Medscape | Kristin Jenkins
Highlighting once again the overdiagnosis and overtreatment of thyroid cancer, experts argue for deintensifying care and for considering active surveillance in an essay titled, "Saving Thyroids — Overtreatment of Small Papillary Cancers".
The authors of the essay argue against total removal of the thyroid.
"Currently, about 80% of patients who have surgery for localized papillary thyroid cancer (≤2 cm in diameter) undergo a total thyroidectomy," they note. But these tiny tumors cause neither clinical illness nor death, they point out.
Active surveillance with three-dimensional monitoring of potential tumor growth could be a better choice than immediate surgery, researchers suggested last year, as previously reported by Medscape Medical News.
Total thyroidectomy carries a risk for injury to either of the recurrent laryngeal nerves (or, rarely, both of them) and a risk for hypoparathyroidism due to damage to all four parathyroid glands. It also necessitates lifelong thyroid hormone replacement, the essay authors note. Thyroid lobectomy is a better option, they suggest.
Removing half of the thyroid eliminates the risks for serious, lifelong morbidity associated with total thyroidectomy, and "it has become increasingly clear" that there is little difference in the effect on the risk for death from thyroid cancer, they argue.
The authors are H. Gilbert Welch, MD, MPH, of the Dartmouth Institute for Health Policy and Clinical Practice, in Hanover, New Hampshire, and Gerard M. Doherty, MD, of Brigham and Women's Hospital in Boston, Massachusetts. Their essay was published online July 25 in the New England Journal of Medicine.
"We support the option of active surveillance for selected patients with small papillary thyroid cancers, but we recognize that some patients will prefer to have their cancer removed. In such cases, the question becomes how much thyroid to resect," they write. For patients whose disease warrants surgery, "we should make it clear that lobectomy is often the best choice," Welch and Doherty say.
Huge Problem of Overdiagnosis
This year, it is expected that the number of people in the United States who will be diagnosed with thyroid cancer will climb to more than 50,000, effectively tripling the number diagnosed just 25 years ago, the authors point out. Women will represent the vast majority of these new cancer patients.
Although the mortality rates for thyroid cancer have stayed much the same (0.5 per 100,000 in 1979 and in 2009), advances in imaging technology have led to a worldwide "epidemic" of overdiagnosis of small papillary thyroid cancers, say researchers. As previously reported by Medscape Medical News, overdiagnosis accounts for 90% of thyroid cancer cases in South Korea, up to 80% in the United States, Italy, France, and Australia, and 50% in Japan, the Nordic countries, England, and Scotland.
These tiny tumors cause neither clinical illness nor death, Welch and Doherty point out. A 2017 US study in 300 patients with low-risk papillary thyroid cancers showed that active surveillance with three-dimensional monitoring of potential tumor growth could be a better choice than immediate surgery. Overall, rates of tumor growth were low, and serial measurements of tumor volume were able to signal cancers that required therapeutic intervention.
In spite of this, 150,000 women and 50,000 men in the United States with small, low-risk papillary cancers have undergone total thyroidectomy during the past 25 years, say Welch and Doherty.
"We worry that the rationale for the persistence of total thyroidectomy is less about insufficient data and more about insufficient knowledge and motivation. Surgeons may underestimate their own complication rates, particularly if they rarely perform the operation. Furthermore, low-volume surgeons may be unaware of new practice guidelines, since thyroid surgery represents a small part of their practice."
Thyroidectomy can damage the recurrent laryngeal nerve as well as the parathyroid glands. After this surgery, all patients require thyroid hormone replacement, and "thousands of them have hypoparathyroidism or have faced unnecessary voice changes," the authors write.
Case for Limited Surgery
"This article is really making a case for limited surgery when surgery has to be done," said John C. Morris III, MD, professor of medicine at the Mayo Clinic, in Rochester, Minnesota, when approached for comment. This strategy is in keeping with American Thyroid Association (ATA) guidelines, added Morris, who is immediate past president of the ATA.
