Causes and common treatments of malignant thyroid nodules

Causes of malignant thyroid nodules:

1. Oncogenes and growth factors: Modern studies have shown that the occurrence of many animal and human tumors is related to the overexpression, mutation or deletion of oncogene sequences.

2. Ionizing radiation: It has been found that external radiation to the head and neck is an important carcinogenic factor for the thyroid gland.

3. Genetic factors: Some medullary thyroid carcinomas are autosomal dominant genetic diseases; in some thyroid cancer patients, family history can often be inquired.

4. Iodine deficiency: As early as the beginning of the 20th century, some people had proposed that iodine deficiency could lead to thyroid tumors.

5. Estrogen: Recent studies suggest that estrogen can affect the growth of the thyroid gland mainly by inducing the pituitary gland to release TSH, because when the estrogen level in the plasma increases, the TSH level also increases. As to whether estrogen directly acts on the thyroid gland, it is still unclear.

Common treatments for malignant thyroid nodules:

Endocrine therapy

Patients who have undergone subtotal or total thyroidectomy should take thyroid hormone tablets for life to prevent hypothyroidism and inhibit TSH. Both papillary carcinoma and follicular carcinoma have TSH receptors, and TSH can affect the growth of thyroid cancer through its receptors. The dosage of thyroid hormone tablets should be adjusted according to TSH levels, but there is still a lack of sufficient and effective data to support the precise range of TSH inhibition. Generally speaking, for patients with residual cancer or high-risk factors for recurrence, TSH should be maintained below 0.1mU/L; however, for disease-free patients with low risk of recurrence, TSH should be maintained near the lower limit of normal (slightly higher or slightly lower than the lower limit of normal); for low-risk patients with positive laboratory tests but no organic lesions (positive thyroglobulin, negative imaging), TSH should be maintained at 0.1-0.5mU/L; for patients who have been disease-free for many years, their TSH may be maintained within the normal reference value. Levothyroxine sodium tablets (Euthyrox) can be used, 75ug-150ug per day, and blood T4 and TSH should be measured regularly, and the dosage should be adjusted according to the results.

Radionuclide therapy (131 iodine therapy)

For papillary carcinoma and follicular carcinoma, the postoperative application of iodine is suitable for patients over 45 years old, those with multiple cancer foci, locally invasive tumors, and those with distant metastases. It is mainly used to destroy the residual thyroid tissue after thyroidectomy, which is beneficial for reducing recurrence and mortality in high-risk cases. The purpose of iodine treatment is: ① to destroy the hidden microcancer in the residual thyroid; ? to easily use radionuclides to detect recurrence or metastatic lesions; ③ to increase the value of using thyroid globulin as a tumor marker during postoperative follow-up.