Thyroid cancer diagnosis and treatment Thyroid cancer accounts for 1% of all malignant tumors and is a common and frequent disease among head and neck tumors, accounting for 10-15% of malignant tumors admitted to the hospital and taking the first place. Because of the different biological behaviors of different histological types, the slow progression and long natural course of most thyroid cancers, and the many factors affecting the prognosis, there are some difficulties in interpreting the statistics of thyroid cancer. Because of this, there are many controversies in the management of thyroid cancer. In the last decade, with the accumulation of clinical experience, especially in oncology hospitals through clinical medical and clinical research, there has been further understanding of the etiology of thyroid cancer and some progress in the diagnosis and treatment methods. According to the analysis of systematic and complete data from the Cancer Hospital of the Academy of Medical Sciences, the 10-year survival rate of differentiated thyroid cancer, which accounts for more than 80% of thyroid cancer, is about 90%, which is better than the domestic and foreign data, and it is agreed that the 5-year survival rate of undifferentiated thyroid cancer, which has the worst outcome, can reach 15% after active and reasonable treatment. Therefore, it is believed that the treatment of thyroid cancer can achieve better results if the correct treatment principles are followed. The etiology of thyroid cancer, like other tumors, is still being explored. The more discussed ones are radiation and endemic goiter, which are closely related to papillary and follicular carcinoma of the thyroid. Since the 1950s, epidemiological and laboratory studies have shown that radiation can cause thyroid cancer, and that low-dose x-rays and children are more likely to develop. In China, the application of radiation was late and not yet popular, so it is not obvious that radiation is one of the factors causing thyroid cancer. Recent clinical studies have shown that the chance of radionuclide iodine causing thyroid cancer seems to be very small. The relationship between endemic goiter and thyroid cancer is mainly due to iodine deficiency and mostly follicular and undifferentiated carcinoma of the thyroid gland, while in non-goiter endemic areas it is mostly seen as papillary carcinoma, and the epidemiological pattern of thyroid cancer occurrence in China is the same. Theoretically, a prolonged exposure to radiation and all factors that can promote thyroid follicular cell proliferation including thyroid lobectomy, iodine deficiency and anti-thyroid drugs are causative factors of thyroid tumors. In addition, recent studies have found the presence of high estrogen receptors in differentiated thyroid cancer tissues, suggesting that it may be related to estrogen levels; mutated forms of oncogenes such as H-ras, K-ras and N-ras have been found in a variety of thyroid tumors, and recent oncogene studies have shown that the ptc oncogene is present in only a few papillary thyroid cancers, and some medullary carcinomas, especially in patients with a family history, have been studied from Molecular level studies have obtained cytogenetic evidence of chromosomal abnormalities; some lymphomas may arise from lymphocytic thyroiditis. The preoperative diagnosis of thyroid cancer is based mainly on history and clinical examination, and its diagnostic conformity is related to the experience of the clinician. The clinical significance of radionuclide iodine scan is not considered significant in recent years. 99mTc scan is not affected by the iodine uptake status of the thyroid gland, which increases the scope of adaptation and its short half-life is suitable for adolescent and pediatric patients. Especially, ultrasound with CT or MRI can improve the diagnosis rate of lymph nodes in the neck, or can clearly show the relationship between the neck mass and the surrounding weaving organs, which is very meaningful for guiding the surgical treatment. The preoperative qualitative diagnosis of thyroid cancer is generally accepted at home and abroad by fine needle aspiration cytology, which has a very small false positive rate and a false negative rate of about 10% according to domestic and foreign data. In addition, the use of immunochemistry and immunohistochemistry in the last decade has been important in the differential diagnosis of undifferentiated thyroid cancer, medullary carcinoma and lymphoma, and the measurement of calcitonin has clinical significance in the diagnosis of medullary thyroid cancer, and radioimmunoassay of TSH and TG tracks postoperative recurrence and metastasis in patients with total thyroidectomy. In order to avoid some unnecessary surgery, the following more standardized and reasonable diagnostic steps have been promoted by domestic and foreign scholars in recent years: 1. physical examination with or without ultrasound of the thyroid; 2. fine needle aspiration cytology for thyroid nodules <3CM, and puncture biopsy for those >3CM; 3. positive results or suspicion for surgical excision. If the result is positive or suspected, surgical excision is performed. If the nodule is clearly benign and no significant changes are observed over a long period of time, no treatment is needed, or if the nodule is eliminated by taking thyroxine preparations for 6 months or 1 year, tissue biopsy or surgical exploration is performed again if it does not subside. Different biological behaviors and pathological types of thyroid cancer should be treated according to their respective characteristics. The treatment involves surgery, radiotherapy, chemotherapy, etc. Surgery is the main treatment, and accurate judgment and standardized treatment during the first treatment of thyroid cancer is the key to reduce the chance of recurrence. It is the trend and requirement of surgical oncology development in recent years to preserve as much physiological function as possible on the basis of tumor eradication and to improve survival rate and quality of life. 1. Treatment of primary thyroid lesions: In differentiated thyroid cancer (papillary and follicular carcinoma), many scholars abroad advocate total thyroidectomy. Some of them and most of the data in China suggest that one lobe of the thyroid gland can be resected according to the