August 2, 2018


The Case Against Screening For Thyroid Cancer (Christie Aschwanden, 8/02/18, 538)

The bad news first: Thyroid cancer incidence in the U.S. has tripled since the mid-1990s, and although the number of deaths remains very low, thousands of people are having their thyroid glands removed. Now here's the good news: We can bring those cancer rates down and save most of those thyroids with one weird trick -- stop looking for these cancers.

Forgoing cancer screening might seem like a reckless choice, but the current U.S. Preventive Services Task Force recommends against screening for thyroid cancer in people with no symptoms, and neither the American Thyroid Association nor the American Cancer Society advise routine thyroid cancer screening. "There's no evidence that screening for thyroid cancer saves lives," said Otis Brawley, chief medical and scientific officer at the American Cancer Society.

That's because most thyroid cancers aren't life-threatening. Even as rates of thyroid cancer have risen, one number hasn't budged: 98.1 percent of patients diagnosed with thyroid cancer survive at least five years -- the highest survival rate among the 12 most common cancers. Among patients whose cancer had not spread beyond the thyroid, the five-year survival rate is 99.9 percent. Most of the new cases being diagnosed are a type called papillary thyroid cancer, which is almost always benign, Brawley said. (The deadly types are less common and rarely found early by screening.)

Thyroid cancer screening isn't a routine check like breast cancer or prostate cancer screenings are, so why are we finding so many more cases now than 25 years ago? The answer is a combination of "haphazard screening" that happens as part of general health care (a doctor feeling the patient's neck during a visit for something else) and incidental findings seen on imaging tests done for some other reason, said H. Gilbert Welch, a physician at Dartmouth. Last week in The New England Journal of Medicine, Welch and surgeon Gerard M. Doherty wrote that "efforts to reduce thyroid cancer detection are clearly warranted."

The current slapdash, somewhat unintentional method of screening may also explain why about 75 percent of thyroid cancers are diagnosed in women. Women tend to get more health care than men do, Welch said, often because they're seeking reproductive health care.

Posted by at August 2, 2018 7:02 PM