Stage I-II thyroid cancers are confined to the thyroid, but many include multiple sites of cancer within the thyroid. Thyroid cancer that has spread to nearby lymph nodes is still considered to be in stage I-II when the patient is younger than 45 years of age as the presence of cancer in the lymph nodes does not worsen the prognosis for these younger patients.
Early stage thyroid cancer is very treatable, and most patients are cured. Treatment of stage I-II thyroid cancer typically consists of surgery with or without radiation therapy. Combining two treatment techniques has become an important approach for increasing a patient’s chance of cure and prolonging survival.
Surgery for Stage I-II Thyroid Cancer
Surgical treatment of thyroid cancer may consist of removing all or part of the thyroid. Surgery to remove the entire thyroid is called a total thyroidectomy. Partial removal of the thyroid is called a lobectomy. The choice of procedure depends on age of the patient and the size of the cancer. Patients treated with these two procedures appear to experience similar durations of survival, but different rates of surgical complications and varying risk for a recurrence of their cancer in the thyroid area.
Total thyroidectomy: Thyroid cancer often affects both lobes of the thyroid, necessitating the removal of the entire thyroid. Patients who are at a high risk of cancer recurrence are also treated with total thyroidectomy.
Total thyroidectomy is associated with a greater risk of side effects. The thyroid produces and releases a hormone—called parathyroid hormone—that is important for maintaining calcium levels in the blood. Without a functioning thyroid, blood calcium levels become abnormally low, causing a variety of symptoms that typically include weakness and muscle cramps and tingling, burning, and numbness in the hands. This condition is called hypoparathyroidism. This complication may be reduced if a small amount of thyroid tissue is left, a procedure that may be referred to as a near-total thyroidectomy.
A total thyroidectomy is a very specialized procedure and is best executed by a skilled surgeon who has performed this operation many times. The thyroid is in close proximity to the voice box and there is a risk of injuring the nerve and thus function of the voice box. Surgical complications are less common when specialized procedures are performed by an experienced surgeon.
Lobectomy: Select patients may be able to have only part of their thyroid removed. This approach is associated with a reduced risk of complications—including problems with blood calcium levels discussed above—but may be associated with a higher risk of local-regional cancer recurrence, which is cancer in or near the thyroid. Lobectomy does not appear to be associated with a higher risk of cancer recurrence in areas that are distant from the thyroid, such as bones or lungs, a circumstance which is associated with a worse prognosis.1
In general, young patients (20-40 years) with isolated cancers that are small (less than 1 cm) and no history of radiation exposure may be treated with a lobectomy. However, the decision between surgical procedures is very individualized and may depend on other factors.
Thyroid Hormone Replacement
Regardless of whether a patient has a lobectomy or has the entire thyroid gland removed, they will receive supplemental thyroid hormone for the rest of their lives. Thyroid hormone is produced by the thyroid gland and is critical for maintaining metabolism. Supplemental thyroid hormone serves two purposes: to maintain hormone levels in the absence of a functioning thyroid and to suppress further growth of the gland and thus the cancer. The pituitary gland located in the brain produces a hormone that stimulates the thyroid to grow—called thyroid-stimulating hormone (TSH). In the presence of thyroid hormone, TSH remains low and removes the stimuli to any remaining cancer cells.
Radioactive Iodine Treatment
Radioactive iodine is also a well-established treatment for thyroid cancer and other thyroid conditions. Iodine is a natural substance that the thyroid uses to make thyroid hormone. The thyroid gland collects the radioactive form of iodine just as it would the non-radioactive iodine. Since the thyroid gland is the only area of the body that uses iodine, radioactive iodine does not travel to any other areas of the body, and the radioactive iodine that is not taken up by thyroid cells is eliminated from your body, primarily in urine. It is therefore a safe and effective way to treat thyroid conditions.
Research indicates that treatment with RAI improves survival for some patients with papillary or follicular thyroid cancer, specifically those with cancer that has spread to nearby lymph nodes or to distant locations in the body. Many patients with stage I-II thyroid cancer do not RAI treatment. However, older patients and those with larger cancers, spread to lymph nodes or other areas, or more aggressive cancers may benefit from this therapy. Anaplastic and medullary thyroid carcinoma are inherently non-sensitive to radioactive iodine treatment.2
References
1 Hay ID, Grant CS, Bergstralh EJ, et al. Unilateral total lobectomy: is it sufficient surgical treatment for patients with AMES low-risk papillary thyroid carcinoma? Surgery. 1998;124(6):958-64.
2 Podnos YD, Smith D, Wagman LD, Ellenhorn JD. Radioactive iodine offers survival improvement in patients with follicular carcinoma of the thyroid. Surgery. 2005;128(6):1072-6.