Thyroidectomy Still Popular Despite Less Aggressive Treatment Recommendations

The number of total thyroidectomies has not gone down despite recommendations encouraging less aggressive lobectomy for patients with small papillary thyroid cancers, according to the results of a recent study published in the journal Surgery.

“Guidelines are saying that doing less is probably better. Why do people not adopt the guidelines? This is everybody’s big question,” said Naifa Lamki Busaidy, MD, director of the Thyroid Nodule Clinic at The University of Texas MD Anderson Cancer Center in Houston, in an exclusive interview with Cancer Network.

In a retrospective cohort study, James et al mined data from the National Cancer Institute Surveillance, Epidemiology, and End Results cancer registries. During the 14-year study period (2000–2014), 44,537 patients received surgical treatment for papillary thyroid cancer (77% female; 81.3% white).

The researcher found that the incidence of papillary thyroid cancer doubled during this time period, from 6.2 to 13.0 cases per 100,000. Furthermore, the proportion of total thyroidectomy among all papillary patients increased from 78.16% in 2000 to 85.67% in 2014, whereas the proportion of thyroid lobectomy decreased from 16.62% to 11.41%. During the study period, a widening gap was noted in terms of the proportion of total thyroidectomy to thyroid lobectomy, after stratifying by tumor size.

About 46% of patients were diagnosed between the ages of 40 and 59 years, and 27.6% were diagnosed between the ages of 20 and 39 years. Nearly one-third of the tumors were < 1 cm in size, and 8.6% were > 4 cm. Furthermore, 64% of cancers were localized, and only 2.5% of cancers were metastatic. In total, 84.3% of patients underwent a total thyroidectomy while 12.4% had a thyroid lobectomy.

Thyroid cancer incidence has increased by 3% annually during the past several decades-most of which are small papillary thyroid cancers. Factors that may be contributing to this trend include increased rates of diagnostic radiography or use of flame-retardant chemicals, although the majority of this increase is likely due to incidental findings.

“Multiple studies have shown that this change in incidence has not been associated with a change in mortality,” wrote James and coauthors. “This finding gains more significance when placed in the context of the significant financial and psychologic burden attributed to thyroid cancer treatment.”

In light of overdiagnosis and overtreatment of nonaggressive papillary thyroid cancers, significant changes in the recommendations for surgical treatment of thyroid cancer have transpired over the past 12 years.

In 2009, the American Thyroid Association (ATA) updated its guidelines to recommend defining thyroid lobectomy as cancers ≤ 1.5 cm. Other guidelines have recommended thyroid lobectomy as a safe option for the treatment of papillary thyroid cancers ≤ 4 cm in size.

In light of changing recommendations, Busaidy wonders why such low rates of lobectomy for the treatment of papillary thyroid cancer are reported in the current study. “I can’t explain why total thyroidectomy rates went up by that much and lobectomies went down. How do you explain that? You always think of biases,” she said.

According to Busaidy, there are several potential reasons why the frequency of lobectomies noted in the study was low.

First, in community settings where many thyroid surgeries are performed, the decision to perform a lobectomy vs total thyroidectomy may rest with a general surgeon, who might have limited knowledge of current guidelines. In other words, specialists such as endocrinologists and oncologists may not be making the call for lobectomy in conjunction with surgeons. “One [explanation] is that nobody’s read a book; they’re operating and not keeping up because they do 20 other surgeries,” she said. “They’ve kept up with some technology, but not necessarily a rare disease that you occasionally operate on.”

Second, there exists room for interpretation in guidelines, and some specialists may be consciously choosing to overtreat based on anecdotal experience. “It’s human nature to be burned by your experiences. Your own experiences will tell you how to treat things, and this is very common with physicians,” Busaidy said.

Third, the decision to overtreat with thyroidectomy may be rooted in concerns about litigation. “I feel that if people undertreat they are more fearful of being sued than [of] overtreatment,” she said.

Finally, patients themselves may be requesting total thyroidectomies with the misguided notion that the cancer will never return if the thyroid is totally resected.

Busaidy reiterated that thyroid cancer treatment guidelines have changed in 2005, 2009, and, most recently, in 2016, to recommend less aggressive treatment. Although she finds the James et al study to be well done, breaking up the follow-up period to better reflect changes in guidelines would be a good idea, she said.

Pooja Manroa, MD, an endocrinologist and assistant professor of medicine at the University of Pittsburgh School of Medicine in Pittsburgh, also spoke with Cancer Network about the implications of the study results.

“This study underscores the need to address the delay in adoption of professional guidelines and demonstrates clearly that two iterations of ATA guidelines did not impact the clinical decision-making for low risk thyroid cancers,” she said. “Other factors that may be playing a role in physician and patient decision-making should be carefully evaluated and addressed.”

Nevertheless, Manroa is optimistic that lobectomy rates will go up. “As the latest set of ATA guidelines on management of thyroid nodules and differentiated thyroid cancers was released in 2016, as well as the results of studies from centers advocating observation vs surgery in low-risk thyroid cancers [from] Kuma Hospital in Japan and Memorial Sloan Kettering Cancer Center are available, I anticipate that the incidence and proportion of lobectomy for thyroid cancers will rise over time,” she said.