September 11, 2014 | by Denise Heady
Thyroid cancer has become one of the fastest-growing cancers in the United States for both men and women. The chance of being diagnosed with the cancer has nearly doubled since 1990.
This year an estimated 63,000 people will be diagnosed with thyroid cancer in the United States and nearly 1,900 people will die from it. These numbers may sound alarming, but thyroid cancer is still relatively rare compared to other cancers. Even better, it's highly treatable at all stages.
Here, Robert Kang, M.D., assistant clinical professor in City of Hope's Division of Otolaryngology/Head and Neck Surgery, presents a fuller picture of thyroid cancer and explains what you should know about the disease.
1. Thyroid cancer is one of the most treatable cancers.
“Thyroid cancer is treatable at all stages,” said Kang. “Five-year survival outcomes for well-differentiated thyroid cancers approach 100 percent for both Stages 1 and 2. Stage 3 papillary thyroid cancers have demonstrated a five-year survival rate of 93 percent.”
2. Growth statistics may be somewhat misleading.
“The incidence of thyroid cancer has increased almost two to three-fold over the last three decades,” said Kang. “However, the mortality from thyroid cancer has not changed. This rapid increase in incidence has been attributed largely to overdiagnosis. Overdiagnosis results in detection of diseases that would otherwise cause neither symptoms nor death."
"Several factors are responsible for this increase in diagnosis. First, there is a relatively large reservoir of occult or undetected well-differentiated thyroid cancer in the general population. Up to 8 to 35 percent of autopsies reveal the presence of occult papillary thyroid carcinoma. Second, an increased utilization of diagnostic imaging tools such as ultrasounds and CT scans and an increased access to health care may be contributing. Interestingly, a recent study correlated the incidence of papillary thyroid cancer with multiple sociodemographic markers of health care access, including positive correlations with income and college education, and negative correlations with poverty, unemployment and being uninsured.”
3. Thyroid cancer is much more common in women than men.
“Thyroid cancer occurs three times more commonly in women than in men,” said Kang. “The reason for this is unclear. Some studies have demonstrated an increase in thyroid cancer incidence in women less than 45 years of age who have borne children, but other studies do not demonstrate a significant correlation. High levels of estrogens stimulate the thyroid gland and potentially promote tumor growth. This may explain the higher incidence of thyroid cancer immediately following childbirth, although again not all studies have confirmed this finding. Thyroid cancer is also the most common type of cancer in women aged 20 to 29. Reasons for this are unclear.”
4. Most people who develop thyroid cancer do not have a family history.
“Generally speaking, cancer screening is important in that cure rates are higher when treated at an early stage,” said Kang. “However, standardized screening has not been shown to improve thyroid cancer outcomes. A primary care provider should perform a thyroid and neck exam during routine physical exams. Those with a family history of medullary thyroid cancer, however, do require screening for a specific gene that would potentially warrant a prophylactic thyroidectomy.”
5. Most people with thyroid cancer have no known risk factors.
“Risk factors for thyroid cancers include being female, being of childbearing age, having a history of radiation exposure such as X-rays as a child and lack of dietary iodine,” said Kang. “Thyroid cancers can arise without the presence of these risk factors however, and any physical exam by a physician should include a thyroid and neck exam. In the United States, table salt contains iodine so the lack of dietary iodine is less common, but ensuring proper intake of foods containing iodine is important. Exposure to radiation should be minimized especially in childhood. Medullary thyroid cancer is often related to a specific gene, and those with a family history should be tested accordingly.”
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