OBJECTIVE: To investigate the effectiveness of surgical treatment of differentiated thyroid cancer and the factors affecting prognosis.
METHODS: Surgery was performed with different resection ranges according to the assessment of the risk of differentiated thyroid cancer.
RESULTS: The 5-year survival rate was 97% and the 10-year survival rate was 95% in 656 cases of differentiated thyroid cancer after surgery.
Conclusion: Surgical resection is the main treatment for differentiated thyroid cancer, and the use of appropriate surgical approach with postoperative endocrine therapy can improve the survival rate.
Thyroid cancer is a common malignant tumor, the incidence of which is increasing year by year worldwide. China belongs to the region with high incidence of thyroid disease, and the domestic census data shows that the average incidence of thyroid cancer is 11.5/100,000. According to the WHO pathological staging in 1988, differentiated thyroid cancer (papillary carcinoma and follicular carcinoma) accounts for 85%-95% of thyroid malignant tumors, and surgical resection is the main treatment for differentiated thyroid cancer. This study aims to investigate the clinical characteristics and surgical treatment of differentiated thyroid cancer.
Clinical data
1.General data
From 1997 to 2006, 656 cases of papillary carcinoma and follicular carcinoma were admitted to our hospital. Among them, 622 cases were papillary carcinoma, 191 males and 431 females; 34 cases were follicular carcinoma, 12 males and 22 females. The ages ranged from 8 to 81 years, with a median age of 42 years. All cases were treated surgically, and the pathological diagnosis was clarified after surgery.
2. Clinical manifestations
Thyroid nodules were found in all cases; 376 cases came to the clinic for finding neck lumps and 280 cases were found by physical examination, among which 127 cases were found by ultrasonography for the first time. All cases were confirmed to have hypoechoic thyroid nodules by ultrasonography, 96 cases were accompanied by enlarged lymph nodes in the neck, 113 cases were found to have thyroid masses by CT examination, 6 cases were found to have preoperative lung metastases, 1 case had lumbar metastases, and 2 cases had brain metastases.
3.Surgical treatment
All cases were treated surgically. There was one case of simple thyroid swelling resection, three cases of partial resection of one thyroid lobe, 17 cases of subtotal resection of one lobe, 29 cases of total resection of one lobe, 545 cases of resection of one lobe plus isthmus, 35 cases of subtotal resection of one lobe plus isthmus plus contralateral lobe plus lymph node dissection of the neck, and 26 cases of total bilateral thyroid resection plus lymph node dissection of the neck. All 8 cases with distant organ metastases underwent bilateral total thyroidectomy with cervical lymph node dissection.
4. Complications
The vocal cord paralysis was confirmed by fiberoptic laryngoscopy, and the voice returned to normal from 1 to 6 months after surgery. Hand and foot convulsions in 6 cases were relieved by calcium supplementation and returned to normal in 2 to 8 weeks. One case of postoperative neck hematoma was reoperated on the third postoperative day to stop the hemorrhage.
5. Postoperative treatment
All differentiated thyroid cancer with clear pathological diagnosis were routinely treated with endocrine therapy after surgery. 134 cases were treated with oral thyroxine tablets, 80-120 mg/day, and 522 cases were treated with oral levothyroxine sodium tablets, 100-175ug, to maintain TSH at 0.1 mU/L or less. Eight cases with distant organ metastases who had bilateral total thyroidectomy plus cervical lymph node dissection were treated with radioisotope therapy. Chemotherapy and external radiation radiotherapy were not administered in all cases.
Results
The 656 cases of differentiated thyroid cancer were followed up for 1 to 10 years after surgery, with a median follow-up of 7 years, a 5-year survival rate of 97%, and a 10-year survival rate of 95%.
Discussion
The main factors affecting the development of differentiated thyroid cancer are age, gender, history of head and neck radiation exposure and family history, etc. From the data of this group, it can be seen that the incidence rate is higher in women than in men. The incidence of thyroid cancer in women is higher than that in men. Patients usually present with a neck mass or a thyroid nodule on ultrasound. Whether thyroid cancer can be diagnosed before surgery is a controversial issue. Thyroid nodules are highly prevalent and can present as thyroid nodules in any thyroid disease, such as Hashimoto’s thyroiditis, nodular goiter, and thyroid adenoma.
Ultrasonography can indicate the size of the nodule, whether the echogenicity is uniform, whether the boundary is clear, whether there is sand-like calcification and whether there is abnormal blood flow signal, helping us to determine the possibility of malignancy, and it is non-invasive, low cost, and is our first choice for clinical diagnosis of thyroid nodules. Enhanced scans are needed to show vascularity when the involvement of adjacent organs of the thyroid gland is needed.
We also do not use thyroid isotope scanning as a routine test because it provides poor information and localization as described above, and we only use it clinically when we need to know if a thyroid nodule has function. Preoperative ultrasound-guided fine-needle aspiration biopsy is very important to clarify the diagnosis and determine the timing of surgery. Surgical resection is the mainstay of treatment for differentiated thyroid cancer, but there is ongoing debate about the choice of surgical approach, the significance of postoperative thyroxine replacement therapy and 131I ablation of the residual thyroid gland. [1] Scholars who advocate total or near-total thyroidectomy believe that this procedure can reduce postoperative recurrence and facilitate postoperative 131I ablation therapy, improving survival rates; opponents believe that expanding the scope of surgical resection will undoubtedly increase the incidence of complications.
Because of the slow progression of differentiated thyroid cancer and the long-term survival of most patients after surgery, the literature is dominated by retrospective analysis of clinical practice data, making it difficult to organize multicenter, prospective randomized controlled clinical studies, so it is difficult to reach a consensus on this issue, and even among experienced surgeons, opinions about the optimal extent of surgical resection still vary widely [2]. Some authors, including some scholars from the AJCC and ATA, advocate the classification of differentiated thyroid cancer into low-risk and high-risk groups according to age, mass size, and the presence of lymph node metastases, in order to serve as a reference for the selection of surgery or treatment plan.
[3] According to the AMES assessment method, the low-risk group includes.
1. all men under 41 years of age and women under 51 years of age with no clinical distant metastases;
2, all men over 41 years of age and women over 51 years of age with a primary tumor diameter of 5 cm, or a widely infiltrating follicular carcinoma of the envelope. According to this principle, in our study, for patients with unilateral lesions and low-risk group, we routinely performed resection of one glandular lobe plus isthmus, and if there were enlarged lymph nodes, we also resected them at the same time; while for patients with bilateral lesions or high-risk group, we performed total bilateral thyroidectomy plus cervical lymph node dissection, mainly including pre-tracheal lymph nodes and cervical lymph chain.
Postoperative endocrine therapy is particularly important, with the main aim of suppressing thyroid function with exogenous thyroxine feedback, thus achieving control of possible recurrence. The indication for complete suppression is that TSH is controlled to a TSH of less than 0.1 mU/L. Because differentiated thyroid cancer is not sensitive to chemotherapy and radiotherapy, it is not used as a treatment for differentiated thyroid cancer, and postoperative 131I ablation therapy is only used for patients with distant metastases and after total thyroidectomy has been performed.