"I think that everyone who is in the know these days understands that many patients are being overtreated because of overdiagnosis," said Morris.
The most important thing...is to spread this word. Treatment can be worse than the disease. "Certainly within the ATA, there is very little controversy about this. Everybody agrees. The most important thing about this article is to spread this word. Treatment can be worse than the disease," he added.
In its latest guidelines, from 2015, for the management of thyroid nodules and differentiated thyroid cancer, the ATA recommends active surveillance for small papillary cancers and thyroid lobectomy for low-risk patients with well-differentiated thyroid carcinomas smaller than 4 cm.
(This was a change from the previous guidelines, from 2009, in which the ATA recommended total thyroidectomy for any well-differentiated thyroid carcinomas larger than 1 cm.)
Clinicians are getting the message, suggests a study published in May 2018, which found a significant decrease in total thyroidectomy rates following implementation of the guidelines. At a tertiary care center in Jerusalem, Israel, rates for total thyroidectomy dropped from 61.0% to 31.4%. Among patients who underwent initial thyroid lobectomy, the rate of complete thyroidectomy fell from 74% to 20%, the study showed.
For Welch and Doherty, however, decreases in the rates of unnecessary thyroidectomy are not happening fast enough. Telling a patient that she has cancer but that she does not need surgery challenges older patterns of clinical practice and can fuel physician anxiety about fallout from perceived undertreatment.
"Conventional practice pathways and surveillance strategies were designed for patients with higher-risk disease," the authors explain. "It is hard for providers to deintensify care. To do less for today's patients than for the patients of the past may make clinicians feel exposed...."
But there is an increasing realization that deintensification of treatment may be appropriate in other areas of oncology: early small tumors in breast, prostate, kidney, and lung may not always necessarily need immediate treatment. "In these cases, too, backing off practice conventions developed for higher-risk disease may raise clinical anxiety and threaten revenue streams," the authors comment. "Deintensifying care may also increase patients' anxiety."
"Changes Like This Take a Long Time "
Louise Davies, MD, associate professor at the Dartmouth Institute, Lebanon, New Hampshire, is considered one of the leading authorities on overdiagnosis. In an email to Medscape Medical News, she warned that major shifts in the current practice of thyroidectomy for small thyroid cancers can't be expected "until people really internalize the evidence and believe it on a personal level.
"Unfortunately, we know from watching other areas in the field of medicine that changes like this take a long time," she commented.
Thyroid-sparing approaches provide part of the solution to managing overdiagnosis, Davies told Medscape Medical News. She also emphasized that other measures, such as ensuring that patients with thyroid nodules do not undergo inappropriate biopsy procedures, are needed to provide a "complete approach to overdiagnosis."
Evidence for deintensifying treatment must also be frequently communicated to both physicians and patients in different settings and in different formats, said Davies.
In the end, it may take economic and policy incentives to fully address the issue. "The judicious application of population-based quality metrics, policy changes, and payment models to encourage physicians and patients to adopt guideline concordant care practices in the US health care system may be a powerful tool in the future to manage overdiagnosis," said Davies.
In the meantime, Welch and Doherty suggest that cancer researchers offset the new reality of more patients with less disease by better predicting the natural history of different cancers.
Tumor registries such as the National Cancer Institute Surveillance, Epidemiology and End Result (SEER) database could add data on cancer detection, they say. By determining whether a cancer was diagnosed as a result of clinical signs and symptoms, through screening (breast, prostate, lung), or incidentally (thyroid), new light would be shed on the biology of the patient and would "add important prognostic information."
Information concerning Dr Welch's and Dr Doherty's relevant financial relationships is available at NEJM.org. Dr Morris and Dr Davies have disclosed no relevant financial relationships.
N Engl J Med. Published online July 25, 2018. Abstract
Kijk voor meer informatie ook eens op Schildkliertje.
Raadpleeg altijd een arts als je twijfelt over je gezondheid.
Het Schildklierforum kan niet worden beschouwd als vervanging van een consult of een behandeling.