Thyroid Cancer: A Common Cancer with Excellent Long Term Outcomes
Earlier this year, when northern Japan suffered a catastrophic earthquake and subsequent tsunami that damaged a large nuclear power generating facility, the worldwide media speculated about the potential impact on public health. There were two major concerns – the immediate impact of radiation sickness on those who lived and worked in the vicinity, and the long term potential of developing cancer, especially thyroid cancer and leukemia, for large segments of the exposed population. This created alarm among people as far away from the meltdown site as the western U.S. and generated public interest in the thyroid gland and thyroid cancer.
Ionizing radiation has long been identified as a cause of cancer in humans, and the thyroid gland is especially vulnerable. Thyroid cancer is in fact increasing in the United States, although it is unclear if this is a true increased incidence or if it reflects advancements in early detection of thyroid cancers on imaging studies and needle biopsies. Either way, the outlook for thyroid cancer is mostly positive – it is a common cancer, but it can be treated with surgery and medication, most often with excellent outcomes.
Thyroid disease in general is one of the fastest growing health problems in the U.S., with an estimated 27 million people affected, often unknowingly. Thyroid disease takes the form of abnormalities of thyroid hormone production – hypo or hyper thyroidism - or by abnormal thyroid growths, called nodules. Thyroid nodules are common, and although most will prove to be cysts or small growths of thyroid tissue, any abnormal swelling or lump in the thyroid area needs to be assessed to determine if it is thyroid cancer.
Fortunately, most thyroid nodules are benign, according to Shelly McQuone, M.D., FACS, a board-certified otolaryngology surgeon at West Penn Allegheny Health System who is an expert in thyroid surgery. Even when they are malignant, the prognosis for the majority of cases is excellent.
"As surgeons, it is our job to determine which nodules carry the highest risk for cancer, and those nodules are removed," Dr. McQuone explains. "A benign nodule may be removed if it has suspicious features on a needle biopsy specimen or an ultrasound, or is associated with other risk factors such as family history or history of radiation. In these instances, a portion of the thyroid is removed for the purpose of obtaining a definitive diagnosis on the nodule. If it later proves to be benign, no further surgery is necessary. If the nodule turns out to be malignant, often the remaining half of the thyroid gland is removed at a second surgery."
Thyroid cancer most typically presents as a painless nodule or a lump in the neck. It is not usually associated with any abnormalities in blood tests, including thyroid function tests. Risk factors for thyroid cancer include history of radiation therapy and family history of thyroid cancer. Malignancy is more common in men, although thyroid nodules, and therefore thyroid cancers overall, are more common in women. Thyroid cancer is treated with a combination of surgery and a radioactive iodine pill called I-131. Thyroid cancers do not respond well to radiation therapy or chemotherapy.
Surgery for thyroid cancer is delicate, due to the butterfly-shaped gland's proximity to the vocal cords and parathyroid glands, which control calcium metabolism. But in the hands of an experienced surgeon such as Dr. McQuone, the risks are minimal. Depending on biopsy results, the patient will have either a total thyroidectomy – removal of the thyroid – or a hemi thyroidectomy, which is partial removal of the gland. A complete thyroidectomy is generally performed in patients who have biopsy-positive thyroid cancer. Sometimes it is also performed when there are suspicious nodules on both sides of the thyroid. A hemi thyroidectomy is removal of half of the thyroid gland, or one lobe. It is generally selected when a biopsy is suspicious for a particular type of thyroid cancer, or when a biopsy is repeatedly inconclusive.
Hemi-thyroidectomy is generally an outpatient procedure. Total thyroidectomy usually requires an inpatient admission, or 23 hour overnight observation, so that blood calcium levels can be assessed post-operatively. This procedure generally takes a little over an hour. "Patients have little pain, and usually recover quickly. They can generally resume regular diet and normal activity right away," says Dr. McQuone.
Patients who undergo a total thyroidectomy will need to take thyroid hormone on a daily basis for the remainder of their lives, as the thyroid is the body's only source of that essential hormone. Those who have a partial thyroidectomy may not need thyroid hormone supplementation if the partial gland is able to produce sufficient amounts.
Dr. McQuone completed her residency training as well as a fellowship in Head and Neck Oncologic Surgery at Johns Hopkins University. She has been practicing at West Penn for 10 years and has an office at Mellon Pavilion.
To learn more about thyroid nodules, visit West Penn Allegheny Health System's website at www.wpahs.org and click on "Health Topics A to Z." To contact Dr. McQuone, call her office at (412) 621-2656.
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