About 65438 00% of the standard sample of simple nodular goiter is thyroid cancer. The most common age of thyroid cancer is 40 ~ 60 years old, but the age of patients has declined in recent years. Generally speaking, the 10 annual survival rate of thyroid cancer after manual resection is about 80% to 60%.
Generally speaking, the condition of most thyroid cancers after pretreatment is not very good, and the survival rate of 10 years after manual resection can reach 80%. Moreover, the existing thyroidectomy is not very mature, and the complications after thyroidectomy are very rare (4%). I hope such patients dare to undergo hand surgery. Generally speaking, we divide thyroid cancer into four types: papillary thyroid cancer, follicular thyroid cancer, somatic thyroid cancer and undifferentiated thyroid cancer, and each type is slightly different before and after treatment.
Malignant tumor of thyroid (thyroid cancer)
Dr. Lin Zhong Xing (updated on165438+122 October 2005)
Department of Internal Medicine Metabolism, Kaohsiung Rong General Hospital.
Associate Professor of Internal Medicine, National Yangming University School of Medicine, and Clinical Professor of Internal Medicine, National Defense University School of Medicine.
< 1 > etiology:
Thyroid malignant tumor (cancer) accounts for about 1% of all malignant tumors. The real cause of thyroid cancer is not clear, but it may be related to the following factors.
(1) People who received X-ray or radiotherapy for lymphadenitis or mumps in childhood are more likely to develop thyroid cancer.
(2) Some patients with Hashimoto's thyroiditis may be related to the occurrence of thyroid malignant lymphoma.
(3) Genetic factors: especially in patients with familial medullary thyroid cancer, the family heritability is as high as 20%.
< 2 > classification:
< a > primary thyroid cancer: according to histological types, it can be divided into the following types:
(1) Papillary carcinoma: It comes from follicular epithelial cells, accounting for about 50-70% of thyroid carcinoma, and the tumor grows the slowest, and its 10-year survival rate is about 90%. Cancer lacks capsule, and it is multiple (refers to multiple lesions in different parts of the thyroid gland). Local metastasis (about 30-40%) is easier than distant metastasis through blood flow. About half of the patients are under 40 years old, and the incidence rate of women is three times that of men. The growth of cancer cells is mainly influenced by thyroid stimulating hormone. Therefore, when taking thyroxine (L-T4) to inhibit TSH, the metastasis of mastoid cancer often degenerates. The factors affecting prognosis are: over 50 years old, male, tumor diameter greater than 4 cm, cancer cells invading capsule, distant metastasis, etc., all of which are important factors for poor prognosis.
(2) Follicular carcinoma: It originated from follicular epithelial cells, accounting for 65,438+05% of thyroid carcinoma. Tumors grow slowly and usually belong to a single lesion with capsule, and its 65,438+00 survival rate is about 80%. It usually occurs after the age of 40, and it is less likely to metastasize to local lymph nodes, but more likely to metastasize to lungs, bones, liver, etc. Through the blood stream, it sometimes invades the tissues around the thyroid gland.
(3) Anaplastic cancer: It comes from follicular epithelial cells, accounting for about 10% of thyroid cancer, and usually occurs after 50 years old, with a little more women. The malignant degree is extremely high, and it often quickly invades peripheral tissues or transfers to various organs of the whole body, resulting in local lymph node swelling and pain, hoarseness, breathing and wheezing, dysphagia and so on. Patients often die within a few months after diagnosis. Histomorphologically, local necrosis or infiltration of polymorphonuclear leukocytes (PMN) is common, and even cell types similar to mastoid carcinoma or follicular carcinoma can be seen in some parts, so some people suspect that these two may be precursors of undifferentiated carcinoma. Unlike papillary carcinoma and follicular carcinoma, it does not accumulate iodine, so it cannot be treated with radioactive iodine (I- 13 1).
(4) Medullary carcinoma: It originated from parathyroid cells (C cells, a neuroendocrine cell), accounting for about 65,438+0-2%. It is more likely to occur after the age of 40, and women are slightly more than men. Its malignant degree is between follicular carcinoma and undifferentiated carcinoma, and the annual survival rate of 10 is about 60-70%. It can be transferred to other parts of the gland or local lymph nodes through lymph nodes in the gland, and can also be transferred to lung, bone, liver and other distant places through blood flow. Because it can secrete calcitonin, it provides an opportunity for early diagnosis and treatment (the basic value of calcitonin in blood or the value stimulated by intravenous injection of pentagastrin or calcium can be checked for diagnosis). It occasionally secretes other substances, such as serotonin, adrenocorticotropic hormone, prostaglandin, kinin and vasoactive peptide, leading to carcinoid syndrome, Cushing syndrome and diarrhea. Medullary carcinoma can be familial or sporadic, in which familial carcinoma accounts for about 20%, mostly invading bilateral thyroid gland, and often complicated with abnormal hyperplasia of other endocrine glands (portal -2A or portal -2B). It is worth noting that male -2A or male -2B patients must be treated with adrenal pheochromocytoma first.
