Why Are Doctors Removing Too Many Thyroids?

More Americans than ever are being diagnosed with thyroid cancer, and most are having the entire gland removed in response.

But that is an overreaction to a cancer that likely will not kill most people who are diagnosed with it, two doctors argue in a new report.

Most cases of thyroid cancer could be treated either by partial removal of the thyroid gland or by simply keeping an eye on the cancer in case it becomes aggressive, explained co-author Dr. H. Gilbert Welch, a professor with the Dartmouth Institute for Health Policy and Clinical Practice in Lebanon, N.H.

People who have their thyroid gland completely removed run the risk of developing hypoparathyroidism, a condition where low levels of hormone produced by the gland cause their calcium levels to decline, said co-author Dr. Gerard Doherty, surgeon-in-chief at Brigham and Women's Hospital in Boston.

These patients have to take multiple doses of calcium and vitamin D daily, and still suffer from chronic bone problems, Doherty said.

"There is zero risk of that for the smaller procedure. If the surgeon removes half the thyroid gland, there is no risk of hypoparathyroidism," Doherty said. "They're taking on that risk for no benefit, and that's the real issue."

Three decades ago, thyroid cancer was diagnosed when the tumor became large enough that a doctor could actually feel it by hand, Doherty said.

Advances in imaging technology now allow doctors to find trace amounts of thyroid cancer in people, often by accident as the person undergoes an MRI or CT scan for some other medical purpose, Doherty and Welch said.

"It used to be the patient either felt a lump in their neck, or their doctor felt a lump in their neck," Doherty said. "Most of the disease we find now is not something we can feel even once we know it's there."

This year, more than 50,000 people in the United States will be diagnosed with thyroid cancer, the doctors said.

"We've seen a threefold increase since the mid-1990s in a disease we've known for decades is a frequent finding at autopsy," Welch said. "A lot of us harbor small thyroid cancers. This is one of the cancers where, if you look hard, you'll find a lot of thyroid cancer."

Despite this dramatic rise in diagnosis rates, the rate of deaths due to thyroid cancer has remained stable. Only about 2 percent of people will die from their thyroid cancer over 25 years, the doctors said.

Welch and Doherty said this is because most of the thyroid cancer being detected would not cause a person to either become ill or die.

The situation with thyroid cancer is similar to that of prostate cancer, where there's an ongoing debate over whether the cancer should be treated if it is detected, Doherty said. Men who undergo prostate removal risk impotence and incontinence, even though the cancer likely would not have killed them.

Guidelines for thyroid cancer treatment have kept up with the times, recommending active surveillance or partial removal of the thyroid for smaller cancers detected through imaging, Doherty said.

But 4 out of 5 patients who have surgery to treat thyroid cancer will still undergo a full removal of the gland anyway, the doctors noted.

"We're doing more aggressive treatment for less aggressive cancers over time," Doherty said. "The question really is, why is that happening?"

Doherty suspects that many doctors treating thyroid cancer simply are unaware of the newer guidelines that call for less drastic measures in treating smaller tumors.

"About 60 percent of thyroid operations are done by people who do 10 or fewer thyroid operations a year," Doherty said. "It could be that management of this problem is such a small amount of many people's practices that they don't keep up with the guidelines as they're updated."

There's also the possibility that doctors are overtreating to make sure they completely cure the patient, he added.

Doctors used to treating thyroid cancers so big they can be felt by hand "are uncomfortable with doing less treatment for the disease just because they can't feel it," Doherty said. "They worry they're undertreating people and so they're erring on the individual level, saying, I just want to be thorough with this one person."

Welch said: "We think it's important that patients be given the option of active surveillance, but if they want to have surgery they should have half their thyroid taken out, not all of it. This is all about de-intensifying the treatment for an early cancer that most often would never be relevant to patients during their lives."

Dr. Richard Wender, chief cancer control officer for the American Cancer Society, said the new paper "raises a very good point about how we're approaching thyroid cancer in the United States.

"It really does call for a careful look to make sure we fully understand all the factors that are leading to a specific treatment choice," Wender said. "No one group has really taken charge of the issue and said, 'Hey, this is a serious quality issue we need to address more consciously.' "

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