elderly patients

2. MTC with cervical lymph node and / or distant organ metastasis;

3. Patients who need to undergo extensive surgery;

4. MEN2B type hereditary MTC patients;

5. SMTC patients with M918T gene mutation;

6. Blood calcitonin levels rise rapidly, especially in patients who have doubled in 6 months.

The following conditions suggest a better prognosis:

1. FMTC hereditary patients;

2. The level of blood calcitonin increases slowly or decreases;

3. Sustained elevated blood calcitonin, but no evidence of imaging and clinical relapse;

4. The diameter of local metastatic lesions of MTC is less than 1 cm, especially in patients with CT and CEA doubling time longer than 2 years.

Medullary thyroid cancer disease prevention

People at risk for medullary thyroid cancer

The population susceptible to MTC disease is as follows:

1. Female, aged between 30 and 60 years;

2. Have a family history of MEN syndrome: such as those with thyroid, parathyroid, and adrenal tumor disease.

Medullary thyroid cancer prevention

The prevention method is as follows:

1. First know if there is a member of hereditary MTC family;

2. Early genetic screening;

3. Early clinical intervention of the disease without obvious symptoms.

Nursing Care for Medullary Thyroid Cancer

Patients after surgery need to pay attention to the following aspects:

1. Diet: post-operative diet care is particularly important and needs to be done:

· Nutritional balance, from eating less and eating more frequently to regular quantitative;

· Eat more fresh vegetables, fruits, kelp, laver, etc .;

· If malignancy, vomiting, decreased appetite and other discomforts occur during postoperative radiotherapy, please consult the doctor.

Chinese medicine treatment

2. Exercise: In the bed after the exercise, continue to exercise after getting out of bed, after the incision healing, shoulder and neck functional exercises until 3 months after discharge;

3. Rehabilitation: Avoid excessive neck movement and excessive speech within 2 days after surgery to prevent incision bleeding, effectively cough and sputum under the guidance of doctors and nurses, perform necessary psychological care and maintain good mood;

4. Regular checkup after discharge.

Guidelines for visiting medullary thyroid cancer

You can ask your doctor any questions about this disease, here are some recommended questions:

1. What type of pathology is the disease I have, and according to your diagnosis, what kind of treatment is appropriate?

2. Is my disease early or late?

3. How likely is my disease to be cured?

4. What is the best treatment you recommend for my disease? Why is this method the best? What are the side effects?

5. How many of these patients have you successfully cured?

6. Is there a better expert to recommend this to me?

Expert opinion on medullary thyroid cancer

My views on this disease

1. Generally speaking, the increase and decrease of blood calcitonin levels in patients with MTC directly reflect the severity and change of the disease, especially when the physician uses it as a test standard for patients who can be cured after surgery. At times, people are more easily confused by their appearance;

2. A large number of clinical studies have confirmed that if you still have a continuous elevated blood calcitonin level after surgery, but there is no evidence of clinical palpation and imaging recurrence (called a clinically cured patient), the prognosis proves to be good, And there is no significant difference in 5-, 10-, and 15-year survival rates between patients with normalized calcitonin levels, so patients with the above conditions do not need to be overly nervous.