Nodules in the thyroid are diagnosed as benign or malignant, and then management and treatment proceeds accordingly.
Treatment of benign tumors
If nodules are benign, they will not interfere with daily life and can be left untreated. However, if a patient is concerned about large or conspicuous nodules, treatment may be considered. Options include thyroid-stimulating hormone (TSH) suppression therapy, percutaneous ethanol injection therapy (PEIT), and surgery. Also, if cancer cannot be ruled out, surgery may be pursued.
- (1) PEIT
- In this method, a type of alcohol (ethanol) is injected to shrink the tumors. This therapy has two effects. First, direct injection of ethanol into a tumors causes the death of tumor cells. Second, ethanol injected into blood vessels suppresses the transport of nutrients to the tumors. Recently, this therapy has often been used for cysts as well.
- (2) Surgery
- If thyroid tumors enlarge, they may cause severe pressure on the trachea or spread inside the clavicle (mediastinum) and descend. In these cases, surgery is required to remove the tumors.
- (3) TSH suppression therapy (oral treatment)
- TSH promotes the proliferation of both benign and malignant tumor cells. Although recently TSH suppression therapy tends not to be chosen as a first-line treatment, administration of thyroid hormone replacement medication suppresses the secretion of TSH. Lower levels of TSH can effectively prevent the proliferation of tumor cells, thereby suppressing the enlargement of nodules.
Treatment of malignant tumors
For thyroid cancer, surgery is the fundamental treatment.In most cases, thyroid cancer can be completely removed, including metastases in the lymph nodes. Effectiveness of surgery is due to the fact that thyroid cancer tends to progress slowly.
- (1) Surgery
- The extent of the removal of the thyroid gland and lymph nodes is determined according to the degree of cancer progression.
- (2) Isotope (radioiodine) therapy
- If there is metastasis to distant organs, such as the lungs or bone, patients undergo isotope therapy. When radioactive iodine is ingested, it accumulates in thyroid cells. If the thyroid is completely removed, the radioactive iodine will accumulate in metastatic thyroid tumors that occur in the lungs, bone, or other locations. When radioactive iodine is incorporated into tumors, it emits radiation (β-rays) that destroy cancer cells from within. Radioactive iodine is also used for testing of thyroid function and treatment of Basedow’s disease, but a higher dose is used for cancer treatment.
- (3) External beam radiotherapy (linear accelerator [LINAC])
- In this type of therapy, cancerous lesions are selectively irradiated with high-energy X-rays to shrink or destroy tumors. The device used to emit the X-rays is a LINAC.
- (4) Molecular targeted therapy
- Thyroid cancer is primarily treated with surgery. After surgery, however, recurrence may occur. If the cancer reappears in a location where surgery is impossible or it is accompanied by distant metastases, patients will undergo oral radioiodine therapy or TSH suppression therapy. However, these treatments may also be ineffective. In such cases, we turn to molecular targeted therapy which makes use of a recently developed and approved class of drugs that attacks the molecular mechanisms of development and progression of thyroid cancer. Specifically, the medications are tyrosine kinase inhibitors (sorafenib, lenvatinib and vandetanib) that aim to suppress tumor growth and more effectively treat the cancer.
- (5) TSH suppression therapy
- After surgery, thyroid hormone replacement medication may be administered to prevent recurrence. Secretion of thyroid hormones is promoted by TSH, a hormone secreted by the pituitary gland in the brain. TSH also stimulates the proliferation of both benign and malignant tumor cells. However, if thyroid hormones are excessive, the secretion of TSH will be suppressed. This mechanism is basis for treatment with thyroid hormone replacement medication. The purpose of this treatment is to suppress the secretion of TSH by administering a slightly higher amount of thyroid hormone. This inhibits the proliferation of tumor cells and therefore reduces the possibility of recurrence.