specific situation of the intraoperative tumor, or most of the isthmus and the contralateral lobe can be resected, so that the chance of recurrence is not high and the survival rate is not reduced. Even medullary thyroid carcinoma can be treated similarly, but of course, total thyroidectomy should also be performed if the lesion involves bilateral or bilateral multiple foci and is confirmed by intraoperative rapid pathology. If the intraoperative rapid pathology is negative but the postoperative pathology is positive, a second operation is still necessary, which is more likely to occur in follicular carcinoma. About 50% of thyroid cancers admitted to the Cancer Hospital of the Academy of Medical Sciences in the past years were first treated surgically in other hospitals, and most of them were locally excised, and the residual cancer was found in 82% of the thyroid lobe specimens resected again. The 5-year survival rate of undifferentiated thyroid carcinoma is about 7% in most reports. If early diagnosis can be obtained, surgery can be performed, and postoperative radiotherapy can improve the survival rate. Very few of them can even obtain long-term survival. 2. Treatment of the neck: If there is lymph node metastasis in the neck, neck debridement surgery is performed. It is controversial whether prophylactic neck dissection should be performed when there is no obvious lymph node metastasis in the neck, and the criteria for judging N0 may be related to the clinical experience of doctors. According to most foreign reports and the authors’ own data, the chance of future metastasis in the neck without prophylactic neck clearance is only less than 10%. For those with large primary tumors or those who have invaded the thyroid envelope, the most important thing is to carefully remove the lymphatic tissue around the tracheoesophageal groove, including the lymph nodes at the entrance of the thorax, which are the first lymphatic drainage areas, after resection of the glandular lobes. Medullary thyroid carcinoma often appears earlier and more widely as lymph node metastasis in the neck, which is not easy to find clinically in time, so B ultrasound or CT examination should be used to examine the suspicious lymph nodes and send frozen rapid sections during surgery, and careful lateral neck lymph node dissection should be performed as soon as it is confirmed. 3. Treatment of invasion of important tissues: With the development of surgical skills and various repair methods, some advanced tumors of thyroid cancer that invade the adjacent important tissues and organs can still be cured surgically and restore the function as much as possible with active and appropriate treatment. The author’s improved flap design in recent years has repaired more than 10 cases of large tracheal defects with very satisfactory results; mediastinal lymph node metastasis in papillary thyroid cancer has been completely cured by splitting the sternum and clearing the mediastinum. Bilateral laryngeal nerve resection followed by microsurgical method of transplantation and anastomosis, autologous parathyroid gland transplantation in the pectoralis major muscle to successfully relieve hypocalcemia symptoms have been reported from time to time, although success has been reported, but more observation and research are needed; the authors’ extra findings during the study of anterior cervical lymph nodes 10 years ago, the intraoperative application of nano-carbon parathyroid negative contrast technique greatly reduced the incidence of hypoparathyroidism. 4.Comprehensive treatment of thyroid cancer: postoperative radiotherapy for thyroid cancer includes external irradiation and radionuclide 131I. The former has certain effect on undifferentiated thyroid cancer and poorly differentiated differentiated carcinoma remaining after surgery, and the data from Cancer Hospital of Medical Academy of Sciences show that the 5-year survival rate can be increased from 33% to 71% with the addition of radiotherapy for late stage cancer with tumor residue that is difficult to be removed by thyroid cancer surgery, and undifferentiated cancer The mortality rate within 1 year after surgery plus radiotherapy decreased from 69.4% to 38.5% compared with that of surgery alone. Most of the thyroid cancers are papillary carcinomas, and radiotherapy has no significant effect on the residual or recurrent papillary carcinomas in the local area and neck. It should be limited to palliative treatment for those who cannot be completely removed by surgery because of invasion of important tissues and organs or other reasons. Isotope iodine 131 treatment has good effect on distant metastasis of follicular carcinoma and papillary carcinoma with iodine absorption function, the total efficiency is about 50-60%, it is more commonly used in foreign countries, some domestic medical structures have a wider grasp of indications, and there is even a trend of abuse. The results of the authors’ study share the conclusion of many national and international oncologists that iodine 131 has very limited effect on residual and lymph node metastatic lesions of thyroid cancer in the neck. For medullary thyroid carcinoma with distant metastases, it is ineffective because it does not absorb iodine, but the biologic therapy carried out in recent years may suggest good prospects for some refractory differentiated thyroid carcinoma and medullary carcinoma, and targeted therapy to obtain effective control. Chemotherapy has only partial remission for undifferentiated thyroid cancer with adriamycin and cisplatin. Postoperative thyroxine administration is mainly a replacement effect. There are different views on whether it can prevent recurrence, and the dosage can be adjusted within the normal range according to thyroid function tests, or TSH approaching the lower limit of normal value and T3 and T4 approaching the upper limit of normal value. There are many factors affecting the prognosis of thyroid cancer, the main ones being the type of pathology, clinical stage, age and whether the treatment is appropriate or not. Therefore, it is necessary to consider the characteristics of each factor comprehensively in the treatment of thyroid cancer and to give reasonable standardized treatment so that patients with thyroid cancer can obtain better quality of life and survival outcome.