Ask the Doctors

Dear Doctor: A recent study suggested that cancer for thyroid treatment can be delayed. What would be the point?

Dear Reader: The question is a logical one -- as I know firsthand, having been diagnosed with papillary thyroid cancer about 20 years ago. At that time, the only thought that my family and I had was: How quickly can we get this cancer out? I have had no recurrence and have not regretted my decision. But now cancer patients have the advantage of data.

Thyroid cancer rates have increased over the last 40 years. In 1975, the rate of papillary thyroid cancer -- the most common form of thyroid cancer -- was 4.8 per 100,000 people in the United States; in 2012, the rate was 14.9 per 100,000 people. While the increase in diagnosis is partly due to exposure to radiation from cancer therapy, X-rays and nuclear waste, it's mostly due to detection. Thyroid cancers are simply found more often today, often incidentally when imaging of the neck or chest, done for other reasons, shows a mass in the thyroid.

Such cancers are not uncommon. In U.S. and other countries' autopsy studies of people who have died for other reasons, researchers have found that 5.7 percent to 13 percent of people have small papillary thyroid cancers. That suggests that people with these cancers may never develop negative effects from them.

That brings us to the 2017 study that followed 291 patients with papillary thyroid cancers of less than 1.5 centimeters. Instead of having surgery on their thyroid, they received ultrasounds every six months for two years and then yearly afterward. On average, patients were followed for 25 months and received four follow-up ultrasounds. Only 11 (3.8 percent) of the 291 patients saw their tumors grow more than 3 millimeters during the study period. However, tumor volume increased by 50 percent in 36 patients (12.1 percent) and decreased in volume by 50 percent in 19 patients (6.5 percent). Those younger than 50 had a five-times-greater likelihood of tumor growth than people older than 50. Japanese studies have found similar results.

Traditionally, for thyroid cancers less than 1 centimeter, treatment involves removal of one of the two lobes of the thyroid. For cancers greater than 1 centimeter, the entire thyroid is removed. Because such surgery requires a patient to take thyroid hormone for the rest of his or life, it's better to avoid surgery if possible. So, here's what does the data tell us:

In essence, older patients with small papillary thyroid cancers can postpone a decision on surgery and rely on twice-a-year ultrasounds of the thyroid, at least for a while. That means, if you're a 70-year-old with a papillary thyroid cancer of 1 centimeter, simply monitoring the cancer could help you avoid unnecessary surgery. However, if you're 70 years old with a 2-centimeter lesion, then surgery to remove the thyroid is appropriate.

The same does not always hold true for younger patients. If you're a 35-year-old with a 1.2-centimeter papillary thyroid cancer, postponing surgery can be risky due to the higher likelihood that the cancer will increase in size.

Regardless, with the rates of thyroid cancer increasing in our population, it is important to continue studies on the most appropriate treatment.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)

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