Cancer of the thyroid is less prevalent than other forms of cancer; however, it accounts 90% of endocrine malignancies. According to the American Cancer Society (2002), about 20, 700 new cases of thyroid cancer are diagnosed each year. Women account for 15, 800 of the new cases and men 4, 900. About 800 women and 500 men die annually from this malignancy. There are several types of cancer of the thyroid gland.
External radiation of the head, neck, or chest in infancy and childhood increases the risk of thyroid carcinoma.
Between 1940 and 1960, radiation therapy was occasionally used to shrink enlarged tonsillar and adenoid tissue, to treat acne, or to reduce an enlarged thymus. For people exposed to external radiation in childhood, there appears to be an increased incidence of thyroid cancer 5 to 40 years after irradiation. Consequently, people who underwent such treatment should consult a physician, request an isotope thyroid scan as part of the evaluation, follow recommended treatment of abnormalities of the gland, and continue with annual checkups (Tierney, 2001).
Lesions that are single, hard, and fixed on palpation or associated with cervical lymphadwnopathy suggest malignancy.
Thyroid function tests may be helpful in evaluating thyroid nodules and masses; however, their results are rarely conclusive. Needle biopsy of the thyroid gland is used as an outpatient procedure to make a diagnosis of thyroid cancer, to differentiate cancerous thyroid nodules from noncancerous nodules, and to stage the cancer if detected.
The procedure is safe and usually requires only a local anesthetic. Patients who undergo who undergo the procedure are followed closely, however, because cancerous tissues may be missed during the procedure (Tierney, 2001).
A second type of aspiration or biopsy uses a large-bore needle rather than the fine needle used in standard biopsy; it may be used when the results of the standard biopsy are inclusive, or with rapidly growing tumors. Additional diagnostic studies include ultrasound, MRI, CT scans, thyroid scans, radioactive iodine uptake studies, and thyroid suppression tests.
The treatment of choice for thyroid carcinoma is surgical removal. Total or near-total thyroidectomy is performed when possible. Modified neck dissection or more extensive radical neck dissection is performed if there is lymph node involvement.
Efforts are made to spare parathyroid tissue to reduce the risk for postoperative hypocalcemia and tetany. After surgery, ablation procedures are carried out with radioactive iodine to eradicate residual thyroid tissue if the tumor is radiosensitive. Radioactive iodine also maximizes the chance discovering thyroid metastasis at a later date if the total-body scans are carried out.
After surgery, thyroid hormone is administered in suppressive doses to lower the levels of TSH to a euthyroid state (Thyroid Carcinoma Guidelines, 2001). If remaining thyroid tissue is inadequate to produce sufficient thyroid hormone, thyroxine is required permanently.
Several routes are available for administering radiation to the thyroid or tissues of the neck, including oral administration of radioactive iodine and external administration of radiation therapy. The patient who receives external sources of radiation therapy is at risk for mucositis, dryness of the mouth, dysphagia, and redness of the skin, anorexia, and fatigue. Chemotherapy is infrequently used to treat thyroid cancer.
Patients whose thyroid cancer is detected early and who are appropriately treated usually do very well. Patients who have had papillary cancer, the most common and least aggressive tumor, have a 10-year survival rate greater than 90%. Long-term survival is also common in follicular cancer, a more aggressive form of thyroid cancer (Tierney, 2001). Continued thyroid hormone therapy and periodic follow-up and diagnostic testing, however, are important to ensure the patient’s well-being (Thyroid Carcinoma Guidelines, 2001).
Postoperatively, the patient is instructed to take exogenous thyroid hormone to prevent hypothyroidism. Later follow-up includes clinical assessment for recurrence of nodules or masses in the neck and signs of hoarseness, dysphagia, or dyspnea. Total-body scans are performed 2 to 4 months after surgery to detect residual thyroid tissue or metastatic disease. Thyroid hormones are stopped for about 6 weeks before the tests. Care must be taken to avoid iodine-containing foods and contrast agents. A repeat scan is done 1 year after the initial surgery. If measurements are stable, a final scan is obtained in 3 to 5 years.
FT4 TSH, serum calcium, and phosphorus levels are monitored to determine whether the thyroid hormone supplementation is adequate and to note whether calcium balance is maintained.
Although local and systematic reactions to radiation may occur and may include neutropenia or thrombocytopenia, these complications are rare when radioactive iodine is used. Patients who undergo surgery that is combined with radioiodine have a higher survival rate than those undergoing surgery alone. Patient teaching emphasizes the importance of taking prescribed medications and following recommendations for following-up monitoring. The patient who is undergoing radiation therapy is also instructed in how to assess and manage side effects of treatment Thyroid Carcinoma Guidelines, 2001).
Partial or complete thyroidectomy may be carried out as primary treatment of thyroid carcinoma, hyperthyroidism, or hyper-parathyroidism. The type and extent of the surgery depend on the diagnosis, goal of surgery, and prognosis. Thyroidectomy may be treatment of choice for patients with symptomatic hyperthyroidism is given appropriate medications to return the thyroid hormone levels and metabolic rate to normal and to reduce the risk for thyroid storm and hemorrhage during the postoperative period. Medications that may prolong clotting (eg, aspirin) are stopped several weeks before surgery to minimize the risk for postoperative bleeding.
Important preoperative goals are to gain patient’s confidence and reduce anxiety. Often, the patient’s home life has become tense because of his or her restlessness, irritability, and nervousness secondary to hyperthyroidism. Efforts are necessary to protect the patient from such tension and stress to avoid precipitating thyroid storm. If the patient reports increased stress when with family or friends, suggestions are made to limit contact with them. Quiet and relaxing forms of recreation or occupational therapy may be helpful (American Cancer Society (2002).
The patient may be discharged the evening of surgery or within 1 0r 2 days. Therefore, the patient and family need to be acknowledgeable about the signs and symptoms of the complications that may occur and those that should be reported. Strategies are suggested for managing postoperative pain at home and for increasing humidification. The nurse explains to the patient and family the need for rest, relaxation and nutrition. The patient is permitted to resume his or her former activities and responsibilities completely once recovered from surgery (Tierney, 2001).
In conclusion, if indicated, a referral to home care is made. The home care nurse assesses the patient’s recovery from surgery. The nurse also assesses the surgical incision and reinforces instruction about limiting activities that put strain on the incision and sutures. Family responsibilities and factors relating to the home environment that produce emotional tension have often been implicated as precipitating causes of thyrotoxicosis.