(5) Thyroid lymphoma: extremely rare, accounting for about 1% of thyroid cancer. It is suspected that long-term Hashimoto's thyroiditis will develop into thyroid lymphoma.
Metastatic thyroid cancer: extremely rare, which means that cancer cells from other organs of the body have metastasized to the thyroid gland.
Most thyroid cancers originate from the epidermal cells of thyroid follicles, and these differentiated thyroid cancers (mastoid and follicular cancers) often retain the characteristics of thyroid epidermal cells. These characteristics include: iodine intake, thyroglobulin synthesis, thyroid peroxidase synthesis and so on.
< 3 > clinical features:
(1) If the thyroid gland is locally enlarged or has a lump, and the size of the lump is increasing day by day, the possibility of thyroid cancer should be suspected.
(2) Symptoms of local compression: hoarseness, dysphagia when invading esophagus, hemoptysis when losing weight, dyspnea, chest discomfort, invading or compressing trachea.
(3) Symptoms of local metastasis of cancer: cervical lymph node enlargement, especially papillary carcinoma and medullary carcinoma.
(4) Symptoms of distant metastasis: headache and vomiting caused by brain metastasis, cough, congestion and chest discomfort caused by lung or mediastinal cavity metastasis, pain caused by pathological fracture caused by bone metastasis, numbness or weakness of hands and feet caused by spinal cord metastasis, etc.
Clinically, some people divide thyroid cancer into four stages: the first stage is whether the cancer cells are confined to the primary site (in the unilateral lobe of the thyroid gland), the second stage is whether the cancer cells have spread to the contralateral lobe of the thyroid gland but are still confined to the thyroid capsule, the third stage is whether the cancer cells invade local tissues such as lymph nodes through the capsule, and the fourth stage is whether there are distant metastases such as liver, lung or bone, brain and peritoneum.
< 4 > diagnosis:
(1) Physical examination: thyroid palpation and cervical lymph node examination.
(2) Nuclear medical examination: Because the ability of thyroid cancer cells to accumulate iodine is not as good as that of normal thyroid cells, if cold nodules appear in thyroid scanning with radioactive iodine or selenide, the possibility of thyroid cancer should be suspected.
(3) Ultrasound examination: It can distinguish whether the thyroid gland is a cyst or a solid tumor. Generally, the former has a low chance of canceration.
(4)X-ray examination: Esophageal barium X-ray examination, if there is tracheal stenosis, defect, displacement, irregular thyroid margin, or cystic body, the possibility of thyroid cancer should be suspected.
(5) Thyroid function examination: Except for a few cases of "extensive metastatic follicular carcinoma" complicated with hyperthyroidism, the thyroid function examination of general thyroid cancer is mostly normal, which has little diagnostic value for thyroid cancer.
(6) Fine needle aspiration cytology of tumor: This is the simplest diagnostic method. Puncture the tumor with a fine needle (which is more accurate under the guidance of ultrasound), suck the tumor cells and put them on a glass slide, and observe the cell morphology under a microscope after staining, so as to get a preliminary diagnosis. Besides cytological examination, pathological examination of thyroid biopsy can be used for diagnosis and classification.
< 5 > treatment:
(1) surgical treatment:
Once diagnosed as thyroid cancer, surgical resection is the best treatment. Surgical methods often vary according to cancer cell type, tumor size (some surgeons decide the surgical method based on whether the tumor is larger than 1.5 or 2 cm), metastasis, age, gender and other factors. According to the scope of surgical resection, it can be roughly divided into "total thyroidectomy", "near total thyroidectomy or subtotal thyroidectomy" and "partial thyroidectomy" (of course, it also includes extensive cervical lymphadenectomy). Complications of surgical treatment include hypoparathyroidism (leading to hypocalcemia) and vocal cord paralysis. These symptoms may be temporary or permanent.
