Any increase in cancer is worrisome, but the dramatic rise in thyroid cancer is particularly troubling. In just 30 years, the incidence in the US has more than tripled, from 3.6 cases per 100,000 people in 1973 to 11.6 per 100,000 in 2009.
It is among the fastest-growing diagnoses in the US. This is an alarming trend—but not for the reason you might think.
Experts have concluded that the vast majority of thyroid cancers were there all along. Better imaging tests such as ultrasound and magnetic resonance imaging (MRI) now make it possible to detect minuscule cancers that would have been missed before. What looks like an increase in disease actually is an increase in diagnosis.
Isn’t it good to detect cancers when they’re still small? Not in this case. The most common type of thyroid cancer grows slowly—if it grows at all. Most patients would never have symptoms or need treatment. But once you know you have cancer, you want that thing out of there. Unfortunately, the treatments often cause more problems than they solve.
There’s a saying in medicine, “When you have a new hammer, everything looks like a nail.”
In the 1980s, ultrasound was the new hammer. Endocrinologists used it routinely during office visits. Even if you came in with vague symptoms that could be caused by just about anything, such as fatigue from insomnia, you would likely be given a neck ultrasound and possibly an MRI or a computerized tomography (CT) scan. These tests can detect nodules as small as 2 millimeters (mm) in diameter.
In many cases, tests that were ordered for other conditions happened to detect a growth in the thyroid. More cases of thyroid cancer are diagnosed incidentally than when doctors actually are looking for them. Doctors call these unexpected findings ”incidentalomas.”
Does finding small cancers save lives? Despite the tremendous increase in diagnosed thyroid cancers, the death rate has scarcely budged—it was 0.5 per 100,000 people a generation ago, and it is virtually the same today. All that has changed is the ability to detect them.
About 90% of diagnosed thyroid cancers are small papillary cancers. They usually are indolent—cancers that are unlikely to grow or cause problems. Two Japanese studies and one American study have tracked nearly 1,500 patients who did not receive active treatment for papillary cancers less than one centimeter. After an average of five years, none of these patients has died.
Yet most people who are diagnosed with papillary thyroid cancers opt for treatment—usually a complete thyroidectomy, the removal of the thyroid gland. Once the gland is removed, patients require lifelong treatment with thyroid-replacement medications. Some suffer nerve damage that causes permanent voice changes. When surgery is followed by radioactive iodine therapy, patients face additional risks.
There are other types of thyroid cancer—follicular, medullary and anaplastic—that are more serious. These typically require surgery, usually the total removal of the thyroid gland and sometimes the removal of lymph nodes in the neck. Patients with these cancers typically are given postsurgical radioactive iodine to destroy remaining parts of the gland and any cancer cells that were left behind during surgery.
Experts don’t recommend widespread screening for thyroid cancer. A neck ultrasound is recommended only for specific patients-people who have a family history of thyroid cancer…had previous exposure to head/neck radiation…or a nodule that can be felt during an exam. If a test reveals a nodule that is one centimeter or more in diameter, a biopsy often is performed to determine the seriousness of the growth.
Also important…
Question the ultrasound. If your doctor recommends neck ultrasonography during a routine checkup or because you’re experiencing somewhat vague symptoms (such as fatigue), ask if you really need it and what the benefits and risks are if you do the test or don’t do the test. You should clearly understand the goal of doing the test and how you will benefit.
Consider a second opinion before agreeing to surgery. According to data from the US National Cancer Institute, death rates in patients who didn’t have immediate surgery for papillary cancers were virtually the same as for those who did have surgery. Watchful waiting-forgoing treatment but getting checkups every six months at the beginning and then every year after that to see if a tumor has grown—usually is the best approach for these cancers.
Keep your emotions in check. It is emotionally difficult to know that you have a cancer and not do something about it. You will want it gone whether it poses a threat or not. But most thyroid cancers—like the majority of slow-growing prostate cancers—are simply not dangerous. Some experts believe that they shouldn’t even be called cancer. An alternative, less frightening term that has been proposed is papillary lesions of indolent course (PLIC).
Get the treatment that fits you. If you have a papillary cancer that does need treatment, ask your doctor if you can have a partial rather than a total thyroidectomy. The partial procedure is safer and, for most papillary cancers, just as effective.
Don’t agree to postsurgical treatment with radioactive iodine unless your doctor insists that you need it. It usually is not recommended for low-risk thyroid cancers because it can cause serious side effects, including an altered sense of taste and inflamed salivary glands. The treatment also has been linked to a 5.7-fold increase in the risk for leukemia.