(2) Radioisotope iodine (I- 13 1) therapy:
Tissue iodine is a unique function of thyroid cells. Although not as good as normal thyroid cells, tumor cells still retain this function. Even poorly differentiated thyroid cancer cells still have 60% to 80% functions like normal thyroid cells, and their affinity for iodine is 400-600 times higher than that of cells in other parts of the body. Therefore, radioactive iodine can be effectively brought into thyroid cells, and because the range of β rays released by radioactive iodine is only about 2 mm in the tissue, it has little effect on normal tissues near the thyroid gland and cells in other parts of the body. In addition, the ability of thyroid cells to accumulate iodine is affected by TSH, so if you want to treat thyroid cancer with radioactive iodine, you must first remove the thyroid completely through surgery. After about four to six weeks, if the TSH concentration in the patient's blood is greater than 30μU/ml (or synthetic TSH is given directly after operation), it is best to give 100 mCi radioactive iodine. Radioactive iodine has little side effects. Generally, there are anorexia, nausea, dizziness, skin itching, cervical pain (radiation thyroiditis), salivary gland or gastric gland enlargement, bone marrow suppression, etc., but they are generally temporary and disappear after 1 ~ 2 weeks. However, in recent years, some scholars have suggested that the cumulative lifetime dose should not exceed 500 mCi, and the interval between two treatments should be at least one year to reduce the incidence of leukemia and pulmonary fibrosis. Generally speaking, radioactive iodine therapy is more effective for mastoid cancer and follicular cancer, and can be used as an auxiliary treatment for postoperative soft tissue metastasis. However, the therapeutic effect on bone metastasis or pulmonary nodular metastasis is poor. As for undifferentiated carcinoma, medullary carcinoma and lymphoma, it has no response to radioactive iodine therapy. Whether patients with distant metastasis but no clinical symptoms should be treated with radioactive iodine again has not been agreed. In particular, considering that patients must be placed in an environment with high TSH concentration in blood before each radioactive iodine treatment, whether it will accelerate the growth of cancer cells is also a matter for clinicians to consider.
(3) external radiotherapy:
For the severe pain caused by extremely malignant undifferentiated cancer or thyroid cancer with bone metastasis, because of its poor or no response to radioactive iodine, we can try to use the radiation energy generated by "Cobalt 60" linear accelerator to destroy and kill cancer tissue, thus slowing down the growth of cancer cells and relieving pain.
(4) drugs and chemotherapy:
Generally speaking, chemotherapy has limited therapeutic effect on thyroid cancer, so it is rarely used. As for drug therapy, the growth of well-differentiated thyroid cancer cells (especially papillary carcinoma and follicular carcinoma) is stimulated by TSH, so these patients should receive thyroxine therapy after surgery and radioactive iodine therapy, and the dose should be higher than that of general "complementary therapy" to maintain the thyroid function at a normal high value, so as to suppress the TSH concentration in blood at a normal low value and slow down the growth of cancer cells.
(5) Prospect: Gene therapy: Because the mutation of P53 oncogene is the inducement for follicular thyroid cancer cells to transform into poorly differentiated cells, in vitro experiments, normal P53 gene can be implanted into poorly differentiated thyroid cancer cells, so that the poorly differentiated cancer cells can be transformed into highly differentiated cancer cells that can secrete thyroglobulin and take iodine, and the cell proliferation can be slowed down, so it may be applied to clinic in the future.
< 6 > tracking:
Blood thyroxine (T4 or free T4), HS-TSH and human thyroglobulin (hTg) should be checked every three months within one year after operation and radioactive iodine treatment. Check it every six months after one year. If everything is all right, check it once a year after two years. It is worth mentioning that the concentration of thyroglobulin in blood can be used as an indicator of recurrence of well-differentiated thyroid cancer. If its value suddenly rises, the whole body radioactive iodine scan should be arranged to check the recurrence site and arrange appropriate treatment. For patients with Graves' disease, TSH- receptor antibody can accelerate the growth of thyroid cancer cells, so TSH- receptor Ab should also be followed up. As for patients with medullary cancer, the concentration of calcitonin in their blood can be tracked to detect whether their cancer cells recur and predict their prognosis. In addition, all patients should have a chest X-ray examination every year to detect whether there is lung metastasis. Because excessive thyroxine supplementation can cause side effects of osteoporosis, female patients should have their bone mineral density checked once a year.
http://www.vghks.gov.tw/meta/thyroidc.htm